nStore data in format of XML string in SAP HANA system

In older SAP HANA versions, no XML functions were provided. With HANA 2.0, these two functions are provided- XMLEXTRACT and XMLEXTRACTVALUE for extracting XML string in SAP HANA.

Use of XMLEXTRACT

XMLEXTRACT(<XML_document>, <XPath_query> [,<NamespaceDeclarations>])

Syntax to use −

<XML_document>

Specifies an XML document of type CLOB, NCLOB, VARCHAR, or NVARCHAR.

<XPath_query>

Specifies an XPath expression of type VARCHAR or NVARCHAR.

<NamespaceDeclarations>

Specifies a namespace declaration of type VARCHAR or NVARCHAR.

Description

Returns the matching XML element. The return value is of type VARCHAR/NVARCHAR or CLOB/NCLOB depending on the type given for .

If an XML element is empty (for example, ), then an empty result is returned. If an XML element is not found, then the function returns an error.

SELECT XMLEXTRACT(                        
   '<doc xmlns:ns1="http://namespace1.sap.com" xmlns:ns2="http://namespace2.sap.com">
<ns1:item><ns1:id>1</ns1:id><ns1:name>Box</ns1:name></ns1:item>
<ns1:item><ns1:id>2</ns1:id><ns1:name>Jar</ns1:name></ns1:item>
<ns2:item><ns2:id>3</ns2:id><ns2:name>Table</ns2:name></ns2:item>
</doc>',
   '/doc/ns1:item[2]/ns1:name',
   'xmlns:ns1="http://namespace1.sap.com" xmlns:ns2="http://namespace2.sap.com"'
) FROM DUMMY;

Use of XMLEXTRACTVALUE

XMLEXTRACTVALUE(<XML_document>, <XPath_query> [,<NamespaceDeclarations>])
<XML_document>

Specifies an XML document of type CLOB, NCLOB, VARCHAR, or NVARCHAR.

<XPath_query>

Specifies an XPath expression of type VARCHAR or NVARCHAR.

<NamespaceDeclarations>

Specifies a namespace declaration of type VARCHAR or NVARCHAR.

Description

Returns the text contents of the matching XML element. The return value is of type VARCHAR/NVARCHAR or CLOB/NCLOB depending on the type given for.

If an XML element is empty (for example, ), then an empty result is returned. If an XML element is not found, then the function returns an error.

This function is only supported for single elements of child XML nodes. For example, you can use XMLEXTRACTVALUE to query the and elements in the XML document below, as these are single elements of child nodes. However, you cannot query the or elements of the document, as both of these elements contain multiple child nodes.

<parent>
   <child>
      <name>Tom</name>
      <age>18</age>
   </child>
</parent>