SQL Server column relationships

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)
  ...
)