Joomla! allows multiple users to be logged into the website at once. Some of these users will have privileges for editing existing records in the database. When multiple users attempt to edit the same record in the database conflicts can occur. Consider the following scenario two administrators log into the website and pull up the same record for editing within a few minutes of each other. The first user is making heavy edits and will not be saving the record for at least 20 minutes. The second user pops in, makes a small edit, and saves the record right away. When the first user finally saves the record, it ends up overwriting the second user's work.

To avoid all this, Joomla! has a system that you can use for checking in and checking out records so that only one person can at a time work on a given record. For the system to work correctly, your database table needs to have the columns checked_out and checked_out_time, as jos_critic does. The checked_out...