Sybase XML manual Unique general properties, Unique fields properties

Models: XML

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Chapter 2 Building an XML model

The UNIQUENUM unique constraint, defined on the project element, specifies that the numEmployee attribute must be unique or null within the employee element

To display a unique property sheet, double-click its name or its icon in the

Browser tree view.

Unique general properties

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

Property

Description

Name

Name of the unique constraint. It must be a no-colon-name

 

(See Glossary)

Code

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

Comment

Descriptive label of the unique 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 unique constraint. Its value must be of type ID and

 

unique within the model containing the unique 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.

Unique fields properties

The Fields page of a unique 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.

XSM User's Guide

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Page 77
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Sybase XML manual Unique general properties, Unique fields properties