How to code a simple versioning system?

Question

I want to do a simple versioning system but i don\'t have ideas on how to structure my datas, and my code.

Here is a short example:

1. User logs in
2. U

Answer 1

I recently built a simple versioning system for some static data entities. The requirement was to have an 'Active' version and 0 or 1 'pending' versions.

In the end, my versioned entity had the following attributes relevant to versioning.

VersionNumber (int/long) ActiveVersionFlag (boolean)

Where:-

• only 1 entity can be ActiveVersionFlag = 'Y'
• only 1 entity can be Version number > the 'Active' version (i.e. the 'pending' version)

The kind of operations I allowed were

Clone current version.

• Fail if there is already a version > the Versionnumber of the 'Active' version
• Copy all of the data to the new version
• increment the version number by one

Activate Pending Version

• Fail if the specified version is not the 'Active' version + 1
• find the 'Active' version and set its ActiveVersionFlag to 'N'
• set the ActiveVersionFlag of the 'pending' version to 'Y'

Delete Pending Version

• Delete the Pending Entity

This was reasonably successfull and my users now clone and activate all the time :)

Michael