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  • 1. Sl. Subject Complexit Questions AnswersNo. y 1 Informatica simple What is sql override ? Overriding a SQL in source qualifier or lookup for additional logic. 2 Informatica simple Can we have multiple Yes conditions in a Lookup? 3 Informatica simple Can we have multiple Yes conditions in a Filter? 4 Informatica simple How the flags are called in 0 - DD_INSERT , 1- DD_UPDATE , 2- DD_DELETE , 3- DD_REJECT Update strategy? 5 Informatica simple Is it possible to run the YES USING PMCMD session other than Server manager? If so how? 6 Informatica simple What is diff. Things u can do Start, Stop and abort the session using PMCMD? 7 Informatica average/si What is the use of power For 3rd party connectors to sap, mainframe, Peoplesoft mple plug? 8 Informatica average/si What kind of Test plan? What In Informatica we create some test SQL to compare the number or records and validate scripts if mple kind of validation you do? the data in the warehouse is loaded for the logic incorporated. 9 Informatica simple What is the usage of We use a lookup for connecting to a table in the source or a target. There are 2 ways in which a unconnected/connected look lookup can be configured i.e. connected or unconnected up?10 Informatica simple What is the difference Connected Lookup Receives input values directly from the pipeline. Unconnected Lookup Receives between Connected and input values from the result of a :LKP expression in another transformation. Connected Lookup You Unconnected Lookups ? can use a dynamic or static cache. Unconnected Lookup You can use a static cache. Connected Lookup Cache includes all lookup columns used in the mapping (that is, lookup table columns included in the lookup condition and lookup table columns linked as output ports to other transformations). Unconnected Lookup Cache includes all lookup/output ports in the lookup condition and the lookup/return port.Connected Lookup Can return multiple columns from the same row or insert into the dynamic lookup cache. Unconnected Lookup The dynamic lookup cache, Designate one return port (R). Returns one column from each row. Connected Lookup If there is no match for the lookup condition, the Informatica Server returns the default value for all output ports. If you configure dynamic caching, the Informatica Server inserts rows into the cache. Unconnected Lookup If there is no match for the lookup condition, the Informatica Server returns NULL. Connected Lookup Pass multiple output values to another transformation. Link lookup/output ports to another transformation. Unconnected Lookup Pass one output value to another transformation. The lookup/output/return port passes the value to the transformation calling: LKP expression.Connected Lookup Supports user-defined default values. Unconnected Lookup Does not support user-defined default values
  • 2. 11 Informatica simple If u have data coming from Joiner Transformation diff. sources what transformation will u use in your designer?12 Informatica simple What are different ports in Input, Output, Variable, Return/Rank, Lookup and Master. Informatica?13 Informatica simple What is a Variable port? Variable port is used to store intermediate results. Variable ports can reference input ports and Why it is used? variable ports, but not output ports.14 Informatica average Diff between Active and Transf can be active or passive , activ tranf can change the no of rec passed th it, a passive tranf passive transormation ? can never change the rec cnt, Active trsnf that might change the rec cnt are advan ext proc, aggrega, filter,joiner,normalizer, rank , updte strategy, source qualifier, if u use powerconnect to access erp sources, erp source quail is also an active tranfor Passive tranf :- lookup, expression, external procedure, seq generator, stored procedure U can connect only 1 active tranf to the same tranf or target can connect any no of pass tranf15 Informatica simple What are Mapplet? A mapplet is a reusable object that represents a set of transformations. It allows you to reuse transformation logic and can contain as many transformation as you need.16 Informatica simple What is Aggregate An aggregator transformation allows you to perform aggregate calculations, such as average and transformation sums. The Aggregator transformation is unlike the Expression transformation, in that you can use the Aggregator transformation to perform calculations on groups.17 Informatica simple What is Router A Router transformation is similar to a Filter transformation because both transformations allow Transformation? How is it you to use a condition to test data. A Filter transformation tests data for one condition and drops different from Filter the rows of data that do not meet the condition. However, a router transformation tests data for transformation? one or more conditions and gives you the option to route rows of data that do not meet any of the conditions to default output group.18 Informatica simple What are connected and Connected transformations are the transformation, which are in the data flow, whereas unconnected transformations? unconnected transformation will not be in the data flow. These are dealt in Lookup and Stored procedure transformations.19 Informatica simple What is Normalizer Normalizer transformation normalizes records from COBOL and relational sources allowing you to transformation? organize the data according to your needs. A normalizer transformation can appear anywhere in a data flow when you normalize a relational source.20 Informatica simple How to use a sequence By using Stored procedure transformation. created in Oracle in Informatica?21 Informatica simple What are source qualifier The source qualifier represents the records that the Informatica Server reads when it runs a transformations? session.
  • 3. 22 Informatica simple What are cache and their The Informatica server creates index and data cache for aggregator, Rank, joiner and Lookup types in Informatica? transformations in a mapping. The Informatica server stores key values in the index cache and output values in the data cache.23 Informatica simple What is an incremental In Incremental aggregation, you apply captured changes in the source to aggregate calculations in aggregation? a session. If the source changes only incrementally and you can capture changes, you can configure the session to process only those changes. This allows the Informatica server to update your target incrementally, rather than forcing it to process the entire source and recalculate the same calculation each time you run the session.24 Informatica complex What is Reject loading? During a session, the Informatica server creates a reject file for each target instance in the mapping. If the writer or the target rejects data, the Informatica server writes the rejected row into reject file. The reject file and session log contain information that helps you determine the cause of the reject. You can correct reject files and load them to relational targets using the Informatica reject load utility. The reject loader also creates another reject file for the data that the writer or target reject during the reject loading.25 Informatica average WHAT IS SESSION and SESSION - A Session Is A set of instructions that tells the Informatica Server How And When To BATCHES? Move Data From Sources To Targets. After creating the session, we can use either the server manager or the command line program pmcmd to start or stop the session. BATCHES - It Provides A Way to Group Sessions For Either Serial Or Parallel Execution By The Informatica Server. There Are Two Types Of Batches : 1. SEQUENTIAL - Run Session One after the Other. 2. CONCURRENT - Run Session At The Same Time.26 Informatica simple Significance of Source When you add a relational or a flat file source definition to a mapping, you need to connect it to a Qualifier Transformation Source Qualifier transformation. The Source Qualifier represents the records that the Informatica Server reads when it runs a session. · To join data originating from the same DB. · Filter records in the Source itself. · To specify an outer join instead of a default inner join. · To specify sorter ports. · To select distinct values from the source. · To create a custom query to issue a special select statement for the Informatica server to read source data. For example, we might use a custom query to perform aggregate calculations or execute a stored procedure.
  • 4. 27 Informatica average What are 2 modes of data The data movement mode depends on whether Informatica Server should process single byte or movement in Informatica multi-byte character data. This mode selection can affect the enforcement of code page Server? relationships and code page validation in the Informatica Client and Server. a) Unicode – IS allows 2 bytes for each character and uses additional byte for each non-ascii character (such as Japanese characters) b) ASCII – IS holds all data in a single byte28 Informatica simple Why we use lookup Lookup Transformations can access data from relational tables that are not sources in mapping. transformations? With Lookup transformation, we can accomplish the following tasks: a) Get a related value - Get the Employee Name from the Employee table based on the Employee ID b) Perform Calculation Update slowly changing dimension tables - We can use unconnected lookup transformation to determine whether the records already exist in the target or not.29 Informatica simple What are confirmed Confirmed dimensions are linked to multiple fact tables dimensions30 DataWareh simple What is Data warehousing A DW is a DB used for query,analysis and reporting . By definition DW is a subject oriented, ousing intergrated, non volatile and time variant Subject Oriented:- Represents a subject Aread like sales, Mktg Integrated :- Data Colleted from multiple source systems integrated into a user readable unique format Ex:- male, female ,0,1, M,F, T, F Non Volatile :- Dw stores historical data Time Variant :- Stores data timewise like weekly,monthly,quarterly, yearly31 Informatica simple What is a reusable transf.. Reusable tranformation:- if u want to create tranfor that perform common tasks such as avg sal in What is a mapplet . Explain a dept diff. Bet them Mapplet:- Is a reusuable object that represents a set of transformations32 Informatica simple What happens when u use the Inserts:- treats all records as inserts , while inserting if the record violates primary, foreign key or delete or update or reject or foreign key in the database it rejects the record insert statement in your update strategy?33 Informatica simple Where do u design ur designer mappings34 Informatica simple Where do u define users and Repository manager privileges in Informatica
  • 5. 35 Informatica simple How do u debug the data in Use debugger in designer Informatica tool36 Informatica simple when u run the session does If you select the option discard target data then it will not load to target debugger loads the data to target ?37 Informatica simple Can u use flat file and table yes (relational) as source together ?38 Informatica simple suppose I need to separate Router or filter the data for delete and insert to target depending on the codition, which transformation u use ?39 Informatica average What is the difference Index cache:Contains columns used in condition between lookup Data cache Data cache: :Contains other output columns than the condition columns. and Index cache.40 Informatica average What is an indicator file and Indicator file is used for Event Based Scheduling when you don’t know when the Source Data is how it can be used. availaible., A shell command ,script or a batch file creates and send this indicator file to the directory local to the Informatica Server.Server waits for the indicator file to appear before running the session.41 Informatica simple Different Tools in Designer · Source Analyzer · Warehouse designer · Transformation Developer · Maplet designer · Mapping designer42 Informatica simple Components of · Designer Informatica · Workflow Manager · Workflow Monitor43 Informatica simple Different Tools in · Task Developer Workflow Manager · Worklet designer · Workflow Designer44 Informatica simple What is overview window ? It’s a window in which you can see all the transformations that are used for a mapping. Why it is used ?
  • 6. 45 Informatica simple · While using Debugger, how The left hand corner of the transformation that has an arrow looks like moving. will you fined out which transformation is currently running ?46 Informatica simple How do u load the data using Using workflow manager Informatica?47 Informatica simple What is an Filter The Filter transformation provides the means for filtering records in a mapping. You pass all the Transformation? or what rows from a source transformation through the Filter transformation, then enter a filter condition options u have in Filter for the transformation. All ports in a Filter transformation are input/output, and only records that Transformation? meet the condition pass through the Filter transformation.48 Informatica simple What happens to the Discarded rows do not appear in the session log or reject files discarded rows in Filter Transformation.49 Informatica average What are the two programs Informatica provides Server Manager and pmcmd programs to communicate with the Informatica that communicate with the Server: Informatica Server? Server Manager. A client application used to create and manage sessions and batches, and to monitor and stop the Informatica Server. You can use information provided through the Server Manager to troubleshoot sessions and improve session performance. pmcmd. A command-line program that allows you to start and stop sessions and batches, stop the Informatica Server, and verify if the Informatica Server is running.50 Informatica simple What u can do with Designer ? The Designer client application provides five tools to help you create mappings: Source Analyzer. Use to import or create source definitions for flat file, Cobol, ERP, and relational sources. Warehouse Designer. Use to import or create target definitions. Transformation Developer. Use to create reusable transformations. Mapplet Designer. Use to create mapplets. Mapping Designer. Use to create mappings.
  • 7. 51 Informatica avrage What are different types of Tracing Levels in Transformations :- Tracing Levels u hv in Level Description Transformations? Terse Indicates when the Informatica Server initializes the session and its components. Summarizes session results, but not at the level of individual records. Normal Includes initialization information as well as error messages and notification of rejected data. Verbose initialization Includes all information provided with the Normal setting plus more extensive information about initializing transformations in the session. Verbose data Includes all information provided with the Verbose initialization setting. Note: By default, the tracing level for every transformation is Normal. To add a slight performance boost, you can also set the tracing level to Terse, writing the minimum of detail to the session log when running a session containing the transformation.52 Informatica simple What is Mapplet and how do u A mapplet is a reusable object that represents a set of transformations. It allows you to reuse create Mapplet? transformation logic and can contain as many transformations as you need. Create a mapplet when you want to use a standardized set of transformation logic in several mappings. For example, if you have a several fact tables that require a series of dimension keys, you can create a mapplet containing a series of Lookup transformations to find each dimension key. You can then use the mapplet in each fact table mapping, rather than recreate the same lookup logic in each mapping.
  • 8. 53 Informatica simple If data source is in the form of PowerMart and PowerCenter treat a Microsoft Excel source as a relational database, not a flat file. Excel Spread sheet then how Like relational sources, the Designer uses ODBC to import a Microsoft Excel source. You do not do use? need database permissions to import Microsoft Excel sources. To import an Excel source definition, you need to complete the following tasks: · Install the Microsoft Excel ODBC driver on your system. · Create a Microsoft Excel ODBC data source for each source file in the ODBC 32-bit Administrator. · Prepare Microsoft Excel spreadsheets by defining ranges and formatting columns of numeric data. · Import the source definitions in the Designer. Once you define ranges and format cells, you can import the ranges in the Designer. Ranges display as source definitions when you import the source.54 Informatica simple When do u use connected A connected Lookup transformation is part of the mapping data flow. With connected lookups, you lookup n when do u use can have multiple return values. That is, you can pass multiple values from the same row in the unconnected lookup? lookup table out of the Lookup transformation. Common uses for connected lookups include: => Finding a name based on a number ex. Finding a Dname based on deptno => Finding a value based on a range of dates => Finding a value based on multiple conditions Unconnected Lookups : - An unconnected Lookup transformation exists separate from the data flow in the mapping. You write an expression using the :LKP reference qualifier to call the lookup within another transformation. Some common uses for unconnected lookups include: => Testing the results of a lookup in an expression => Filtering records based on the lookup results => Marking records for update based on the result of a lookup (for example, updating slowly changing dimension tables) => Calling the same lookup multiple times in one mapping55 Informatica simple How many values it Connected Lookup can return multiple values where as Unconnected Lookup will return only one (informatica server) returns values that is Return Value. when it passes thru Connected Lookup n Unconncted Lookup?
  • 9. 56 Informatica simple What kind of modifications u Using transformations, you can modify data in the following ways: can do/perform with each ----------------- ------------------------ Transformation? Task Transformation ----------------- ------------------------ Calculate a value Expression Perform an aggregate calculations Aggregator Modify text Expression Filter records Filter, Source Qualifier Order records queried by the Informatica Server Source Qualifier Call a stored procedure Stored Procedure Call a procedure in a shared library or in the External Procedure COM layer of Windows NT Generate primary keys Sequence Generator Limit records to a top or bottom range Rank Normalize records, including those read Normalizer from COBOL sources Look up values Lookup Determine whether to insert, delete, update, Update Strategy or reject records Join records from different databases Joiner or flat file systems
  • 10. 57 Informatica simple Expressions in Expressions in Transformations Transformations, Explain To transform data passing through a transformation, you can write an expression. The most briefly how do u use? obvious examples of these are the Expression and Aggregator transformations, which perform calculations on either single values or an entire range of values within a port. Transformations that use expressions include the following: --------------------- ------------------------------------------ Transformation How It Uses Expressions --------------------- ------------------------------------------ Expression Calculates the result of an expression for each row passing through the transformation, using values from one or more ports. Aggregator Calculates the result of an aggregate expression, such as a sum or average, based on all data passing through a port or on groups within that data. Filter Filters records based on a condition you enter using an expression. Rank Filters the top or bottom range of records, based on a condition you enter using an expression. Update Strategy Assigns a numeric code to each record based on an expression, indicating whether the Informatica Server should use the information in the record to insert, delete, or update the target. In each transformation, you use the Expression Editor to enter the expression. The Expression Editor supports the transformation language for building expressions. The transformation language uses SQL-like functions, operators, and other components to build the expression. For example, as in SQL, the transformation language includes the functions COUNT and SUM. However, the PowerMart/PowerCenter transformation language includes additional functions not found in SQL. When you enter the expression, you can use values available through ports. For example, if the transformation has two input ports representing a price and sales tax rate, you can calculate the final sales tax using these two values. The ports used in the expression can appear in the same transformation, or you can use output ports in other transformations.58 Informatica average In case of Flat files (which U get a fatal error which cause server to fail/stop the session. comes thru FTP as source) has not arrived then what happens
  • 11. 59 Informatica average What does a load manager The Load Manager is the primary PowerCenter Server process. It accepts requests from the do ? PowerCenter Client and from pmcmd. The Load Manager runs and monitors the workflow. It performs the following tasks: Starts the session, creates DTM process and sends pre & post session emails. 1.Manages the session and batch scheduling 2.locks the session and reads the session properties. 3. expands the session and server variables and parameters 4. validates the source and target code pages 5. verifies the permissions and privileges 6. creates session log file 7. creates DTM process which executes the session60 Informatica simple What is a cache Temporary memory area used to store intermediate results61 Informatica simple What is an Expression Expression transformation is used to calculate expressions on a row by row basis. Total_sal = Com transformation? * sal62 Informatica simple I have two sources S1 having S1 should be the master as it contains few records so that the usage of cache can be reduced , S2 100 records and S2 having should be detail. 10000 records, I want to join them, using joiner transformation. Which of these two sources (S1,S2) should be master to improve my performance? Why?63 Informatica average I have a source and I want to YES, Write a stored procedure and use Stored Procedure Transformation generate sequence numbers using mappings in informatica. But I don’t want to use sequence generator transformation. Is there any other way to do it?64 Informatica average What is a bad file? Bad file is the file which contains the data rejected by the writer or target.
  • 12. 65 Informatica average What is the first column of the Record / Row indicator bad file? 0,1,2,3 0 – insert -- Rejected by writer/target 1- update -- Rejected by writer/target 2- delete -- Rejected by writer/target 3-reject -- Rejected by writer --- coz update st. has marked it for reject.66 Informatica average What are the contents of the Index cache files and Data caches cache directory in the server67 Informatica simple Is lookup a Active Passive. transformation or Passive transformation ?68 Informatica simple What is a Mapping? Mapping Represent the data flow between source and target69 Informatica simple What are the types of Passive and active transformations70 Informatica simple If a sequence generator (with Each target will get the value in multiple of 3 increment of 1) is connected to (say) 3 targets and each target uses the NEXTVAL port, what value will each target get?71 Informatica average Have you used the Abort, Abort can be used to Abort / stop the session on an error condition. Decode functions? If the primary key column contains NULL, and you need to stop the session from continuing then you may use ABORT function in the default value for the port. It can be used with IIF and DECODE function to Abort the session.72 Informatica average What do you know about the o Load Manager is the first process started when the session runs. It checks for validity of Informatica server mappings, locks sessions and other objects. architecture? Load Manager, o DTM process is started once the Load Manager has completed its job. It starts a thread for each DTM, Reader, Writer, pipeline. Transformer o Reader scans data from the specified sources. o Writer manages the target/output data. o Transformer performs the task specified in the mapping.73 Informatica simple What are the default values String = Null, Number = 0, Date = 1/1/1753 for variables?
  • 13. 74 Informatica simple How many ways you can filter 1. Source Qualifier the records? 2. Filter transformation 3. Router transformation 4. Ranker 5. Update strategy
  • 14. 75 Informatica complex · How do you identify the Bottlenecks can occur in bottlenecks in Mappings? 1. Targets The most common performance bottleneck occurs when the informatica server writes to a target database. You can identify target bottleneck by configuring the session to write to a flat file target. If the session performance increases significantly when you write to a flat file, you have a target bottleneck. Solution : Drop or Disable index or constraints Perform bulk load (Ignores Database log) Increase commit interval (Recovery is compromised) Tune the database for RBS, Dynamic Extension etc., 2. Sources Set a filter transformation after each SQ and see the records are not through. If the time taken is same then there is a problem. You can also identify the Source problem by Read Test Session – where we copy the mapping with sources, SQ and remove all transformations and connect to file target. If the performance is same then there is a Source bottleneck. Using database query – Copy the read query directly from the log. Execute the query against the source database with a query tool. If the time it takes to execute the query and the time to fetch the first row are significantly different, then the query can be modified using optimizer hints. Solutions: Optimize Queries using hints. Use indexes wherever possible. 3. Mapping If both Source and target are OK then problem could be in mapping. Add a filter transformation before target and if the time is the same then there is a problem. (OR) Look for the performance monitor in the Sessions property sheet and view the counters. Solutions: If High error rows and rows in lookup cache indicate a mapping bottleneck. Optimize Single Pass Reading: Optimize Lookup transformation : 1. Caching the lookup table: When caching is enabled the informatica server caches the lookup table and queries the cache during the session. When this option is not enabled the server queries the lookup table on a row-by row basis. Static, Dynamic, Shared, Un-shared and Persistent cache 2. Optimizing the lookup condition Whenever multiple conditions are placed, the condition with equality sign should take precedence. 3. Indexing the lookup table
  • 15. 76 Informatica complex How to improve the Session 1 Run concurrent sessions performance? 2 Partition session (Power center) 3. Tune Parameter – DTM buffer pool, Buffer block size, Index cache size, data cache size, Commit Interval, Tracing level (Normal, Terse, Verbose Init, Verbose Data) The session has memory to hold 83 sources and targets. If it is more, then DTM can be increased. The informatica server uses the index and data caches for Aggregate, Rank, Lookup and Joiner transformation. The server stores the transformed data from the above transformation in the data cache before returning it to the data flow. It stores group information for those transformations in index cache. If the allocated data or index cache is not large enough to store the date, the server stores the data in a temporary disk file as it processes the session data. Each time the server pages to the disk the performance slows. This can be seen from the counters . Since generally data cache is larger than the index cache, it has to be more than the index. 4. Remove Staging area 5. Tune off Session recovery 6. Reduce error tracing77 Informatica What is Business It is available in navigator inside the folder. components ? Where it exists ?78 Informatica complex What are Short cuts ? Where Shortcuts allow you to use metadata across folders without making copies, ensuring uniform it is used ? metadata. A shortcut inherits all properties of the object to which it points. Once you create a shortcut, you can configure the shortcut name and description. When the object the shortcut references changes, the shortcut inherits those changes. By using a shortcut instead of a copy, you ensure each use of the shortcut matches the original object. For example, if you have a shortcut to a target definition, and you add a column to the definition, the shortcut inherits the additional column. · Scenario1 Here is a table with Single Row, in a target table the same row should be populated 10 times. Using Normalizer, we can do it. Hint : Normalizer / Occurs make it 10 and Have 10 inputs and a output. You will get 10 rows.
  • 16. 79 Informatica simple While importing the relational Source name source definition from Database location database, what are the meta Column names data of source U import? Data types Key constraints80 Informatica simple . How many ways U can Two ways update a relational source 1. Edit the definition definition and what r they? 2. Re-import the definition81 Informatica simple How many ways u create Two ways ports? 1. Drag the port from another transformation 2. Click the add button on the ports tab.82 Informatica average .What r the unsupported COBOL source definition repository objects for a Joiner transformations mapplet? Normalizer transformations Non reusable sequence generator transformations. Pre or post session stored procedures Target definitions Power mart 3.5 style Look Up functions XML source definitions IBM MQ source definitions83 Informatica simple What r the mapping Mapping parameter represents a constant value that U can define before running a session. A parameters and mapping mapping parameter retains the same value throughout the entire session. variables? When u use the mapping parameter ,U declare and use the parameter in a mapping or maplet. Then define the value of parameter in a parameter file for the session. Unlike a mapping parameter, a mapping variable represents a value that can change throughout the session. The informatica server saves the value of mapping variable to the repository at the end of session run and uses that value next time U run the session.
  • 17. 84 Informatica simple Can U use the mapping NO. parameters or variables We can use mapping parameters or variables in any transformation of the same mapping or created in one mapping into mapplet in which U have created mapping parameters or variables. another mapping?85 Informatica simple Can u use the mapping Yes. Because reusable transformation is not contained with any maplet or mapping. parameters or variables created in one mapping into any other reusable transformation?86 Informatica simple How can U improve session Use sorted input. performance in aggregator transformation?87 Informatica simple .What r the difference U can join heterogeneous data sources in joiner transformation which we can not achieve in between joiner transformation source qualifier transformation. and source qualifier U need matching keys to join two relational sources in source qualifier transformation. Where transformation? as u doesnt need matching keys to join two sources. Two relational sources should come from same data source in sourcequalifier. U can join relational sources which r coming from different sources also.88 Informatica simple In which conditions we can Both pipelines begin with the same original data source. not use joiner Both input pipelines originate from the same Source Qualifier transformation. transformation(Limitations of Both input pipelines originate from the same Normalizer transformation. joiner transformation)? Both input pipelines originate from the same Joiner transformation. Either input pipelines contains an Update Strategy transformation. Either input pipelines contains a connected or unconnected Sequence Generator transformation.89 Informatica simple What r the settings that u use Master and detail source to configure the joiner Type of join transformation? Condition of the join90 Informatica simple What r the join types in joiner Normal (Default) transformation? Master outer Detail outer Full outer
  • 18. 91 Informatica simple How the informatica server When the informatica server runs in the ASCII data movement mode it sorts session data using sorts the string values in Rank Binary sort order. If U configure the session to use a binary sort order, the informatica server transformation? calculates the binary value of each string and returns the specified number of rows with the highest binary values for the string.92 Informatica simple What is the Rank index in The Designer automatically creates a RANKINDEX port for each Rank transformation. The Rank transformation? Informatica Server uses the Rank Index port to store the ranking position for each record in a group. For example, if you create a Rank transformation that ranks the top 5 salespersons for each quarter, the rank index numbers the salespeople from 1 to 5:93 Informatica simple What is the Router Input group transformation? Output group A Router transformation is similar to a Filter transformation because both transformations allow you to use a condition to test data. However, a Filter transformation tests data for one condition and drops the rows of data that do not meet the condition. A Router transformation tests data for one or more conditions and gives you the option to route rows of data that do not meet any of the conditions to a default output group. If you need to test the same input data based on multiple conditions, use a Router Transformation in a mapping instead of creating multiple Filter transformations to perform the same task94 Informatica simple What r the types of groups in The designer copies property information from the input ports of the input group to create a set Router transformation? of output ports for each output group. Two types of output groups User defined groups Default group U can not modify or delete default groups.95 Informatica simple Why we use stored procedure For populating and maintaining data bases. transformation?
  • 19. 96 average What r the types of data that 3 types of data passes between informatica Input/Out put parameters server and stored procedure? Return Values Status code.97 Informatica average What is the status code? Status code provides error handling for the informatica server during the session. The stored procedure issues a status code that notifies whether or not stored procedure completed sucessfully. This value can not seen by the user. It only used by the informatica server to determine whether to continue running the session or stop.98 Informatica simple What r the tasks that source Join data originating from same source data base. qualifier performs? Filter records when the informatica server reads source data. Specify an outer join rather than the default inner join specify sorted records. Select only distinct values from the source. Creating custom query to issue a special SELECT statement for the informatica server to read source data.99 Informatica simple What is the default join that Inner equi join. source qualifier provides?100 Informatica simple . What r the basic needs to Two sources should have primary and Foreign key relation ships. join two sources in a source Two sources should have matching data types. qualifier?101 Informatica simple what is update strategy This transformation is used to maintain the history data or just most recent changes in to transformation ? target table.102 Informatica simple Describe two levels in which Within a session. When you configure a session, you can instruct the Informatica Server to either update strategy treat all records in the same way (for example, treat all records as inserts), or use instructions transformation sets? coded into the session mapping to flag records for different database operations. Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.103 Informatica average What is the default source Data driven. option for update strategy transformation?
  • 20. 104 Informatica average What is Data driven? The informatica server follows instructions coded into update strategy transformations with in the session mapping determine how to flag records for insert, update, delete or reject. If u do not choose data driven option setting, the informatica server ignores all update strategy transformations in the mapping.105 Informatica simple What r the options in the Insert target session of update Delete strategy transformation? Update Update as update Update as insert Update else insert Truncate table106 Informatica simple What r the types of mapping The Designer provides two mapping wizards to help you create mappings quickly and easily. Both wizards that r to be provided wizards are designed to create mappings for loading and maintaining star schemas, a series of in Informatica? dimensions related to a central fact table. Getting Started Wizard. Creates mappings to load static fact and dimension tables, as well as slowly growing dimension tables. Slowly Changing Dimensions Wizard. Creates mappings to load slowly changing dimension tables based on the amount of historical dimension data you want to keep and the method you choose to handle historical dimension data.107 Informatica simple What r the types of mapping Simple Pass through mapping : in Getting Started Wizard? Loads a static fact or dimension table by inserting all rows. Use this mapping when you want to drop all existing data from your table before loading new data. Slowly Growing target : Loads a slowly growing fact or dimension table by inserting new rows. Use this mapping to load new data when existing data does not require updates.
  • 21. 108 Informatica avrage What r the mappings that we Type1: Rows containing changes to existing dimensions are updated in the target by overwriting use for slowly changing the existing dimension. In the Type 1 Dimension mapping, all rows contain current dimension data. dimension table? Use the Type 1 Dimension mapping to update a slowly changing dimension table when you do not need to keep any previous versions of dimensions in the table. Type 2: The Type 2 Dimension Data mapping inserts both new and changed dimensions into the target. Changes are tracked in the target table by versioning the primary key and creating a version number for each dimension in the table. Use the Type 2 Dimension/Version Data mapping to update a slowly changing dimension table when you want to keep a full history of dimension data in the table. Version numbers and versioned primary keys track the order of changes to each dimension. Type 3: The Type 3 Dimension mapping filters source rows based on user-defined comparisons and inserts only those found to be new dimensions to the target. Rows containing changes to existing dimensions are updated in the target. When updating an existing dimension, the Informatica Server saves existing data in different columns of the same row and replaces the existing data with the updates109 Informatica average What r the different types of Type2 Dimension/Version Data Mapping: In this mapping the updated dimension in the Type2 dimension mapping? source will gets inserted in target along with a new version number. And newly added dimension in source will insert into target with a primary key. Type2 Dimension/Flag current Mapping: This mapping is also used for slowly changing dimensions. In addition it creates a flag value for changed or new dimension. Flag indicates the dimension is new or newly updated. Recent dimensions will gets saved with current flag value 1. And updated dimensions r saved with the value 0. Type2 Dimension/Effective Date Range Mapping: This is also one flavor of Type2 mapping used for slowly changing dimensions. This mapping also inserts both new and changed dimensions in to the target. And changes r tracked by the effective date range for each version of each dimension.
  • 22. 110 Informatica average How can u recognize whether In the Type2 mapping we have three options to recognize the newly added rows or not the newly added rows Version number in the source r gets insert in Flag value the target ? Effective date Range111 Informatica average What r two types of processes Load manager Process: Starts the session, creates the DTM process, and sends post-session email that informatica runs the when the session completes. session? The DTM process. Creates threads to initialize the session, read, write, and transform data, and handle pre- and post-session operations.112 Informatica What r the features of the U can use command line arguments for a session or batch. This allows U to change the server manager in the values of session parameters, and mapping parameters and mapping variables. informatica 5.0? Parallel data processing: This feature is available for power center only. If we use the informatica server on a SMP system, U can use multiple CPUs to process a session concurrently. Process session data using threads: Informatica server runs the session in two processes. Explained in previous question.113 Informatica simple Can u generate reports in Yes. By using Metadata reporter we can generate reports in informatica. Informatica?114 Informatica simple What is metadata reporter? It is a web based application that enables you to run reports against repository metadata. With a meta data reporter, u can access information about Ur repository with out having knowledge of sql, transformation language or underlying tables in the repository.115 Informatica simple Define mapping and sessions? Mapping: It is a set of source and target definitions linked by transformation objects that define the rules for transformation. Session : It is a set of instructions that describe how and when to move data from source to targets.116 Informatica simple Which tool U use to create Informatica server manager. and manage sessions and batches and to monitor and stop the informatica server?
  • 23. 117 Informatica simple Why we use partitioning the Partitioning achieves the session performance by reducing the time period of reading the session in informatica? source and loading the data into target.118 Informatica simple To achieve the session Configure the session to partition source data. partition what r the necessary tasks u have to do? Install the informatica server on a machine with multiple CPUs.119 Informatica avrage How the informatica server For relational sources informatica server creates multiple connections for each partition of a increases the session single source and extracts separate range of data for each connection. Informatica server reads performance through multiple partitions of a single source concurently. Similarly for loading also informatica server partitioning the source? creates multiple connections to the target and loads partitions of data concurrently. For XML and file sources, informatica server reads multiple files concurrently. For loading the data informatica server creates a separate file for each partition(of a source file).U can choose to merge the targets.120 Informatica simple . Why u use repository When u edit, schedule the session each time, informatica server directly communicates the connectivity? repository to check whether or not the session and users r valid. All the metadata of sessions and mappings will be stored in repository.
  • 24. 121 Informatica average What r the tasks that Load Manages the session and batch scheduling: When u start the informatica server the load manager manger process will do? launches and queries the repository for a list of sessions configured to run on the informatica server. When u configure the session the load manager maintains list of list of sessions and session start times. When u start a session load manger fetches the session information from the repository to perform the validations and verifications prior to starting DTM processLocking and reading the session: When the informatica server starts a session load manager locks the session from the repository. Locking prevents U starting the session again and again. Reading the parameter file: If the session uses a parameter files, load manager reads the parameter file and verifies that the session level parameters are declared in the file Verifies permission and privileges: When the session starts load manger checks whether or not the user have privileges to run the session.122 Informatica average What is DTM process? After the load manger performs validations for session, it creates the DTM process. DTM is to create and manage the threads that carry out the session tasks. I creates the master thread. Master thread creates and manages all the other threads.123 Informatica average What r the different threads in Master thread: Creates and manages all other threads DTM process? Mapping thread: One mapping thread will be creates for each session. Fetches session and mapping information. Pre and post session threads: This will be created to perform pre and post session operations. Reader thread: One thread will be created for each partition of a source. It reads data from source. Writer thread: It will be created to load data to the target. Transformation thread: It will be created to transform data.
  • 25. 124 Informatica average What r the data movement Data movement modes determines how informatica server handles the character data. U modes in informatica? choose the data movement in the informatica server configuration settings. Two types of data movement modes available in informatica. ASCII mode Uni code mode.
  • 26. 125 Informatica average What r the out put files that Informatica server log: Informatica server(on UNIX) creates a log for all status and error the informatica server creates messages(default name: pm.server.log).It also creates an error log for error messages. These files during the session running? will be created in informatica home directory. Session log file: Informatica server creates session log file for each session. It writes information about session into log files such as initialization process, creation of sql commands for reader and writer threads, errors encountered and load summary. The amount of detail in session log file depends on the tracing level that u set. Session detail file: This file contains load statistics for each target in mapping. Session detail include information such as table name, number of rows written or rejected. U can view this file by double clicking on the session in monitor window Performance detail file: This file contains information known as session performance details which helps U where performance can be improved. To generate this file select the performance detail option in the session property sheet. Reject file: This file contains the rows of data that the writer does not write to targets. Control file: Informatica server creates control file and a target file when U run a session that uses the external loader. The control file contains the information about the target flat file such as data format and loading instructions for the external loader. Post session email: Post session email allows U to automatically communicate information about a session run to designated recipients. U can create two different messages. One if the session completed successfully the other if the session fails. Indicator file: If u use the flat file as a target, U can configure the informatica server to create indicator file. For each target row, the indicator file contains a number to indicate whether the row was marked for insert, update, delete or reject. output file: If session writes to a target file, the informatica server creates the target file based on file properties entered in the session property sheet.126 Informatica complex In which circumstances that When it encounters the DD_Rejectserver creates memory cache it also creates cache files. For the Cache files: When the informatica in update strategy transformation. informatica server creates Violates database constraint following circumstances informatica server creates index and data cache files. Reject files? Filed in the rows was truncated or overflowed. Aggregator transformation Joiner transformation Rank transformation Lookup transformation
  • 27. 127 Informatica average What is polling? It displays the updated information about the session in the monitor window. The monitor window displays the status of each session when U poll the informatica server128 Informatica average Can u copy the session to a Yes. By using copy session wizard u can copy a session in a different folder or repository. different folder or repository? But that target folder or repository should consists of mapping of that session. If target folder or repository is not having the mapping of copying session , u should have to copy that mapping first before u copy the session.129 Informatica average . What is batch and describe Grouping of session is known as batch. Batches r two types about types of batches? Sequential: Runs sessions one after the other Concurrent: Runs session at same time. If u have sessions with source-target dependencies u have to go for sequential batch to start the sessions one after another. If u have several independent sessions u can use concurrent batches. Which runs all the sessions at the same time.130 Informatica average Can u copy the batches? NO131 Informatica average .How many number of Any number of sessions. sessions that u can create in a batch?132 Informatica simple When the informatica server If one of session is configured to "run if previous completes" and that previous session fails. marks that a batch is failed?133 Informatica simple . What is a command that pmcmd is used to start a batch. used to run a batch134 Informatica simple What r the different options Two optionsRun the session only if previous session completes successfully. used to configure the Always runs the session. sequential batches?135 Informatica simple In a sequential batch can u Yes. By setting the option always runs the session. run the session if previous session fails?136 Informatica average Can u start batches with in a U can not. If u want to start batch that resides in a batch, create a new independent batch and batch? copy the necessary sessions into the new batch.
  • 28. 137 Informatica average Can u start a session inside a We can start our required session only in case of sequential batch. in case of concurrent batch batch individually? we can’t do like this.138 Informatica average How can u stop a batch? By using server manager or pmcmd.139 Informatica simple What r the session Session parameters r like mapping parameters, represent values U might want to change between parameters? sessions such as database connections or source files. Server manager also allows U to create user defined session parameters. Following r user defined session parameters. Database connections Source file names: use this parameter when u want to change the name or location of session source file between session runs Target file name :Use this parameter when u want to change the name or location of session target file between session runs. Reject file name :Use this parameter when u want to change the name or location of session reject files between session runs.140 Informatica simple What is parameter file? Parameter file is to define the values for parameters and variables used in a session. A parameter file is a file created by text editor such as word pad or notepad. U can define the following values in parameter file Mapping parameters Mapping variables session parameters
  • 29. 141 Informatica simple How can u access the remote Relational source: To access relational source which is situated in a remote place ,u need to source into Ur session? configure database connection to the data source. File Source : To access the remote source file U must configure the FTP connection to the host machine before u create the session. Heterogeneous : When Ur mapping contains more than one source type, the server manager creates a heterogeneous session that displays source options for all types.142 Informatica average What is difference If u partition a session with a relational target informatica server creates multiple connections between portioning of to the target database to write target data concurrently. If u partition a session with a file relational target and target partitioning of file targets? the informatica server creates one target file for each partition. U can configure session properties to merge these target files.143 Informatica average what r the transformations Advanced External procedure transformation and External procedure transformation: This that restricts the partitioning transformation contains a check box on the properties tab to allow partitioning. of sessions? Aggregator Transformation: If u use sorted ports u can not partition the associated source Joiner Transformation : U can not partition the master source for a joiner transformation Normalizer Transformation XML targets.
  • 30. 144 Informatica complex . Performance tuning in Informatica? The goal of performance tuning is optimize session performance so sessions run during the available load window for the Informatica Server. Increase the session performance by following. The performance of the Informatica Server is related to network connections. Data generally moves across a network at less than 1 MB per second, whereas a local disk moves data five to twenty times faster. Thus network connections often affect on session performance. So avoid network connections. Flat files: If ur flat files stored on a machine other than the informatica server, move those files to the machine that consists of informatica server. Relational data sources: Minimize the connections to sources ,targets and informatica server to improve session performance. Moving target database into server system may improve session performance. Staging areas: If u use staging areas u force informatica server to perform multiple data passes. Removing of staging areas may improve session performance. U can run the multiple informatica servers against the same repository. Distributing the session load to multiple informatica servers may improve session performance. Run the informatica server in ASCII data movement mode improves the session performance. Because ASCII data movement mode stores a character value in one byte. Unicode mode takes 2 bytes to store a character. If a session joins multiple source tables in one Source Qualifier, optimizing the query may improve performance. Also, single table select statements with an ORDER BY or GROUP BY clause may benefit from optimization such as adding indexes. We can improve the session performance by configuring the network packet size, which allows data to cross the network at one time. To do this go to server manger ,choose server configure database connections. If u r target consists key constraints and indexes u slow the loading of data. To improve the session performance in this case drop constraints and indexes before u run the session and rebuild them after completion of session. Running a parallel sessions by using concurrent batches will also reduce the time of loading the data. So concurrent batches may also increase the session performance. Partitioning the session improves the session performance by creating multiple connections to sources and targets and loads data in parallel pipe lines. In some cases if a session contains an aggregator transformation ,u can use incremental aggregation to improve session performance.
  • 31. 145 Informatica simple Define informatica repository? The Informatica repository is a relational database that stores information, or metadata, used by the Informatica Server and Client tools. Metadata can include information such as mappings describing how to transform source data, sessions indicating when you want the Informatica Server to perform the transformations, and connect strings for sources and targets. The repository also stores administrative information such as usernames and passwords, permissions and privileges, and product version. Use repository manager to create the repository. The Repository Manager connects to the repository database and runs the code needed to create the repository tables.These tables stores metadata in specific format the informatica server, client tools use.146 Informatica simple What r the types of metadata Following r the types of metadata that stores in the repository that stores in repository? Database connections Global objects Mappings Mapplets Multidimensional metadata Reusable transformations Sessions and batches Short cuts Source definitions Target definitions Transformations147 Informatica simple What is power center The PowerCenter repository allows you to share metadata across repositories to create a data mart repository? domain. In a data mart domain, you can create a single global repository to store metadata used across an enterprise, and a number of local repositories to share the global metadata as needed.148 Informatica average How can u work with remote To work with remote data source u need to connect it with remote connections. But it is not database in informatica? did u preferable to work with that remote source directly by using remote connections .Instead u work directly by using remote bring that source into U r local machine where informatica server resides. If u work directly with remote source the session performance will decreases by passing fewer amounts of data across the network in a particular time.
  • 32. 149 Informatica average what is incremental When using incremental aggregation, you apply captured changes in the source to aggregate aggregation? calculations in a session. If the source changes only incrementally and you can capture changes, you can configure the session to process only those changes. This allows the Informatica Server to update your target incrementally, rather than forcing it to process the entire source and recalculate the same calculations each time you run the session.150 Informatica simple . What r the scheduling U can schedule a session to run at a given time or interval, or u can manually run the session. options to run a session? Different options of scheduling Run only on demand: Informatica server runs the session only when user starts session explicitly Run once: Informatica server runs the session only once at a specified date and time. Run every: Informatica server runs the session at regular intervals as u configured. Customized repeat: Informatica server runs the session at the dates and times specified in the repeat dialog box.151 Informatica simple What is tracing level and what Tracing level represents the amount of information that informatica server writes in a log file. r the types of tracing level? Types of tracing level Normal Verbose Verbose init Verbose data152 Informatica simple What is difference between In case of stored procedure transformation procedure will be compiled and executed in a stored procedure relational data source. U need data base connection to import the stored procedure in to ur transformation and external maping. Where as in external procedure transformation procedure or function will be executed out procedure transformation? side of data source. ie u need to make it as a DLL to access in u r mapping. No need to have data base connection in case of external procedure transformation.
  • 33. 153 Informatica complex Explain about Recovering If you stop a session or if an error causes a session to stop, refer to the session and error sessions? logs to determine the cause of failure. Correct the errors, and then complete the session. The method you use to complete the session depends on the properties of the mapping, session, and Informatica Server configuration. Use one of the following methods to complete the session: · Run the session again if the Informatica Server has not issued a commit. · Truncate the target tables and run the session again if the session is not recoverable. · Consider performing recovery if the Informatica Server has issued at least one commit.154 Informatica complex If a session fails after loading As explained above informatica server has 3 methods to recovering the sessions. Use performing of 10,000 records in to the recovery to load the records from where the session fails. target. How can u load the records from 10001st record when u run the session next time?155 Informatica complex Explain about perform When the Informatica Server starts a recovery session, it reads the OPB_SRVR_RECOVERY table recovery? and notes the row ID of the last row committed to the target database. The Informatica Server then reads all sources again and starts processing from the next row ID. For example, if the Informatica Server commits 10,000 rows before the session fails, when you run recovery, the Informatica Server bypasses the rows up to 10,000 and starts loading with row 10,001. By default, Perform Recovery is disabled in the Informatica Server setup. You must enable Recovery in the Informatica Server setup before you run a session so the Informatica Server can create and/or write entries in the OPB_SRVR_RECOVERY table.156 Informatica complex How to recover the standalone A standalone session is a session that is not nested in a batch. If a standalone session fails, you session? can run recovery using a menu command or pmcmd. These options are not available for batched sessions. To recover sessions using the menu: 1. In the Server Manager, highlight the session you want to recover. 2. Select Server Requests-Stop from the menu. 3. With the failed session highlighted, select Server Requests-Start Session in Recovery Mode from the menu. To recover sessions using pmcmd: 1.From the command line, stop the session. 2. From the command line, start recovery.
  • 34. 157 Informatica complex How can u recover the session If you configure a session in a sequential batch to stop on failure, you can run recovery starting in sequential batches? with the failed session. The Informatica Server completes the session and then runs the rest of the batch. Use the Perform Recovery session property To recover sessions in sequential batches configured to stop on failure: 1.In the Server Manager, open the session property sheet. 2.On the Log Files tab, select Perform Recovery, and click OK. 3.Run the session. 4.After the batch completes, open the session property sheet. 5.Clear Perform Recovery, and click OK. If you do not clear Perform Recovery, the next time you run the session, the Informatica Server attempts to recover the previous session. If you do not configure a session in a sequential batch to stop on failure, and the remaining sessions in the batch complete, recover the failed session as a standalone session.158 Informatica complex How to recover sessions in If multiple sessions in a concurrent batch fail, you might want to truncate all targets and run the concurrent batches? batch again. However, if a session in a concurrent batch fails and the rest of the sessions complete successfully, you can recover the session as a standalone session. To recover a session in a concurrent batch: 1.Copy the failed session using Operations-Copy Session. 2.Drag the copied session outside the batch to be a standalone session. 3.Follow the steps to recover a standalone session. 4.Delete the standalone copy.159 Informatica complex How can u complete Under certain circumstances, when a session does not complete, you need to truncate the target unrecoverable sessions? tables and run the session from the beginning. Run the session from the beginning when the Informatica Server cannot run recovery or when running recovery might result in inconsistent data.160 Informatica complex What r the circumstances that The source qualifier transformation does not use sorted ports. informatica server results an If u change the partition information after the initial session fails. unrecoverable session? Perform recovery is disabled in the informatica server configuration. If the sources or targets changes after initial session fails. If the mapping consists of sequence generator or normalizer transformation. If a concurrent batch contains multiple failed sessions.
  • 35. 161 Informatica average If ive done any modifications NO. Informatica is not at all concern with back end data base. It displays u all the information for my table in back end does that is to be stored in repository. If want to reflect back end changes to informatica screens, it reflect in informatica again u have to import from back end to informatica by valid connection. And u have to replace warehouse or mapping the existing files with imported files. designer or source analyzer?162 Informatica average After dragging the ports of NO. Unless and until u join those three ports in source qualifier u cannot map them directly. three sources(sql server,oracle,informix) to a single source qualifier, can u map these three ports directly to target?163 Informatica Server Variables 1. $PMRootDir 2. $PMSessionLogDir 3. $PMBadFileDir 4. $PMCacheDir 5. $PMTargetFileDir 6. $PMSourceFileDir 7. $PMExtProcDir 8. $PMTempDir 9. $PMSuccessEmailUser 10. $PMFailureEmailUser 11. $PMSessionLogCount 12. $PMSessionErrorThreshold 13. $PMWorkflowLogDir 14. $PMWorkflowLogCount 15. $PMLookupFileDir
  • 36. 164 Informatica Folders Folders provide a way to organize and store all metadata in the repository, including mappings, schemas, and sessions. Folders are designed to be flexible, to help you logically organize the repository. Each folder has a set of configurable properties that help you define how users access the folder. For example, you can create a folder that allows all repository users to see objects within the folder, but not to edit them. Or, you can create a folder that allows users to share objects within the folder. You can create shared and non-shared folders. Note: You must create a folder in a repository before you can connect to the repository using the Designer or Workflow Manager. You create and maintain folders in the Repository Manager. In the Repository Manager, you can view the users accessing folders and the objects within each folder. You can also copy and replace folders within the repository or across repositories.165 Informatica Multiple Servers Register multiple PowerCenter Servers. When you register multiple PowerCenter Servers, choose the PowerCenter Server for a workflow in the workflow properties.
  • 37. Sl.No Category Complexity Questions 1 Performance tuning Simple What are the types of optimizer? A: Rule-based and Cost-based optimizers 2 Performance tuning Medium Which optimizer mode is the default one? A: Optimizer takes the rule based approach as default. 3 Performance tuning Medium What is explain plan? A:The sequence of steps the optimizer chooses to execute the SELECT, UPDATE, INSERT, DELETE statements. 4 Performance tuning Complex Can you force the optimizer to choose the optimal execution plan? A:Yes. By using hints option. 5 Performance tuning Medium How will you tune the following query? Select empid, ename, dno from emp where dno in(select deptno from dept) A: select empid, ename,dno from emp, dept where dno=deptno 6 Performance tuning Simple Which is faster? Using IN or EXISTS? A: EXISTS is faster compared to IN. 7 Joins Simple What are the types of joins? What are they? A:Simple join, Outer join, Self join Simple join returns the common rows between two or more tables. Outer join returns the matching rows from one, and all the rows from the other table, with the unmatched rows marked as NULL. Self join is joining a table to itself. 8 Queries Simple How will you fetch the first 10 records of a table? A: select * from emp where rownum<11 9 Fundamentals Simple How many types of SQL statements are there in Oracle? A: DDL - create, alter, drop DML - select, insert, update, delete TCL - commit, savepoint, rollback DCL – Grant, Revoke 10 PL/SQL Simple What are cursors? A: A cursor is a handle ( name or a pointer) for the memory associated with a specific statement. A cursor is basically an area allocated by Oracle for executing the SQL Statement. Oracle uses an implicit cursor statement for Single row query and Uses Explicit cursor for a multi row query. 11 PL/SQL Simple What are attributes of cursor? %FOUND , %NOTFOUND , %ISOPEN,%ROWCOUNT
  • 38. 12 Queries Medium How will you identify the duplicates in a particular column? A:Select col1, count(*) from table1 group by col1 having count(*)>113 PL/SQL Medium What are packages? Advantages of packages? A:Packages Provide a method of encapsulating and storing related procedures, functions, variables and other Package Contents.14 PL/SQL Simple How many types of parameters can be passed to a stored procedure? A:3 types: IN, OUT, INOUT15 PL/SQL Simple Difference between Stored procedure and functions A: Function returns a value to the calling block whereas the Stored procedure does not.16 PL/SQL Simple What are Database Triggers and Stored Procedures A: Database Triggers are Procedures that are automatically executed as a result of insert in, update to, or delete from table.17 Partition Medium What are partitions? A: Partitions are segments of a logical table split by range of key column values.18 Partition Complex Syntax of creating a partition Create table A(a varchar(1), b numeric(10)) Partition by range(b) (partition p1 values less than 10, Partition p2 values less than 20, Partition p3 values less than maxvalue)19 Normalization Simple What is ER model? A: It is a conceptual data model that views the real world as entities and relationships. A basic component of the model is the Entity-Relationship diagram which is used to visually represents data objects.20 PL/SQL Simple How many types of Exceptions are there There are 2 types of exceptions. They are a) System Exceptions e.g. When no_data_found, When too_many_rows b) User Defined Exceptions e.g. My_exception exception When My_exception then21 Locks Medium How many types of Locks are there? What are they? A: Shared, Share Update, Exclusive
  • 39. You are asked to model a many-many relationship given the students and22 Normalization Medium teachers data. How many tables would you require to implement the same? A: 323 Queries Medium What is the difference between a sub query and a correlated sub query? A: Subquery is a query inside a query, where the sub query gets executed only once. In a correlated sub query, the sub query gets executed once for each row processed by the parent query.24 Fundamentals Simple What are the two types of synonyms? What is the difference between the two? A: Private and Public. Private synonyms are created by the database user and is available only to the user, where as public synonym is created by the database administrator and is available to all users.25 PL/SQL Simple How many types of Exceptions are there? What are they? A: There are 2 types of exceptions. They are a) System Exceptions e.g. When no_data_found, When too_many_rows b) User Defined Exceptions e.g. My_exception exception26 PL/SQL Complex Can you execute DDL statements inside a PL/SQL block? How? A: Yes. By using execute immediate clause.27 Queries Medium What are embedded SQLs? A: Sql Statements embedded in a high level language such as C are called embedded sqls.28 Fundamentals Medium Table Emp has 3 records: A B C Sequence of 4 sql stmts are executed: Delete emp where val=A Alter table emp modify(val varchar2(5)) Delete emp where val=B Rollback What is the status of the table emp? A: Table emp has 2 records B & C.
  • 40. 29 PL/SQL Complex What are mutating tables? A: Mutating table is a table that is currently being modified by insert update or delete statement causing a trigger to fire that again tries to modify the same table30 Fundamentals Simple What is the difference between deleting and truncating of tables A: Deleting a table will remove the rows from the table but space consumed by these rows is not released. But truncating a table deletes it completely and release the space consumed by it too.31 Fundamentals Simple Name a few pseudocolumns. A: NEXTVAL, CURRVAL, ROWNUM etc..32 Queries Medium What is on delete cascade option? A: When a key value is deleted, if you want to also delete the references of the key, go for on delete cascade option.33 Fundamentals Medium How many columns can table have? A: The number of columns in a table can range from 1 to 254.34 Database connection Medium What is tnsnames.ora? A tnsnames.ora file provides the ability to reference oracle databases by a simple alias.35 Performance tuning Complex How do you generate statistics of a particular table involved in a query? A: Analyze table compute statistics36 PL/SQL Complex What are PL/SQL tables? A: PL/SQL tables are not stored in the database, and is usually created inside a PL/SQL block with only one column.37 Database connection Medium What is Oracle SID? Where do you set that? A: If Oracle is used in a UNIX server, then Oracle SID is set in the .profile file. It denotes the database.38 Queries Medium How do u implement the If statement in the Select Statement? A: Using DECODE39 Queries Simple How can you fetch the uncommon rows from the result set of 2 queries? A: Using MINUS operator40 Conversion functions Medium What is the difference between to_char() & to_number() function/ A: To_char converts a number or date to a char. To_number converts a char or varchar to a number.41 What are inline views? Views
  • 41. What are the advantages of force42 views? Views What type of DBMS is supported by Oracle43 8i? Fundamentals What are materialized44 views? Views What are the rules that are to be followed while inserting data45 into views? Views Can you insert records into materialized46 views? Views What is the difference between a snapshot and a materialized47 view? Fundamentals What is the advantage of using a clustered48 index? Index What are the enhancements on49 Views in Oracle 8i? Views What are the new types of triggers added50 in Oracle 8i? Triggers Executing the query on a million records51 performance. Index How will you tune it? Select *, revenue-cost from tableA Difference between Bitmap and B-Tree52 indices. Index
  • 42. Which feature in Oracle 8i supports53 incremental updates? Summary tables Hash and composite54 partitioning techniques Partition What are the constraints imposed on creating a column of55 LONG datatype? Datatypes What happens when you use a for update of clause in a select56 stmt? Locks How are data stored in57 a nested table? Nested tables58 What are REF cursors? PL/SQL What is a star query?59 Give eg. Queries There are 2 exceptions in a PL/SQL block. When will both the exceptions get60 executed? (Twisted) PL/SQL When do you use connect by prior in a61 query? Queries to display records hierarchy tree level What is the difference between a translate and a replace of a62 string? Egs? String functions What happens when you modify and re-63 compile a procedure? Procedure What are bind64 variables? PL/SQL
  • 43. How will you find the byte size of a particular65 column? Numeric functions Select sysdate from dual returns 5 records.66 Whats the implication? Fundamentals How will you fetch the age of a person, given his DOB column in a table, using a simple67 query? Date functions
  • 44. Srl NO # Subject Complexity Questions Answers 1 Control M Average What is Control M? Control-M is a multi-platform job scheduling and control system. It executes as a background activity and schedules, submits, tracks and follows up the execution of jobs. Used in conjunction with Enterprise Control Station (Enterprise/CS) it provides centralised workstation control of the job scheduling production environment. An instance of Control- M resides on each of the machines for which scheduling is required. Enterprise/CS resides on a Sun workstation and can control multiple instances of Control-M. 2 Control M Complex Integerated Components of Enterprise/CS Enterprise/CS is comprised of three integrated components which work in unison to provide centralised control of the entire job scheduling environment. 1. The first component, the data-centre, consists of one or more computers which are managed by one Control-M monitor. Enterprise/ CS can control many data-centres of the same or different types of platforms. 2.The second component, a gateway, provides communication between data-centres and the Enterprise/CS workstation(s). 3.The third component, the Enterprise/CS Workstation, provides an easy-to-use graphical user interface and local SQL database, used to maintain all the data-centres. 3 Control M Simple Owner of the production file controlled prod user.
  • 45. 4 Control M Average General Structure of the HOME dorectory of the runlib - Storage area for all scripts and binaries prod user used by a Control M controlled application overlib - Temporary area for emergency fixes rellib - Used as holding area prior to release into run library oldlib - Contains the previous version of any updated files. adhoc - Emergency one off runs INIT - Initialisation files : ksh.env, csh.env, INIT, pcp related files, etc.5 Control M Simple What the environment variable CTM_ODATE mean? Order date for the job.6 Control M Average Stages of execution 1. Control M checks the permissions of the file, comparing it with the job owner field. It copies the file, making a number of changes to the script. These changes are made so that Control- M can trace and post-process the job output. 2. Control-M switches user to the job owner, changes directory to the job owners HOME directory and executes the .profile/.cshrc scripts. 3. Main script startup 4. The Parameter Construction Program (PCP) is used to create a file of options, parameters and other configuration information, some of which may change depending on the date. 5. Main script execution 6.Control M - Final processing7 Control M Simple PCP The Parameter Construction Program should be used to create any variable configuration, parameters or startup code required by a group of scripts.
  • 46. 8 Control M Average How do you call a sql? Call the oracle login instances and giving the sql script as a parameter 9 Control M Average How do you call a Informatica session? Using pmcmd command in the script10 Control M Simple What is RIT? Its a Run time Information Template. It tell us the information about the control M job reg. Its scheduling time, Inputs reqired, database which it is using, Whether it is doing Insert/ Update / Delete
  • 47. Sl. No. Subject Complexity Questions Answers 1 DataWareho simple what is a Data Warehouse? A data warehouse is a relational database that is designed for query using and analysis rather than for transaction processing. It usually contains historical data derived from transaction data, but it can include data from other sources. It separates analysis workload from transaction workload and enables an organization to consolidate data from several sources. What is the conventional DataWareho definition of a DWH? Explain each 19 using Complex term. Subject-oriented, Integrated, Time-variant, Non-volatile. DataWareho Draw the architecture of a 17 using Medium Datawarehousing system. <Diagram> What are the goals of the Data 35 warehouse? What are the approaches in DataWareho constructing a Datawarehouse 18 using Medium and the datamart? Top-down and Bottom-up approaches. 2 DataWareho simple Data Mart A data structure that is optimized for access. It is designed to using facilitate end-user analysis of data. It typically supports a single, analytic application used by a distinct set of workers. Datawareho 25 using Medium Can a datamart be independent? Yes. Datawareho What are the sources for a 30 using simple datawarehouse? OLTP system, Legacy system, Files, Other sources. 14 DataWareho simple What the difference is between A database is an organized collection of information. using a database, a data warehouse -- A data warehouse is A very large database with special sets of tools and a data mart? to extract and cleanse data from operational systems and to analyze data. -- A data mart is A focused subset of A data warehouse that deals with A single area of data and is organized for quick analysis. 4 DataWareho simple OLAP (On-Line Analytical A method by which multidimensional analysis occurs. using Processing)
  • 48. 5 DataWareho average/simple what do you mean by The ability to manipulate information by a variety of relevant using Multidimensional Analysis? categories or “dimensions” to facilitate analysis and understanding of the underlying data. It is also sometimes referred to as “drilling- down”, “drilling-across” and “slicing and dicing” What is the difference between 42 OLAP, ROLAP, MOLAP ,DOLAP? Difference between OLAP & 40 OLTP? What are the different types of 20 OLAP Medium OLAP? Give an eg. ROLAP eg.BO, MOLAP eg.Cognos, HOLAP, DOLAP MultiDimensional Model. optimized for data warehouse, data mart and Data Which is the suitable data model online analytical processing (OLAP) applications. The main advantage of 24 modelling Medium for a datawarehouse? Why? this database is query performance.7 DataWareho simple Star Schema using
  • 49. 16 DataWareho complex What are Additive Facts? Or what is The fact tables are mostly very huge and almost never fetch a single record using meant by Additive Fact? into our answer set. We fetch a very large number of records on which we then do, adding, counting, averaging, or taking the min or max. The most common of them is adding. Applications are simpler if they store facts in an additive format as often as possible. Thus, in the grocery example, we don’t need to store the unit price. We compute the unit price by dividing the dollar sales by the unit sales whenever necessary.8 DataWareho simple Snowflake Schema An extension of the star schema by means of applying additional using dimensions to the dimensions of a star schema in a relational environment. Datawareho A set of fact tables with some mutual dimension tables is called galaxy 32 using Complex What is Galaxy schema? schema. 36 What is Dimension & Fact ? Confirmed, Degenerate, Junk, Mini, Multivalued, Too-Many, Dirty 41 Different types of Dimensions customer, Demographic mini dimensions Normalizatio Are the dimensional tables 23 n Twisted normalized? If so when? Yes. In snowflake schema, they are normalized. What is Transaction fact table & 37 Centipede Fact table? 38 Different types of Facts? Additive, semi-additive, non-additive What are the types of Factless 48 fact tables? Event tracking & coverage Granularity 43 What is Granularity? The level of detail of the facts stored in a data warehouse. Normalizatio 22 n simple Is the Fact table normalized? Yes12 DataWareho average/simple Can 2 Fact Tables share same Yes using dimensions Tables? Give egs. of the fact, dimensional tables, datamarts/DWH used in Project- your project. Explain what data 21 related Complex each contains. Datawareho 31 using Medium What are fact constellations? Multiple fact tables sharing the dimension tables.
  • 50. 15 DataWareho simple What is a Fact less fact A factless fact table captures the many-to-many relationships between using table ? dimensions, but contains no numeric or textual facts. They are often used to record events or coverage information. ( A fact which does not have any measures ) Common examples of factless fact tables include: o Identifying product promotion events (to determine promoted products that didn’t sell) o Tracking student attendance or registration events o Tracking insurance-related accident events o Identifying building, facility, and equipment schedules for a hospital or University. Datawareho Data that describes data and other structures, such as objects, business 27 using simple What is metadata? rules, and processes.9 DataWareho simple What is data quality? Data quality (information quality) is defined as standardizing and using consolidating customer and/or business data. By cleansing/enhancing the data and combining related records to avoid duplicate entries, you’re able to create a single record view. Within Informatica, this all takes place prior to the initial load to the target database as well as during the on-going data maintenance and updating processes. By Cleansing - The process of resolving inconsistencies and fixing the 28 ETL simple How do you achieve data quality? anomalies in source data, typically as part of the ETL process. 46 What is Parsing & Data Mining. Datawareho System generated, artificial primary keys in alternative to the natural 29 using Medium What are surrogate keys? keys like SSN etc. Datawareho 26 using simple Name a few data modelling tools. Erwin, Embarcedaro, Rational Rose, Oracle Designer. Datawareho 33 using Medium Materialized views? Views storing pre-computed results are called materialized views. Datawareho Can you insert into materialized 34 using Medium views? No. 44 Definition of Adhoc Queries? What is ODS (Operational Data Store), DSS (Decision support System), Data Staging Area, Data 45 Presentation Area.
  • 51. 47 What is Market-Basket analysis?49 DataWareho average/simple SCD Types Type 1 : Keep Most recent Values in Target using Type 2 : Keep a full history of changes in the target Type 3 : Keep the current and previous values in the target.6 DataWareho simple what is a Hypercube? A means of visually representing multidimensional data. using11 DataWareho complex/average Explain the performance Partition, aggregation, indexing.. using improvement techniques in DW? To slice and dice is to break a body of information down into smaller parts or to examine it from different viewpoints so that you can understand it better. This term can be compared to drill down, which is the process of dividing an information area up into finer and finer layers in a hierarchy, but with the Explain slice and dice ? purpose of narrowing in to one small area or item.