I am trying to create a trigger to insert a new row conditionally based on an insert on another table...I can't seem to nail the syntax.
Here is what I have thus far:
DELIMETER $$
CREATE TRIGGER overPricedCar
AFTER INSERT ON cars
FOR EACH ROW
BEGIN
IF (new.sellPrice > '80000' )THEN
INSERT INTO listings VALUES(new.carName,'GOLD','0',' ');
END IF;
END$$
DELIMETER ;
For some reason I keep getting an error, they syntax seems to be OK, I'm not sure where I may have gone wrong.
EDIT
After correcting the typo, the trigger 'works'.
I have added a comment to be output when the trigger happens.
I have tested it, and the output message gets printed to the screen but the trigger does not actually complete the inserts:
DELIMITER $$
CREATE TRIGGER overPricedCar
BEFORE INSERT ON cars
FOR EACH ROW
BEGIN
IF (new.sellPrice > '80000' )THEN
INSERT INTO listings VALUES(new.carName,'GOLD','0',' ');
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = "New Gold car!"; // this line throws it off
END IF;
END$$
DELIMITER ;
Where can I place the messages I want to be printed to the screen when this trigger runs?
Typo:
DELIMETER
^--- should be an I: DELIMITER
Related
im trying to create trigger that prevent insert on buku_dalam_pinjam with certain condition from other table which is anggota_dosen. this is my current trigger
CREATE DEFINER=`root`#`localhost` TRIGGER `buku_dalam_pinjam_BI`
BEFORE INSERT ON `buku_dalam_pinjam`
FOR EACH ROW BEGIN
if (buku_dalam_pinjam.id_agt_dosen=anggota_dosen.id_agt_dosen and
anggota_dosen.ttl_proses_pinjam >=5) then
signal sqlstate '45000' set message_text="error message";
end if;
END
it was succesfully created, then when i try to insert data on buku_dalam_pinjam
it gave me error message, but when i erase the trigger it let me insert on buku_dalam_pinjam table. so is there any mistake in my trigger?
anggota_dosen table
buku_dalam_pinjam table
error message when i include the trigger
try this
drop trigger if exists buku_dalam_pinjam_BI;
delimiter $$
CREATE TRIGGER `buku_dalam_pinjam_BI`
BEFORE INSERT ON buku_dalam_pinjam
FOR EACH ROW BEGIN
if exists (select 1 from anggota_dosen
where new.id_agt_dosen = anggota_dosen.id_agt_dosen and
anggota_dosen.ttl_proses_pinjam >=5) then
signal sqlstate '45000' set message_text="error message";
end if;
END $$
delimiter ;
I am trying to set up a TRIGGER to clear empty strings before INSERT. Not rocket science but I can't find the error in my syntax!
Here is the TRIGGER itself
USE `ga_abtest_logging`;
DELIMITER $$
CREATE TRIGGER avoid_empty
BEFORE INSERT ON daily_analytics
FOR EACH ROW
BEGIN
IF profileID = ''
THEN SET profileID = NULL
END IF;
END$$
Here is what workbench is showing:
On hover over the END IF it reads syntax error, unexpected END, expecting ';'
Could I have a problem with the settings on my DB? I have gone through the MySQL docs and I think the trigger looks right! Does anyone see anything obviously wrong?
You should make a few changes:
Use the NEW. prefix when referencing a column value
Add a semi-colon at the end of the line where you set the value
For example:
DELIMITER $$
CREATE TRIGGER tr_b_ins_daily_analytics BEFORE INSERT ON daily_analytics FOR EACH ROW BEGIN
IF (NEW.profileID = '')
THEN
SET NEW.profileID = NULL;
END IF;
END $$
DELIMITER ;
The code below should work.
DELIMITER $$
CREATE TRIGGER avoid_empty
BEFORE INSERT ON daily_analytics
FOR EACH ROW
BEGIN
IF NEW.profileID = ''
THEN SET NEW.profileID = NULL;
END IF;
END;$$
DELIMITER ;
I have used this trigger to restrict the insertion of those records for which the date of birth is less then 18. This is working fine for the new insertion, but I also want to restrict the modification of the date of birth if it is set to less then 18. Please tell how can I do this?
DELIMITER $$
CREATE TRIGGER `test_candidate_before_insert` BEFORE INSERT ON `candidate` FOR EACH ROW
BEGIN
IF
DATEDIFF(CURDATE(), NEW.date_of_birth)/365 < 18
THEN
SIGNAL SQLSTATE '12345';
END IF;
END$$
DELIMITER ;
You need to define a separate UPDATE trigger.
MySQL, unfortunately, can't create trigger "before insert or update" like other common RDBMSs.
Just create another trigger for updating:
DELIMITER $$
CREATE TRIGGER `test_candidate_before_update` BEFORE UPDATE ON `candidate` FOR EACH ROW
BEGIN
IF
DATEDIFF(CURDATE(), NEW.date_of_birth)/365 < 18
THEN
SIGNAL SQLSTATE '12345';
END IF;
END$$
DELIMITER ;
I have this trigger
CREATE TRIGGER checkcollision AFTER UPDATE ON players BEGIN
SELECT RAISE(ABORT, 'collision') FROM walls WHERE NEW.x=x AND NEW.y=y;
END;
mysql 5.1.72-0ubuntu0.10.04.1 (Ubuntu)
But I am getting a syntax error, and I don't see where...
EDIT:
DELIMITER //
CREATE TRIGGER checkcollision AFTER UPDATE ON players BEGIN SELECT RAISE(ABORT, 'collision') FROM walls WHERE NEW.x=x AND NEW.y=y; END//
DELIMITER ;
This is still getting a syntax error...
This is getting a syntax error:
DELIMITER //
CREATE TRIGGER checkcollision AFTER UPDATE ON players
FOR EACH ROW
BEGIN
IF (SELECT count(*) FROM walls WHERE NEW.x=x AND NEW.y=y)>0 THEN
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Collision detected';
END IF;
END;//
DELIMITER ;
You probably didn't change DELIMITER
How do I do that?
With the DELIMITER command, described here
http://dev.mysql.com/doc/refman/5.6/en/mysql-commands.html
http://dev.mysql.com/doc/refman/5.6/en/stored-programs-defining.html
It's important to change the delimiter when you're creating triggers or procedures, because otherwise using the semicolon statement delimiter inside the body of your trigger (e.g. at the end of the SELECT statement) is ambiguous with respect to the semicolon at the end of the CREATE TRIGGER statement.
This is a very common source of confusion for MySQL developers.
Edit 1:
How do I get it to roll back the change if there is a collision then
Rollback, commit are not allowed in triggers.
Instead, you can raise a signal by setting specific sqlstate on a condition failure.
IF ( condition_for_collision_true ) THEN
SET error_message = 'Invalid XYZ'; -- set proper message
-- set proper error state number
SIGNAL SQLSTATE <ERROR_STATE_NUMBER> SET message_text = error_message;
END IF;
This causes the transaction be aborted.
Original answer:
Triggers get fired for each row affected.
And you are missing the same in your trigger definition.
DELIMITER //
CREATE TRIGGER checkcollision
AFTER UPDATE ON players
FOR EACH ROW
BEGIN
SELECT RAISE(ABORT, 'collision') FROM walls WHERE NEW.x=x AND NEW.y=y;
END;
//
DELIMITER ;
And, it is obvious. Triggers are not regular routines. They are for background action. You can't expect them to return a cursor or any other result. But perform an action like setting or resetting a value in a row or any DML operation on other related table, etc.
Change the body accordingly.
With the following tables:
Party.(PartyId, PartyTypeCode) and Member.(MemberId (FK), Name)
I want to fill in the MemberId column with the value of the PartyId after a new Party is created.
I know the SQL below is wrong but that is why I am looking for help in making it right.
CREATE TRIGGER tgr_member_create AFTER INSERT on Party
FOR EACH ROW BEGIN
IF NEW.PartyTypeCode = 'M' THEN
INSERT Member(MemberId)
VALUES('Party.PartyId')
END IF;
END;
Thanks to Nanne's input this is what works:
DELIMITER $$
CREATE TRIGGER tgr_member_create AFTER INSERT on Party
FOR EACH ROW BEGIN
IF NEW.PartyTypeCode = 'M' THEN
INSERT Member (MemberId,Name)
VALUES(NEW.PartyId, 'someName');
END IF;
END;$$
DELIMITER ;
Your values should call the NEW row, just as you do with the partytypecode I guess? I'm assuming
delimiter $$
CREATE TRIGGER tgr_member_create AFTER INSERT on Party
FOR EACH ROW BEGIN
IF NEW.PartyTypeCode = 'M' THEN
INSERT Member (MemberId,Name)
VALUES(NEW.PartyId, 'someName')
END IF;
END;$$
Pay attention to the delimiter code. Because you are using ; inside, you can't use it as a normal 'end-of-command' token. that's why the &&
For debugging:
Make sure the query works when you perform it outside a trigger:
INSERT Member (MemberId,Name)
VALUES(party-id goes here, 'someName')
There could be a small mistake there. Fill in your partyId obviously.
Try this
CREATE TRIGGER tgr_member_create AFTER INSERT on Party
FOR EACH ROW BEGIN
IF NEW.PartyTypeCode = 'M' THEN
INSERT Member(MemberId)
VALUES('New.PartyId')
END IF;
END;