An OpenEdge application can access one or more OpenEdge or non-OpenEdge databases simultaneously. The databases can be located on different operating systems using different networking protocols. To access non-OpenEdge databases, you must use the appropriate DataServer, such as DataServer for Oracle. You must connect to a database before you can access it. There are four ways to connect to a database:

• As a command-line argument (connection parameter) when starting OpenEdge
• With the CONNECT statement (in the Procedure Editor or in an ABL—Advanced Business Language—procedure or class)
• With the OpenEdge Data Dictionary or other database administration tools
• Using the auto-connect feature

Note that a multi-user application can simultaneously connect to a database for only as many times as specified in the Number of Users (–n) startup parameter. For information on exceeding this user count, see Connection failures and disruptions. For more information on database connection management, see Startup Command and Parameter Reference and Manage ABL Applications.