This routine initializes a database work area for use by future
calls to 'dbxxx' routines.
work_area array allocated by the user for use with the database
length length of the work array in bytes
The exact amount of memory to be allocated depends upon the specific
information being accessed and may be approximated by the following:
6 + 4(# requests) + (max # of bytes expected in reply)
If a NULL is passed for work_area, dbwain will disconnect from the
database and return success.
This function requires the following include files:
dbproc, dbreq, dbrpdb, dbareq, dbrdi, dbrmc, dbget, dbgeti, dbsize