The EM tools
◦Can turn the entity model into program classes
◦Can turn the entity model into database schema
◦Or turn database schema into an entity model
◦Or turn a set of classes into an entity model
Pizza Shop is simple
enough to be specified by database schema + one execution of tool
For complex systems, you
need to work with the XML mapping files to get the full use
of these systems today. (JPA uses source annotations instead of XML mapping files)
Luckily, only elementary XML is needed, let’s
look at some files…