Hello everyone! I am trying to represent this entity relationship database diagram thanks to XMLDB tool in Moodle.
As you can see, it is a generalisation relation, so the children will have the same id that the father (myactivity) but when I try to represent this in XMLDB the select doesn't give the option to define a field as PK and FK to the main table. First, I define it as primary and then I add a new key but an error appears
The error is : this field is use as a key