6.1.4 Feature Queries

Selecting this option brings up a Feature/Attribute Query Panel, which allows the user to create feature queries by defining constraints on their geometric data (feature constraint) or on attributes of the feature (attribute constraint). The steps to create feature/attribute queries are as follows:

1. Select I/O Feature Queries to invoke the Feature/Attribute Query panel.

2. Construct a feature query in the Feature/Attribute Query panel in sets of constraints connected by junctions (e.g., and, or). Each constraint must contain a field name, a relationship (e.g., =), and a value. Select a field name by pressing the Field button on the Feature/Attribute Query panel and then selecting the desired field name on the resultant popup menu. Select a relationship with the Relation button. Enter a value in the Value text field, remembering to register the text by typing a carriage return after the text. If there are multiple constraints, select the desired junction from the Combination buttons (it defaults to and) to connect the next constraint and press the Enter Feature Constraint button. If there is no next constraint, then just push the Enter Feature Constraint button. The constraint just entered will appear in the Feature Constraints text field at the top of the Feature/Attribute Query panel. Each constraint is followed by a junction, even the last constraint, but this is stripped off by the query and will not result in an error. Finally, in order to delete a constraint, highlight a specific constraint in the Feature Constraints text field, and press the Delete Feature Constraint button.

3. If the query consists of both feature constraints and attribute constraints, choose a junction from the Feature/Attribute Combination buttons to connect the feature constraint part of the query and the attribute constraint part. The query defaults to or.

4. Construct an attribute query in the Feature/Attribute Query panel in sets of constraints similar to those found for feature queries. For attribute queries select the attribute name by pressing the Attribute button on the Feature/Attribute Query panel and then selecting the desired attribute name on the resultant pop-up menu. Choosing relations, values, and combinations for attributes as well as entering and deleting constraints follow the same manner as for features except that attributes have a separate work area.

5. Select the type of object to retrieve by pressing the Object Type button, and selecting the desired object type from the resultant pop-up menu.

6. Choose a site graphic to receive the query results by selecting the Graphic button. Following the documentation line prompt, choose an object site graphic from the view in which the objects should be displayed. A menu will appear with the available site graphics for that view. Select the desired site graphic from the list. The name of the selected site graphic will appear in the Query button of the Feature/Attribute Query panel. If the selected site graphic is not visible in the view, use the RCDE View Feature Sets menu to correct this.

7. When all of the constraints, the site graphic and the object type have been entered, press the Execute Query button. The documentation line will display information about the objects or site graphics retrieved, and any retrieved objects will become visible in the selected view.

8. To enter new queries, delete any undesired feature constraints previously entered by selecting them in the Feature Constraints text field at the top of the Feature/Attribute Query panel, and pressing the Delete Feature Constraint button. Likewise, unnecessary attribute constraints should be deleted by highlighting attribute constraints and pressing the Delete Attribute Constraint button.

9. To clear the site graphic between queries to the database, press the Clear Graphic button. This removes all objects from that site graphic and should be used with caution.