The DBCAREA is originally allocated by the application program and then passed to DBCHINI, where it is cleared and some fields are initialized to their default values. DBCHINI initializes the area for an application.
After initialization, the application program sets appropriate input values in the DBCAREA before each call to the DBCHCL.
When the application program regains control from DBCHCL, it can obtain the appropriate output values from the DBCAREA.