18.4. DTD and XML Schema

DTD and XML Schema are the grammars to validate whether a XML document is correctly formated when being parsed by a XML parser.

In DTD, data type cannot be defined, and its grammar is not described in XML.

In XML Schema, the syntax is described in XML format, features such as data type definition and namespace handling that not included in DTD are available.

SophiaFramework supports DTD and XML Schema. When DTD or XML Schema is used to parse a XML document, if there is some data that is not regulated by the grammar, error will occur.

Furthermore, when parsing a WSDL document, the XML Schema is prerequisite.

18.4.1. Processing a XML Document with DTD

The processing of a XML document with DTD uses the following functions of SFXXMLDOMParser/SFXXMLSAXParser

Table 18.10. Function of processing XML documents with DTD

Purpose	Function Name of `SFXXMLDOMParser` class	Function Name of `SFXXMLSAXParser` class
Verify XML document by DTD	`SFXXMLDOMParser::SetValidationDTD`	`SFXXMLSAXParser::SetValidationDTD`
Load extended DTD file into XML document with DTD	`SFXXMLDOMParser::SetLoadExternalDTD`	`SFXXMLSAXParser::SetLoadExternalDTD`

	Function of Loading External DTD File
	If DTD is defined as a separate file with the XML document, SetLoadExternalDTD is set to true and DTD file is loaded.

The following operations can be used to get a SFXXMLDocumentType object from the XML tree object.

Table 18.11. Function of Processing DTD file

Function Name	Description
GetEntities	get all the entities declared in DTD
GetNotations	get all the notations declared in DTD
GetPublicID	get the public ID of an external subset
GetSystemID	get the system ID of an external subset

18.4.2. Processing a XML Document with XML Schema

When processing XML documents with XML Schema, use the following functions of SFXXSDDOMParser or SFXXMLSAXParser class

Table 18.12. Function of Processing XML Documents with XML Schema

Purpose	Function Name of `SFXXMLDOMParser` class	Function Name of `SFXXMLSAXParser` class
Proccess XML schema	`SFXXMLDOMParser::SetDoSchema`	`SFXXMLSAXParser::SetDoSchema`
Verify XML document by XML schema	`SFXXMLDOMParser::SetValidationSchema`	`SFXXMLSAXParser::SetValidationSchema`
Invalidate Annotation element of XML document with XML Schema	`SFXXMLDOMParser::SetIgnoreAnnotations`	`SFXXMLSAXParser::SetIgnoreAnnotations`
Specify the XSD file of the XML document with XML Schema	`SFXXMLDOMParser::SetSchemaLocation`	`SFXXMLSAXParser::SetSchemaLocation`

	Function of Setting Namespace
	If SetDoNamespaces is "true", namespace can be set.