A_DB2_LOGIN indicates the user name under which you want to connect to the database system. Not all data sources require a user login name. Those that do may have case requirements. Check your data source documentation to determine if login is case-sensitive.
Example
To connect to the database with the user name MYNAME, you could specify:
A_DB2_LOGIN MYNAME
or
A_DB2_LOGIN myname
in the Acu4GL. There is no default value for this variable. If no login is specified, none is used.