描述数据模型的好数据模型是什么？

I'm considering a "simple" project, where I can create a datamodel based on an existing database and store this datamodel inside another database. Consider it a meta-datamodel. Basically, I would have a "Database" table, listing the databases and linked to this the "Table" table listing the tables per database. Then a "Fields" table listing all fields per table. And then I need to fit in the keys, constraints and other stuff...I'm considering a "simple" project, where I can