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Oracle Tips by Burleson

Create and Configuration Database

What the Oracle kernel does when given a CREATE DATABASE command is easy, first the system creates control, redo log, and database files. Next, the system creates the SYSTEM rollback segment in the SYSTEM tablespace, creates and loads data dictionary tables, and mounts and opens the database.

On virtually all platforms you will have a Java-based tool called the Database Configuration Assistant (on UNIX and Linux DBCA in the $ORACLE_HOME/bin directory). This tool will help you create Oracle databases. On NT and W2K, this should be named Database Configuration Assistant and will be in the menu tree - Start -- Programs -- Oracle -- Oracle_home -- Database Administration -- Database Configuration Assistant. Let’s look at an example database creation using the Database Creation Assistant on Linux.

At the Linux command line in the Oracle user at the users’ home directory we type "dbca." The DBCA command will be effective only if the values for PATH and ORACLE_HOME are set correctly. Generally, if you can run the other Oracle utilities, such as SQL*Plus (the command would be sqlplus), you won’t have a problem running DBCA.

The next screen (reached by selecting the Next button on the welcome screen) allows you to choose between several options:

* Create a database.

* Configure database options in a database.

* Delete a database.

* Manage templates.

For this example, we want to create a database. The other options are fairly self-explanatory. In the Oracle9i version of the DBCA, the Manage templates option has been added to allow the DBA to manage the precreated or newly created templates used to create databases. The Configure database options allows the DBA to choose from the available databases and perform reconfiguration of the server mode (dedicate or shared), or the options installed. The Delete database option lists the current instances and allows you to delete from them. We have selected the Create a database option for this example. Its radio button is shown as set in Figure 2.2, the Operations screen.

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