Database Connections

Before your program can access any data in a database, it must make a connection to the database.

There are two methods your program can use to connect to a database.

• Explicit connection (recommended method):

  The CONNECT statement is used typically if either of the following is true:

  • The program is designed to access different data sources whose names are not known at compilation time.
  • The program is going to access multiple databases.
• Implicit connection

  This is generally used if your program is only going to connect to one database which is known at compilation time. If you specify the INIT option of the SQL Compiler directive, the compiler inserts a call at the start of the program to automatically connect the program to the data source specified in the DB option of the SQL Compiler directive using the login information specified in the PASS option.

When your application has finished working with a database, the application should disconnect from the database. This is done using the DISCONNECT statement.

If implicit connection is being used, OpenESQL automatically disconnects from the data source when the program terminates.

If you want OpenESQL to perform an implicit disconnect and rollback in the event of abnormal program termination this can be achieved by specifying the INIT=PROT option of the SQL Compiler directive.