DISPLAY UPON ENVIRONMENT-NAME (and VALUE) sets the value of the specified environment variable in the ENVIRONMENT-NAME register.
DISPLAY name UPON ENVIRONMENT-NAME DISPLAY value UPON ENVIRONMENT-VALUE
name and value are alphanumeric Working-Storage data items that is the name and value of an environment variable or configuration variable.
DISPLAY UPON ENVIRONMENT-NAME sets ENVIRONMENT-NAME to the value of the environment variable or configuration variable specified by name. The value of ENVIRONMENT-NAME can be queried with a Format 13 ACCEPT statement.
DISPLAY "DEFAULT-HOST" UPON ENVIRONMENT-NAME DISPLAY "MSSQL" UPON ENVIRONMENT-VALUE
Now, any file operations should go through SQL Server instead of Vision. Note that you can ACCEPT my-value FROM DEFAULT-HOST and get MSSQL back into my-value.