I have a table in MySql table like the following
row_timestamp timestamp
, row_id int(11) auto_increment
, mrn char(17)
, patients_last_name varchar(50)
, patients_first_name varchar(50)
, ssn char(4) default '0000'
, visit_key NULL
upon the insertion of a record, I'd like visit_key to bet set to visit_key = concat(mrn, row_id) I was trying to accomplish this with a before insert trigger to no avail, I kept getting that the mrn column was not in the field select list.
Update
I tried the following, which seems not to work because the auto_increment has not yet incremented:
set new.visit_key = concat(new.mrn, new.row_id)
I also tried
set new.visit_key = concat(new.mrn, max(row_id)+1)
I am thinking of the trigger to sort of act like a calculated field in MS Access, is this reasonable? Thoughts? Would it not be possible to do since the visit_key would technically be NULL and you cannot update a new value?
UPDATE
I used the following code that I adapted from this question here
DELIMITER //
CREATE TRIGGER vkt AFTER INSERT ON demographic_information
FOR EACH ROW
BEGIN
UPDATE `demographic_information` SET visit_key_test = concat(new.mrn, mew.row_id) WHERE row_id = NEW.row_id;
END;
//
DELIMITER ;
and got the following error message:
INSERT INTO `manchuco_nys_trauma`.`demographic_information` (
`row_timestamp` ,
`row_id` ,
`mrn` ,
`patients_last_name` ,
`patients_first_name` ,
`ssn` ,
`visit_id` ,
`visit_key_test`
)
VALUES (
CURRENT_TIMESTAMP , NULL , '123456', 'Sanderson', 'Steven', '1234', '12345670', NULL
)
MySQL said: Documentation
#1442 - Can't update table 'demographic_information' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
Thank you,
What you observe seems normal: since you're using BEFORE INSERT the id value doen't exist yet.
And the same applies for your try with concat(new.mrn, **new**.row_id): NEW has no sense at the moment.
So I suggest you use AFTER INSERT instead.
Try selecting the auto increment value inside the trigger:
CREATE TRIGGER trigger_name AFTER INSERT ON yourTable FOR EACH ROW
BEGIN
DECLARE next_id integer;
SET next_id = (SELECT AUTO_INCREMENT
FROM information_schema.TABLES
WHERE TABLE_SCHEMA='yourDB' AND TABLE_NAME='yourTable');
SET new.visit_key = CONCAT(new.mrn, next_id);
END
I discovered this approach in this SO article.
Related
I am running a MySQL Query. But when a new row is added from form input I get this error:
Error: Can't update table 'brandnames' in stored function/trigger because it is
already used by statement which invoked this stored function/trigger.
From the code:
CREATE TRIGGER `capital` AFTER INSERT ON `brandnames`
FOR EACH
ROW UPDATE brandnames
SET bname = CONCAT( UCASE( LEFT( bname, 1 ) ) , LCASE( SUBSTRING( bname, 2 ) ) )
What does this error mean?
You cannot change a table while the INSERT trigger is firing. The INSERT might do some locking which could result in a deadlock. Also, updating the table from a trigger would then cause the same trigger to fire again in an infinite recursive loop. Both of these reasons are why MySQL prevents you from doing this.
However, depending on what you're trying to achieve, you can access the new values by using NEW.fieldname or even the old values --if doing an UPDATE-- with OLD.
If you had a row named full_brand_name and you wanted to use the first two letters as a short name in the field small_name you could use:
CREATE TRIGGER `capital` BEFORE INSERT ON `brandnames`
FOR EACH ROW BEGIN
SET NEW.short_name = CONCAT(UCASE(LEFT(NEW.full_name,1)) , LCASE(SUBSTRING(NEW.full_name,2)))
END
The correct syntax is:
FOR EACH ROW SET NEW.bname = CONCAT( UCASE( LEFT( NEW.bname, 1 ) )
, LCASE( SUBSTRING( NEW.bname, 2 ) ) )
A "BEFORE-INSERT"-trigger is the only way to realize same-table updates on an insert, and is only possible from MySQL 5.5+. However, the value of an auto-increment field is only available to an "AFTER-INSERT" trigger - it defaults to 0 in the BEFORE-case. Therefore the following example code which would set a previously-calculated surrogate key value based on the auto-increment value id will compile, but not actually work since NEW.id will always be 0:
create table products(id int not null auto_increment, surrogatekey varchar(10), description text);
create trigger trgProductSurrogatekey before insert on product
for each row set NEW.surrogatekey =
(select surrogatekey from surrogatekeys where id = NEW.id);
#gerrit_hoekstra wrote: "However, the value of an auto-increment field is only available to an "AFTER-INSERT" trigger - it defaults to 0 in the BEFORE-case."
That is correct but you can select the auto-increment field value that will be inserted by the subsequent INSERT quite easily. This is an example that works:
CREATE DEFINER = CURRENT_USER TRIGGER `lgffin`.`variable_BEFORE_INSERT` BEFORE INSERT
ON `variable` FOR EACH ROW
BEGIN
SET NEW.prefixed_id = CONCAT(NEW.fixed_variable, (SELECT `AUTO_INCREMENT`
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'lgffin'
AND TABLE_NAME = 'variable'));
END
I have the same problem and fix by add "new." before the field is updated. And I post full trigger here for someone to want to write a trigger
DELIMITER $$
USE `nc`$$
CREATE
TRIGGER `nhachung_province_count_update` BEFORE UPDATE ON `nhachung`
FOR EACH ROW BEGIN
DECLARE slug_province VARCHAR(128);
DECLARE slug_district VARCHAR(128);
IF old.status!=new.status THEN /* neu doi status */
IF new.status="Y" THEN
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id;
ELSE
UPDATE province SET `count`=`count`-1 WHERE id = new.district_id;
END IF;
ELSEIF old.province_id!=new.province_id THEN /* neu doi province_id + district_id */
UPDATE province SET `count`=`count`+1 WHERE id = new.province_id; /* province_id */
UPDATE province SET `count`=`count`-1 WHERE id = old.province_id;
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id; /* district_id */
UPDATE province SET `count`=`count`-1 WHERE id = old.district_id;
SET slug_province = ( SELECT slug FROM province WHERE id= new.province_id LIMIT 0,1 );
SET slug_district = ( SELECT slug FROM province WHERE id= new.district_id LIMIT 0,1 );
SET new.prov_dist_url=CONCAT(slug_province, "/", slug_district);
ELSEIF old.district_id!=new.district_id THEN
UPDATE province SET `count`=`count`+1 WHERE id = new.district_id;
UPDATE province SET `count`=`count`-1 WHERE id = old.district_id;
SET slug_province = ( SELECT slug FROM province WHERE id= new.province_id LIMIT 0,1 );
SET slug_district = ( SELECT slug FROM province WHERE id= new.district_id LIMIT 0,1 );
SET new.prov_dist_url=CONCAT(slug_province, "/", slug_district);
END IF;
END;
$$
DELIMITER ;
Hope this help someone
I'd like one column's value to be forced to DEFAULT in trigger by some conditions.
In example below, if b IS NULL, a should be set with defined DEFAULT (that is 'SYSTEM').
CREATE TABLE `t_default` (
`n` VARCHAR(50) NOT NULL
, `a` VARCHAR(50) NOT NULL DEFAULT 'SYSTEM'
, `b` VARCHAR(50) NULL DEFAULT NULL
-- To moderators: please do not edit my formatting :)
);
DELIMITER //
CREATE TRIGGER `TRG_t_default_BeforeInsert` BEFORE INSERT ON `t_default` FOR EACH ROW BEGIN
IF NEW.b IS NULL THEN
SET NEW.a = DEFAULT(a);
END IF;
END
//
DELIMITER ;
Unfortunately, this gives error message "Unknown column 'a' in 'field list'" on insert:
INSERT INTO t_default (n) VALUES ('1');
I've found similar question, however providing table name or db + table name does not work as well:
CREATE TRIGGER `TRG_t_default_BeforeInsert` BEFORE INSERT ON `t_default` FOR EACH ROW BEGIN
IF NEW.b IS NULL THEN
SET NEW.a = DEFAULT(t_default.a);
-- SET NEW.a = DEFAULT(test.t_default.a);
END IF;
END
In this case message is slightly different: "Unknown table 't_default' in field list"
Also, I tried to use back quotes around column name with no success.
So, is it possible to get column DEFAULT in trigger at all? I'm using MySQL 5.7.
Thanks.
P.S. Sure, I know that I can do SET NEW.a = 'SYSTEM';
You can try
IF NEW.b IS NULL THEN
SELECT COLUMN_DEFAULT INTO #def FROM information_schema.COLUMNS
WHERE table_schema = 'database_name'
AND table_name = 't_default'
AND column_name = 'a';
SET NEW.a = #def;
END IF;
Summary: I am trying to add a Username to the db.username_table with a unique ID incremented by 1. However, I keep receiving an error 1111 related to my CASE statement. It should make the first User_ID 1, then all other new ones the max(user_id) +1. Any help would be greatly appreciated!
Background: This is for my first MySQL project - I have some experience with MS SQL that may be hindering me here. I googled many references and streamlined my code as much as possible, but the aggregate for the counter returns a 1111 error with an IF or with a CASE statement.
DELIMITER $$
CREATE PROCEDURE db.add_user
(
in new_username varchar(45)
)
begin
-- Set Counter ID
declare new_user_id int;
set new_user_id = if(max(db.username_table.User_ID) is null, 1, max(db.username_table.User_ID) + 1);
-- Add Username with Counter
insert into db.username_table (user_id, username)
values (new_user_id, new_username);
END$$
DELIMITER ;
Expected Result - Add a Username to the db.username_table with a unique ID incremented by 1.
Actual Result - Error 1111.
You are using the funtion MAX but not in SQL statements .. so the max of is used improperly . you need a select for retrive a MAX(db.username_table.User_ID.)
declare new_user_id int;
select case when
max(ifnull(db.username_table.User_ID,0)) = 0
then 1
else max(db.username_table.User_ID) + 1 end
INTO new_user_id
from your_table ;
but could you simply need an autoincrement column for User_id and avoid this SP
CREATE TABLE your_table (
User_ID int(11) NOT NULL AUTO_INCREMENT,
....
)
Please I did this trigger to update table rating after each insert when 2 columns (id_prof,id_etud) inserted are already in the table but it gives mi this error
> #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 6
The trigger :
CREATE TRIGGER Before_Insert_Rate
BEFORE INSERT ON rating
FOR EACH ROW
BEGIN
IF (EXISTS(SELECT * FROM rating WHERE id_prof=NEW.id_prof and id_etud = NEW.id_etud)) THEN
UPDATE `rating` SET `rate` = NEW.rate WHERE `id_prof` = NEW.id_prof and `id_etud` = NEW.id_etud;
ELSE INSERT INTO rating VALUES (NEW.idprof,New.rate,New.id_etud);
END IF
END
DELIMITER ;
You must set the DELIMITER before. Change it to:
DELIMITER //
CREATE TRIGGER Before_Insert_Rate
BEFORE INSERT ON rating
FOR EACH ROW
BEGIN
IF (EXISTS(SELECT * FROM rating WHERE id_prof=NEW.id_prof and id_etud = NEW.id_etud)) THEN
UPDATE `rating` SET `rate` = NEW.rate WHERE `id_prof` = NEW.id_prof and `id_etud` = NEW.id_etud;
ELSE INSERT INTO rating VALUES (NEW.idprof,New.rate,New.id_etud);
END IF
END; //
DELIMITER ;
from the official reference manual.
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.
This means no query on table X can INSERT, UPDATE, or DELETE from table X; it also means that if a trigger on table X modifies table Y, it will fail for any query using both table X and Y that "triggers" it.
Example: UPDATE x INNER JOIN y ON x.id = y.id SET x.something = 1, y.something = 2 will cause a BEFORE UPDATE ON x trigger (that updates, inserts, or deletes from y) to fail.
I solved it using ON DUPLICATE KEY on a query instead of trigger
CREATE TABLE `rating` (
`id_prof` int(11) NOT NULL,
`rate` float NOT NULL,
`id_etud` int(11) NOT NULL,
UNIQUE (id_prof,id_etud)
)
the query :
INSERT INTO rating (id_prof,rate,id_etud) VALUES (1,2,5)
ON DUPLICATE KEY UPDATE rate=2
I saw another post explaining the use of sequence table to create prefixed AUTO INCREMENT ID.
Link to referenced post
SQL Fiddle
http://sqlfiddle.com/#!2/0ed88/1
I need the generated auto increment format to be: YYMM + AUTO INCREMENT VALUE that reset every month. For example now is January, 2015. The generated id should be: 15011, 15012, 15013, etc. Next month February 2015, the generated id should be: 15021, 15022, 15023, etc. I can use the above method to generate the prefix, however how do I reset the AUTO INCREMENT value each month? Database is InnoDB. Any help will be greatly appreciated :)
MODIFIED CODE
CREATE TABLE table1_seq
(
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
)|
CREATE TABLE Table1
(
id VARCHAR(7) NOT NULL PRIMARY KEY DEFAULT '0', name VARCHAR(30)
)|
CREATE TRIGGER tg_table1_insert
BEFORE INSERT ON table1
FOR EACH ROW
BEGIN
INSERT INTO table1_seq VALUES (NULL);
SET NEW.id = CONCAT(DATE_FORMAT(NOW(),'%y%m'), LAST_INSERT_ID());
END |
INSERT INTO Table1 (name) VALUES ('Jhon'), ('Mark')|
If you have a field DATE or DATETIME in your table then this solution maybe can help you.
Let say your table name my_table and has PK id (INT) and also a field bila (DATE). I just need to get last (biggest) id in current month from my_table then add by 1.
SET #mos= (SELECT MAX(id) FROM my_table WHERE MONTH(`bila`) = MONTH(NOW()) AND YEAR(`bila`) = YEAR(NOW()));
SET #mos = IF(
#mos IS NULL,
CONCAT(YEAR(NOW()),MONTH(NOW()),'001'),
#mos + 1
);
Then u can use #mos in your query next
To reset the AUTO_INCREMENT value, drop and recreate the table1_seq table. Given your example, a TRUNCATE statement would be sufficient (given that there aren't any foreign keys, and we assume the table is using either the MyISAM or InnoDB engine).
TRUNCATE TABLE table1_seq ;
(MySQL behavior for this statement is to create a new, empty table, with the AUTO_INCREMENT set back to the value when the table was created.)
This effectively achieves the same result as a DROP table followed by CREATE table.
That answers the question you asked. As a side note, generating a key value this way usually turns out to be a bad idea.
i've relied on the last answer above, i've used the orderDate field from my table and compared it with the current date during insertion , to decide finally if i want to reset or increment the purchaseOrderRef field:
The aim is to insert custom auto increment order id (field name: "purchaseOrderRef" ) with the format DD-MM-XXX in table [Products_SumOrders]. such that it resets the XXX to 0 automatically every month:
USE [Mydatabase] -- here you need to use your own database
GO
/****** Object: Trigger [dbo].[customAutoIncrement] Script Date: 10/1/2016 10:07:41 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [dbo].[customAutoIncrement]
ON [dbo].[Products_SumOrders]
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
declare #maxOrderID int;
declare #maxOrderRef nvarchar(max);
declare #relativeID varchar(max);
declare #orderId int;
select #orderId =orderid from inserted;
print(#orderId);--allow me to display the inserted order id
SET #maxOrderID = (SELECT Max(orderid) FROM [Products_SumOrders] WHERE MONTH([OrderDate]) = (MONTH(GETDATE())) AND YEAR([OrderDate]) = YEAR(GETDATE()) and orderid < #orderId );
print(#maxOrderID);--last added order
--custom month format (always MM):
declare #mon int;
declare #stringMon nvarchar(10);
set #mon= MONTH(GETDATE());
IF #mon <10
set #stringMon ='0' + CONVERT(VARCHAR(1),#mon) ;
ELSE
set #stringMon = CONVERT(VARCHAR(2),#mon) ;
IF #maxOrderID is null --no orders has been added in this month:
begin
set #maxOrderRef = Substring(CONVERT(VARCHAR(4),YEAR(GETDATE())),3,4)+ '-'+ CONVERT(VARCHAR(2),#stringMon)+'-001';
end
ELSE
--custom order id format (always XXX):
begin
set #relativeID =(SELECT [purchaseOrderRef] FROM [Products_SumOrders] WHERE orderid=#maxOrderID);
set #relativeID = Substring(#relativeID,LEN(#relativeID)-(Charindex('-', REVERSE(#relativeID))-2),LEN(#relativeID));
print(CONVERT(int,#relativeID));
IF CONVERT(int,#relativeID) < 9
set #relativeID ='00' + CONVERT(VARCHAR(2),#relativeID+1) ;
ELSE
begin
if CONVERT(int,#relativeID) < 99
set #relativeID ='0' + CONVERT(VARCHAR(3),#relativeID+1) ;
else
set #relativeID = CONVERT(VARCHAR(3),#relativeID+1) ;
end
set #maxOrderRef = Substring(CONVERT(VARCHAR(4),YEAR(GETDATE())),3,4)+ '-'+ CONVERT(VARCHAR(2),#stringMon)+'-'+ CONVERT(VARCHAR(3),#relativeID);
end
print(#maxOrderRef);
UPDATE Products_SumOrders
SET purchaseOrderRef = #maxOrderRef
FROM inserted INNER JOIN [Products_SumOrders] On inserted.orderid = [Products_SumOrders].orderid
END
GO