Creating a Blank Query

You can create a blank query using the PAL Expression Editor. To do this, you can open the editor in one of three ways:

• Directly create a query at the PAL Queries Tab 
• Create the query as an instance of :PAL-CONSTRAINT at the Instances Tab
• Attach a query to a class at the Classes Tab

The first two methods give identical results; they just reflect different ways of viewing queries in Protégé. The third method actually attaches the query to the class. Attaching a query to a class creates an implicit range definition over all instances of the class, for all variables that appear in the query statement and that are not defined by an explicit range definition.

At the Queries Tab

To open the editor at the Queries tab: 

1. Go to the PAL Queries Tab
2. Click the Create button at the upper right of the Choose Queries pane.
   A new query is created and the editor opens in a separate window.
   
   
   

At the Instances Tab

1. Go to the Instances Tab.
2. Display the classes under :SYSTEM-CLASS, display the classes under :CONSTRAINT, and click on :PAL-CONSTRAINT to highlight it. 
   
   
   
3. Go to the Direct Instances pane and click the Create button.
   A new query is created and the PAL Expression Editor appears in the Forms pane of the Instances tab.

At the Classes Tab

To create a query at the Classes Tab, and attach it to a class, you must first make sure the class is queriable. See Making a Class Queriable for more information.

Once your class is queriable, you can create and attach a query:

1. Go to the Classes Tab.
2. Highlight the class to which you wish to attach the query to be created.
   The Class Form for the selected class is displayed at the right of the Classes Tab.
3. Click the Create button at the upper right of the Class Queries pane in the Class Form. 
   A new query is created and the PAL Expression Editor opens in a separate window.

Working With a New Query

Once the query has been created, you can:

• Name it by typing directly in the Name field
• Enter a description by typing directly in the Description field. 
• Define variable ranges by typing directly in the Range area, or using the Range Editor. 
• Create a statement by typing directly in the Statement area, or using the Statement Editor.

PAL Queries User Interface/Creating a Blank Query

Next: Viewing a Query

PAL Table of Contents