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XML Schema key Element

Definition and Usage

The key element specifies that the attribute or element value (or set of values) must be a key within the specified scope. The scope of the key is the containing element in the instance document. A key implies that the data should be unique, non-null, and always present within the specified scope.

The key element must contain the following elements in order:

Element Information

Syntax

(? symbol declares that the element can appear zero or one time, + symbol declares that the element must appear one or more times.)

Attribute Description
id Optional. Specifies a unique ID for the element.
name Required. Specifies the name of the key element.
any attributes Optional. Specifies any other attributes with non-schema namespaces.
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