What is XSD?

XML Schemas express shared vocabularies and allow machines to carry out rules made by people. They provide a means for defining the structure, content and semantics of XML documents.

Explained by w3schools:

XML Schema is an XML-based alternative to DTDs. An XML Schema describes the structure of an XML document. The XML Schema language is also referred to as XML Schema Definition (XSD). In this tutorial you will learn how to read and create XML Schemas, why XML Schemas are more powerful than DTDs, and how to use the XML Schema language in your application.

My tutorials :

3rd party tutorials :

w3schools

Schema Tutorial

Simple Types

Complex Types

Data Types

Other

References

Software and downloads :

General questions and answers :

Common problems and solutions :

Techniques and common solutions:

Project site & reference documentation:

Project website