unique key based on 2 columns in SQl Server 2008?

Question

is it posible to have SQL Server to have a unique key based on 2 columns?

I can have duplicates in both columns but not at the same time:

MfgID  :   Cu         


        

Answer 1

CREATE TABLE table1(
  MfgID INTEGER NOT NULL,
  CustNum VARCHAR(255) NOT NULL,
  CONSTRAINT unique_1 UNIQUE (MfgID, CustNum)
)

OR

ALTER TABLE table1 ADD CONSTRAINT unique_1 UNIQUE(fgID, CustNum)

Answer 2

Yes, It is called composite primary key.

CREATE TABLE table1(
  MfgID INTEGER NOT NULL,
  CustNum VARCHAR(255) NOT NULL,
  PRIMARY KEY (MfgID, CustNum)
)

Answer 3

CREATE UNIQUE NONCLUSTERED INDEX IX_TableName_MfgID_CustNum ON TableName
(
        MfgID  ,
        Column2
) WITH( IGNORE_DUP_KEY = OFF)