Various options are available here.
Database cleanup helps you with weeding the databases: deleting records without copies, etc.Customizable Actions is about the customizable statistics visible in the Reporting tab or update requests processed on a regular basis which may be saved here.
Database update is a very important option. It helps you to update the structure of your database when you install a new version of PMB. This process does not involve any risks of data loss.
Tables description as its name suggests displays the tables structure of your database and their properties.
MySQL maintenance allows you to check the integrity of your database namely.
Parameters allow you to customize the general settings of the application, e.g the library address or the weather forecast activation in the OPAC...