EnterpriseDB Clusters and Databases Oracle Tips by Burleson Consulting

A database in EnterpriseDB is much different from a database in Oracle.  In Oracle, a database is all of the data files in an instance.  Many applications may share a database and its data files.  In Oracle, a database is a physical separation of data. 

In EnterpriseDB, a database tends to separate applications rather than data files.  The combination of cluster and database(s) would encompass what we consider a database in Oracle.  This isn’t a one to one comparison though. 

When you first install EnterpriseDB, the installer creates a Cluster using the initdb command:

initdb –D <data_directory>

The initdb command initializes the data directory (where the data for all of your databases will be stored).  You can run this command on an empty server and install a new EnterpriseDB cluster yourself, but it is a much easier process to allow the installer to execute the required steps for you.

After a cluster has been created, you can then create a new database with the CREATE DATABASE command.  The CREATE DATABASE command will create a new sub-directory in your database cluster data directory.  The entire syntax to create a new database is:

CREATE DATABASE <databasename>;

That’s it.  Compare that to creating a database in Oracle.  Creating a database in Oracle is not something to be done lightly (or at a command prompt).  In EnterpriseDB, a database is just a logical separation of data. 

There are a few additional optional parameters to the create database statement.  You can assign an owner different from the OS user executing the command, you can override the default template (template1), you can change the language encoding for the database or you can assign a default tablespace.

When you first use EnterpriseDB after installation, you will have four databases in the database cluster available to you.  The first two, template0 and template1, are template databases that will be used whenever you create a new database (and are created by the initdb command).  The templates are seeded with system required tables, procedural languages, etc.  You will never use, modify or remove these templates (unless you get some expert assistance).

The other two databases are edb and mgmtsvr.  The edb database is the seed database that you will begin with.  This database has a sample set of tables and you can create your own tables and other objects here.  We will use this database for the rest of this book.

The mgmtsvr database supports the Remote DBA Management Server.  You will interact with this database via the Management Server screens. 

You can drop a database using the DROP DATABASE command or by using the dropdb command line utility.  Dropping a database is not recoverable so proceed with caution should you choose to do so.

This is an excerpt from the book "EnterpriseDB: The Definitive Reference" by Rampant TechPress.