Description:
------------
I did not see any mention of the lack of simple type restriction/facet enforcement in SDO DAS XML in the php documentation so I am assuming this is a bug.

Page 13 of SDO 2.1 Spec:

If a client sends a modified data graph to a DAS, (the original DAS or a different one), then the
DAS will check the data graph for errors. These errors include lack of closure of the data graph,
values outside the lower and upper bounds of a property, choices spanning several properties or
DataObjects, deferred constraints, or any restrictions specific to the DAS (for example, XML
Schema specific validations). Closure means that any DataObject references, made within the
graph of DataObjects, point to a DataObject that is in the graph. Usually, the DAS will report
update problems by throwing exceptions.

Reproduce code:
---------------
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">

<xsd:element name="request" type="requestType"/>

<xsd:complexType name="requestType" abstract="true"/>

<xsd:complexType name="collectionInfo">
  <xsd:complexContent>
    <xsd:extension base="requestType">
      <xsd:sequence minOccurs="0" maxOccurs="unbounded">
        <xsd:element name="collection">
          <xsd:simpleType>
            <xsd:restriction base="xsd:token">
              <xsd:minLength value="2"/>
              <xsd:maxLength value="2"/>
            </xsd:restriction>
          </xsd:simpleType>
        </xsd:element>
      </xsd:sequence>
      <xsd:attribute name="kind" type="xsd:string" fixed="collectionInfo"/>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="request-list">
  <xsd:complexType>
     <xsd:sequence>
        <xsd:element ref="request" minOccurs="0" maxOccurs="unbounded"/>
     </xsd:sequence>
  </xsd:complexType>
</xsd:element>

</xsd:schema>


<?php

try {
	$xmldas = SDO_DAS_XML::create("request.xsd");
	try {
		$doc = $xmldas->createDocument('', 'request-list');
		$rdo = $doc->getRootDataObject();
		$request = $xmldas->createDataObject('', 'collectionInfo');
		$request->collection->insert('Collection data should not be longer or shorter than 2 characters.');
		$request->kind = 'collectionInfo';
		$rdo->request->insert($request);
		print($xmldas->saveString($doc));
	} catch (SDO_Exception $e) {
		print($e);
	}
} catch (SDO_Exception $e) {
	print("Problem creating an XML document: " . $e->getMessage());
}

?>

Expected result:
----------------
Throw an exception (different exceptions depending on restriction?) to enforce restriction/facet.

Actual result:
--------------
Allows any data and totally disregards type and restriction.