Everyone likes a good story, even one that relates to a database. When you are working with a database that is shared among different users you will eventually see this scene, or perhaps experience it yourself:
You, or someone else, are staring at the computer screen looking at a record that has changed since the last time you looked at it and you mutter to yourself, “Who changed this record? This is not the same as the last time I looked at it!”
An audit log is like looking at a record through time. It will let you trace any changes that have been made on a piece of data in your database. For example, in a contact management system an audit log will let you see address changes over time for a particular person. You can use an audit log in an ordering system to track changes made to each invoice over time. It is also an important tool for determining workflow processes. Remember the old adage, “who what when where why and how”. Who changed this record? What data was changed? When was it changed? Why was it changed?and How? An audit log can tell you all of these things (except probably the “Why”).