2.1.2.3 [XMLSCHEMA1/2] 3.3.2 XML Representation of Element Declaration Schema Components

V0038:

The specification states the following:

 The XML representation for an element declaration schema component is an <element> element information item. It specifies a type definition for an element either by reference or explicitly, and may provide occurrence and default information. The correspondences between the properties of the information item and properties of the component(s) it corresponds to are as follows:
  
 XML Representation Summary: ... Element Information Item
  
 <element
   abstract = boolean : false
   block = (#all | List of (extension | restriction | substitution))
   default = string
   final = (#all | List of (extension | restriction))
   fixed = string
   form = (qualified | unqualified)
   id = ID
   maxOccurs = (nonNegativeInteger | unbounded)  : 1
   minOccurs = nonNegativeInteger : 1
   name = NCName
   nillable = boolean : false
   ref = QName
   substitutionGroup = QName
   type = QName
   {any attributes with non-schema namespace . . .}>
   Content: (annotation?, ((simpleType | complexType)?, (unique | key | keyref)*))
 </element>

Microsoft SQL Server 2008 R2 and Microsoft SQL Server 2012 vary as follows:

Transact-SQL partially supports this representation. Transact-SQL rejects schemas in which the block or final attribute has repeated values, such as "restriction restriction" and "extension extension".

This variation pertains to XML Schemas [XMLSCHEMA1/2] [XMLSCHEMA2/2] functionality in SQL Server.