ODBC Programming Considerations
ODBC Driver
The CONNX ODBC driver can be used successfully with off-the-shelf products and by those who wish to write applications that call the driver.
Record Locking
Record locking in RMS, IBM DB2, CICS/VSAM, DBMS, and Oracle database tables is handled automatically based on the type of SQL statement sent to the SQL server. UPDATE and DELETE statements lock the record at the start of the action, and immediately release the lock when complete. SELECT statements do not lock records, but can still read locked records in RMS using the RMS GET REGARDLESS flag.
During the record-locking procedure, a READLOCK is put on all transactions going forward. The application gets the latest copy of the record and prevents other users from modifying the record. It then issues an update and a COMMIT command, after which it retrieves the most recently saved record to make sure it matches.