I have multiple user_roles. Each user_role has multiple privileges and each privileges has multiple values. I need to create a procedure with user_role_name,description,priviliges_fk(array),values(arrayofstring) as inputs.
This is the procedure I have written.
DELIMITER $$
DROP PROCEDURE IF EXISTS `save_role`$$
CREATE DEFINER=`event_admin`#`%` PROCEDURE `save_role`(IN p_role_name INT,
IN p_description INT,
IN p_privilege_fk INT(),
IN p_values VARCHAR(1000)
)
BEGIN
DECLARE i int default 0;
DECLARE V_ROLE_FK int;
DECLARE counter INT DEFAULT 0;
INSERT INTO ROLE (ROLE_NAME,DESCRIPTION) VALUES(p_role_name,p_description);
SELECT ROLE_PK INTO V_ROLE_FK FROM ROLE WHERE ROLE_NAME=p_role_name AND DESCRIPTION=p_description;
simple_loop:LOOP
SET counter = counter + 1;
INSERT INTO ROLE_PRIVILEGE_BRIDGE (ROLE_FK,PRIVILEGE_FK,VALUE) VALUES(V_ROLE_FK,p_privilege_fk(i),p_values);
END LOOP simple_loop;
END;
You can't. There are two workarounds that would work
Call the procedure one time per element in the array
Concatenate the array elements into one string separated by something (ie |, ;, :) and then split that string internally in the procedure.
I would go with the first alternative. It's cleaner, easier to understand and easier to test.
I'd suggest you to use AUTO_INCREMENT option for primary keys, it will help to work with them. Then use auto-incremented primary key values to insert new rows into a child table - one by one, not using array as a string parameter.
For example (data is simplified):
CREATE TABLE ROLE(
ID INT(11) NOT NULL AUTO_INCREMENT,
ROLE_NAME INT,
DESCRIPTION INT,
PRIMARY KEY (ID)
)
ENGINE = INNODB;
CREATE TABLE ROLE_PRIVILEGE_BRIDGE(
ID INT(11) NOT NULL AUTO_INCREMENT,
PRIVILEGE_FK INT(11) DEFAULT NULL,
VALUE INT(11) DEFAULT NULL,
PRIMARY KEY (ID),
CONSTRAINT FK FOREIGN KEY (PRIVILEGE_FK) REFERENCES ROLE (ID)
)
ENGINE = INNODB;
INSERT INTO ROLE(ROLE_NAME, DESCRIPTION) VALUES(1, 1);
SET #new_id = LAST_INSERT_ID();
INSERT INTO ROLE_PRIVILEGE_BRIDGE(PRIVILEGE_FK, VALUE) VALUES (#new_id, 1);
INSERT INTO ROLE_PRIVILEGE_BRIDGE(PRIVILEGE_FK, VALUE) VALUES (#new_id, 2);
INSERT INTO ROLE_PRIVILEGE_BRIDGE(PRIVILEGE_FK, VALUE) VALUES (#new_id, 3);
Related
i am trying to get used to triggers. I created a small database and a trigger. When i go to insert something in ship category it does not let me do it.If i drop the trigger with the same commend i can insert values at the table. I get this error: #1048 - Column 'IMO' cannot be null
My trigger code is:
/*ship insert*/
DELIMITER //
CREATE TRIGGER `ship_insert_logs`
AFTER INSERT ON `ship`
FOR EACH ROW
BEGIN
DECLARE ship_IMO INTEGER;
SET ship_IMO=new.IMO;
INSERT INTO ship_logs VALUES (null, concat('A new row is inserted with IMO ', ship_IMO, 'at',
date_format(now(), '%d-%m-%y %h:%i:%s %p')));
END //
DELIMITER ;
and ship table is:
CREATE TABLE ship(
department_id INTEGER NOT NULL,
IMO BIGINT PRIMARY KEY NOT NULL,
Latitude DOUBLE PRECISION NOT NULL,
Longitude DOUBLE PRECISION NOT NULL,
current_speed DOUBLE PRECISION NOT NULL,
heading VARCHAR (30),
status VARCHAR(30),
FOREIGN KEY(department_id) REFERENCES department (department_id) ON UPDATE CASCADE
);
while ship_logs table is:
CREATE TABLE ship_logs(
IMO BIGINT PRIMARY KEY NOT NULL,
audit_description VARCHAR(500)
);
I created the following table called books:
CREATE TABLE IF NOT EXISTS `books` (
`id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
`name` TEXT NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
I created another tablet called compare to compare any 2 books from the books table:
CREATE TABLE IF NOT EXISTS `compare` (
`id_1` BIGINT UNSIGNED NOT NULL,
`id_2` BIGINT UNSIGNED NOT NULL,
PRIMARY KEY (`id_1`,`id_2`),
FOREIGN KEY (`id_1`) REFERENCES books(`id`),
FOREIGN KEY (`id_2`) REFERENCES books(`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
The previous works as expected but I need to force MYSQL to allow ONLY unique combination of values in the compare table.
For example if I have the following row in compare table:
id_1 | id_2
------------
1 | 2
I want to force MYSQL to NOT allow me to insert the following row:
id_1 | id_2
------------
2 | 1
So I want MYSQL to allow only either 1,2 or 2,1 NOT both.
Another way would be to swap the values in a before-insert trigger to make sure id_1 < id_2:
CREATE TRIGGER `compare_before_insert` BEFORE INSERT ON `compare` FOR EACH ROW
BEGIN
DECLARE t BIGINT;
IF(NEW.id_1 > NEW.id_2) THEN
SET t = NEW.id_1;
SET NEW.id_1 = NEW.id_2;
SET NEW.id_2 = t;
END IF;
END
This will allow you to use the key to make the pairs unique.
In MySQL (at least prior to version 8), you need to do this using a trigger if you want the database to enforce the constraint.
delimiter $$
create trigger compare_insert_trigger before insert on compare
for each row
begin
if (exists (select 1
from compare c
where c.id2 = new.id1 and c.id1 = new.id2
)
) then
signal sqlsate '45000'
set message_text = 'Book pair already exists in compare';
end if;
end;$$
delimiter ;
Of course, you still need the unique constraint.
Challenge:
Create a method to set "auto_increment" values for tables in a non-sequential way.
The goal is to override the "auto_increment" mechanism and allow the function "LAST_INSERT_ID()" to continue working as expected (returning an INT), so that no changes are needed in software side.
My Solution
The method I found is based on an auxiliary table (unique_id), that stores values available to be assigned. Values are then selected randomly, and removed from the tables as used. When the table gets empty, a new set of ID's is created.
This example is working as expected, but with one problem.
Tables for the demo:
CREATE TABLE `unique_id` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
AUTO_INCREMENT=100;
CREATE TABLE `test_unique_id` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(50) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
AUTO_INCREMENT=1;
Defined a stored procedure and a function:
DELIMITER $$
DROP PROCEDURE IF EXISTS `UNIQUE_ID_REFILL`$$
CREATE PROCEDURE UNIQUE_ID_REFILL()
BEGIN
DECLARE a INT Default 0 ;
simple_loop: LOOP
SET a=a+1;
INSERT INTO unique_id (id) values(null);
IF a=100 THEN
LEAVE simple_loop;
END IF;
END LOOP simple_loop;
END $$
DROP FUNCTION IF EXISTS `UNIQUE_ID_GET`$$
CREATE FUNCTION UNIQUE_ID_GET()
RETURNS INT(11)
MODIFIES SQL DATA
BEGIN
DECLARE new_id INT(11);
DECLARE unique_id_count INT(11);
SET new_id = 0;
SELECT COUNT(*) INTO unique_id_count FROM unique_id;
IF unique_id_count=0 THEN
CALL UNIQUE_ID_REFILL();
END IF;
SELECT id INTO new_id FROM unique_id ORDER BY RAND() LIMIT 1;
DELETE FROM unique_id WHERE id = new_id;
RETURN new_id;
END $$
Created a Trigger on the destination table (test_unique_id):
CREATE TRIGGER test_unique_id__unique_id BEFORE INSERT ON test_unique_id
FOR EACH ROW
SET NEW.id = UNIQUE_ID_GET();
The solution is getting the random ID's as expected:
INSERT INTO test_unique_id(name) VALUES ('A'),('B'),('C');
Creates the rows:
id name
154 'A'
129 'B'
173 'C'
The Problem
The main problem is that LAST_INSERT_ID() stops working... and the software side is broken:
SELECT LAST_INSERT_ID();
0
Any ideas on how to solve this problem? or any other different approach to the challenge?
Thank you very much.
I am just want to create after insert trigger to insert a new row in history table. Why am I getting an error when I run the query?
orders
create table orders
(
id int auto_increment
primary key,
id_user int not null,
picture_name varchar(100) not null,
time date not null,
constraint FK_USER
foreign key (id_user) references stef.users (id)
)
;
create index FK_USER_idx
on orders (id_user)
;
history
create table history
(
id int auto_increment
primary key,
id_order int not null,
id_action int not null,
time date not null,
constraint FK_ORDER
foreign key (id_order) references stef.orders (id),
constraint FK_ACTION
foreign key (id_action) references stef.actions (id)
)
;
create index FK_ORDER_idx
on history (id_order)
;
create index FK_ACTION_idx
on history (id_action)
;
my trigger...
CREATE TRIGGER orders_AFTER_INSERT
AFTER INSERT ON stef.orders
FOR EACH ROW
BEGIN
INSERT INTO history('id_order', 'id_action', 'time')
VALUES (NEW.id, 1, NOW());
END;
I am just want to create after insert trigger to insert a new row in history table. Why am I getting an error when I run the query?
Try this
DELIMITER $$
CREATE TRIGGER orders_AFTER_INSERT
AFTER INSERT ON stef.orders
FOR EACH ROW
BEGIN
INSERT INTO history(`id_order`, `id_action`, `time`)
VALUES (NEW.id, 1, NOW());
END$$
DELIMITER ;
You need to temporarily override the delimiter so MySQL can differentiate between the end of a statement within the body of a trigger (or procedure, or function) and the end of the body.
Edit: Single quotes (') are only ever used to denote string values, for field names use the ` (or in some configurations the ")
CREATE TRIGGER orders_AFTER_INSERT
AFTER INSERT ON stef.orders
FOR EACH ROW
BEGIN
INSERT INTO stef.history()
VALUES (null, NEW.id, 1, NOW());
END
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.