Release 10.1A: OpenEdge Development:
Programming Interfaces

Creating dynamic 4GL objects from XML Schema

Both the READ-XML() and READ-XMLSCHEMA() methods can take an XML Schema and create a temp-table or ProDataSet definition from it.

The READ-XML() method can find and use XML Schema from the following sources, in the order defined below:

  1. The XML Schema specified with the schema-location option of the READ-XML() method. If this option is used, XML Schema references embedded in XML data are ignored.

  2. A <schema> child element of the root element of the XML data document. Provided the method does not specify a schema-location, then any one or combination of this and the remaining list item are used.

  3. An xsi:schemaLocation or xsi:noNamespaceSchemaLocation attribute on an instance data in the XML data document.

In the following example, the READ-XMLSCHEMA() method will produce a temp-table named Person with fields name, height, weight, and gender. 

       <xsd:schema 
       <!-- namespace declarations go here --> 
<xsd:element name="Person"> 
         <xsd:complexType> 
           <xsd:sequence> 
             <xsd:element name="PersonRow" minOccurs="0" maxOccurs="unbounded"> 
               <xsd:complexType> 
                 <xsd:sequence> 
                   <xsd:element name="name" type="xsd:string" nillable="true"/> 
                   <xsd:element name="height" type="xsd:int" nillable="true"/> 
                   <xsd:element name="weight" type="xsd:int" nillable="true"/> 
                 </xsd:sequence> 
                 <xsd:attribute name="gender" type="xsd:string"/> 
               </xsd:complexType> 
             </xsd:element> 
            </xsd:sequence> 
           </xsd:complexType> 
         </xsd:element> 
       </xsd:schema>

In the next example, the READ-XMLSCHEMA() method produces a ProDataSet named dsGarden with two temp-tables: one for holding information about the plots in the garden and another for holding information about vegetables in the garden. 

<?xml version="1.0"?> 
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="" 
xmlns:prodata="urn:schemas-progress-com:xml-prodata:0001"> 
  <xsd:element name="dsGarden" prodata:proDataSet="true"> 
    <xsd:complexType> 
      <xsd:sequence> 
        <xsd:element name="ttPlots" minOccurs="0" maxOccurs="unbounded"> 
          <xsd:complexType> 
            <xsd:sequence> 
              <xsd:element name="plotId" type="xsd:int" nillable="true"/> 
              <xsd:element name="plotDesc" type="xsd:string" nillable="true"/> 
              <xsd:element name="isFallow" type="xsd:boolean" nillable="true"/> 
            </xsd:sequence> 
          </xsd:complexType> 
        </xsd:element> 
        <xsd:element name="ttVeggies" minOccurs="0" maxOccurs="unbounded"> 
          <xsd:complexType> 
            <xsd:sequence> 
              <xsd:element name="veggieId" type="xsd:int" nillable="true"/> 
              <xsd:element name="veggieDesc" type="xsd:string" nillable="true"/> 
              <xsd:element name="plotId" type="xsd:int" nillable="true"/> 
            </xsd:sequence> 
          </xsd:complexType> 
        </xsd:element> 
      </xsd:sequence> 
    </xsd:complexType> 
  </xsd:element> 
</xsd:schema>

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