I am trying to learn the proper way to implement triggers. I have read numerous entries on the web that were supposed to work with Derby. I dought that, since they have different code strings and different logic.
I am looking at two scenarios. The first scenario invloves using a column trigger to sum two columns (A and B) and place the result in a thrid column (C) within the same table (mytable). I have built the following code: CREATE TRIGGER mytrig AFTER UPDATE INSERT of ColumnA, ColumnB ON MyTable UPDATE MyTable SET ColumnC = ColumnA + ColumnB WHERE id = key My questions on this scenario are: 1. Is this a correct trigger for the scenario if described? 2. Is it necessary to include the WHERE clause or will the trigger default to the current record? 3. Must I use the Update clause or is there a more direct way? The second scenario involves a column(A) that contains a decimal(7,6) value. I need to set another column(B) to a decimal(1) value based on where the value in A falls within in a range of values. For example: if A =11 and there are 3 ranges (0-10, 11-20, 21-30), B would equal "1". I do not know of a way to do this with SQL, so I would probaly need to do to this through a stored Procedure or Function referencing some code in my application. However, I am totaly unclear what type of TRIGGER would be required, how the column (B) would be updated. I have seen some references to a read only set of code that can not update the table. I assume this means it can not issue any SQL commands. Can you provide some guidance? -- View this message in context: http://old.nabble.com/Help-with-Triggers-tp28805126p28805126.html Sent from the Apache Derby Users mailing list archive at Nabble.com.
