INTRODUCTION TO ORACLE DATABASE ADMINISTRATION Lynnwood Brown System Managers LLC Introduction – Lecture 1 Copyright System Managers LLC 2007 all rights reserved.

INTRODUCTION TO DATABASES Companies have information that must be captured and stored. The information may include: Customer Billing Payroll Product orders Services sold Inventory Bank account Copyright System Managers LLC 2003 all rights reserved.

INTRODUCTION TO DATABASES Types Of Databases Utility companies, banks, and airlines, mail order businesses and pharmacies are examples of companies that may use a database for Online Transaction Processing (OLTP). OLAP database (data warehouse). Data warehouses do not contain mission-critical data and as such do not require response times as quick as OLTP databases. OLAP databases rely on complex queries that must take millions of records into consideration for knowledge discovery. Copyright System Managers LLC 2007 all rights reserved.

INTRODUCTION TO DATABASES Relational Database A relational database allows the definition of data structures, storage and retrieval operations and integrity constraints. In such a database the data and relations between them are organized in tables. A table is a collection of records and each record in a table contains the same fields. Certain fields may be designated as keys, which means that searches for specific values of that field will use indexing to speed them up. Everything within the relational model can be stored in tables. Copyright System Managers LLC 2007 all rights reserved.

RELATIONAL DATABASE VENDORS Several companies have relational database products. These products include: Oracle RDBMS Sybase Informix DB2 (IBM) Microsoft SQL-Server Red Brick Microsoft ACCESS MySQL Copyright System Managers LLC 2007 all rights reserved.

ORACLE PRODUCTS SUMMARY Oracle offers many products The main product is the Relational DataBase Management System. The Oracle RDBMS is based on the research paper “A Relational Model of Data for Large Shared Databanks” written by the IBM mathematician Dr. Ted Codd. Oracle offers several products designed for application development and end user support. Copyright System Managers LLC 2007 all rights reserved.

ORACLE PRODUCT SUMMARY cont.

ORACLE PRODUCTS cont. The Oracle RDBMS is used as a data repository. End user programs communicate with the Oracle RDBMS through Oracle’s communication product NET8. Client applications can be developed using various applications development tools (Visual Basic, PowerBuilder, PRO*C, OCI etc...) Client application software generates SQL and PL/SQL to communicate with the RDBMS. Copyright System Managers LLC 2007 all rights reserved.

Structured Query Language All relational databases use SQL Basic SQL Commands SELECT – To get data from a database table INSERT – To place new data into the database table UPDATE – Modify existing data DELETE – Remove data ALTER – Modify a database objects structure Copyright System Managers LLC 2007 all rights reserved.

THE ORACLE RDBMS ARCHITECTURE The Oracle RDBMS is separated into two distinct parts. The Oracle instance and the Oracle database.

RDBMS ARCHCITECTURE cont. The Oracle instance includes the Oracle background processes (PMON, SMON, DBWR, LGWR, TNSLSNR etc...) and a group of buffers called the System Global Area The database consist of the data files, log files and initialization files that are stored on the disk. The Oracle RDBMS consist of the instance and the database. Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Data files are the physical entity that makes up the logical entity called the tablespace. The database will consist of at least one tablespace called the SYSTEM tablespace. The SYSTEM tablespace contains the data dictionary. User data (tables, views, indexes, synonyms etc..) should never be stored in the SYSTEM tablespace. End users are assigned to a default tablespace. All database objects are stored in a tablespace.

RDBMS ARCHITECTURE cont. Oracle represents tables and indexes as segments. There are four types of Oracle segments. Table, index, temporary and rollback or UNDO segments. Segments consist of extents. Extents consist of data blocks. The finest granularity is the Oracle data block. The Oracle data block size should be some multiple of the operating system block-size. Copyright System Managers LLC 2007all rights reserved.

RDBMS ARCHITECTURE cont. Oracle Data file Layout

RDBMS ARCHITECTURE cont. There are three other types of files. They are log files, control files and initialization files Log files contain data used for database recovery. Control files contain information concerning the database creation and organization. Initialization files contain the database tuning parameters and various database startup parameters. Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Database initialization file (init.ora ########################################### # Cache and I/O ########################################### db_block_size=8192 db_cache_size= sga_max_size= ########################################### # Cursors and Library Cache ########################################### open_cursors=1000 Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Database initialization file (init.ora ########################################### # Diagnostics and Statistics ########################################### background_dump_dest=/u02/oracle/admin/bdump core_dump_dest=/u02/oracle/admin/cdump timed_statistics=TRUE user_dump_dest=/u02/oracle/admin/udump ########################################### # File Configuration ########################################### control_files=("/u02/oracle/oradata/CONTROL01.CTL", "/u02/oracle/oradata/CONTROL02.CTL", "/u02/oracle/oradata/CONTROL03.CTL") Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Database initialization file (init.ora ########################################### # Miscellaneous ########################################### compatible= db_name=10g ########################################### # Network Registration ########################################### instance_name=10g ########################################### # Processes and Sessions ########################################### processes=300 Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Database initialization file (init.ora ########################################### # Sort, Hash Joins, Bitmap Indexes ########################################### sort_area_size= shared_pool_size= ########################################### # System Managed Undo and Rollback Segments ########################################### undo_management=AUTO undo_tablespace=UNDOTBS undo_retention = 900 Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. The Oracle memory structure called the System Global Area contains the various Oracle database buffers. The SGA contains the database buffer cache, redo log buffer, data dictionary cache, the library cache and the sort area. The data dictionary cache and the library cache are often refereed to as the shared pool. Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. Unit for SGA allocation is called a 'Granule' A granule is a unit of contiguous virtual memory Granule size = 4MB if the SGA size is less than 128MB Granule size = 16MB if the SGA size is greater than 128MB The maximum size of the SGA is controlled by the database initialization parameter SGA_MAX_SIZE Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. There are several Oracle processes. There are four main processes are DataBase WRiter, LoG WRiter, System MONitor and Process MONitor. The Oracle communication process TNSLSNR. The ARCH process is used for automatic archiving of redo log files. The CKPT process is used to flush data from the buffers to the data files (checkpoint). Copyright System Managers LLC 2007 all rights reserved.

RDBMS ARCHITECTURE cont. On the Windows Platform: Oracle runs as a single process. The Oracle process will create multiple threads Oracle runs as a Windows service. Various Oracle “keys” are stored in the Windows registry. Copyright System Managers LLC 2007 all rights reserved.

Oracle Single Executable On Windows

Oracle Service On Windows

RDBMS ARCHITECTURE cont. On the UNIX Platform: Oracle executable creates multiple processes. Requires a pre-allocated UNIX memory area to store the SGA. Support for most versions of UNIX and Linux Copyright System Managers LLC 2007 all rights reserved.

Oracle Memory Structure On UNIX

RDBMS ARCHITECTURE SUMMARY Oracle Corporation makes many products. The central product is the RDBMS. Oracle’s RDBMS is divided into two parts. One part is called the instance and the other part is called the database. The instance consist of the various processes and memory structures. The database consist of the data files, log files, control files and the initialization file called init.ora. Copyright System Managers LLC 2007 all rights reserved.