Upgrade script from v3 to v3.1

[abhishekdelta]

A script that will upgrade an existing Pragyan CMS v3.0 website to Pragyan CMS v3.1. During installation of Pragyan CMS v3.1, there should be an option of whether the user wants to "UPGRADE from v3.0" or "Fresh Install". Incase of Fresh Install, the normal procedure is adopted. In case the user choses UPGRADE, then the user should give information about the database of old v3.0 website. Then the upgrade script will come into action and instead of creating new tables and values, the existing v3.0 database is converted into v3.1 so that the v3.1 cms files can work with them.

It should basically compare the databases of v3.0 and v3.1. The v3.0 table structure should be converted into v3.1 table structure. For new columns in v3.1 that aren't there in v3.0, a default value should be inserted that doesn't conflict with the table properties. Also new tables which are missing in v3.0 have to be created and appropriately populated with values which may be linked to values in some existing table.

After the database changes are done, the normal installation is done, with the only exception being that no new database and tables were created. And when the new website runs, it will already have the pages and modules that existed in v3.0 old version.

This requires knowledge about all the changes in database which have been done between v3.0 and v3.1. Also whenever, a new database change is done for any new feature, then the upgrade script should be appropriated modified. And the same script should be extendible for other upgrade versions.