How to implement Auditing/versioning of Table Modifications on PostgreSQL

Question

hi all,

We're implementing a New system using Java/Spring/Hibernate on PostgreSQL. This system needs to make a copy of Every Record as soon as a modification/deletion is done on the record(s) in the Tables(s). Later, the Audit Table(s) will be queried by Reports to display the data to the users.

I was planning to implement this auditing/versioning feature by having a trigger on the table(s) which would make a copy of the modified row(deleted row) "TO" a TABLE called ENTITY_VERSIONS which would have about 20 columns called col1, col2, col3, col4, etc which would store the columns from the above Table(s); However, the problem is that if there is more than 1 Table to be versioned and ONLY 1 TARGET table(ENTITY_VERSIONS) to store all the tables' versions, how do I design the TARGET table ?

OR is it better that there will be a COPY of the VERSION Table for each Table that needs versioning ?

It will be bonus if some pointers towards PostgreSQL Triggers (and associated Stored Procedure ) code for implementing the auditing/versioning can be shared.

P.S : I looked at http://stackoverflow.com/questions/3823/suggestions-for-implementing-audit-tables-in-sql-server and kinda like the answer except I would NOT know what type should OldValue and NewValue be ?

P.P.S : If the Tables use SOFT DELETEs (phantom deletes) instead of HARD deletes, do any of your advice change ?

Answer 1

I would have a copy of each table to hold the versions of that table you wish to keep. It sounds like a bit of a nightmare to maintain and use a global versioning table.

This link in the Postgres documentation shows some audit trigger examples in Postgres.