XML Diagrams

An XML diagram provides a graphical view of the elements that comprise an XML schema definition in a tree format.

Note: To create an XML diagram in an existing XSM, right-click the model in the Browser and select New > XML Model Diagram. To create a new model, select File > New Model, choose XML Model as the model type and XML Model Diagram as the first diagram, and then click OK.

With the user-friendly graphical interface of PowerDesigner XML Model, you can build an XML diagram and then generate automatically an XSD, a DTD or an XDR file.

The following example shows the diagram of an XSM which models an XML schema for Resume documents:

Right-click a symbol in an XML diagram and select one of these features:

Expand - the hierarchy below a symbol is partially expanded (only the first level).
Expand All - the hierarchy below a symbol is fully expanded (all levels).
Collapse - the hierarchy below a symbol is hidden.
Arrange Symbols- the hierarchy below a symbol is properly displayed.

Note: The Symbol > Group Symbols feature is only available for free symbols in an XML diagram.

If an XML model is too large or too complex, you can create several diagrams to have partial views of the model and focus on certain objects.

For example, the original Resume diagram could be split into five diagrams, corresponding to the five main objects of the model (Main, Contact, Achievement, Description and Address).

The following illustration shows the Achievement sub-diagram:

XML Diagram Objects
PowerDesigner supports all the objects necessary to build XML diagrams.
External Shortcuts (through References and Data Types)
External shortcuts allow you to share objects between different models.
Elements (XSM)
Elements are the basic building blocks of an XML model.
Group Particles (XSM)
An element composed of other elements is a parent element with child elements.
Any Elements (XSM)
Any elements allow you to attach any type of object to a choice or a sequence group particle.
Attributes (XSM)
Attributes are used to give additional information about elements.
Constraints: Keys, Uniques, and KeyRefs (XSM)
Constraints indicate that element values must be unique within their specified scope. Constraints are only available in a model targeted with XSD.
Groups (XSM)
A group of elements is a set of elements arranged by a group particle (all, choice or sequence), which is then referenced in the model by various elements.
Attribute Groups (XSM)
Attribute groups are not supported by XDR.
Simple Types (XSM)
You can only create simple types in a model targeted with XSD.
Complex Types (XSM)
You can only create complex types in a model targeted with XSD.
Derivations: Extensions, Restrictions, Lists and Unions (XSM)
You can use derivations to extend or restrict the values of elements and of simple and complex types.
Annotations (XSM)
Annotations are only available in models targeted with XSD.
Notations (XSM)
Notations allow you to define and process non-XML objects within an XML model.
Entities (XSM)
Entities enable you to include predefined values, external XML or non-XML files in an XML model targeted with a DTD.
Instructions: Import, Include and Redefine (XSM)
Import, Include and Redefine allow you to enrich your XML model with external namespaces, schema files or schema components.
Business Rules (XSM)
A business rule is a rule that your business follows. It is a written statement specifying what an information system must do or how it must be structured. It could be a government-imposed law, a customer requirement, or an internal guideline.