I have two tables from Xenforo:
xf_user
xf_user_authenticate
Table xf_user stores all the info of a user except password hashes, which are stored in xf_user_authenticate.
Both tables have the same column called user_id.
When data is inserted into xf_user_authenticate I need to get the user_id from the new inserted row, then use that user_id to get the username from xf_user and set its value to xf_user_authenticate.
I tried this code, but it doesn't work:
CREATE TRIGGER name_sync AFTER INSERT ON xf_user_authenticate
begin
SELECT 'username' INTO #username FROM xenforo.xf_user WHERE 'user_id'=NEW.user_id;
UPDATE xenforo.xf_user_authenticate SET 'username' = #username;
end
You have few syntax related issues, in addition you are trying to update the same table where you have after insert trigger. You may need to change the trigger to before insert as
delimiter //
create trigger name_sync before insert on xf_user_authenticate
for each row
begin
declare user_name_sel varchar(100);
select user_name into user_name_sel
from xf_user
where user_id = NEW.user_id;
set new.username = user_name_sel;
end;//
delimiter ;
CREATE TRIGGER name_sync BEFORE INSERT ON xf_user_authenticate
BEGIN
DECLARE cUsername VARCHAR(255);
SELECT username INTO cUsername FROM xenforo.xf_user WHERE user_id=NEW.user_id;
SET NEW.username = cUsername;
END
Related
I'm new to triggers and all of these procedures stuff. I'm trying to create a simple AFTER INSERT trigger which will duplicate a friendship but swap user_id's, so both users have one. Here's the structure:
And here's my trigger:
DELIMITER $$
CREATE
/*[DEFINER = { user | CURRENT_USER }]*/
TRIGGER `combat`.`friendship_insert_trigger` AFTER INSERT
ON `combat`.`friendships`
FOR EACH ROW BEGIN
DECLARE userID INT;
DECLARE friendID INT;
SET userID = NEW.friend_id;
SET friendID = NEW.user_id;
INSERT INTO friendships VALUES(userID, friendID, NEW.status);
END$$
DELIMITER ;
As you can see, it calls INSERT with swapped values.
Is there any way to 'tell' the new insert statement to not call the trigger again?
I'm using SQLyogg and Ubuntu 16 Mysql
An example:
I insert a friendship with user_id = 1, friend_id = 2 and status = 0.
It should also insert a friendship with user_id = 2, friend_id = 1 and status = 0;
A user is only meant to have up to 3 keys registered to his account at any one time. To add a new key, the user must first delete another key to "make room" for a new one.
I want this to be checked server-side, but I can't get the query to work. Here is what I tried:
IF (SELECT COUNT(serial_key_nbr)
FROM keys_table WHERE user_id = 9) <= 2
THEN INSERT INTO keys_table (user_id, serial_key_nbr)
VALUES (9, 'abc123')
How to do this?
You can use the below mention Script for the same:
INSERT INTO keys_table (user_id, serial_key_nbr)
SELECT 9, 'abc123' FROM DUAL
WHERE
(SELECT COUNT(serial_key_nbr)
FROM keys_table WHERE user_id = 9)<=2
if you want to use an if to do a conditional select then I would put it in a variable like so.
BEGIN
DECLARE var1 INT;
SELECT COUNT(serial_key_nbr) INTO var1
FROM keys_table
WHERE user_id = 9;
IF var1 <= 2
THEN
INSERT INTO keys_table (user_id, serial_key_nbr)
VALUES (9, 'abc123')
END IF;
A trigger might be the way to go. If a condition is met, a trigger before inserting in the table can perform an invalid operation and cause the insert operation to fail:
delimiter $$
create trigger keep_three before insert on keys_table for each row
begin
if (select count(serial_key_nbr) from keys_table where user_id = new.user_id) >= 3 then
insert into non_existent_table (non_existent_field) values (new.user_id);
end if;
end$$
delimiter ;
Ugly, but it might work.
Reference:
"MySQL Triggers: How do you abort an INSERT, UPDATE or DELETE with a trigger?"
Another solution (better I think) is to forcibly delete an entry before attepting the insert. When there are less than 3 entries, the insert procedes normally:
delimiter $$
create trigger keep_three before insert on keys_table for each row
begin
while (select count(serial_key_nbr) from keys_table where user_id = new.user_id) >= 3 do
delete from keys_table where user_id = new.user_id
-- OPTIONAL: Add an ordering criteria to define which entry is deleted first
limit 1;
end while;
end$$
delimiter ;
I think this is cleaner.
A third way (I've found it here). It will return an error message (by signaling sqlstate 45000: Unhandled user defined exception) associated with the defined condition:
delimiter $$
create trigger keep_three before insert on keys table for each row
begin
declare msg varchar(255);
declare n int default 0;
set n = (select count(serial_key_nbr) from keys_table where user_id = new.user_id);
if n >= 3 then
set msg = "INSERT failed: There must be only three entries for each user. Delete an entry first";
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = msg;
end if;
end$$
delimiter ;
A cleaner version of my first option.
This is the database vehicle table's trigger
DROP TRIGGER IF EXISTS InsertVehTrig;
DELIMITER $$
CREATE TRIGGER InsertVehTrig AFTER INSERT
ON Vehicle FOR EACH ROW
SWL_return:
BEGIN
DECLARE Cph CHAR(50);
DECLARE DevID CHAR(12);
DECLARE VehID BIGINT;
DECLARE TmpID BIGINT;
DECLARE DevCount INT;
SET Cph = rtrim(ltrim(NEW.cph));
SET VehID = NEW.ID;
SET DevID = NEW.DevID;
if(VehID is null) then
select count(id) into #DevCount from vehicle where (cph=#Cph) or (DevID=#DevID);
-- 条件：当前的车牌号 或 设备ID
end if;
if (DevCount > 1) then -- 如果记录数，超过1，则认为有重复
-- Rollback not supported in trigger
SET #SWV_Null_Var = 0;
Leave SWL_return;
else
if (DevCount = 1) then
select ID INTO #TmpID from Vehicle where (Vehicle.cph = #Cph) or (Vehicle.DevID = #DevID);
if (TmpID != VehID) then -- --如果增加的车牌号码与数据库中的在相同的，则不允许增加
-- Rollback not supported in trigger
Leave SWL_return;
SET #SWV_Null_Var = 0;
end if;
end if;
end if;
update vehicle set cph = #Cph where ID = #VehID;
END;
Right now i m trying to insert new data row in the vehicle table, but error with this
ERROR 1442: Can't update table 'vehicle' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
SQL Statement:
INSERT INTO `gis_server`.`vehicle` (`TrackerNum`, `cph`, `DevID`, `DevType`) VALUES ('1', 'NR09B00555', 'NR09B00555', '2')
those database are designed by 3 party company,
How do i insert data to vehicle table?
You can achieve this by making two changes to your approach:
Firstly, use a BEFORE trigger rather than an AFTER
Secondly, rather than updating the same table, update the NEW table, setting the column value to the new value before the NEW table hits the table targeted by the INSERT.
For example, replace your UPDATE line with the following:
UPDATE NEW SET cph = Cph;
MySQL doesn't allow you to edit the data in the table on which a trigger is created in that trigger, but you can edit the NEW table to modify the values going into that table.
This is my first attempt at creating a trigger so any help would really be appreciated. I have two tables that look like this:
likes(username, comment_id)
user(username, password, points)
I am trying to create a trigger such that when a user likes a comment (new entry in likes), the point value for that user is incremented by 1. This is what I have attempted:
DELIMITER $$
create trigger update_points
after insert on likes
for each row
begin
SET #username = new.username;
UPDATE user
SET points = points + 1
WHERE username = #username
end$$
I keep getting MySQL errors. Can anyone help me?
I think you are missing a DELIMITER call at the end. And also a semi-colon:
DELIMITER $$
create trigger update_points after insert on likes
for each row begin
SET #username = new.username;
UPDATE user SET points = points + 1 WHERE username = #username;
end$$
DELIMITER ;
I trying execute an trigger on mysql database.
The command executes successfully, but the trigger not working.
DELIMITER #
CREATE TRIGGER generate_coupon AFTER INSERT ON order
FOR EACH ROW
BEGIN
DECLARE userid, couponvalue INT;
DECLARE couponcode VARCHAR;
SELECT idUser INTO userid FROM indication WHERE email = NEW.email;
SET couponvalue = 20;
SET couponcode = 'abc123';
INSERT INTO coupon(idUser,idOrder,couponvalue,couponcode) values(userid, NEW.id, couponvalue, couponcode);
END#
DELIMITER ;
I suspect your problem arises from the collisions between your variables couponvalue and couponcode with the same-named columns in your coupon table. As documented under Local Variable Scope and Resolution:
A local variable should not have the same name as a table column.
You could simplify your trigger to the following and, in so doing, avoid this problem entirely:
CREATE TRIGGER generate_coupon AFTER INSERT ON order FOR EACH ROW
INSERT INTO coupon
(idUser, idOrder, couponvalue, couponcode)
SELECT idUser, NEW.id, 20, 'abc123'
FROM indication
WHERE email = NEW.email
;