I would like to creating a trigger that updates the database when a new message is sent.
If the SenderId and RecipentId already have a conversationId, then update the database so that the New.conversationId = existing conversationId.
Table: mailbox_message
Create a trigger that updates the conversationId to the same value whenever users 11 & 5 send messages to each other.
delimiter $$
create trigger before_insert_conversationId
before insert on data25k29_mailbox_message
for each row
begin
IF ( EXISTS (
SELECT data25k29_mailbox_message.conversationId FROM data25k29_mailbox_message
WHERE (data25k29_mailbox_message.senderId='5'
and data25k29_mailbox_message.recipientId = '11')
and (data25k29_mailbox_message.senderId= '11'
and data25k29_mailbox_message.recipientId= '5')
)
)
THEN
SET NEW.conversationId = data25k29_mailbox_message.conversationId;
ELSE
SET NEW.conversationId = NEW.conversationId;
END IF;
end
$$
The value doesn't change after inserting values. Any help in this regard is greatly appreciated. Thanks
This is my working snippet of this question.
Drop trigger if exists after_insert_conversationId;
delimiter |
CREATE TRIGGER after_insert_conversationId
before insert ON data25k29_mailbox_message
FOR EACH ROW
BEGIN
Declare v1 int;
select conversationId into v1 from data25k29_mailbox_message
where senderId = new.senderId and recipientId = new.recipientId limit 1;
if v1 is NULL
then
set new.conversationId = new.conversationId;
else
set new.conversationId = v1;
End if;
END|
Related
i am setting triggerafter_inser and i dont know how to resolve it
DELIMITER $$
USE `solocloud_dev_2`$$
DROP TRIGGER IF EXISTS table_10_summary_after_insert $$
CREATE TRIGGER table_10_summary_after_insert AFTER INSERT ON table_10
FOR EACH ROW BEGIN
DECLARE var INT;
SET var=0;
SELECT COUNT(*) FROM table_10_summary WHERE client_id = new.client_id;
IF var > 0
THEN
UPDATE table_10_summary SET records = records+1 WHERE client_id = new.client_id;
ELSE
INSERT INTO table_10_summary (new.client_id,1);
END$$
DELIMITER$$
There are several problems with your trigger :
you need to SET var from the results of the query ; as it is now, you are not setting this value
the IF block must be terminated with END IF
The following codes compiles successfully in this DB Fiddle :
DELIMITER $$
DROP TRIGGER IF EXISTS table_10_summary_after_insert $$
CREATE TRIGGER table_10_summary_after_insert AFTER INSERT ON table_10
FOR EACH ROW
BEGIN
DECLARE var INT;
SET var = (SELECT COUNT(*) FROM table_10_summary WHERE client_id = new.client_id);
IF (var > 0) THEN
UPDATE table_10_summary SET records = records + 1 WHERE client_id = new.client_id;
ELSE
INSERT INTO table_10_summary VALUES(new.client_id,1);
END IF;
END$$
DELIMITER ;
This is my trigger.
I want to make trigger on 1 table (rezervare).
Trigger
DELIMITER //
CREATE TRIGGER verificare_nr_locuri
BEFORE INSERT ON Rezervare
FOR EACH ROW
BEGIN
IF ( SELECT Masa.NrLocuri FROM Rezervare, Masa
WHERE Masa.NumarMasa = Rezervare.NumarMasa ) < Rezervare.NumarPersoane THEN
SET NEW.NumarMasa = NULL;
END IF;
END //
DELIMITER ;
INSERT INTO Rezervare VALUES (123,106,2,'2016-12-11','2016-12-24',5);
INSERT INTO Rezervare VALUES (124,106,2,'2016-12-11','2016-12-24',4);
When I execute the trigger, it has been created. But, when I insert data into table rezervare, It become
#1109 - Unknown table 'rezervare' in field list.
How can I resolve this?
Table
I think you might need to use a JOIN for your SELECT clause.
BEGIN
IF (SELECT Masa.NrLocuri, Rezervare.NumarMasa FROM Masa JOIN Rezervare
WHERE Masa.NumarMasa = Rezervare.NumarMasa) < Rezervare.NumarPersoane THEN
SET NEW.NumarMasa = NULL;
END IF;
I have a problem with my trigger before insert.
I try to control the row number of my table 'user_search' for one 'id_user' and if this row number > 4, the oldest row should be deleted.
My actual trigger is this :
DELIMITER $$
CREATE TRIGGER before_insert_user_search
BEFORE INSERT
ON user_search FOR EACH ROW
BEGIN
DECLARE sDate DATETIME;
SELECT MIN(date_search) FROM user_search WHERE id_user = NEW.id_user INTO sDate;
IF ((SELECT COUNT(id) FROM user_search WHERE id_user = NEW.id_user) > 4) THEN
BEGIN
DELETE FROM user_search WHERE date_search = sDate;
END;
END IF;
END$$
DELIMITER ;
However, it does not work. Do someone have a solution to help me please.
Thanks.
You can not delete same table row during using INSERT trigger because it holds the lock of table. So try to write a Stored Procedure to insert new record.
Stored Procedure should be something like bellow:
CREATE PROCEDURE insert_user_search(new_id_user INT, ......other variable to inert)
BEGIN
DECLARE #minId INT;
//INSERT using parameter
SET #minId = SELECT MIN(id) FROM user_search WHERE id_user = new_id_user;
IF ((SELECT COUNT(id) FROM user_search WHERE id_user = new_id_user) > 4) THEN
BEGIN
DELETE FROM user_search WHERE id_user = #minId;
END;
END IF;
END;
I have a MySQL table , look like this
t id lang title
1 7 en_UK my_title
1 7 kh_KH
I want write a trigger that update title to my_title with the same id is 7
Result
t id lang title
1 7 en_UK my_title
1 7 kh_KH my_title
From my understanding.
DELIMITER $$
CREATE TRIGGER upd_title BEFORE UPDATE ON `term`
FOR EACH ROW BEGIN
IF (NEW.title IS NULL OR NEW.title= '') THEN
SET NEW.title= ??? ;
END IF;
END$$
DELIMITER ;
[UPDATE1]->not works (trigger not being created)
DELIMITER $$
DROP TRIGGER IF EXISTS `update_category_after_insert`
CREATE TRIGGER `update_category` AFTER INSERT ON `categories`
FOR EACH ROW BEGIN
DECLARE loc_title text;
IF (NEW.libelle_categorie IS NULL OR NEW.libelle_categorie= '') THEN
select libelle_categorie into loc_title from categories where NEW.num_noeud= num_noeud and langue = 'en_UK';
SET NEW.libelle_categorie = loc_title;
END IF;
END
DELIMITER ;
[UPDATE2]
DELIMITER $$
CREATE TRIGGER ``update_category_after_insert`` BEFORE INSERT ON `categories`
FOR EACH ROW BEGIN
DECLARE loc_title text;
IF (NEW.libelle_categorie IS NULL OR NEW.libelle_categorie= '') THEN
select libelle_categorie into loc_title from categories where NEW.num_noeud= num_noeud and langue = 'en_UK';
SET NEW.libelle_categorie = loc_title;
END IF;
END
DELIMITER ;
Finally , I found the good solution for my case
UPDATE categories c INNER JOIN categories c2 ON (
c.num_noeud = c2.num_noeud
) SET c.libelle_categorie = c2.`libelle_categorie`
Can you clarify?
Are you trying to pull the value from the title column in the 'en_UK' row that exists when you insert an new row with the same id that HAS the title column not entered?
okay
CREATE TRIGGER upd_title BEFORE UPDATE ON `term`
FOR EACH ROW BEGIN
DECLARE loc_title VARCHAR(20);
IF (NEW.title IS NULL OR NEW.title= '') THEN
select title into loc_title from term where NEW.id = id and lang = 'en_UK';
SET NEW.title= loc_title;
END IF;
END
This should do the trick.
This was my trigger def:
CREATE DEFINER = CURRENT_USER TRIGGER `therinks`.`glreturndata_BEFORE_UPDATE` BEFORE UPDATE ON `glreturndata` FOR EACH ROW
BEGIN
DECLARE myVal VARCHAR(20);
if NEW.DESCRIPTION IS NULL or new.description = '' THEN
SELECT min(description) into myVal from glreturndata where category = NEW.category and new.idglreturndata <> idglreturndata;
Set NEW.DESCRIPTION = myval;
end if;
END
It seems that you can't do all this in a trigger. According to the documentation:
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.
According to this answer, it seems that you should:
create a stored procedure, that inserts into/Updates the target table, then updates the other row(s), all in a transaction.
With a stored proc you'll manually commit the changes (insert and update). I haven't done this in MySQL, but this post looks like a good example.
I am trying to create a mysql trigger. The error code 1064 is very generic. The trigger is to see if a record exists for a particular key; and if it does update a particular column in the newly inserted row with that value. I am using a select query on the same table as the trigger is on. Does that cause a problem? Here is the code:
DELIMITER $$
CREATE TRIGGER classid_insert
AFTER INSERT ON courses_semester
FOR EACH ROW
BEGIN
SET #class_id = (SELECT class_id FROM courses_semester WHERE
course_id = NEW.`course_id`
AND `dept_id` = NEW.`dept_id`
AND `univ_id` = NEW.`univ_id`
AND `section_id` = NEW.`section_id`
AND `semester` = NEW.`semester`
AND `year` = NEW.`year`);
IF(#class_id = NULL)
THEN
NEW.class_id = UUID()
ELSE
NEW.class_id = #class_id
END IF;
END
DELIMITER ;
your entire trigger code should look like below. remove the spaces after DELIMITER $$ and before DELIMITER ;. Also, the last END need to changed to END $$. Also, it has to be an BEFORE trigger and not an AFTER trigger.
Moreover, NEW.class_id = UUID() is not correct.It's missing SET as
SET NEW.class_id = UUID();
CORRECTED TRIGGER CODE:
DELIMITER $$
CREATE TRIGGER classid_insert
BEFORE INSERT ON courses_semester
FOR EACH ROW
BEGIN
SET #class_id = (SELECT class_id FROM courses_semester WHERE
course_id = NEW.`course_id`
AND `dept_id` = NEW.`dept_id`
AND `univ_id` = NEW.`univ_id`
AND `section_id` = NEW.`section_id`
AND `semester` = NEW.`semester`
AND `year` = NEW.`year`);
IF(#class_id = NULL)
THEN
SET NEW.class_id = UUID();
ELSE
SET NEW.class_id = #class_id;
END IF;
END $$
DELIMITER ;