Yes, using the MySQL User-Defined Function (see MySQL 5.5 FAQ: Triggers) and installing the lib_mysqludf_sys
Then, for example, you can write your own trigger calling the sys_exec like this:
CREATE TRIGGER testtrigger BEFORE UPDATE ON T1
FOR EACH ROW BEGIN
DECLARE result int(10);
IF NEW.Flag <> OLD.Flag THEN
SET result = sys_exec('/path/to/javabin -jar your.jar');
-- other kind of works and checks...
result contains the exit code of the external program
There are other useful functions in this library:
- sys_eval : executes an arbitrary command, and returns it's output.
- sys_get : gets the value of an environment variable
- sys_set : create an environment variable, or update the value of an existing environment variable
- sys_exec : executes an arbitrary command, and returns it's exit code
More info here
Try it on a dev env and...
Be very careful in deciding whether you need this function. UDFs are
available to all database users - you cannot grant EXECUTE privileges
for them. As the commandstring passed to
sys_exec can do
pretty much everything, exposing the function poses a very real
But anyway, I agree with the proposal of Remus Rusanu