depends, we write an inhouse wrapper using perl/ksh that hooks into our PVCS repository and based upon promotion groups (set in PVCS), promotes/moves/compiles code in appropriate databases. We do have dev,acpt,qa,rel databases to promote before any code hits production.

There is no hard an fast rule, but from my experience such practices are developed in-house unless you run a vendor supplied apps in which case you follow your vendor's instructions.

HTH
Raj