[+] implement task deletion, closes #28

Author: pashagolub

forms/fmmain.pas

@@ -339,8 +339,7 @@ procedure TfmMain.acTaskToolbarUpdate(Sender: TObject);
   acTaskAdd.Enabled := CanModify;
   acMoveTaskUp.Enabled := CanModify and (dmPgEngine.qryTasks.RecNo > 1);
   acMoveTaskDown.Enabled := CanModify and (dmPgEngine.qryTasks.RecNo < dmPgEngine.qryTasks.RecordCount);
-  acTaskDelete.Enabled := CanModify and
-    (not (dmPgEngine.qryTasks.BOF and dmPgEngine.qryTasks.EOF));
+  acTaskDelete.Enabled := CanModify and dmPgEngine.IsTaskDeleteAllowed();
   acTaskEdit.Enabled := CanModify and not (dmPgEngine.qryTasks.State in dsEditModes);
   acTaskPost.Enabled := CanModify and (dmPgEngine.qryTasks.State in dsEditModes);
   acTaskCancel.Enabled := CanModify and (dmPgEngine.qryTasks.State in dsEditModes);

udatamodule.lfm

@@ -201,6 +201,9 @@ object dmPgEngine: TdmPgEngine
       '  )'
       'WHERE task_id = :"task_id"'
     )
+    DeleteSQL.Strings = (
+      'SELECT timetable.delete_task(:"task_id")'
+    )
     Options = [sqoKeepOpenOnCommit, sqoAutoApplyUpdates, sqoAutoCommit, sqoRefreshUsingSelect]
     Params = <    
       item

udatamodule.pas

@@ -39,6 +39,7 @@   TdmPgEngine = class(TDataModule)
     function SelectSQL(const sql: string): string;
     procedure MoveTaskUp(const ATaskID: integer);
     procedure MoveTaskDown(const ATaskID: integer);
+    function IsTaskDeleteAllowed: boolean;
   end;
 
 var
@@ -217,4 +218,9 @@ procedure TdmPgEngine.MoveTaskDown(const ATaskID: integer);
   PQConn.ExecuteDirect(Format('SELECT timetable.move_task_down(%d)', [ATaskID]));
 end;
 
+function TdmPgEngine.IsTaskDeleteAllowed: boolean;
+begin
+  Result := not qryTasks.BOF and not qryTasks.EOF and not qryTasks.FieldByName('parent_id').IsNull;
+end;
+
 end.