Table: items
Create Table:
CREATE TABLE `items` (
`ite_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`itemName` varchar(40) DEFAULT NULL,
`itemNumber` int(10) unsigned NOT NULL,
PRIMARY KEY (`ite_id`),
UNIQUE KEY `itemName` (`itemName`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1
delimiter |
create trigger item_beforeinsert before insert on items
for each row begin
if new.itemNumber < 50 then
set new.ite_id = null;
end if;
end;
|
now the following command doesn't cause a trigger
insert items( itemname, itemnumber) values ( 'xyz', 1 );
any help would be very much appreciated, thanks!
Your ite_ID is not null and you want to set it null with your trigger, beside that it's auto increment, so you wont be able to 'control' all the values to assign to that field, I.E it wont overwrite values
It'd be
insert INTO items( itemname, itemnumber) values ( 'xyz', 1 );
also, since you have set ite_id as NOT NULL, you can't use a set new.ite_id = null;
For auto incremented primary key fields you can pass NULL value while inserting. MySQL automatically assigns auto generated value. It is not an error setting up NULL to it BEFORE insert. And hence trigger didn't fire an error.
Example:
insert into items( ite_id, ... ) values ( null, ... );
The above statement is valid and works, since ite_id field is primary key with auto increment.
Related
I'll like to find out if it's possible to do the following:
after insertion of data into table a, a row will be created automatically in table b and the Note_Id (its primary key) will be stored in one of the attributes (which is a foreign key that references to the primary key in table b) in table a.
CREATE TABLE table_a ( D_Id int(5) NOT NULL AUTO_INCREMENT,
User_Id int(8) not null,
Note_Id int(5) not null, -- this is the foreign key that points to table b
PRIMARY KEY (D_Id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE table_b ( Note_Id int(5) NOT NULL AUTO_INCREMENT,
Note_Description varchar(50) null,
PRIMARY KEY (Note_Id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Thanks!
delimiter $$
CREATE TRIGGER ins_Document
AFTER INSERT ON TABLE_A FOR EACH ROW
BEGIN
set #notenum=(Select max(Note_Id) from TABLE_B);
if(#notenum=0) then begin new.Note_Id=1;
end;
else
new.Note_Id=#notenum+1;
end if;
INSERT INTO TABLE_B (Note_Id) VALUES (NEW.Note_Id);
END$$
delimiter ;
Have a look into triggers: Create Trigger
Here you can react on events like inserts into a table and define respective actions for that.
This is my schema:
I am trying to have an insert into "desktops" or "laptops" insert an id generated automatically from "computers". That works.
My issue is when I insert into either table, I can not select last_insert_id();
Is there something I am doing wrong? I am trying to pass the id all the way forward to my application, for further processing. Selecting MAX(id) is not a valid solution. My SQL connection makes one insert statement, and the trigger should not break that functionality...
Use test;
CREATE TABLE `laptops` (
`id` int(11) NOT NULL,
`name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=innodb DEFAULT CHARSET=utf8;
CREATE TABLE `desktops` (
`id` int(11) NOT NULL,
`name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`),
) ENGINE=innodb DEFAULT CHARSET=utf8;
CREATE TABLE `computers` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`type` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=innodb DEFAULT CHARSET=utf8;
CREATE TRIGGER `laptops_BINS` BEFORE INSERT ON `laptops` FOR EACH ROW
BEGIN
IF (EXISTS(SELECT id FROM laptops WHERE name = NEW.name)) THEN
SET NEW.id = NULL;
ELSE
INSERT INTO computers (type) VALUES ('laptop');
SET NEW.id = LAST_INSERT_ID();
SET NEW.id = LAST_INSERT_ID(NEW.id);
END IF;
END
CREATE TRIGGER `desktop_BINS` BEFORE INSERT ON `desktops` FOR EACH ROW
BEGIN
IF (EXISTS(SELECT id FROM desktops WHERE name = NEW.name)) THEN
SET NEW.id = NULL;
ELSE
INSERT INTO computers (type) VALUES ('desktop');
SET NEW.id = LAST_INSERT_ID();
SET NEW.id = LAST_INSERT_ID(NEW.id);
END IF;
END
INSERT INTO laptops (name) VALUES ('laptop1');
INSERT INTO laptops (desktop) VALUES ('desktop1');
INSERT INTO laptops (name) VALUES ('laptop2');
INSERT INTO laptops (desktop) VALUES ('desktop2');
SELECT last_insert_id();
Expecting 4, actually its 0.
Any thoughts as to how I can fix the trigger? Maybe someone can help me format the AFTER_INSERT statement to fix last_insert_id?
I tried setting the values to auto-increment, and unique in the laptops and desktops table, neither will fix the issue.
Rather than trying to deal with the 'confusion' of 'last_insert_id'. I decided to change the table structure to be a more 'common' format.
That is change the 'laptops' and 'desktops' tables to have the 'auto_increment' keys. This changes the 'computers' table to have a primary key of 'computer_id' from 'laptops' or 'desktops' and a 'computer_type'.
Here are the table structures and triggers.
It has been tested on mysql 5.5.16 on windows xp.
CREATE TABLE `laptops` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
CREATE TABLE `desktops` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
CREATE TABLE `computers` (
`computer_id` int(11) NOT NULL,
`computer_type` varchar(45) NOT NULL,
PRIMARY KEY (`computer_id`,`computer_type`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
DELIMITER $$
USE `testmysql`$$
DROP TRIGGER /*!50032 IF EXISTS */ `laptop_bins`$$
CREATE
/*!50017 DEFINER = 'test'#'localhost' */
TRIGGER `laptop_bins` AFTER INSERT ON `laptops`
FOR EACH ROW BEGIN
INSERT INTO computers (computer_id, computer_type ) VALUES (new.id, 'laptop');
END;
$$
DELIMITER ;
DELIMITER $$
USE `testmysql`$$
DROP TRIGGER /*!50032 IF EXISTS */ `desktop_bins`$$
CREATE
/*!50017 DEFINER = 'test'#'localhost' */
TRIGGER `desktop_bins` AFTER INSERT ON `desktops`
FOR EACH ROW BEGIN
INSERT INTO computers (computer_id, computer_type ) VALUES (new.id, 'desktop');
END;
$$
DELIMITER ;
Sample Queries and Output:
INSERT INTO laptops (NAME) VALUES ('laptop1');
INSERT INTO desktops (NAME) VALUES ('desktop1');
INSERT INTO laptops (NAME) VALUES ('laptop2');
INSERT INTO desktops (NAME) VALUES ('desktop2');
Laptops:
id name
------ ---------
1 laptop1
2 laptop2
Desktops:
id name
------ ----------
1 desktop1
2 desktop2
Computers:
computer_id computer_type
----------- ---------------
1 desktop
1 laptop
2 desktop
2 laptop
This more a possible approach to the requirement than an answer.
I can create the code if required. It is not a lot of code on top of what is here.
The problem is to maintain tables in an other database, in sync, without doing lots of repeat work.
My suggestion:
In the 'computers' database - have a 'computers_new' table that is inserted to by the 'after insert' trigger and holds the relevant key information. Including a 'unprocessed' column.
I would then run a script at regular intervals or was triggered when the 'computers_new' table changed. It would:
1) transfer the 'unprocessed' details to the 'laptops', 'desktops' tables in the other database.
2) mark the transferred records as processed.
Advantages:
Lots of small chunks of work.
By using transactions it is reliable.
Drawbacks.
Ensuring tables are in sync.
I Want to add an Integer Column to a String that's because i need to generate a varchar variable with a numeric part that automatically increments. For example, P000001,P000002...
In order to do that what i am doing while creation of table i have taken an int field ID which auto_increments and i am Concatenating P with 00000 and the ID value
The Table i have created is :
CREATE TABLE tblAcceptTest(
ID int AUTO_INCREMENT NOT NULL primary key,
PatientID as CONCAT('P' , CONCAT('000000',CAST(ID as char)))
);
It Shows me the error from as keyword.
Please help
MySQL's documentation (http://dev.mysql.com/doc/refman/5.1/en/create-table.html) says, "the default value must be a constant; it cannot be a function or an expression." Why don't you just get the PatientID value afterward as part of the SELECT:
SELECT CONCAT('P', LPAD(ID, 6, 0)) AS PatientID FROM tblAcceptTest;
It looks like you want six digits after the "P", so try this for your expression:
CONCAT('P', LPAD(ID, 6, '0'))
Mysql has little support for computed columns.
Patient ID from your specification could be a char(7)
CREATE TABLE tblAcceptTest(
ID int AUTO_INCREMENT NOT NULL primary key,
PatientID char(7)
);
Then create some triggers. Note that the following insert trigger will cause issues with high concurrency servers.
DELIMITER |
CREATE TRIGGER tblAcceptTest_insert BEFORE INSERT ON tblAcceptTest
FOR EACH ROW BEGIN
DECLARE next_id INT;
SET next_id = (SELECT AUTO_INCREMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='tblAcceptTest');
SET NEW.PatientID = CONCAT('P' , RIGHT(CONCAT('000000',next_id),6)) ;
END;
|
CREATE TRIGGER tblAcceptTest_update BEFORE UPDATE ON tblAcceptTest
FOR EACH ROW BEGIN
SET NEW.PatientID = CONCAT('P' , RIGHT(CONCAT('000000',NEW.ID),6)) ;
END;
|
DELIMITER ;
You use relationships and views to achieve the same result.
CREATE TABLE `patient` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`patient` varchar(60) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `accepted_test` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`patient_id` int(11) NOT NULL,
`accepted` timestamp NULL DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `patient_id` (`patient_id`),
CONSTRAINT `accepted_test_ibfk_1` FOREIGN KEY (`patient_id`) REFERENCES `patient` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
create or replace view accepted_test_veiw as
select CONCAT('P' , RIGHT(CONCAT('000000',patient_id),6)) patient_key
, accepted
, id accepted_test_id
, patient_id
from accepted_test ;
select * from `accepted_test_veiw`
Within a BPM web application, I have a field for an invoice # on a particular page but I need for it to be auto generated every time a user attaches an invoice and views that page. That number must be unique and preferably auto-incremented. A value for the invoice # field can be displayed by querying from a table from an external MYSQL database. So every time a user lands on that particular page, a SELECT query statement can be fired.
On MYSQL end, how would I set this up? So basically, I would like to setup a query for that invoice # field where it will for run a query for example,
SELECT invoice_num FROM invoice_generator
and every time this query runs, it would return the next incremented number.
You can use mysql trigger concept here....
I have added one example here...
It will be very usefull for u (see this link also :http://www.freemindsystems.com/mysql-triggers-a-practical-example/)
CREATE TABLE `products` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL DEFAULT '',
`price` int(20) NOT NULL DEFAULT '0',
`other` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `products_name_idx` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `freetags` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`tag` varchar(50) NOT NULL DEFAULT '',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `freetagged_objects` (
`tag_id` int(20) NOT NULL DEFAULT '0',
`object_id` int(20) NOT NULL DEFAULT '0',
`tagged_on` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`module` varchar(50) NOT NULL DEFAULT '',
PRIMARY KEY (`tag_id`, `object_id`),
KEY `freetagged_objects_tag_id_object_id_idx` (`tag_id`, `object_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
INSERT_PRODUCTS_TAGS
DELIMITER ||
DROP TRIGGER IF EXISTS insert_products_tags;
||
DELIMITER ##
CREATE TRIGGER insert_products_tags AFTER INSERT ON products
FOR EACH ROW
BEGIN
DECLARE current_id integer;
DECLARE tag_id integer;
DECLARE next integer;
DECLARE tag_field varchar(255);
DECLARE next_sep integer;
DECLARE current_tag varchar(255);
DECLARE right_tag varchar(255);
-- We use the field other as comma-separated tag_field
SET tag_field = NEW.other;
-- Check for empty tags
IF (CHAR_LENGTH(tag_field) <> 0) THEN
-- Loop until no more ocurrencies
set next = 1;
WHILE next = 1 DO
-- Find possition of the next ","
SELECT INSTR(tag_field, ',') INTO next_sep;
IF (next_sep > 0) THEN
SELECT SUBSTR(tag_field, 1, next_sep - 1) INTO current_tag;
SELECT SUBSTR(tag_field, next_sep + 1, CHAR_LENGTH(tag_field)) INTO right_tag;
set tag_field = right_tag;
ELSE
set next = 0;
set current_tag = tag_field;
END IF;
-- Drop spaces between comas
SELECT TRIM(current_tag) INTO current_tag;
-- Insert the tag if not already present
IF (NOT EXISTS (SELECT tag FROM freetags WHERE tag = current_tag)) THEN
-- Insert the tag
INSERT INTO freetags (tag) values (current_tag);
SELECT LAST_INSERT_ID() INTO tag_id;
ELSE
-- Or get the id
SELECT id FROM freetags WHERE tag = current_tag INTO tag_id;
END IF;
-- Link the object tagged with the tag
INSERT INTO freetagged_objects
(tag_id, object_id, module)
values
(tag_id, NEW.id, 'products');
END WHILE;
END IF;
END;
##
Now If you execute an insert on products table:
INSERT INTO PRODUCTS
(name, price, other)
values
("product1", 2, "tag1, tag2,tag3 , tag 4");
i have a problem in after insert trigger. when i am inserting the data in the table it should automatically update the date and it should be the current date. but when i am executing the following query it is not working properly in my table.
first i created a table:
DROP TABLE IF EXISTS `ignite`.`products`;
CREATE TABLE `ignite`.`products`(
`products_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`products_model` varchar(30) NOT NULL,
`model_hash` bigint(20) unsigned NOT NULL,
`Product_name` varchar(45) NOT NULL,
`created` datetime NOT NULL,
PRIMARY KEY (`products_id`)
) ENGINE=MyISAM AUTO_INCREMENT=977 DEFAULT CHARSET=latin1;
Then i created this trigger:
use ignite;
CREATE TRIGGER created_date BEFORE INSERT ON products
FOR EACH ROW
SET NEW.created = NOW();
but when i am inserting the data in this table:
use ignite;
INSERT INTO products
(products_id, products_model, model_hash, Product_name)
values
(123, "456645", 457567, "awetert");
This is showing the following error:
field 'created' does not have default value. error-1364
It's because on your INSERT statement does not include the created values. You need to include it for example with zero datetime value:
INSERT INTO products
(products_id, products_model, model_hash, Product_name, created)
values
(123, "456645", 457567, "awetert", "0000-00-00 00:00:00");