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  1. #1

    Cluster or unique index MySql DB?

    Hi men!
    I have one interesting question.
    what is difference between cluster index and unique index? What's better and faster and why?
    Thanks for watching.

  2. #2
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
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    Hanover Germany

    Re: Cluster or unique index MySql DB?

    Victor Nijegorodov

  3. #3
    Join Date
    Aug 2016

    Re: Cluster or unique index MySql DB?

    CLUSTER INDEXES are used to sort and store data rows in the table and they are viewed based on the rows. There can be only one cluster index for one table because the data is stored in the rows in an order. The cluster index does not constraint you from adding non unique key data. but a clustered index key needs to uniquely identify a row, even if it's created on a column containing duplicate entries.

    UNIQUE CLUSTERED INDEX is created only on a column or combination of columns that contains no duplicate data. Since Unique keyword is used to create this index, it constraint the users from adding duplicate data or non unique data.
    Last edited by Claire_Anderson; October 15th, 2016 at 01:03 AM.

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