This recipe provides different ways to collect changes to data contained in the tables for auditing purposes.
First, you must take the following decisions:
Do you need to audit all changes or only some?
What information about the changes do you need to collect? Only the fact that the data has changed?
When recording the new value of a field or tuple, do you also need to record the old value?
Is it enough to record what user did the change, or do you also need to record the IP address and other connection information?
How secure (tamper-proof) must the auditing information be? For example, does it need to be kept separately, away from the database being audited?
Based on answers to these questions, you can select the right auditing method from the methods we present next.