XML (v)-schema validation

SchemaWhat is schema

Schema (Schema) : It acts as a DTD and is used to validate the validity of an XML document, except that it provides more powerful functionality and finer-grained data types than DTDs. In addition, schema can customize the data type.

The schema is also an XML file, and the DTD is not.

Comparison of schema and DTD

　　

Why to Schema

Schema document structure:

For all schema documents, the root element must be called schema. Schemas can contain attributes, such as:

<? XML version= "1.0" ?> <  xmlns:xs= "Http://www.w3.org/2001/XMLSchema"targetnamespace= "http// www.w3school.com.cn "xmlns=" http://www.w3school.com.cn "elementformdefault = "qualified" > ...... </ Xs:schema >

An example of a schema

Create a new DTD file

<?XML version= "1.0" encoding= "UTF-8"?><Xs:schemaXmlns:xs= "Http://www.w3.org/2001/XMLSchema"elementFormDefault= "qualified"attributeFormDefault= "unqualified">    <xs:elementname= "Name"type= "Xs:string"></xs:element>    <xs:elementname= "Health"type= "Xs:int"></xs:element>    <xs:elementname= "Love"type= "Xs:int"></xs:element>    <xs:elementname= "Strain"type= "Xs:string"></xs:element>    <Xs:groupname= "MyGroup" >        <xs:sequence>            <xs:elementref= "Name"></xs:element>            <xs:elementref= "Health"></xs:element>            <xs:elementref= "Love"></xs:element>            <xs:elementref= "Strain"></xs:element>        </xs:sequence>    </Xs:group>
<!--define a composite type--<Xs:complextypename= "Dogtype">        <Xs:groupref= "MyGroup"></Xs:group>    </Xs:complextype>    <xs:elementname= "Dog"type= "Dogtype"></xs:element></Xs:schema>

XML file written according to the DTD above

<?XML version= "1.0" encoding= "UTF-8"?><DogXmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"xsi:nonamespaceschemalocation= "C:\Users\x\Desktop\schema\my3.xsd">    <name>Shinzo Abe</name>    < Health>0</ Health>    < Love>0</ Love>    <Strain>Grass Dog</Strain></Dog>

Data type of Schema

Basic data types

Extended Data types

Other data types

Constraints on data types

Rules

The element type of the schema

Schema element:

Role: Contains the schema usage that has already been defined:<xs:schema> properties: xmlns targetnamespace elementformdefault Attri Buteformdefault

Element elements

Group Element

Attribute elements

attributegroup Elements

Comprehensive case:

Schema

<?XML version= "1.0" encoding= "UTF-8"?><Xs:schemaXmlns:xs= "Http://www.w3.org/2001/XMLSchema"elementFormDefault= "qualified"attributeFormDefault= "unqualified">    <xs:elementname= "Name"type= "Xs:string"></xs:element>    <xs:elementname= "Health"type= "Xs:int"></xs:element>    <xs:elementname= "Love"type= "Xs:int"></xs:element>    <xs:elementname= "Strain"type= "Xs:string"></xs:element>    <Xs:groupname= "MyGroup" >        <xs:sequence>            <xs:elementref= "Name"></xs:element>            <xs:elementref= "Health"></xs:element>            <xs:elementref= "Love"></xs:element>            <xs:elementref= "Strain"></xs:element>        </xs:sequence>    </Xs:group>    <Xs:attributename= "id"type= "Xs:string"></Xs:attribute>    <Xs:attributename= "Color"type= "Xs:string"></Xs:attribute>    <Xs:attributegroupname= "MyAttr">        <Xs:attributeref= "id"></Xs:attribute>        <Xs:attributeref= "Color"></Xs:attribute>    </Xs:attributegroup>    <xs:elementname= "Dog">        <Xs:complextype>                <Xs:groupref= "MyGroup"></Xs:group>                <Xs:attributegroupref= "MyAttr"></Xs:attributegroup>        </Xs:complextype>            </xs:element></Xs:schema>

Xml

<?XML version= "1.0" encoding= "UTF-8"?><DogXmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"xsi:nonamespaceschemalocation= "C:\Users\xx\Desktop\schema\my4.xsd"Color= "Red"ID= "ID01">    <name/>    < Health>10</ Health>    < Love>10</ Love>    <Strain/></Dog>

XML (v)-schema validation