I'm trying to create a history table. In the case of an update I want to be able to select the "old" data and move it to the delta table. Therefore i created the following trigger:
delimiter $$
drop trigger if exists entity_url_before_update_to_delta;
create trigger entity_url_before_update_to_delta
before update on entity_url
for each row
begin
insert into delta.entity_url
(url_id, updated_at, title, description, h1, h2, content, main_entity,
entity_sentence_id, entity_id)
values(old.url_id, old.updated_at, old.title, old.description, old.h1, old.h2,
old.content, old.main_entity, old.entity_sentence_id, old.entity_id);
end $$
delimiter ;
However when an update statement is fired the database gives the following error:
"Error code 1142. Insert command denied to users "user#..." for table entity_url".
Is this due to using an insert statement in an update trigger or because i do not have the proper rights for this?
Thank you!
Related
I'm trying to remove a row after inserted in a temp table and I get this error:
INSERT INTO `temp_program_counter` (`id`, `program_id`) values (NULL, '275')
Can't update table 'temp_program_counter' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
And here is my trigger:
DELIMITER $$
DROP TRIGGER IF EXISTS `testtemp`$$
CREATE
TRIGGER `testtemp` AFTER INSERT ON `temp_program_counter`
FOR EACH ROW BEGIN
UPDATE `program` SET `view_count`=`view_count`+1;
DELETE FROM `temp_program_counter` WHERE id=new.id;
END;
$$
DELIMITER ;
this table is a temp table that get's data with delay and after receiving must update the main table and be deleted from temp.
thanks for helping in advance.
You probably have already resolved this in some way but I'll post the answer anyway:
You cannot refer to the same table that triggered the trigger in a trigger (or a combination of trigger and stored procedure). This could mean an infinite loop, so sql prevents it by giving that error, resulting in always the same error.
Try BEFORE INSERT
Because, you are trying to delete a record which has just been inserted but may be not yet committed in this session. Hence you are getting the error.
If you use BEFORE INSERT, then all other record in the table with id=new.id would be deleted and the new record will be inserted successfully.
DELIMITER $$
DROP TRIGGER IF EXISTS `testtemp`$$
CREATE
TRIGGER `testtemp` BEFORE INSERT ON `temp_program_counter`
FOR EACH ROW BEGIN
UPDATE `program` SET `view_count`=`view_count`+1;
DELETE FROM `temp_program_counter` WHERE id=new.id;
END;
$$
DELIMITER ;
In MySQL I tried to define a trigger like this:
DELIMITER $$
CREATE TRIGGER vipInvite
AFTER INSERT ON meetings
FOR EACH ROW
BEGIN
IF(NOT EXISTS (SELECT * FROM participants
WHERE meetid = NEW.meetid AND pid ='vip'))
THEN
IF(EXISTS(SELECT * FROM meetings WHERE meetid = NEW.meetid AND slot > 16))
THEN
INSERT INTO participants(meetid, pid)
VALUES (NEW.meetid,(SELECT userid
FROM people WHERE people.group = 'tap' GROUP BY invite));
END IF;
END IF;
END $$
DELIMITER ;
Produces this error:
This version of MySQL doesn't yet support 'multiple triggers with the same action time and event for one table.
Is there a way to work around this so I can define multiple triggers?
This error means you already have an AFTER INSERT trigger on meetings table.
If it is the same trigger (meaning vipInvite) that you created earlier and now you want to replace it then you need to drop it first
DROP TRIGGER vipInvite;
DELIMITER $$
CREATE TRIGGER vipInvite
...
END$$
DELIMITER ;
Now if you have some other trigger you have to merge code from both triggers into one, then drop existing trigger, and then create a new one.
To show the list of existing triggers use SHOW TRIGGERS.
SHOW TRIGGERS WHERE `table` = 'meetings';
How to reproduce this error in MySQL:
ERROR 1235 (42000): This version of MySQL doesn't yet support 'multiple
triggers with the same action time and event for one table'
Run the following queries:
DELIMITER //
CREATE TRIGGER mytrigger1 AFTER INSERT ON mytable
FOR EACH ROW
BEGIN
END//
DELIMITER //
CREATE TRIGGER mytrigger2 AFTER INSERT ON mytable
FOR EACH ROW
BEGIN
END//
If you want to hook more than one action onto the same event/table, you will have to cram all of it into one trigger. You could call many stored procedures like this:
DELIMITER //
CREATE TRIGGER mytrigger1 AFTER INSERT ON mytable
FOR EACH ROW
BEGIN
CALL fromulate_the_moobars(NEW.myid);
CALL its_peanut_butter_jelly_time(NEW.myname);
END//
My trigger fails when i try to insert a new row in my table because Mysql doesn't support updating rows in the same table the trigger is assigned to. Does anyone have suggestions on a good workaround/alternative?
My trigger:
-- Trigger DDL Statements
DELIMITER $$
CREATE TRIGGER check_sequence
BEFORE INSERT ON data FOR EACH ROW
BEGIN
IF EXISTS(SELECT TRUE FROM data WHERE sequence = NEW.sequence) THEN
UPDATE data SET sequence=sequence+1 WHERE sequence >= NEW.sequence;
END IF;
END $$
DELIMITER ;
Error Sql that is displayed when i try to insert new row:
ERROR 1442 (HY000): Can't update table 'data' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
Thanks for answer,
In MySQL, You can't update (or insert in) table A in a trigger for table A.
http://dev.mysql.com/doc/refman/5.0/en/stored-program-restrictions.html
You can try a sproc and use a transaction, or consider PostgreSQL, which can do this.
I'm trying to comprehend triggers, and I think I fully understand them, but I haven't been able to implement any of them. I want this code to delete a user with the name "test". So if anyone updates their name to "test" the user should be deleted.
My example code:
CREATE TRIGGER `my_trigger`
BEFORE UPDATE ON `my_db` FOR EACH ROW
BEGIN
DELETE FROM my_table WHERE `username` = 'test';
END
My error:
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 4
I can't figure out why the delete statement is giving me an error. Any ideas?
Here is the syntaxically correct SQL:
DELIMITER ;
DROP TRIGGER IF EXISTS `my_trigger`;
DELIMITER $$
CREATE TRIGGER `my_trigger`
BEFORE UPDATE ON `my_table` FOR EACH ROW
BEGIN
DELETE FROM my_table WHERE `username` = 'test';
END$$
DELIMITER;
But it won't work, because you can't delete from the table, you are updating:
A trigger can access both old and new data in its own table. A trigger
can also affect other tables, but it is not permitted to modify a
table that is already being used (for reading or writing) by the
statement that invoked the function or trigger.
http://dev.mysql.com/doc/refman/5.5/en/faqs-triggers.html#qandaitem-B-5-1-9
If you want a simple example, try this:
DELIMITER ;
DROP TRIGGER IF EXISTS `my_trigger`;
DELIMITER $$
CREATE TRIGGER `my_trigger`
BEFORE UPDATE ON `my_table` FOR EACH ROW
BEGIN
SET NEW.`username` = 'aaa';
END$$
DELIMITER;
This will always set 'aaa' as the user name when updating.
It's possible to associated trigger only with a table.
Also within a stored function or trigger, it is not permitted to modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger.
Restrictions on Stored Programs
this is the query that i am using
create trigger trig1 after insert on participant for each row
begin
insert into team(sap) select sap from participant order by ID desc limit 1,1
end;
it is supposed to copy the sap field from the participant table into the sap field of the team table after a new row is inserted into the participant table
the engine shows me an unexpected end of input error at the end of "end"
i've tried numerous methods to rework the query but i keep getting the same error
what am i doing wrong?
thanks
You are using trigger than no need to run a query on same table to get latest sap value, you can directly get that value using new.sap.
Problem in your query, In your query you haven't put semicolon(;) after INSERT..SELECT query and END keyword.
This will work for you:
DELIMITER $$
DROP TRIGGER /*!50032 IF EXISTS */ `trig1`$$
CREATE
TRIGGER `trig1` AFTER INSERT ON `participant`
FOR EACH ROW BEGIN
INSERT INTO team(sap)
VALUES(new.sap);
END;
$$
DELIMITER ;