I am structuring a DB in SQL Server 2017 and I had a question about whether I could do the following in this case:
I have 4 Tables:
The structure is this:
Maestro id , Nombre , Apellido DetalleMaestro id , idMaestro , idSeccion , idSubSeccion <-- este ultimo campo es NOT NULL . Seccion id , Seccion SubSeccion id , SubSeccion
The question is this:
There are two types of sections: one has more subsections - this one we will call A- and the other one will not call us B -
If I have a teacher and this is assigned to section B that does not have subsections,
How can I make the 'SubSection' field NULL only for that specific teacher?
Is it possible to alter the type of the value of a field only for a record?