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5 Replies Latest reply: Feb 10, 2013 7:36 PM by jeneesh RSS

Clustered vs Non clustered index when used?

800839 Newbie
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Hi,

When we need to go for a clustered index and when to go for a non clustered index? Whether Oracle supports clustered index?
Any examples are highly appreciated.

Thanks.
  • 1. Re: Clustered vs Non clustered index when used?
    jeneesh Guru
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    read at AskTom
  • 2. Re: Clustered vs Non clustered index when used?
    damorgan Oracle ACE Director
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    Tom's explanation refers to an Oracle cluster which has precisely nothing in common with anything in SQL Server ... the Microsoft does not have cluster objects.

    Cluster Index in SQL Server is equivalent, in Oracle, to an Index Organized Table (IOT).
    To quote a SQL Server doc:
    At the most basic level, a clustered index provides order to a table because the data is stored based on the clustered index columns.
    The IOT is far more valuable a construct due to the many storage enhancements Oracle provides.

    Note to the community: Do not assume because Oracle and Microsoft use the same word there is any relationship between their definitions. Basic words like "database", "instance", and "cluster" do not correspond. If you do not know both products ... do not assume identical or similar functionality. The most appalling non-similarity is between two products named "Enterprise Edition." SQL Server Enterprise Edition can barely be compared to Oracle's Standard Edition: It is most comparable to Oracle SE One. You can build a RAC cluster with Oracle Standard Edition for free. You can't build one with SQL Server with all of Bill Gates', Paul Allen's, and Steve Ballmer's money combined.
  • 3. Re: Clustered vs Non clustered index when used?
    6363 Guru
    Currently Being Moderated
    797836 wrote:

    When we need to go for a clustered index and when to go for a non clustered index? Whether Oracle supports clustered index?
    You have already been told, that In Oracle there is no clustered index. {message:id=10839049}. So no Oracle does not support clustered index.
    Any examples are highly appreciated.
    You want an example of something that does not exist?

    Please post a link to a reference describing an Oracle clustered index.
  • 4. Re: Clustered vs Non clustered index when used?
    Peter Gjelstrup Guru
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  • 5. Re: Clustered vs Non clustered index when used?
    jeneesh Guru
    Currently Being Moderated
    damorgan wrote:
    Tom's explanation refers to an Oracle cluster which has precisely nothing in common with anything in SQL Server ... the Microsoft does not have cluster objects.
    It was my mistake, I was posting from my mobile, and actually wanted to copy this link :http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:4514641276987 - Which is talking about the sybase clustered index concept..

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