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What is the difference with or without ON [PRIMARY] - Microsoft SQL / MS SQL Server

Hello what is the difference? Which one should I use? a) CREATE UNIQUE INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid]) WITH DROP_EXISTING ON [PRIMARY] b) CREATE UNIQUE INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid]) WITH DROP_EXISTING Thanks! Andreas...

  1. #1

    Default What is the difference with or without ON [PRIMARY]

    Hello
    what is the difference? Which one should I use?

    a)
    CREATE UNIQUE
    INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid])
    WITH
    DROP_EXISTING
    ON [PRIMARY]


    b)
    CREATE UNIQUE
    INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid])
    WITH
    DROP_EXISTING


    Thanks!
    Andreas


    Andreas Klemt Guest

  2. #2

    Default Re: What is the difference with or without ON [PRIMARY]

    ON [PRIMARY] indicates on which filegroup the index will be created. It can
    be a performance benefit to create the indexes of large tables on different
    filegroups on different disks from the table itself. The Primary filegroup
    is the default filegroup if you noyl have one filegroup, so you can omit
    ON[PRIMARY].

    --
    Jacco Schalkwijk MCDBA, MCSD, MCSE
    Database Administrator
    Eurostop Ltd.


    "Andreas Klemt" <aklemt68hotmail.com> wrote in message
    news:#BcX3a8RDHA.3700tk2msftngp13.phx.gbl...
    > Hello
    > what is the difference? Which one should I use?
    >
    > a)
    > CREATE UNIQUE
    > INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid])
    > WITH
    > DROP_EXISTING
    > ON [PRIMARY]
    >
    >
    > b)
    > CREATE UNIQUE
    > INDEX [uniqueKey] ON [dbo].[companies] ([co_loginname], [groupid])
    > WITH
    > DROP_EXISTING
    >
    >
    > Thanks!
    > Andreas
    >
    >

    Jacco Schalkwijk Guest

  3. #3

    Default Re: What is the difference with or without ON [PRIMARY]

    ON [PRIMARY] simply specifies that the index is created on the primary
    filegroup. When you do not specify this clause it uses the default filegroup
    (which is primary). You can also use a different filegroup & refer it in
    this clause. See more details about files & filegroups in SQL Server Books
    Online.

    --
    - Anith
    ( Please reply to newsgroups only )


    Anith Sen Guest

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