The incorrect type for the union element is returned when you run XQuery against XML data that contains the union element in SQL Server 2005

View products that this article applies to.

SYMPTOMS

Consider the following scenario. You specify the value of the xsi:type attribute of a union element. Then, you use XQuery to query against the XML data that contains the union element. In this scenario, the query returns the incorrect type for the union element.

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CAUSE

This problem occurs because the value of the xsi:type attribute of the union element will be the primitive base type of the value. During XML serialization, the primitive base type that is actually set for the value of the xsi:type attribute is returned.

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RESOLUTION

Service pack information

To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2005. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

913089 (http://support.microsoft.com/kb/913089/ ) How to obtain the latest service pack for SQL Server 2005

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Microsoft SQL Server 2005 Service Pack 1.

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MORE INFORMATION

Steps to reproduce the problem

Open SQL Server Management Studio, and then connect to the instance of SQL Server 2005.
Click New Query on the toolbar.

Paste the following code in the query editor, and then press F5.

use master
use master
if (db_id('MyDatabase') is not null)
	drop database MyDatabase
go

create database MyDatabase
go

use MyDatabase
go

CREATE XML SCHEMA COLLECTION unionType AS N'
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
	targetNamespace="MyDatabase" xmlns:tn="MyDatabase">
	
	<xs:simpleType name="myInt">
		<xs:restriction base="xs:integer">
			<xs:maxInclusive value="1000"/>
		</xs:restriction>
	</xs:simpleType>
	
	<xs:element name="s">
		<xs:simpleType>
			<xs:union memberTypes="xs:double tn:myInt"/>
		</xs:simpleType>
	</xs:element>	
</xs:schema>'
go

CREATE TABLE testTable ( PK int identity primary key, xmlCol XML(unionType))
go

insert into testTable values ('<tn:s xmlns:tn="MyDatabase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="tn:myInt">123</tn:s>')

select xmlCol from testTable
go

SELECT xmlCol.query('/') FROM testTable
go

The following is the expected result.

<tn:s xmlns:tn="MyDatabase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="tn:myInt">123</tn:s>
<tn:s xmlns:tn="MyDatabase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="tn:myInt">123</tn:s>

However, the following is the actual result.

<tn:s xmlns:tn="MyDatabase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="tn:myInt">123</tn:s>
<tn:s xmlns:tn="MyDatabase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p1="http://www.w3.org/2001/XMLSchema" xsi:type="p1:decimal">123</tn:s>

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