Chapter 2 Building an XML model

Defining simple types

You can only define simple types in a model targeted with XSD.

What is a simple type?

A simple type is a data type definition for elements or attributes with text- only content.

A simple type cannot contain elements or attributes.

A simple type is defined by derivation of an existing simple type (built-in data type or derived simple type).

There are three kinds of derivation for a simple type:

Type of derivation

Description

List

The simple type contains a white space-separated list of

 

values of an inherited simple type

Restriction

The simple type has a range of values restricted to a

 

subset of those of an inherited simple type

Union

The simple type contains a union of values of two or

 

more inherited simple types

 

 

For more information on simple type derivations, see section Defining derivations.

Once defined in a model, a simple type can be reused in the definition of an attribute, an element or a complex type.

Example of a simple type in a schema:

XSM User's Guide

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Sybase XML manual Defining simple types, What is a simple type?, Type of derivation Description