You must tell the runtime system which database to use for your DBMaker file. You accomplish this by setting the configuration variable A_DBM_DATABASE to the exact name that you set up in DBMaker. You can set this variable in your COBOL configuration file if you will be using only one database. This variable is described in section F.4, "Acu4GL for DBMaker Configuration File Variables".
For example, if the database you want to use is:
Testdb
you should add the following line to your configuration file:
A_DBM_DATABASE Testdb
If you do not know the database name in advance, or if you intend to use more than one database, you may set the database name dynamically at runtime. In your COBOL program, you would add code similar to this prior to the statement that opens the file:
SET ENVIRONMENT "A_DBM_DATABASE" TO "Testdb"