Relax NG

Definition

Relax NG is an XML Schema language that represents a sort of compromise between the simplicity of DTDs and the complexity of W3C SML Schema.

The language

• RELAX NG exists in two syntactic versions, an XML syntax and a short syntax.

Example

Copied from the Clark and Murato (2001) RELAX NG Tutorial.

Copyright © The Organization for the Advancement of Structured Information Standards [OASIS] 2001. All Rights Reserved.

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Consider a simple XML representation of an email address book: <addressBook> <card> <name>John Smith</name> <email>js@example.com</email> </card> <card> <name>Fred Bloggs</name> <email>fb@example.net</email> </card> </addressBook> The DTD would be as follows: <!DOCTYPE addressBook [ <!ELEMENT addressBook (card*)> <!ELEMENT card (name, email)> <!ELEMENT name (#PCDATA)> <!ELEMENT email (#PCDATA)> ]> A RELAX NG pattern for this could be written as follows: <element name="addressBook" xmlns="http://relaxng.org/ns/structure/1.0"> <zeroOrMore> <element name="card"> <element name="name"> <text/> </element> <element name="email"> <text/> </element> </element> </zeroOrMore> </element>

References

• Clark, James and Murata, Makoto (2001), RELAX NG Tutorial, HTML

• Clark, James and Murata, Makoto (2001), RELAX NG Specification, HTML