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Indexes

It is sometimes desirable to add indexes to your data model, whether to optimize queries or add a uniqueness constraint to a field. This is done through the DataObject::$indexes map, which maps index names to descriptor arrays that represent each index. There're several supported notations:

<?php

class MyObject extends DataObject {

    private static $indexes = array(
        '<column-name>' => true,
        '<index-name>' => array('type' => '<type>', 'value' => '"<column-name>"'),
        '<index-name>' => 'unique("<column-name>")'
    );
}

The <index-name> can be an arbitrary identifier in order to allow for more than one index on a specific database column. The "advanced" notation supports more <type> notations. These vary between database drivers, but all of them support the following:

  • index: Standard index
  • unique: Index plus uniqueness constraint on the value
  • fulltext: Fulltext content index

In order to use more database specific or complex index notations, we also support raw SQL as a value in the $indexes definition. Keep in mind that using raw SQL is likely to make your code less portable between DBMSs.

mysite/code/MyTestObject.php

<?php

class MyTestObject extends DataObject {

    private static $db = array(
        'MyField' => 'Varchar',
        'MyOtherField' => 'Varchar',
    );

    private static $indexes = array(
        'MyIndexName' => array(
            'type' => 'index', 
            'value' => '"MyField","MyOtherField"'
        )
    );
}

As of 3.7.0 default_sort fields will automatically become database indexes as this provides significant performance benefits.

API Documentation

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