Tracing Query Functions and Predicates

The Tracing Controls Pane allows you to trace a single specified function and/or predicate during query evaluation.

To trace a function or predicate:

1. Make sure the PAL Queries Tab is displayed.
2. Tag the querie(s) you wish to evaluate. For more information about tagging and evaluating queries, see Evaluating Queries.
3. If Trace during evaluation is not selected, click on it to select it.
4. Select a function to trace from the Function to Trace menu 
   AND/OR
   a predicate to trace from the Predicate to Trace menu.
   Once you have made this selection, the next time you evaluate queries by clicking the Evaluate Indicated Queries button, the evaluation information is displayed in the Protégé console window. For each knowledge base instance that is evaluated against the queries, the console window displays:
   • the specified predicate and/or function
   • the arguments of the predicate and/or function being traced
   • the return value (T or F) of the selected predicate and/or the results of the selected function

Note: Tracing is only available for built-in functions and predicates. Although they are in the drop-down list, the predicates = and /= cannot be traced. This is due to the fact that, internally, they are implemented differently from the other predicates.

PAL Queries User Interface/Tracing Query Functions and Predicates

Next: The PAL Expression Editor/Configuring the PAL Expression Editor

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