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Defining complexTypes in XML Schemas

In an XML Schema, an element that contains only data is a simpleType. Elements with any other contents are complexTypes. (Attributes are always simpleTypes.) The XML Schema Recommendation does not include any built-in complexTypes. You must define each complexType you need.

In the Diagram view, when you define a complexType as a top-level definition, it is a global declaration. You can specify that any element in the schema is of this complexType. Similarly, in the Tree view, it is a global declaration when you define a complexType as a child of the Schema node.


Tip		Define the complexType first. Then when you define an element, Stylus Studio includes your complexType's name in the menu that lists the available types for your new element. You can select the name of the complexType from the menu.

You can also define a complexType in the definition of an element. See Defining Elements That Contain Subelements in XML Schemas.

Stylus Studio takes care of most of the details for you. But as you define a complexType, it is helpful to keep in mind that a complexType node can have only one child node that is a model group modifier. However, this modifier node can have any number of child nodes that are modifiers. In this way, you can specify any number of modifiers in a complexType. Each modifier controls the occurrence of its child nodes. You can specify the same modifier more than once. For example, you might want to specify the sequence modifier, with some child nodes, then the choice modifier with some child nodes, and then the sequence modifier again with other child nodes.

This section discusses the following topics:

Defining complexTypes That Contain Elements and Attributes - Diagram View

Defining complexTypes That Contain Elements and Attributes - Tree View

Defining complexTypes That Mix Data and Elements

Defining complexTypes That Contain Only Attributes

Defining complexTypes That Contain Elements and Attributes - Diagram View

To define a complex type in the Diagram view:

1. Right-click the schema node

2. In the shortcut menu, select Add > ComplexType.

Alternatives: This operation is also available from the XMLSchema > Diagram > Add > ComplexType menu and from the Add button .

The new complexType is added to the XML Schema. It is displayed in the diagram and in the text pane (if you have it open). The properties for the new complexType are displayed in the Properties window.

Adding Nodes to a complexType

Once you have created a complexType, you can further define it by adding sequences, elements, and other nodes. The basic procedure for adding nodes to a complexType is to:

1. Select the node.

2. Use the menus or tool bar to add the node.

3. Fully describe the complexType and its nodes by editing values in the Properties window.

You can use this procedure to add the following nodes to a complexType:

all

annotation

anyAttribute

attribute

attributeGroup

choice

group

sequence

Next steps vary according to the constraints on the elements in the complexType. The following instructions show how to achieve some typical constraints.

Choosing an Element

Suppose you want to define a complexType that contains exactly one element, and that element can be one of several different elements. In XML Schema, you do this by defining xsd:choice.

To define xsd:choice in the Diagram tab:

1. Right-click the icon that represents your new complexType.

2. In the shortcut menu that appears, select Add > Choice.

Alternatives: This operation is also available from the XMLSchema > Diagram > Add > Choice menu and from the Add button .

Stylus Studio displays the choice icon alongside the complexType icon.

3. Right-click the choice icon and select Add > Element, or use the Add button

A element is added to the choice icon.

Figure 252. Defining Choice for a complexType

4. Make sure the new element is selected. In the Properties window, click the Type field.

5. Enter or select the type of the element.

6. Repeat step 3 through step 5 for each element that might be in the complexType.

Including All Elements

Suppose you want to define a complexType that contains a number of elements, the elements can be in any order, and there must be zero or one of each element. In XML Schema, you do this by defining xsd:all.

To define xsd:all in the Diagram tab:

1. Right-click the icon that represents your new complexType.

2. In the shortcut menu that appears, select Add > All.

Alternatives: This operation is also available from the XMLSchema > Diagram > Add > All menu and from the Add button .

Stylus Studio displays the all icon alongside the complexType icon.

3. Right-click the choice icon and select Add > Element, or use the Add button

A element is added to the all icon.

4. Make sure the new element is selected. In the Properties window, click the Type field.

5. Enter or select the type of the element.

6. If the element is required, go to step 7. If the element is optional, click the Min Occur. field in the Properties window, and type a zero (0).

7. If there must always be exactly one of this element, go to step 8. If there can be more than one of this element, click the Max Occur. field in the Properties window, and enter the maximum number allowed or click unbounded in the drop-down list.

8. Repeat step 3 through step 7 for each element that can be in the complexType.

Specifying the Sequence of Elements

Suppose you want to define a complexType that contains a number of elements in a particular order. The default is that each element must appear exactly once. However, some elements are optional, and some elements can appear more than once. In XML Schema, you do this by defining xsd:sequence.

To define xsd:sequence in the Diagram tab:

1. Right-click the icon that represents your new complexType.

2. In the shortcut menu that appears, select Add > Sequence.

Alternatives: This operation is also available from the XMLSchema > Diagram > Add > Sequence menu and from the Add button .

Stylus Studio displays the sequence icon alongside the complexType icon.

3. Right-click the sequence icon and select Add > Element, or use the Add button

A element is added to the sequence icon.

4. Make sure the new element is selected. In the Properties window, click the Type field.

5. Enter or select the type of the element.

6. If the element is required, go to step 7. If the element is optional, click the Min Occur. field in the Properties window, and type a zero (0).

8. Repeat step 3 through step 7 for each element that can be in the complexType.

Reordering Nodes

If you make a mistake in the order in which you specify nodes in your XML Schema (when specifying elements in a sequence, for example), you can rearrange them.

To reorder nodes in the diagram view:

1. Click the node you want to move.

2. Click the Move Up

or Move Down

from the Stylus Studio tool bar until the node is positioned where you want it.

Alternative: This operation is also available from the XMLSchema menu and from the node's shortcut menu.

Combining the Sequence and Choice Modifiers

Suppose you want to define a complexType that contains a number of elements in a particular order, but some of them are optional, and you want to ensure that only one element from a particular group of elements is present. In other words, you need to combine the use of the sequence and choice modifiers. To define this, you must define a sequence modifier first. You can then define sequence and choice modifiers that are children of the initial sequence modifier.

Defining complexTypes That Contain Elements and Attributes - Tree View

The purchaseOrder.xsd sample document contains the following complexType definition. This complexType defines three elements, refers to a fourth element, and defines an attribute.

<xsd:complexType name="PurchaseOrderType"> 
               

              
                <xsd:sequence> 
                   
<xsd:element name="shipTo" type="USAddress"/> 
                   
<xsd:element name="billTo" type="USAddress"/> 
                   
<xsd:element ref="comment" minOccurs="0"/> 
                   
<xsd:element name="items" type="Items"/> 
                   
</xsd:sequence> 
                   
<xsd:attribute name="orderDate" type="xsd:date"/> 
                   

                
              
</xsd:complexType>

In the Tree view, to define a complex type with a similar structure:

1. Click the Schema node.

2. In the left tool bar, click New complexType

. In the Tree view, Stylus Studio displays a field for the new complexType.

3. Type a name for this new complexType and press Enter.

4. In the left tool bar, click New Model Group

. Stylus Studio displays a pop-up menu that lists the group modifiers.

5. Double-click the modifier you want. For a description of each modifier, see Model Group Properties in XML Schemas.

You can specify any number of modifiers in a complexType. Each modifier controls the occurrence of its child nodes. You can specify the same modifier more than once. For example, you might want to specify the sequence modifier, with some child nodes, then the choice modifier with some child nodes, and then the sequence modifier again with other child nodes.

6. For each element that you want to define in this complexType with the selected modifier, perform the following steps:

a. Click the modifier name in the Tree view.

b. In the left tool bar, click New Element Definition

. In the Tree view, Stylus Studio displays a field for the new element definition.

c. Type a name for the new element and press Enter. Stylus Studio displays a pop-up menu that lists the built-in simpleTypes and simpleTypes you defined.

d. Double-click the type for the new element.

e. In the Properties window, you can double-click the field for any property to set the value for that property.

For example, you can specify 0 for the Min Occur. property and 1 for the Max property. The effect is that the element is optional.

7. For each element or group that you want to refer to in this complexType with the selected modifier, perform the following steps:

a. Click the modifier name in the Tree view.

b. In the left tool bar, click New Reference to Element

or New Reference to Group

. Stylus Studio displays a pop-up menu that lists the elements or groups defined in the schema.

c. Double-click the element or group you want to reference.

8. To define an attribute in this complexType:

a. Click the name of the complexType in the Tree view.

b. In the left tool bar, click New Attribute

. In the Tree view, Stylus Studio displays a field for the new attribute.

c. Type a name for the new attribute and press Enter. Stylus Studio displays a pop-up menu that lists the built-in simpleTypes and the simpleTypes you defined in this schema.

d. Double-click the type of the new attribute.

9. To reference an attribute or attributeGroup in this complexType:

a. Click the name of the complexType in the Tree view.

b. In the left tool bar, click New Reference to Attribute

or New Reference to Attribute Group

. Stylus Studio displays a pop-up menu that lists the attributes or attributeGroups defined in the schema.

c. Double-click the attribute or attributeGroup you want to reference.

Defining complexTypes That Mix Data and Elements

Suppose you want to define a complexType that mixes elements and data. For example, you have an XML document with contents such as the following:

<letter>
               

              
                <salutation>
                   
Dear Mr.
                   
<name>Robert Smith</name>
                   
,
                   
</salutation>
                   
Your order of 
                   
<quantity>1 </quantity> 
                   
<productName>Baby Monitor </productName> 
                   
shipped from our warehouse on
                   
<shipDate>2001-04-21</shipDate>
                   
. 
                   

                
              
</letter>

The letter element and salutation element have element and data children. You must define complexTypes for both the letter and the salutation elements. Their Mixed property value must be set to true. The Mixed property is the one that allows an element to contain both elements ( <shipDate>, for example) and raw data ( Dear Mr. for example) as children.

This section describes how to achieve this using both the Diagram and Tree views.

Diagram View

To define a complex type that mixes data and elements:

1. Create a complexType as described in Defining complexTypes That Contain Elements and Attributes - Diagram View.

2. In the Properties window, click the Mixed field.

3. In the drop-down menu that appears, click true.

Tree View

In the Tree view, to define a complex type that mixes data and elements:

1. Click the Schema node.

2. In the left tool bar, click New complexType

. In the Tree view, Stylus Studio displays a field for the new complexType.

3. Type a name for this new complexType and press Enter.

4. In the Properties window, double-click the Mixed field.

5. Double-click true.

6. In the left tool bar, click New Model Group

. Stylus Studio displays a pop-up menu that lists the group modifiers.

7. Double-click the modifier you want. For a description of the modifiers, see Model Group Properties in XML Schemas. For the rest of this procedure, assume that you double-click the sequence modifier. By default, the elements that are children of this node each appear exactly once. If you want an element to be optional, or if you want an element to appear more than once, specify appropriate values for the properties for minimum occurrence and maximum occurrence.

8. For each element that you want this complexType to contain:

a. In the left tool bar, click New Element Definition

. In the Tree view, Stylus Studio displays a field for the new element definition.

b. Type a name for the new element and press Enter. Stylus Studio displays a pop-up menu that lists the built-in simpleTypes and any types already defined in the schema.

c. Double-click the type for the new element.

Defining complexTypes That Contain Only Attributes

An XML Schema allows you to create groups of attributes. This makes it easy to create a complexType that contains only attributes. The first step is to create an attributeGroup. You can then create a complexType and add a reference to the attributeGroup to the complexType.

Diagram View

To define a complex type that contains only attributes:

1. Right-click the schema node

2. In the shortcut menu, select Add > AttributeGroup.

Alternatives: This operation is also available from the XMLSchema > Diagram > Add > AttributeGroup menu and from the Add button .

The new attributeGroup is added to the XML Schema. It is displayed in the diagram and in the text pane (if you have it open). The properties for the new attributeGroup are displayed in the Properties window.

3. Right-click the new attributeGroup.

4. In the shortcut menu that appears, select Add > Attribute.

The new attribute is added to the attributeGroup.

Figure 253. attributeGroup with New Attribute

5. Make sure the new attribute is selected. In the Properties window, click the Data Type field.

6. Enter or select the type of the attribute.

7. Repeat step 3 through step 6 for each attribute that you want to be in the group.

8. Create a complexType as described in Defining complexTypes That Contain Elements and Attributes - Diagram View.

9. Drag the attributeGroup to the complexType.

Tree View

To define a complex type that contains only attributes:

1. Click the Schema node.

2. In the left tool bar, click New Attribute Group

. In the Tree view, Stylus Studio displays a field for new attributeGroup.

3. Enter a name for the attributeGroup.

4. In the left tool bar, click New Attribute Definition

. In the Tree view, Stylus Studio displays a field for the new attribute definition.

5. Enter a name for the new attribute. Stylus Studio displays a scrollable, pop-up menu that lists the built-in simpleTypes and any previously defined simpleTypes.

6. Double-click the type of the new attribute.

7. For each additional attribute you want to add to the group, click the name of the attributeGroup in the Tree view, and repeat step 4 through step 6.

8. Click the Schema node.

9. In the left tool bar, click New complexType

. In the Tree view, Stylus Studio displays a field for the new complexType.

10. Type a name for the new complexType and press Enter.

11. In the left tool bar, click New Reference to Attribute Group

. Stylus Studio displays a pop-up menu that contains a list of attributeGroups.

12. Double-click the attributeGroup that you want this complexType to contain.

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