SQL Server Performance Forum – Threads Archive

a composite key or separate P key

I have table A in which I have 3 columns a, b and c all of the columns I have PK and the question is , how its is treated ? a composite key or separate P key ? hsGoswami
[email protected]

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bit confuse
Can you explain this bit more

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It will be ‘composite primary key’.

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Yes, it’s a composite Primary Key —
Frank Kalis
SQL Server MVP
http://www.insidesql.de

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still the question arise will out these keys any of key trated seprately to have relationship with another table (pk & fk )? hsGoswami
[email protected]

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You mean any column in the ‘composite primary key’ set with the other tables primary key. If I understand your question……
Yes you can set the relation.

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Dear Sir,
i am asking i have Table A with 3 column (c1,c2 and c3) is having a composite PK.. and i have another table B for whom i want to create relationship with and in table B i want to build relationship using only c1 from table A as Primary key for table B.
are u getting me sir ? hsGoswami
[email protected]

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If your PK consists of three columns A,B,C all of these columns needs to be in the other table as foreign key to establish a relation. —
Frank Kalis
SQL Server MVP
http://www.insidesql.de

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No, You can not create a relationship, but you can use join in SQL statement. ——————————— if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[Table1]’) and OBJECTPROPERTY(id, N’IsUserTable’) = 1)
drop table [dbo].[Table1]
GO if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[Table2]’) and OBJECTPROPERTY(id, N’IsUserTable’) = 1)
drop table [dbo].[Table2]
GO CREATE TABLE [dbo].[Table1] (
[a1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[b1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[c1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[d1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL
) ON [PRIMARY]
GO CREATE TABLE [dbo].[Table2] (
[c1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[d1] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL
) ON [PRIMARY]
GO ALTER TABLE [dbo].[Table1] WITH NOCHECK ADD
CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
(
[a1],
[b1],
[c1]
) ON [PRIMARY]
GO ALTER TABLE [dbo].[Table2] WITH NOCHECK ADD
CONSTRAINT [PK_Table2] PRIMARY KEY CLUSTERED
(
[c1]
) ON [PRIMARY]
GO

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Thanx sir
now i understand hsGoswami
[email protected]

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