Sybase XML manual Defining a keyRef constraint, Key general properties, Key fields properties

Models: XML

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Chapter 2 Building an XML model

Key general properties

The General page of a key property sheet displays the following properties:

Property

Description

Name

Name of the key constraint. It must be a no-colon-name (See

 

Glossary)

Code

Code of the key constraint. It must be a no-colon-name

Comment

Descriptive label of the key constraint

Stereotype

Sub-classification used to extend the semantics of an object

 

without changing its structure. It can be predefined or user-

 

defined

ID

ID of the key constraint. Its value must be of type ID and

 

unique within the model containing the key constraint

Selector (XPath)

An XML Path Language expression that selects a set of

 

elements across which the values specified in the Fields page

 

must be unique. There must be one and only one selector

 

 

For more information on Selector or XPath, see section Defining an identity constraint selector.

Key fields properties

The Fields page of a key property sheet displays a list of XPath expressions.

If there is more than one field (or XPath expression), the combination of fields must be unique.

For more information on XPath expressions, see section Defining an identity constraint selector.

Defining a keyRef constraint

A keyRef constraint specifies that an element or attribute value (or set of values) corresponds to the value of a specified key or unique constraint.

A keyRef is a reference to a key or a unique constraint.

XSM User's Guide

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Page 79
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Sybase XML manual Defining a keyRef constraint, Key general properties, Key fields properties