Jess Defquery Functions

List of Defquery functions that can be executed by Jess.


8.34. (count-query-results <query-name> <expression>+)

Package:
MiscFunctions
Arguments:
An atom, and zero or more additional expressions
Returns:
INTEGER
Description:
Runs a defquery and returns a count of the matches. See the documentation for defquery for more details. Also see run-query for caveats concerning calling count-query-results on a rule RHS.

8.122. (run-query <query-name> <expression>+)

Package:
MiscFunctions
Arguments:
An atom, and zero or more additional expressions
Returns:
java.util.Iterator, as an EXTERNAL_ADDRESS
Description:
Runs a defquery and returns a java.util.Iterator of the matches. See the documentation for defquery for more details. Note that run-query can lead to backwards chaining, which can cause rules to fire; thus if run-query is called on a rule RHS, other rules' RHSs may run to completion before the instigating rule completes. Putting run-query on a rule RHS can also cause the count of executed rules returned by run to be low.