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constrains or forigen key ?

Author

Topic

tsures77
Starting Member

1 Post

Posted - 2011-01-22 : 09:27:11

hi all !
have a newbe question about constrains.
using sql 2000.
i have 2 tables: customer and customerTypes.

customer table has the follwing columns :
1. CustomerID int pk
2. CustomerName varchar
3.CuatomerLastName varchar
4.CustomerType int

customerTypes table has the follwing columns :
1.TypeID int pk
2.TypeName varchar
3.TypeValue int

now ...
i want that in column customer.CustomerType the values can only come from customerTypes.TypeValue where customerTypes.TypeName equals "regular".

shoul i use constarins or just forigen key ?

thanks in advance
hubby

russell
Pyro-ma-ni-yak

5072 Posts

Posted - 2011-01-22 : 09:48:20

A Foreign Key is a constraint. And that is the type of constraint you want.

ALTER TABLE customer
ADD CONSTRAINT FK_Customer_CustomerType Foreign Key (CustomerType)
	References CustomerTypes (TypeID);
GO

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2011-01-24 : 10:41:02

if you want to enforce that where condition also you need to implement this in a trigger or use CHECK constraint utilizing a UDF where you check this.

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SQL Server MVP
http://visakhm.blogspot.com/

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