The typical database application development life cycle is something like the following:
Deliver a version.
Begin work on the next version.
Perform maintenance on the current version.
Promote changes or deltas to the current version.
Incorporate changes or deltas into the new version.
Repeat the process.
For EDS and 7-Eleven, we had to have a customer signature and scheduled downtime to promote a database application change for any OLTP system. This practice makes good business sense. When OLTP systems run the customer's business, you don't want to make unapproved or unscheduled changes that could result in customer OLTP application downtime, because such downtime could cost the customer real money.
In data warehousing, ...