Question

I’ve got two tables.

One is ‘Corporations’ (e.g., one record is for Taco Bell). The index and PK for this table is named ‘Id’.

I’ve got another table: ‘Branches’ (e.g., one record is for Los Angeles). The Branch table has a column named ‘Corporation’. This column should only accept an ‘Id’ value that corresponds with an ‘Id’ in the ‘Corporations’ table.

How do I enforce this? Do I add a constraint? How do I do that?

If I’m barking up the wrong tree, how do I define this relationship between Corporations and Branches?

Answer 1

Add a FOREIGN KEY to Branches that references Corporations.

i.e. in the CREATE TABLE for Branches:

CREATE TABLE Branches (   ...   CorporationId int NOT NULL     CONSTRAINT FOREIGN KEY FK_Branches_Corporations REFERENCES Corporations(Id)   ... )