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https://github.com/silverstripe/silverstripe-framework
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56 lines
1.6 KiB
Markdown
56 lines
1.6 KiB
Markdown
title: Indexes
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summary: Add Indexes to your Data Model to optimize database queries.
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# Indexes
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It is sometimes desirable to add indexes to your data model, whether to optimize queries or add a uniqueness constraint
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to a field. This is done through the `DataObject::$indexes` map, which maps index names to descriptor arrays that
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represent each index. There're several supported notations:
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:::php
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<?php
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class MyObject extends DataObject {
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private static $indexes = array(
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'<column-name>' => true,
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'<index-name>' => array('type' => '<type>', 'value' => '"<column-name>"'),
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'<index-name>' => 'unique("<column-name>")'
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);
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}
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The `<index-name>` can be an arbitrary identifier in order to allow for more than one index on a specific database
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column. The "advanced" notation supports more `<type>` notations. These vary between database drivers, but all of them
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support the following:
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* `index`: Standard index
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* `unique`: Index plus uniqueness constraint on the value
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* `fulltext`: Fulltext content index
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In order to use more database specific or complex index notations, we also support raw SQL as a value in the
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`$indexes` definition. Keep in mind that using raw SQL is likely to make your code less portable between DBMSs.
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**mysite/code/MyTestObject.php**
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:::php
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<?php
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class MyTestObject extends DataObject {
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private static $db = array(
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'MyField' => 'Varchar',
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'MyOtherField' => 'Varchar',
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);
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private static $indexes = array(
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'MyIndexName' => array(
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'type' => 'index',
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'value' => '"MyField","MyOtherField"'
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)
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);
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}
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## API Documentation
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* [api:DataObject]
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