Sometimes, the normal approach for adding extra fields to a table will just not do. For example, if you don't really know what the other table is going to be. I came across this challenge some days ago. I was working on my sitemaps extension and wanted to have some nice options to use inside Google Sitemaps. To keep it flexible I didn't want to predefine the tables. So how do we add fields to a table, without actually adding them to a table?

When there are no hooks available to get the job done, it's most of the times possible to extend core and extension classes by using XCLASS. This article will describe the steps that need to be taken to do so.