Question

We have table Person(Id, Name, Type) and Role(Id, Name) and a binding M:N table Person_Role(Person_Id, Role_Id) which means “a person can have set of roles”.

All we want to do is to have a UNIQUE constraint in MS SQL 2008 R2 which holds uniqueness of

(Person.Name, Person.Type, Person.SetOfRoles). That is (Jack, 1, {A,B}) and (Jack, 1, {B}) are NOT duplicities.

If we could use Oracle’s pre-insert triggers, it would solve everything.

IMPORTANT UPDATE: We use MS SQL with Entity Framework and we DO NOT have the exact insert SQL command.

Answer 1

You can use INSTEAD OF TRIGGER in Sql Server.

CREATE TRIGGER InsteadTrigger on Role
INSTEAD OF INSERT
AS
BEGIN
  INSERT INTO Role
       -- Your logic goes here
       FROM inserted
END
GO