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Obiee interview questions and answers faq

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Obiee interview questions and answers faq

  1. 1. OBIEE Interview Questions and Answers FAQadminCategories: Business IntelligenceOBIEE Interview Questions and Answers FAQThese questions are related to what previously known as Siebel Analytics is now known asOBIEE i.e Oracle Business Intelligence Enterprise Edition.” Define repository in terms of Siebel Analyticso Repository stores the Meta data information. Siebel repository is a file system ,extensionof the repository file. rpd.o META DATA REPOSITORYo With Siebel Analytics Server, all the rules needed for security, data modeling, aggregatenavigation, caching, and connectivity is stored in metadata repositories.o Each metadata repository can store multiple business models. Siebel Analytics Servercan access multiple repositories” What is the end to end life cycle of Siebel Analytics?o Siebel Analytics life cycle1. Gather Business Requirements2. Identify source systems3. Design ETL to load to a DW if source data doesn’t exist.4. Build a repository5. Build dashboard or use answers for reporting.6. Define security (LDAP or External table…)7. Based on performance, decide on aggregations and/or caching mechanism.8. Testing and QA.” What were you schemas? How does Siebel Architecture works? Explain the threelayers. How do you import sources?o There are five parts of Siebel Architecture.1. Clients2. Siebel analytics Web Server3. Siebel analytics server4. Siebel analytics scheduler5. data sorceso Metadata that represents the analytical Model Is created using the siebel AnalyticsAdministration tool.o Repository divided into three layer1. Physical – Represents the data Sources2. Business – models the Data sources into Facts And Dimension3. Presentation – Specifies the users view of the model;rendered in Siebel answer” If you have 3 facts and 4 dimension and you need to join would you recommendjoining fact with fact? If no than what is the option? Why you won’t join fact to fact?o In the BMM layer, create one logical table (fact) and add the 3 fact table as logical tablesource
  2. 2. ” What is connection pool and how many connection pools did you have in your lastproject?o connection pool is needed for every physical database.o It contains information about the connection to the database, not the database itself.o Can use either shared user accounts or can use pass-through accounts -Use: USER andPASSWORD for pass through .o We can have multiple connection pools for each group to avoid waitin” Purpose of Alias Tableso An Alias table (Alias) is a physical table with the type of Alias. It is a reference to a logicaltable source, and inherits all its column definitions and some properties from the logicaltable source. A logical table source shows how the logical objects are mapped to thephysical layer and can be mapped to physical tables, stored procedures, and selectstatements. An alias table can be a reference to any of these logical table source types.o Alias Tables can be an important part of designing a physical layer. The following is a listof the main reasons to create an alias table:” To reuse an existing table more than once in your physical layer (without having to importit several times)” To set up multiple alias tables, each with different keys, names, or joinso To help you design sophisticated star or snowflake structures in the business model layer.Alias tables are critical in the process of converting ER Schemas to Dimensional Schemas.” How do you define the relationship between facts and dimensions in BMM layer?o Using complex join ,we can define relationship between facts and dimentions in BMMlayer.” What is time series wizard? When and how do you use it?o We can do comparison for certain measures ( revenue.,sales etc.. ) for current year vsprevious year, we can do for month or week and day alsoo Identify the time periods need to be compared and then period table keys to the previoustime period.o The period table needs to contain a column that will contain “Year Ago” information.o The fact tables needs to have year ago totals.o To use the “Time series wizard”. After creating your business model right click thebusiness model and click on “Time Series Wizard”.o The Time Series Wizard prompts you to create names for the comparison measures thatit adds to the business model.o The Time Series Wizard prompts you to select the period table used for the comparisonmeasureso Select the column in the period table that provides the key to the comparison period. Thiscolumn would be the column containing “Year Ago” information in the period table.o Select the measures you want to compare and then Select the calculations you want togenerate. For ex: Measure: Total Dollars and calculations are Change and Percent change.o Once the Time series wizard is run the output will be:a) Aliases for the fact tables (in the physical layer)b) Joins between period table and alias fact tablesc) Comparison measuresd) Logical table sources
  3. 3. o In the General tab of the Logical table source etc you can find “Generated by Time SeriesWizard” in the description sectiono Then you can add these comparision measures to the presentation layer for your reports.o Ex: Total sales of current qtr vs previous qtr vs same qtr year ago” Did you create any new logical column in BMM layer, how?o Yes. We can create new logical column in BMM layer.o Example: Right click on fact table -new lgical column-give name for new logical columnlike Total cost.o Now in fact table source,we have one option column mapping, in that we can do allcalculation for that new column.” Can you use physical join in BMM layer?o yes we can use physical join in BMM layer.when there is SCD type 2 we need complexjoin in BMM layer.” Can you use outer join in BMM layer?o yes we can.When we are doing complex join in BMM layer ,there is one option type,outerjoin is there.” What are other ways of improving summary query reports other than AggregateNavigation and Cache Management” Indexes” Join algorithm” Mat/view query rewrite” Web proper report design its optimal by making sure that it is not getting any additioncolumn or rows” What is level-base matrics?o Leval-base matrics means, having a measure pinned at a certain level of the dimension.For Example, if you have a measure called “Dollars”, you can create a “Level BasedMeasure” called “Yearly Dollars” which (you guessed it) is Dollars for a Year. This measurewill always return the value for the year even if you drill down to a lower level like quarter,month… etc. To create a level based measure, create a new logical column based on theoriginal measure (like Dollars in the example above). Drag and drop the new logical columnto the appropriate level in the Dimension hierarchy (in the above example you will drag anddrop it to Year in Time Dimo A LBM is a metric that is defined for a specific level or intersection of levels.o Monthly Total Sales or Quarterly Sales are the examples.o You can compare monthly sales with quarterly sales. You can compare customer ordersthis quarter to orders this year” What is logging level?Where can you set logging levels?o You can enable logging level for individual users; you cannot configure a logging level fora group.o Set the logging level based on the amount of logging you want to do. In normaloperations, logging is generally disabled (the logging level is set to 0). If you decide toenable logging, choose a logging
  4. 4. o level of 1 or 2. These two levels are designed for use by Siebel Analytics Serveradministrators.o Set Logging Level1. In the Administration Tool, select Manage > Security.2. The Security Manager dialog box appears.3. Double-click the user.s user ID.4. The User dialog box appears.5. Set the logging level by clicking the Up or Down arrows next to the Logging Level field” What is variable in sieble?o You can use variables in a repository to streamline administrative tasks and modifymetadata content dynamically to adjust to a chainging data environment.The AdministrationTool includes a Variable Manager for defining variables” What is system variable and non system variable?o System variableso System variables are session variables that the Siebel Analytics Server and SiebelAnalytics Web use for specific purposes. System variables have reserved names, whichcannot be used for other kinds of variables (such as static or dynamic repository variables,or for nonsystem session variables).o When using these variables in the Web,preface their names with NQ_SESSION. Forexample, to filter a column on the value of the variable LOGLEVEL set the filter to theVariable NQ_SESSION.LOGLEVEL.o Nonsystem variables.o A common use for nonsystem session variables is setting user filters. For example, youcould define a nonsystem variable called SalesRegion that would be initialized to the nameof the user.s sales region. You could then set a security filter for all members of a group thatwould allow them to see only data pertinent to their region.o When using these variables in the Web, preface their names with NQ_SESSION. Forexample, to filter a column on the value of the variable SalesRegion set the filter to theVariable NQ_SESSION.SalesRegion.” What are different types of variables? Explain each.o There are two classes of variables:1. Repository variables2. Session variables.Repository variables.A repository variable has a single value at any point in time. There are two types ofrepository variables:static : This value persists, and does not change until a Siebel Analytics Serveradministrator decides to change it.dynamic:The values are refreshed by data returned from queries. When defining a dynamicrepository variable, you will create an initialization block or use a preexisting one thatcontains a SQL query. You will also set up a schedule that the Siebel Analytics Server willfollow to execute the query and periodically refresh the value of the variable.Session VariablesSession variables are created and assigned a value when each user logs on. There are twotypes of session variables:
  5. 5. 1.system2.nonsystem.” What are the cache management? Name all of them and their uses. For Eventpolling table do u need the table in your physical layer?o Monitoring and managing the cashe is cache management.There are three ways to dothat.o Disable caching for the system.(INI NQ config file), Cashe persistence time for specifiedphysical tables and Setting event polling table.o Disable caching for the system.(INI NQ config file :You can disable caching for the whole system by setting the ENABLE parameter to NO inthe NQSConfig.INI file and restarting the Siebel Analytics Server. Disabling caching stopsall new cache entries and stops any new queries from using the existing cache. Disablingcaching allows you to enable it at a later time without losing any entries already stored inthe cache.o Cashe persistence time for specified physical tables :You can specify a cachable attribute for each physical table; that is, if queries involving thespecified table can be added to the cache to answer future queries. To enable caching for aparticular physical table, select the table in the Physical layer of the Administration Tool andselect the option Make table cachable in the General tab of the Physical Table propertiesdialog box. You can also use the Cache Persistence Time settings to specify how long theentries for this table should persist in the query cache. This is useful for OLTP data sourcesand other data sources that are updated frequently, potentially down to every few seconds.o Setting event polling table :Siebel Analytics Server event polling tables store information about updates in theunderlying databases. An application (such as an application that loads data into a datamart) could be configured to add rows to an event polling table each time a database tableis updated. The Analytics server polls this table at set intervals and invalidates any cacheentries corresponding to the updated tables.o For event polling table ,It is a standalone table and doesn’t require to be joined with othertables in the physical layer” What is Authentication? How many types of authentication.o Authentication is the process by which a system verifies, through the use of a user ID andpassword, that a user has the necessary permissions and authorizations to log in andaccess data. The Siebel Analytics Server authenticates each connection request it receives.” Operaing system autentication” External table authentication” Database authentication” LDAP authentication” What is object level security?o There are two types of object level security: Repository level and Web levelo Repository level : In presention layar we can set Repository level security by givingpermission or deny permission to users/groups to see particular table or column.o web level:thisprovides security for objects stored in the siebel anlytics web catlog,suchas dashboards,dashboards pages,folder,and reportsyou can only view the objects for which
  6. 6. you are authorized. For example,a mid level manager may not be granted access toa dashboard containing summary information for an entire department.” What is data level security?o This controls the type an amount of data that you can see in a report.When multiple usersrun the same report the results that are returned to each depend on their access rights androles in the organization.For example a sales vice president sees results for alll regions,while a sales representative for a particular region sees onlu datafor that region.” What is the difference between Data Level Security and Object Level Security?o Data level security controls the type and amount of data that you can see in areports.Objectlevel security provides security for objects stored in the siebel analytics webcatlog, like dashboards,dashboards pages,folder,and reports.” How do you implement security using External Tables and LDAP?o Instead of storing user IDs and passwords in a Siebel Analytics Server repository, you canmaintain lists of users and their passwords in an external database table and use this tablefor authentication purposes. The external database table contains user IDs and passwords,and could contain other information, including group membership and display names usedfor Siebel Analytics Web users. The table could also contain the names of specific databasecatalogs or schemas to use for each user when querying datao Instead of storing user IDs and passwords in a Siebel Analytics Server repository, you canhave the Siebel Analytics Server pass the user ID and password entered by the user to anLDAP(Lightweight Directory Access Protocol ) server for authentication. The server usesclear text passwords in LDAP authentication. Make sure your LDAP servers are set up toallow this.” If you have 2 fact and you want to do report on one with quarter level and the otherwith month level how do you do that with just one time dimension?o Using levelbase matrics.” Did you work on a stand alone Siebel system or was it integrated to otherplatforms?o Deploying the Siebel analytics platform without other Siebel applications is called Siebelanalytics Stand -Alone .If your deployment includes other siebel Analytics Application itcalled integrated analytics -You can say Stand-Alone siebel analytics” How to sort columns in rpd and web?o Sorting on web column, sort in the rpd its sort order column” If you want to create new logical column where will you create (in repositoryor dashboard) why?o I will create new logical column in repository.because if it is in repository,you can use forany report.If you create new logical column in dashboard then it is going to affect on thosereports ,which are on that can not use that new logical column for otherdashboard(or request)
  7. 7. ” What is complex join, and where it is used?o we can join dimention table and fact table in BMM layer using complex join.when there isSCD type 2 we have to use complex join in Bmm layer.” If you have dimension table like customer, item, time and fact table like sale and ifyou want to find out how often a customer comes to store and buys a particular item,what will you do?o write a query as “SELECT customer_name, item_name, sale_date, sum(qty) FROMcustomer_dim a, item_dim b, time_dim c, sale_fact d WHERE d.cust_key = a.cust_keyAND d.item_key = b.item_key AND d.time_key = c.time_key GROUP BY customer_name,item_name, sale_date”” You worked on standalone or integrated system?o Standalone.” If you want to limit the users by the certain region to access only certain data, whatwould you do?o using data level security.o Siebel Analytics Administrator: go to Manage -> Security in left hand pane u will find theuser, groups, LDAP server, HierarchyWhat you can do is select the user and right click and go to properties, you will find two tabsnamed as users and logon, go to user tab and click at permission button in front of username you have selected as soon as u click at permission you will get a new window withuser group permission having three tabs named as general ,query limits and filter and youcan specify your condition at filter tab, in which you can select presentation table,presentation columns ,logical table and logical columns where you can apply the conditionaccording to your requirement for the selected user or groups.” If there are 100 users accessing data, and you want to know the logging details ofall the users, where can you find that?o To set a user.s logging level1. In the Administration Tool, select Manage > Security.The Security Manager dialog box appears.2. Double-click the user.s user ID. The User dialog box appears.3. Set the logging level by clicking the Up or Down arrows next to the Logging Level field” How do implement event polling table?o Siebel Analytics Server event polling tables store information about updates in theunderlying databases. An application (such as an application that loads data into a datamart) could be configured to add rows to an event polling table each time a database tableis updated. The Analytics server polls this table at set intervals and invalidates any cacheentries corresponding to the updated tables.” Can you migrate the presentation layer only to different servero No we can’t do only presentation layer. And ask him for more information and use one ofthe above answerso Create a ODBC connection in the different serve and access the layer.o Copy the Rpd and migrate it to other server
  8. 8. ” Define pipeline. Did you use it in your projects?o Yes, pipelines are the stages in a particular transaction. assessment, finance etc.” How do you create filter on repository?o Where condition on content tab.” How do you work in a multi user environment? What are the steps?o Create a shared directory on the network for Multi-user Development (MUD).o Open the rpd to use in MUD. From Tools->Options, setup the MUD directory to point tothe above directory.o Define projects within the rpd to allow multiple users to develop within their subject area orFacts.o Save and move the rpd to the shared directory setup in point 1.o When users work in the MUD mode, they open the admin tool and start witho MUD ->Checkout to checkout the project they need to work on (not use the File open asyou would usually do).o After completely the development, user checkin the changes back to the network andmerge the changes.” Where are passwords for userid? Ldap,external table authentication storedrespectively?o passwords for userid are in siebel analytics server repository Ldap authentication in Ldapserver external database in a table in external database” Can you bypass siebel analytics server security ?if so how?o yes you can by-pass by setting authententication type in NQSCONFIG file in the securitysection as:authentication_type=bypass_nqs.instanceconfig.xml and nqsconfig.ini are the 2places” Where can you add new groups and set permissions?o you can add groups by going to manage>security>add new groups> You can givepermissions to a group for query limitation and filter conditions.” what are the things you can do in the BMM layer?o Aggrigation navigation,level base matrics,time series wizard,create new logicalcolumn,comlex join.” what is Ragged hierarchy? and how do u manage ito Ragged Hierarchy is one of the different kinds of hierarchy.o A hierarchy in which each level has a consistent meaning, but the branches haveinconsistent depths because at least one member attribute in a branch level is unpopulated.A ragged hierarchy can represent a geographic hierarchy in which the meaning of eachlevel such as city or country is used consistently, but the depth of the hierarchy varies.o For example, a geographic hierarchy that has Continent, Country, Province/State, andCity levels defined. One branch has North America as the Continent, United States as theCountry, California as the Province or State, and San Francisco as the City. However, thehierarchy becomes ragged when one member does not have an entry at all of the levels.For example, another branch has Europe as the Continent, Greece as the Country, andAthens as the City, but has no entry for the Province or State level because this level is not
  9. 9. applicable to Greece for the business model in this example. In this example, the Greeceand United States branches descend to different depths, creating a ragged hierarchy.” What is the difference between Single Logical Table Source and Multiple LogicalTable Sources?o If a logical table in BMM layer has only one Table as the source table then it is SingleLTS.o If the logical table in BMM layer has more than one table as the sources to it then it iscalled Multiple LTS.o Ex: Usually Fact table has Multiple LTS’, for which sources will be coming from differentPhysical tables.” Can you let me know how many aggregate tables you have in your project? On what basishave you created them?o As per resume justification document” How do you bring/relate the aggregate tables into the Siebel analytics Logicallayer?o One way of bringing the Aggregate Tables into the BMM layer is by bringing them asLogical Table sources for the corresponding Fact table.o This is done by dragging and dropping the aggregate table into the corresponding facttable. After doing that establish the column mappings and the set the aggregation levels.” How do you know which report is hitting which table, either the fact table or theaggregate table?o After running the report, go to “Administration” tab and go to click on “Manage Sessions”.There you can find the queries that are run and in the “View Log” option in the SessionManagement you can find which report is hitting which table.” Suppose I have report which is running for about 3 minutes typically. What is thefirst step you take to improve the performance of the query?o Find the sql query of the report in Admin->manage Session-> run the sql query on toad ->read the explain plan output ->modify the SQL based on the explain plan output” Suppose you have a report which has the option of running on aggregate table.How does the tool know to hit the Aggregate table and for that what the steps youfollow to configure them?o Explain the process of Aggregate navigation” Have you heard of Implicit Facts? If, so what are they?o An implicit fact column is a column that will be added to a query when it contains columnsfrom two or more dimension tables and no measures. You will not see the column in theresults. It is used to specify a default join path between dimension tables when there areseveral possible alternatives.o For example, there might be many star schemas in the database that have the Campaigndimension and the Customer dimension, such as the following stars:” Campaign History star. Stores customers targeted in campaign.” Campaign Response star. Stores customer responses to a campaign.” Order star. Stores customers who placed orders as a result of a campaign.In this example, because Campaign and Customer information might appear in many
  10. 10. segmentation catalogs, users selecting to count customers from the targeted campaignscatalog would be expecting to count customers that have been targeted in specificcampaigns.” To make sure that the join relationship between Customers and Campaigns is through thecampaign history fact table, a campaign history implicit fact needs to be specified inCampaign History segmentation catalog. The following guidelines should be followed increating” segmentation catalogs:” Each segmentation catalog should be created so that all columns come from only onephysical star.” Because the Marketing module user interface has special features that allow users tospecify their aggregations, level-based measures typically should not be exposed tosegmentation users in a segmentation catalog.” What is aggregate navigation? How do you configure the Aggregate tables in SiebelAnalytics?o Aggregate tables store precomputed results, which are measures that have beenaggregated (typically summed) over a set of dimensional attributes. Using aggregate tablesis a very popular technique for speeding up query response times in decision supportsystems.o If you are writing SQL queries or using a tool that only understands what physical tablesexist (and not their meaning), taking advantage of aggregate tables and putting them togood use becomes more difficult as the number of aggregate tables increases. Theaggregate navigation capability of the Siebel Analytics Server, however, allows queries touse the information stored in aggregate tables automatically, without query authors or querytools having to specify aggregate tables in their queries. The Siebel Analytics Server allowsyou to concentrate on asking the right business question; the server decides which tablesprovide the fastest answers.” (Assume you are in BMM layer) We have 4 dimension tables, in that, 2 tables needto have hierarchy, then in such a case is it mandatory to create hierarchies for all thedimension tables?o No, its not mandatory to define hierarchies to other Dimension tables.” Can you have multiple data sources in Siebel Analytics?o Yes.” How do you deal with case statement and expressions in siebel analytics?o use expression builder to create case when…then.. end statement” Do you know about Initialization Blocks? Can you give me an example where youused them?o Init blocks are used for instantiating a session when a user logs in.o To create dynamic variable you have to create IB to write sql statement.” what is query repository tool?o It is utility of Seibel/OBIEE Admin toolo allows you to examine the repository metadata tool
  11. 11. o for example: search for objects based on name,type.o Examine relationship between metadata objects like which column in the presentationlayer maps to which table in physical layer” what is JDK and why do we need it?o Java Development Kit (JDK), A software package that contains the minimal set of toolsneeded to write, compile, debug, and run Java applets.” Oracle doesn’t recommend Opaque Views because of performance considerations,so why/when do we use them?o an opaque view is a physical layer table that consists of select statement. an opaque viewshould be used only if there is no other solution.” Can you migrate the presentation layer to a different server.o No we have to migrate the whole web & rpd files” How do you identify what are the dimension tables and how do you decide themduring the Business/Data modeling?o Dimension tables contain descriptions that data analysts use as they query the database.For example, the Store table contains store names and addresses; the Product tablecontains product packaging information; and the Period table contains month, quarter, andyear values. Every table contains a primary key that consists of one or more columns; eachrow in a table is uniquely identified by its primary-key value or values” Why do we have multiple LTS in BMM layer?What is the purpose?o to improve the performance and query response time.” what is the full form of rpd?o there is no full form for rpd as such, it is just a repository file (Rapidfile Database)” how do i disable cache for only 2 particular tables?o in the physical layer, right click on the table there we will have the option which sayscacheable” How do you split a table in the rpd given the condition. ( the condition given wasBroker and customer in the same table) Split Broker and customer.o we need to make an alias table in the physical layer.” What type of protocol did you use in SAS?o TCP/IP