The NULL issue

The problem concerning NULL not being used in the database has been brought to our attention by some other members of Unity. In Caltrade's blog, he describes some of the issues surrounding the exclusion of NULL.

After I received a few emails from members wanting to know why their lifetime membership had suddenly disappeared, I obviously looked into this problem to see what had caused it. I noticed that Lifetime memberships in D6 were qualified by using NULL to represent the fact that a membership will never expire in the 'DateExpires' column in the ProfileMemLevels table.

The data migration script seems to convert NULL in the corresponding position in the D7 database to a '0000-00-00 00:00:00' which seems to translate as a 'Standard' membership. Once you manually change the membership back to a Lifetime membership via the Admin panel, a new row appears with matching data to the attempt made by the data migration script except that the value in the 'DateExpires' colums now says NULL instead of the '0000-00-00 00:00:00' value.

Please correct me if I am mistaken but this seems to be the opposite problem to what Caltrade has experienced where NULL is not used but actually needed.

In my case, the NULL is automatically inserted into the DateExpires column if you manually change the membership via the admin panel, but not via data migration.

All a bit confusing if you ask me.