What is an XML model?

An XML model is a tree structure of child elements attached to parent elements. Elements are the basic describing items of an XML model. They can be made of other elements combined in different ways through group particles. Elements are specified by attributes and data types which can be predefined or user-defined. Simple and complex data types can be defined as global (directly linked to the <schema> tag) or local (embedded in an element declaration).

The following table displays the specific objects of an XML model:

 

Tool

Object

Description

 

 

Element

The basic object of an XML model. An element

 

 

 

can contain other elements or attributes

 

 

Group

A group of elements arranged by a group particle.

 

 

 

A group is defined once and reused elsewhere in

 

 

 

the model through references

 

 

Any

Any type of object. Any can only be attached to a

 

 

 

sequence or a choice group particle

 

Attribute

Additional information about an element or a

 

 

 

complex type. An attribute is defined by a built-in

 

 

 

data type or a simple data type

 

Attribute Group

A group of attributes. An attribute group is

 

 

 

defined once and reused elsewhere in the model

 

 

 

through references

 

Simple Type

A simple data type. A simple type is used in the

 

 

 

case of elements or attributes with text-only

 

 

 

content. Only available in a model targeted with

 

 

 

XSD

 

 

Complex Type

A complex data type. A complex type is used to

 

 

 

introduce elements or attributes within an element

 

 

 

declaration. Only available in a model targeted

 

 

 

with XSD

 

 

Sequence

A group particle to arrange a set of elements. A

 

 

 

sequence group particle indicates that elements

 

 

 

must appear at least once in the order of their

 

 

 

declaration

 

 

Choice

A group particle to arrange a set of elements. A

 

 

 

choice group particle indicates that one element

 

 

 

must be chosen among all elements

 

 

All

A group particle to arrange a set of elements. An

 

 

 

all group particle indicates that each element can

 

 

 

appear once or not, in any order

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PowerDesigner

 

 

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Sybase XML manual Tool Object Description, Xsd