Introduction to XML Schemas

Introduction to XML Schema

XML Schema is an XML-based DTD replacement.

XML Schema describes the structure of an XML document.

The XML Schema language can also be referenced as XSD (XML Schema Definition).

The basics you should have

Before you move on, you need to have a basic understanding of the following:

• HTML / XHTML
• XML and XML namespaces
• A basic understanding of DTD

If you want to learn about these projects first, visit these tutorials on the home page.

What is XML Schema?

The role of XML Schema is to define legitimate building blocks of XML documents, similar to DTDs.

XML Schema:

• Define the elements that can appear in the document
• Define the properties that can appear in the document
• Define which element is a child element
• Defines the order of child elements
• Defines the number of child elements
• Defines whether the element is empty or can contain text
• The data type that defines the elements and properties
• Defines the default values for elements and properties, as well as fixed values

XML Schema is DTD's successor

We think XML Schema will soon replace DTD in most web applications.

The reasons are as follows:

• XML Schema can be extended to meet future needs
• XML Schema is better and more powerful
• XML Schema is written based on XML
• XML Schema supports data types
• XML Schema supports namespaces

XML Schema is the W3C standard

XML Schema became the W3C standard on May 2, 2001.

You can learn more about the XML Schema standard in our W3C Tutorials.

Related tutorials

DTD tutorial