XML Authority Quick Tour

Welcome

To help you become familiar with XML Authority^tm we have included this step-by-step exercise to create a simple schema. This exercise will teach you how to navigate the product and introduce you to the fundamental features of XML Authority. This exercise should take around 15 minutes to complete. For more information about XML Authority, consult the Help Index.

The Example

In this example, you will build a sample Document Type Definition (DTD) for a price list. A document conforming to this schema could be used by a reseller to define the format in which they receive product information from manufacturers. Here is a guide to the information we'll be using.

NOTE: The use of italics is for identifying the components of the schema and is used throughout this exercise.

For your reference, a complete example of this schema (quicktour.dtd) is included in the Samples directory. (Extensibility \ Samples \ quicktour.dtd)

Getting Started

• Launch XML Authority. From the Welcome Screen (fig 1.1), select "Create a new schema".

  fig 1.1 - Welcome to XML Authority

  Note: A single left click on the "Create a new schema" icon will open the default schema type specified by your Preferences. (The default is initially set as a DTD.) A right click (Ctrl+click for a Mac one-button mouse) on the icon allows you to select a different schema type from a drop down menu, as shown in fig 1.1. For the purposes of this quick tour, be sure to select a DTD.

  This will open the application and default to the Element Types pane. The Element Types pane presents an inventory of all of the element types whose tags are allowed within a document conforming to this schema. The top portion of the screen will display a graphical representation of your schema, the bottom portion is the work area, and where we will focus in the Quick Tour.

• In the Element Type column, select "unnamed" and replace it with manufacturer .

• Tab across to the Attributes column and type in name.

Here you can define attributes for an element. When entering multiple attributes, they should be separated by commas. XML Authority also has an Attribute Types pane that allows you to refine the attributes further.

NOTE: You can navigate around the tables in each pane by using ENTER, TAB, SHIFT-ENTER, and SHIFT-TAB.

• To create the next element type, move your cursor to the row below manufacturer and type date.issued.

• Define date.issued as a date using the following steps.

  Tab to the Content Model column and click on the Elem. checkbox to clear the checkbox. The Content Model column will change to Data Type. You need to provide the date.issued element with an appropriate data type. To further define this element, position your cursor in the Data Type column and select "date" from the Insert menu that appears. (fig 1.2) The Insert function can also be accessed by right clicking in this column. (Note: On a one button mouse, a right click can be performed by holding the Control key down while clicking.)

  fig 1.2 - Content Model Insert Menu

  

  
  NOTE: An element may contain some combination of text and elements or may contain some form of text with associated datatype information.

• Now, go back and be equally as precise about what is expected inside the manufacturer element. Specify a content model for manufacturer to ensure that the manufacturer element always includes the date.issued element. This requires two steps:

  1. Click the Elem. checkbox on the manufacturer row. Position the cursor inside the "( )" which are automatically created when editing an element's content model.

  2. Type date.issued into the Content Model column to restrict the contents of manufacturer to one and only one date.issued element. Since 'name' is an attribute, it does not need to be within the manufacturer element.

• Move to the empty line below date.issued and type product then press tab. As a default, XML Authority selects the Text and Element check boxes.

• Uncheck the Text check box and click into the Content Model column to define what elements may be found within the product element. Move to the content model column for product, position your cursor inside the "( )" and type sku, product.name, price, description, promotion. Tab from this field and select "Create" (fig 1.3) when prompted. Notice that new Element Types are created for you and added to the list. By default, new elements are automatically created as text only.

  fig 1.3 - Auto Create prompt

  

  NOTE: If, as in the above content model, your input exceeds the column width, type Ctrl+E (Open Apple+E on Mac) or select "Expand" from the View menu to open a larger window for editing the selected area (fig 1.4). To exit this window, press Apply then Save to apply and save your work.

fig 1.4 - Content Model Editor

NOTE: The commas between element types are indicative of a Sequence (this followed by this followed by this). Element types may also represent a Choice (this or this or this). Choice uses a "|" rather than a "," between element type names. In the Content Model column, groups of elements can be EITHER Choices or Sequence.

• As it is currently defined, all elements are required. In some instances, you may want an element to be optional. For the purposes of this exercise, description will be made an optional element. To do this, go back to the product content model and highlight description. Once highlighted, click the "optional" button on the tool bar which appears. Notice the '?' that was appended to description.

  NOTE: Elements can be defined as either required OR optional. They may also be defined as repeatable by clicking on the Repeatable button in the Content Model toolbar. This definition will allow for more than one instance of an element to appear in a content model.
  

• Make price a currency data type by clicking on price where it appears in the Element Type column and then tabbing over to the price Data Type column. Then choose currency from the Insert menu (Insert...More...currency).
  
  
• A promotion is a discounted price over some period of time. This will be represented using a combination of elements and attributes. Make a content model for promotion by unchecking the "Text" box, checking the "Elem." box and then entering price into the Content Model column.

Notice the price element type is being reused in a different context. That's perfectly okay in some situations, in others you may find it more convenient to use a different element type - the choice is yours.

• Tab to the Attributes column and enter start.date, end.date. Press Tab.

NOTE: To further refine the definitions of these attributes, you can right-click on each of their names and choose "Go to <name>". This will bring up the Attribute pane with all the information about that attribute. Changing its data type to Date and making it required is left as an exercise for the reader. Use the navigation buttons on the toolbar (fig 1.5) at the top of the screen to move back and forth between the various panes.

fig 1.5 - XML Authority Toolbar

• Every XML schema needs a single root element that contains all other elements. In this instance, our root element will be called price.list. Below promotion, type in price.list, press tab, then uncheck the Text check box.

• Enter manufacturer, product+ as its content model. (The plus sign designates the product element as required and repeatable.) Tab out of the field to save changes. Congratulations! You have completed creating the schema. Save it by going to File menu and saving as pricelist.dtd.

Reviewing the Schema

Graphical view

By defining what elements may be found within what elements, a structure for the document is established. This structure can be thought of as a tree where the "root" is the encompassing element and its branches are the elements that may be contained within it (as defined by the content model). In turn each branch may have branches defined by their content model. The diagram at the top of the Element Types pane provides a graphical view of these relationships. Explore the content model by clicking on the elements to expand and collapse their content. Note that only elements that define a content model can be expanded. Within the diagram, double clicking on the root element, in this case price.list, will produce a graphical view of the entire schema (fig 1.6).

fig 1.6 - Graphical view of completed schema

Right-click on an element in the diagram and choose "Go to Element Type <name>" to make this element active in the list of element type definitions. Right-Click on the background to zoom in or out of the diagram as a whole.

Source view