Recovering databases and maintaining database integrity

• The Basic Checkpoint command, CHKP, which you can use to issue checkpoints from a batch or BMP program
• The Symbolic Checkpoint command, SYMCHKP, which you can use to issue checkpoints from a batch or BMP program and to specify data areas that can be restored when you restart your program
• The Extended Restart command, XRST, which you can use along with symbolic checkpoints to start or restart your batch or BMP program
• The rollback commands, ROLL and ROLB, which you can use to dynamically back out database changes from a batch or BMP program
• The managing-backout-points commands, SETS and ROLS, which you can use to set multiple backout points and then return to these points later
• The Dequeue command, DEQ, which releases previously reserved segments

To use any of the commands, you must have defined an I/O PCB for your program, except for the DEDB DEQ calls, which are issued against a DEDB PCB.