XML·XML from well-formed documents to XSLT

DTD and XSD

Define allowed structure and validate documents against it.

Beginner 13 min read Lesson 4 of 300 Challenge included

What you will be able to do

DTDs are simple but limited.
XSD supports types and namespaces.
Validate at ingestion boundaries.
Schema errors are data errors, not code errors.

In plain English

A DTD is the older, simpler schema language. XSD is typed and supports namespaces, cardinality and datatypes. Validation catches structural errors before code consumes a document.

schema.xsdHTML

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="course">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="title" type="xs:string" />
      </xs:sequence>
      <xs:attribute name="id" type="xs:string" use="required" />
    </xs:complexType>
  </xs:element>
</xs:schema>

Your turn

Make an attribute required

Easy

Set an XSD attribute named id to required.

HTML · starter

<xs:attribute name="id" type="xs:string" />

Check your understanding before moving on.

Knowledge checkQuestion 1

Which schema language supports datatypes and namespaces?

Select an answer to continue

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