To add to/reiterate the above, they use a separate table to store metadata. Whenever you see a situation in a webservice where there is a custom way to store data, it's likely that they either store metadata in a table, store is as a more lose format like JSON or XML, or a combination of both.
In my experience, most services don't make tables on the fly that are meant to hang around, since storing metadata can get you very far.
Comments
To add to/reiterate the above, they use a separate table to store metadata. Whenever you see a situation in a webservice where there is a custom way to store data, it's likely that they either store metadata in a table, store is as a more lose format like JSON or XML, or a combination of both.
In my experience, most services don't make tables on the fly that are meant to hang around, since storing metadata can get you very far.