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Lee oracle

Lee oracle






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    Lee oracle Lee oracle Presentation Transcript

    • Overview of Oracle Database Lee, JeongKyu (jelee@bridgeport.edu)
    • Part 1. Introduction to Database System  Introduction to Database  History of RDBMS  Entity-Relationship Modeling  Database Language
    • Introduction to Database File-Based Approach  Each program defines and manages its own data  Limitation  Separation and isolation of data  Duplication of data  Data dependence  Incompatibility of files  Fixed queries/proliferation of application program Database Approach  A shared collection of logically related data, designed to meet the information needs of an organization
    •  Database Management System(DBMS)  A software system that enables users to define, create and maintain the database and provides controlled access to database  DDL  DML : procedural, non-procedural  Control : security, integrity, concurrency control, recovery control, user-accessible catalog Components of the DBMS Environment  Hardware - Software - Data - Procedures - People
    •  Advantages of DBMS - Control of data redundancy - Economy of scale - Data consistency - Balance of conflicting requirements - More information from the same amount of data - Sharing of data - Improved data accessibility and responsiveness - Improved data integrity - Increased productivity - Improved security - Improved maintenance through data independence - Enforcement of standards - Increased concurrency - Improved backup and recovery services Disadvantages of DBMS - Complexity, Size, Cost of DBMSs, Additional H/W costs - Cost of conversion, Performance, Higher impact of a failure
    •  Three-Level Database Architecture  External Level The users’ view of the database  Conceptual Level The community view of the database  Internal Level The physical representation of the database on the computer
    •  Functions of a DBMS 1. Data storage, retrieval, and update 2. A user-accessible catalog 3. Transaction support 4. Concurrency control services 5. Recovery services 6. Authorization services 7. Support for data communication 8. Integrity services 9. Services to promote data independence 10. Utility services
    •  Components of a DBMS Programmers Users DBA Application Database Queries Programs Schema DML Query DDL DBMS preprocessor processor compiler Program Database Dictionary object code manager manager Access File methods manager System Database and buffers system catalog
    •  Components of Database Manager Authorization control Integrity Command Query checker processor optimizer Transaction Scheduler manager Data Buffer Recovery Manager manager manager
    • History of RDBMS History of DBMS  1960s - Apollo moon-landing project, GUAM  mid 1960s - IMS by IBM (hierarchical DBMS)  mid 1960s - IDS by GE (network DBMS)  1965 - CODASYL(Conference on Data SYStems Language)  1967 -DBTG(Data Base Task Group)  1970 - E.F.Codd of the IBM Research Lab.  Late 1970s - System R project at IBM  1980s - commercial relational DBMS(DB2, Oracle, Informix..)  Now - OODBMS, ORDBMS
    •  Terminology  Relation : a relation is a table with columns and rows  Attribute : an attribute is a named column of a relation  Domain : a domain is the set of allowable values for one or more attributes  Tuple : a tuple is a row of a relation  Degree : the degree of a relation is the number of attributes it contrains  Cardinality : the cardinality of a relation is the number of tuples it contains  Relational database : a collection of normalized relation
    •  Properties of Relations  The relation has a name that is distinct from all other relation names  Each cell of the relation contains exactly on atomic value  Each attribute has a distinct name  The values of an attribute are all from the same domain  The order of attributes has no significance  Each tuple is distinct; there are no duplicate tuples  The order of tuples has no significance, theoretically
    •  When is a DBMS Relational?  Foundational rules Rule 0 : Foundational rule Rule 12 : Nonsubversion rule  Structural rules Rule 1 : Information representation Rule 6 : View updateing  Integrity rules Rule 3 : Systematic treatment of null values Rule 10 : Integrity independance  Data manipulation rules Rule2 : Guaranteed access Rule 4 : Dynamic online catalog based on the relational model Rule5 : Comprehensive data sublanguage Rule7 : High-level insert, update, delete  Data independence rules Rule8 : Physical data independence Rule 9 : Logical data independence Rule11 : Distribution independence
    • Entity-Relationship Modeling Concepts of the E-R Modeling  Entity Types An object or concept that is identified by the enterprise as having an independent existence  Attributes A property of an entity or a relationship type  Relationship Types A meaningful association among entity types
    •  Normalization  A technique for producing a set of relations with desirable properties, given the data requirements of an enterprise  UNF is a table that contains one or more repeating groups  1NF is a relation in which the intersection of each row and column contains one and only one value  2NF is a relation that is in 1NF and every non-primary-key attribute is fully functionally dependent on the primary key.  3NF is a relation that is in 1NF, 2NF in which no non-primary-key attribute is transitively dependent on the primary key  BCNF is a relation in which every determinant is a candidate key  4NF is a relation that is in BCNF and contains no trivial multi-valued dependency  5NF is a relation that contains no join dependency
    •  Conceptual Database Design  The process of constructing a model of the information used in an enterprise, independent of all physical considerations Logical Database Design  The process of constructing a model of the information used in an enterprise based on a specific data model, but independent of a particular DBMS and other physical considerations. Physical Database Design  The process of producing a description of the implementation of the database on secondary storage; it describes the storage structures and access methods used to archieve efficient access to the data
    • Database Language SQL  1974 - SEQUEL by D.Chamberlin (IBM)  1975 - SQUARE by Boyce (System R project)  1976 - SEQUEL/2 (SQL) by Chamberlin and Boyce)  late 1970 - SQL(Oracle), QUEL(Ingres)  1982 - Relational Database Language(RDL) : ANSI  1987 - ISO standard  1989 - Integrity Enhancement Feature (ISO)  1992 - SQL2(SQL92) : ISO
    •  Advanced SQL  View  Integrity Enhancement Feature  Primary key  Unique  Foreign key  Access Control  Embedded SQL  Host Language Variables  Application Programming Interface  Dynamic SQL
    • Part 2. Understanding Oracle Database  Overview of oracle Database Architecture  Memory Structure  Process Structure  Storage Structure  New Features
    • Overview of Oracle ArchitecturePMON SMON RECO D000 S000 P000 * Total SGA Size : 1700 Mbyte * Fixed Size : Redo Log 70 Kbyte SGA Buffer Shared SQL Area Database Buffer Cashe * Variavle Size : 490 MByte TL-812 4,000,000 KByte 1,200,000 KByte 2,100 KByte DBW0 CKPT LGWR Server Data File Raw Device ARCH USER Archive Log Mode(50M)
    • Memory Structure : Shared Pool Shared Pool  Shared Pool Contents - Text of the SQL or PL/SQL statementLibrary Cache Dictionary Cache - Parsed form of the SQL or PL/SQL statement - Execution plan for the SQL or PL/SQL Shared statements SQL Area - Data dictionary cache containing rows of data dictionary information Control Structures for example:  Library CachePL/SQL Procedures - shared SQL area Character Setand Package Conversion - private SQL area Memory Network Security - PL/SQL procedures and package AttributesControl Structures - control structures : lock and library cache handlesfor examples; and so on ..  Dictionary CacheLocksLibrary - names of all tables and views in the databaseCache handles Reusableand so on ... Runtime - names and datatypes of columns in database tables Memory - privileges of all Oracle users  SHARED_POOL_SIZE
    • Memory Structure :Database Buffer Cache Database Buffer Cache holds copies of data blocks read from disk All users concurrently connected to the system share access to the buffer cache Dirty List LRU List Size = DB_BLOCK_SIZE * DB_BLOCK_BUFFERS SGA Database Buffer Cache Shared Pool Shared SQL Area
    • Memory Structure :Redo Log Buffer Circular buffer containing information about changes made to the database save it redo entry Redo Entries is used when Database Recovery DBWR write contents of Redo Log Buffer to Online Redo Log LOG_BUFFER change vector #1 redo record change vector #1 change vector #1
    • Oracle Processes SNPn SMON PMON RECO LCK0 Pnnn SGA Database Buffer Cache Redo Log Buffer Offline Storage Device Dedicated Snnn Server Process DBWR LGWR ARCHDnnn User Process CKPT Control FilesUsers Redo Log Data Files Files
    • Background Process DBWR (Database Writer) - write all dirty buffers to datafiles - Use a LRU algorithm to keep most recently used blocks in memory - Defers write for I/O optimization  dirty list reaches a threshold length  A process scnas a specifed number of buffer in the LRU without finding free buffer  A time-out occurs  DBWR checkpoint occurs LGWR (Log Writer) - writes redo log entries to disk  Commit occurs  The redo log buffers pool becomes one-third full  DBWR completes cleaning the buffer blocks at a checkpoint  LGWR time-out - A commit confirmation is not issued until the tx has been recorded in the rego log file
    • Cont’d PMON (Process Monitor) - Cleans up abnormally terminated connection - Rolls back uncommited transactions - Releases locks held by a terminated process - Frees SGA resources allocated to the failed processes - Database maintenance SMON (System Monitor) - Performs automatic instance recovery - Reclaims space used by temporary segments no longer in use - Merges contiguous area of free space in the datafile
    • Cont’d CKPT (Check Point) - is enabled by setting the parameter CHECKPOINT_PROCESS=TRUE - If enabled, take over LGWR’s task of updating files at a checkpoint - Updates header of datafiles and control files at the end of checkpoint - More frequent checkpoint reduce recovery time from instance failure - CKPT improve the performance of database with many database files ARCH (Archiver) - Copies redo log files to tape or disk for media failure - Operates only when a log switch occurs - Is optional and is only needed when in ARCHIVELOG mode - May write to a tape drive or to a disk LCKn (Lock), Dnnn (Dispatcher), Snnn (Server), RECO (Recover), Pnnn(Parallel), SNPn(Job Queue), QMNn(Queue Monitor),
    • Server/User Process User Processes - A user process is used when a user runs an application program - Runs the tool/application and is considered the client - Passes SQL to the server process and receives the results Server Processes - A server process must place the data in the database buffer cache - Parce and execute SQL statements - Read data blocks from disk into the shred database buffers of the SGA - Return the results of SQL statements to the user process  Parse : check syntax, security access, object resolution, optimization  Execute : applies the parse tree to the data, perform a physical read and change  Fetch : Passes data to the user (only SELECT)
    • Oracle Files Datafile Redo Log Files Control Files Parameter File Archive File Log File (alert*.log, sqlnet.log, listener.log...) Trace File
    • Storage Architecture Physical storage structures  Data files  Segments  Extents  Blocks Logical storage structures  Tablespaces  Tables / Clusters / Indexes  Rows  Columns
    • Physical Storage Architecture Relationship among Segments, Extents, and Blocks Segment 96K Extent Extent 24K 72K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K 2K Database Blocks
    • Logical Storage Architecture Relationship between tablespaces and datafiles Database System Tablespace USER Tablespace DATA1.ORA DATA2.ORA DATA3.ORA
    • Cont’d Objects stored in tablespaces Tablespace (one or more datafiles) Table Table INDEX INDEX INDEX INDEX INDEX INDEX INDEX INDEX Table INDEX INDEX Database Files Objects (Physical structures associated (stored in tablespace may with only one tablespace) span serveral datafiles)
    • Block Header General Block Information Table Dictionary (Block add, Segment type) Row Dictionary 85 ~ 100 bytes Free Space Table info in Cluster Row info in Block (2 byte per row) Row Data using when New Row Insert or Update (pctfree, pctused) Table or Index Data
    • PCTFREE / PCTUSED PCTFREE PCTUSED 20% Free space 61% Free space PCTFREE = 20 PCTUSED = 40 Insert new row until 80%  Can insert new row when below 60%  When Usage is below 40% (61% Free 20% use when Update space), block is listed in FREELIST
    • ExtentA set of contiguous database blocks within a datafile. Extent are allocated when. - The segment is created (INITIAL EXTENT) - The segments grows (NEXT EXTENT) - The table is altered to allocate extents. Extent are de-allocated when the - The segment is dropped and truncated. - The segment is larger than optimal and contains free extents (for rollback segments only) Each segment is created with at least on extend( initial extent ) ( Rollback segment : 2) ALTER TABLE table_name DEALLOCATE UNUSED
    • Segment a set of one or more extents that contains all the data for a specific type of logical storage structure within a tablespace Data Segment - A collection of extents that holds all of the data for a table or a cluster Index Segment - A collection of extents that holds all of the index data for search optimization on large tables and clusters Rollback Segment - A collection of extents that holds rollback data for rollback, read-consistency, or recovery Temporary segment - A collection of extents that holds data belonging to temporary tables created during a sort operation Bootstrap segment - An extent that contains dictionary definitions for dictionary tables to be loaded when the database is opened.
    • Oracle8 New FeatureVLDB, Warehouse OLTPParallel DML Advanced QueuingParallel Index Scans XA rewriteStar Query Optimization Memory reductionPartitioning Serially reusable memoryParallel Backup/Recovery New OCI InterfaceIncremental Backup Improve Function PerformancePoint-in-time RecoveryObjects Network ComputingObject Relational Database Simple User IntegrationObject Type Simple MaintenanceObject View Simple Development
    • Oracle8i New Features Data Warehousing OLTP Summary management  Publish and subscribe capabilities Analytic function  Database event trigger Hash and Composite Paritioning  Single table hash cluster Resource Management  Object type column in partition table Transportable tablespace  Partitioned index-organized table Functional index, virtual column  Stable optimizer execution plansApplication Development Security Oracle Jserver, VM in Database  Virtual Private Database Java stored procedure, function..  LDAP integration SQLJ: embedded SQL in Java  N-tier authentication/authorization WebDB  SSL and X.509v3, RAIDUS support  Data encrypt, decrypt
    • Oracle 9i - The eBusiness Platform Oracle9i continues Oracle8is focus on the Internet by providing a series of specific capabilities and product bundles targeted at eBusiness environments. In addition, Oracle9i continues to add features and capabilities that extends existing investment in mission-critical infrastructure. Oracle9i has been designed with focus on certain key development areas. Key Infrastructure Area Key Application Area Availability  Internet Contents Management Scalability and Performance  B2B and B2C eBusiness Security  Packaged Application Development Platform  Business Intelligence Manageability Windows2000 Integration
    • Oracle Client/Server Architecture NETWORK Client Server bApplication Client/Server Server/Server Server A Benefit of Client/Server Component - Database S/W work on Server - Only Server upgrade to increase size - Minimize network resource - Minimize Client H/W spec - concurrency, consistency, transparency - concurrency, consistency, transparency
    • SQL*Net What is SQL*Net? - Oracle’s Client/Server middleware product - transparent connection from client tool to DB ( from on DB to another ) - works across multiple network protocol and operation system What is TNS? - Transparent Network Substrate - Oracle’s Network applications to access the underlying network protocols transparently - TNS-based application, Oracle Protocol Adapters, Network software like TCP/IP Configuration File - TNSNAME.ORA ( Client ) - TNSNAV.ORA ( Client ) - SQLNET.ORA ( Client, Server ) - LISTENER.ORA ( Server )
    • Net8Networking Challenge Support large mission-critical client/server, and provide migration path towards distributed object architecture Net8 Focus 1. Scalability : Connection Pooling, Multiplexing(Connection Manager) 2. Manageability : Configuration-free installation option, Centralized client administration, Automated client configuration 3. Security : Oracle Security Server
    • ODBC / oo4o / JDBC ODBC (Open Database Connectivity ) - Provide a way for client program (eg VB, Excel, Access) to access database - is a standardized API, developed according to the specification of the SQL Access Group, than allows one to connect to SQL database oo4o (Oracle Object for OLE) - a middleware product manufactured by Oracle that allows native access to Oracle7 databases from client applications via the Microsoft OLE standard - OLE 2.0 Automation Server, Oracle Data Control, Two C++ Class Library JDBC (Java Database Connectivity ) - a set of classes and interfaces written in Java to allow other Java programs to send SQL statements to a relational database management system - JDBC Thin for Java applets, JDBC OCI for Java application