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  1. Derby
  2. DERBY-6

Trigger of the form: create trigger ... values myFunction(); has no effect.

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Details

    • Bug
    • Status: Closed
    • Minor
    • Resolution: Fixed
    • 10.0.2.0
    • 10.0.2.0
    • SQL
    • None

    Description

      Reporting for Jack Klebanoff, filed on derby-dev list.

      > Jack Klebanoff wrote:
      >
      > | I would like to submit a fix for a bug in triggers.
      > |
      > | The bug is that a trigger of the form:
      > | create trigger ... values myFunction();
      > | has no effect. MyFunction is not called even if the trigger is fired.
      > | Side effects of myFunction do not happen. Derby does not allow a "CALL"
      > | statement inside a trigger action so a values statement is the only way
      > | to call a function/procedure in a trigger action.
      > |
      > | The cause of the bug is that since the values are not actually used by
      > | the trigger, the trigger code does not fetch the row(s) returned by the
      > | trigger action. The fix is simple: change class
      > | org.apache.derby.impl.sql.execute.GenericTriggerExecutor to fetch (and
      > | discard) the rows returned by a trigger action.
      > |
      > | Please review the change. The diff file is attached.
      >
      >
      > I think you need to close the ResultSet (rs). Other locations in the
      > code where a ResultSet is processed terminate with an rs.close(). Eg.
      > see DeleteCascadeResultSet, ConstraintConstantAction.
      >
      > Dan.
      >
      I changed the code to close the ResultSet. The diff file is attached.

      Jack
      Index: java/engine/org/apache/derby/impl/sql/execute/GenericTriggerExecutor.java
      ===================================================================
      — java/engine/org/apache/derby/impl/sql/execute/GenericTriggerExecutor.java (revision 37092)
      +++ java/engine/org/apache/derby/impl/sql/execute/GenericTriggerExecutor.java (working copy)
      @@ -157,7 +157,18 @@
      */
      try
      {

      • ps.execute(spsActivation, false, false, false);
        + ResultSet rs = ps.execute(spsActivation, false, false, false);
        + if( rs.returnsRows())
        +
        Unknown macro: {+ // Fetch all the data to ensure that functions in the select list or values statement will+ // be evaluated and side effects will happen. Why else would the trigger action return+ // rows, but for side effects?+ // The result set was opened in ps.execute()+ while( rs.getNextRow() != null)+ { + }+ }

        + rs.close();
        }
        catch (StandardException e)
        {

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            Unassigned Unassigned
            tulika Tulika Agrawal
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              Created:
              Updated:
              Resolved: