Modify xml with namespaces

Question

I'm trying to modify predefined xml (xsd to be more specific) in TSQL. I want to insert enumeration restriction to one of the xsd elements.

The task is to fill xsd restrictions based on a query example:

create table #list(value nvarchar(100))
insert into #list values('item 1')
insert into #list values('item 2')
insert into #list values('item 3')
insert into #list values('item 4')
insert into #list values('item 5')
insert into #list values('item 6')

declare @enumeration as xml
;with xmlnamespaces('http://www.w3.org/2001/XMLSchema' as xs)
select @enumeration = (
    select value as '@value'
    from #list for xml path('xs:enumeration')
)

declare @schema xml
set @schema =
'<xs:schema xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" id="test">
    <xs:element name="test" msdata:IsDataSet="true" msdata:MainDataTable="Example" msdata:UseCurrentLocale="true">
        <xs:complexType>
            <xs:choice maxOccurs="unbounded">
                <xs:element name="Example">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="myList" minOccurs="1" nillable="false">
                                <xs:simpleType>
                                    <xs:restriction base="xs:string">
                                        <xs:maxLength value="50" />
                                    </xs:restriction>
                                </xs:simpleType>
                            </xs:element>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:choice>
        </xs:complexType>
    </xs:element>
</xs:schema>'

set @schema.modify
    ('insert sql:variable("@enumeration")
    into (//xs:element[@name=''myList'']/xs:simpleType/xs:restriction)[1]')

select @schema

The problem is that code outputs unnecessary xmlns attribute

<xs:enumeration xmlns:xs="http://www.w3.org/2001/XMLSchema" value="item 1" />

Can anyone help ?

Answer 1

It got a bit more ugly than I hoped. Mainly because I can't use sql:variable("@enumeration")/delete-me/node() inside a .modify() .

I assume, that you can modify the generation of the @enumeration , as follows:

CREATE TABLE #list (value nvarchar(100));
INSERT  INTO #list
VALUES  ('item 1');
INSERT  INTO #list
VALUES  ('item 2');
INSERT  INTO #list
VALUES  ('item 3');
INSERT  INTO #list
VALUES  ('item 4');
INSERT  INTO #list
VALUES  ('item 5');
INSERT  INTO #list
VALUES  ('item 6');

DECLARE @enumeration AS xml;
WITH XMLNAMESPACES('http://www.w3.org/2001/XMLSchema' AS xs)
SELECT @enumeration = (
    SELECT value AS '@value'
    FROM #list FOR XML PATH('xs:enumeration'), ROOT('delete-me'), TYPE
);

The idea is to use FOR XML with ROOT , so that the generated namespace is at the unnecessary root element (which can be skipped). Otherwise we would have to recreate the xs:enumeration -elements later.

Two solutions

Use .modify() three times

The idea:

1. We insert everything from @enumeration (with the unnecessary root) somewhere into the other xml
2. We copy the desired content to the right place
3. We delete the no longer needed copy of @enumeration in @schema .

DECLARE @schema xml;
SET @schema = '<xs:schema xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" id="test">
    <xs:element name="test" msdata:IsDataSet="true" msdata:MainDataTable="Example" msdata:UseCurrentLocale="true">
        <xs:complexType>
            <xs:choice maxOccurs="unbounded">
                <xs:element name="Example">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="myList" minOccurs="1" nillable="false">
                                <xs:simpleType>
                                    <xs:restriction base="xs:string">
                                        <xs:maxLength value="50" />
                                    </xs:restriction>
                                </xs:simpleType>
                            </xs:element>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:choice>
        </xs:complexType>
    </xs:element>
</xs:schema>';

SET @schema.modify('insert sql:variable("@enumeration")
    into /');

SET @schema.modify('declare namespace xs="http://www.w3.org/2001/XMLSchema";
insert /delete-me/node()
    into (//xs:element[@name=''myList'']/xs:simpleType/xs:restriction)[1]');

SET @schema.modify('delete /delete-me');

SELECT  @schema;

DROP TABLE #list;

.query() to create @schema

If you can change the part where @schema is created, you can generate @schema directly as .query() from @enumeration :

DECLARE @enumeration AS xml;
WITH XMLNAMESPACES('http://www.w3.org/2001/XMLSchema' AS xs)
SELECT @enumeration = (
    SELECT value AS '@value'
    FROM #list FOR XML PATH('xs:enumeration'), ROOT('delete-me'), TYPE
);

DECLARE @schema xml;
SET @schema = @enumeration.query('<xs:schema xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" id="test">
    <xs:element name="test" msdata:IsDataSet="true" msdata:MainDataTable="Example" msdata:UseCurrentLocale="true">
        <xs:complexType>
            <xs:choice maxOccurs="unbounded">
                <xs:element name="Example">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="myList" minOccurs="1" nillable="false">
                                <xs:simpleType>
                                    <xs:restriction base="xs:string">
                                        <xs:maxLength value="50" />
                                        {/delete-me/node()}
                                    </xs:restriction>
                                </xs:simpleType>
                            </xs:element>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:choice>
        </xs:complexType>
    </xs:element>
</xs:schema>');

SELECT  @schema;

Answer 2

You can do a simple string replace if the xml isn't too big:

DECLARE @schemaVARCHAR (MAX)
SET @schemaVARCHAR = CAST(@schema AS VARCHAR(MAX))
SET @schemaVARCHAR = 
    REPLACE(
        @schemaVARCHAR, 
        '<xs:enumeration xmlns:xs="http://www.w3.org/2001/XMLSchema" value="item 1" />',
        ''
    )

SET @schema = CAST(@schemaVARCHAR AS XML)

Answer 3

If your XML isn't too complicated, why not use FOR XML EXPLICIT instead?

Another workaround would be to get generate the XML without the namespace and then add it in afterwards.