mirror of https://gitee.com/bigwinds/arangodb
22 lines
949 B
Markdown
22 lines
949 B
Markdown
DocumentKey {#GlossaryDocumentKey}
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================================================
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@GE{Document Key}: A document key uniquely identifies a document
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in a given collection. It can and should be used by clients when
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specific documents are searched.
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Document keys are stored in the `_key` attribute of documents.
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The key values are automatically indexed by ArangoDB in a collection's
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primary index. Thus looking up a document by its key is regularly a
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fast operation. The `_key` value of a document is immutable once
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the document has been created.
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By default, ArangoDB will auto-generate a document key if no `_key`
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attribute is specified, and use the user-specified `_key` otherwise.
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This behavior can be changed on a per-collection level by creating
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collections with the `keyOptions` attribute.
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Using `keyOptions` it is possible to disallow user-specified keys
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completely, or to force a specific regime for auto-generating the
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`_key` values.
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