The PFILE (initSID.ora) is a text file that can be maintained using a standard operating system editor. The PFILE is read only during instance startup. If the file is modified, the instance must be shut down and restarted in order to make the new parameter values effective. By default, the PFILE is located in the [...]
Database
Installing Oracle Software
To install Oracle 10g, you can use the Oracle Universal Installer (OUI) , a GUI-based Java tool that has the same look and feel regardless of which software platform you are using to install the software. As part of most Oracle installations, you can also install the Oracle Enterprise Manager (OEM) toolset, which is a graphical system [...]
Background Processes in Oracle
A process on a server is a section of a computer program in memory that performs a specific task. When the Oracle server starts, multiple processes are started on the server to perform various functions as part of the Oracle instance. While a detailed discussion of all Oracle background processes is beyond the scope of [...]
Initialization Parameter Files in Oracle
In order to start an instance and open the database, you must connect as SYSDBA and enter the STARTUP command. The Oracle server will then read the initialization parameter file and prepare the instance according to the initialization parameters contained within. Note: You must have SYSDBA privilege. Entries are specific to the instance being started [...]
Starting up & Opening of Database in Oracle
Given below are the various commands & steps which are used to startup & open the database for accessing it in Oracle. STARTUP Command Behavior Order of precedence: spfileSID.ora Default SPFILE initSID.ora Default PFILE Specified PFILE can override precedence. STARTUP PFILE = $ORACLE_HOME/dbs/initDBA1.ora PFILE can indicate to use SPFILE. SPFILE = /database/startup/spfileDBA1.ora Starting Up [...]
Process Structures in Oracle
Oracle takes advantage of various types of processes: • User process: Started at the time a database user requests connection to the Oracle server • Server process: Connects to the Oracle instance and is started when a user establishes a session User Process A program that requests interaction with the Oracle server • Must first [...]
Oracle Memory Structures
The memory allocated to Oracle includes the following types of data: Data from user reading and writing activity Information about database objects SQL commands Stored procedures and functions Transaction information Oracle program executables This information is stored in three major areas: the System Global Area (SGA), the Program Global Area (PGA), and the Software Code [...]
Logical Storage Structures in Oracle
The Oracle database is divided into increasingly smaller logical units to manage, store, and retrieve data efficiently and quickly. The illustration below shows the relationships between the logical structures of the database: tablespaces, segments, extents, and blocks. Logical Structures : Structures in an Oracle database that a database user would see, such as atable, as opposed [...]
Oracle Server Components
An Oracle server consists of both a database and an instance. In Oracle terminology, database refers to only the physical files on disk. These are the files thatstore the data itself, the database state information in the control file, and the changes made to the data in the redo log files. The term instance refers [...]
OCI (Oracle Call Interface)
OCI (Oracle Call Interface) : A set of library routines that allows a C application on virtually any development platform to easily connect to and process SQL statements against an Oracle database. The OCI routines are called as native C library functions; therefore, no preprocessor is necessary when compiling a C application using OCI. OCI [...]
ODBC/JDBC Drivers
ODBC (Open Database Connectivity) : A set of standards that allow applications that are not dependent on any one specific database to process SQL statements against any database that supports SQL Many tools in the Windows (and Unix) environment can take advantage of a common framework known as ODBC, which stands for Open Database Connectivity. [...]
Third-Party Tools in Oracle
Basic network client connectivity is provided during an Oracle client installation. Starting with release 9, Oracle’s network connectivity package is known as Oracle Net Services. Third-party developers can leverage this functionality in their own applications to provide tools customized for a more specific audience and to provide an additional layer of functionality that may [...]
SQL*Plus Worksheet
Oracle Enterprise Manager (OEM) : A GUI tool that allows access, maintenance, and monitoring of multiple databases or services within a single application. If Oracle Enterprise Manager (OEM) is installed, another variation of SQL*Plus, called SQL*Plus Worksheet, is available to the DBA. Here’s the OEM Login dialog box: SQL*Plus Worksheet supports all the commands that standard [...]
How to Create an Oracle9i Database in a UNIX Environment?
Steps to Create a Database There are six steps to creating a useable database: three steps to create the database and three additional steps to make it usable Set the operating system environment variables ORACLE_HOME, ORACLE_SID, PATH, and LD_LIBRARY_PATH. Edit/Create an initsid.ora parameter file. Execute the CREATE DATABASE command in SQL*Plus. Run the required catalog.sql [...]
