trigger to update table contribution calculation using mysql - mysql

Question

I need to calculate contribution base on project per developer
Contribution table
-------------------------------------------------------------
| id | projected | developer id | total hours | contribution|
-------------------------------------------------------------
| 1 | 1 | 1 | 25 | |
-------------------------------------------------------------
| 2 | 1 | 2 | 75 | |
-------------------------------------------------------------
| 3 | 2 | 1 | 10 | |
-------------------------------------------------------------
need to update same table with trigger after insert and update
expected result
Contribution table
-------------------------------------------------------------
| id | projected | developer id | total hours | contribution|
-------------------------------------------------------------
| 1 | 1 | 1 | 25 | 25% |
------------------------------------------------------------
| 2 | 1 | 2 | 75 | 75% |
-------------------------------------------------------------
| 3 | 2 | 1 | 10 | 100% |
-------------------------------------------------------------
calculation for the getting contribution
project 1 :
total hours = 25 + 75 = 100
contribution per developer = 25/100*100
= 25%
i need a trigger to get this result: but don't know how to get this
This is my trigger not getting error but contribution calculation not correct
CREATE TRIGGER `update_contribution` AFTER INSERT ON `tasks`
FOR EACH ROW BEGIN
IF NOT EXISTS
(SELECT p_id ,d_id
FROM contribution
WHERE
p_id = NEW.p_id
AND
d_id = NEW.d_id)
THEN
SET #old_total_dev_hours = (SELECT SUM(total_hours)
FROM contribution
WHERE p_id = NEW.p_id
GROUP BY p_id);
SET #total_hours1 = (SELECT (total_hours)
FROM contribution
WHERE d_id = NEW.d_id AND p_id = NEW.p_id
);
SET #dev_con = #total_hours1/#old_total_dev_hours*100 ;
SET #total_hours = new.hours + new.overtime;
INSERT INTO contribution
( p_id,
d_id,
hours,
overtime,
total_hours,
contribution
)
VALUES
(NEW.p_id,
NEW.d_id,
NEW.hours,
NEW.overtime,
#total_hours ,
#dev_con
);
ELSE
UPDATE contribution
SET
hours = hours + NEW.hours ,
overtime = overtime + NEW.overtime,
total_hours = hours + overtime,
contribution = #dev_con
WHERE
p_id = NEW.p_id
AND
d_id = NEW.d_id;
END IF;
END
This is my code in this code other calculation are working fine
contribution is not getting correctly!!

Answer 1

Here's an updated trigger that would replace the one from your previous question. It calculates
both values for the total_hours and contribution percentage.
DELIMITER |
CREATE TRIGGER update_hours AFTER INSERT ON tasks
FOR EACH ROW
BEGIN
SET #old_total_dev_hours = (SELECT SUM(hours + overtime)
FROM contribution
WHERE p_id == new.p_id && d_id == new.d_id
GROUP BY p_id,d_id);
SET #old_total_hours = (SELECT SUM(hours + overtime)
FROM contribution
WHERE p_id == new.p_id
GROUP BY p_id);
SET #total_hours = #old_total_dev_hours + new.hours + new.overtime;
SET #contrib_percent = (#old_total_dev_hours / #old_total_hours) * 100;
INSERT INTO contribution
( p_id,
d_id,
hours,
overtime,
total_hours,
contribution )
VALUES
(
NEW.p_id,
NEW.d_id,
NEW.hours,
NEW.overtime,
#total_hours,
#contrib_percent
);
END|
DELIMITER ;

Answer 2

Assuming tasks logs hours worked by developers on projects then 2 things can happen 1) there is no note that a developer has worked on a project in contribution 2) a developer has worked on a project and the hours he has worked need to updated in contribution. Both cases imply that all developer contributions need to be recalculated on each insert to tasks.
For example
drop table if exists t,contribution;
create table t(id int auto_increment primary key, developerid int, projectid int,hrs_normal int, hrs_overtime int);
create table contribution(id int auto_increment primary key, projectid int,
developerid int, hrs int, contribution decimal (6,3) default 0);
drop trigger if exists t;
delimiter $$
create trigger t after insert on t
for each row
begin
declare totalhours int default 0;
set totalhours = (select ifnull(sum(hrs),0) from contribution where projectid = new.projectid);
set totalhours = totalhours + ifnull(new.hrs_normal,0) + ifnull(new.hrs_overtime,0);
if not exists (select 1 from contribution where projectid = new.projectid and developerid = new.developerid) then
insert into contribution(projectid,developerid,hrs)
values
(new.projectid,new.developerid,ifnull(new.hrs_normal,0) + ifnull(new.hrs_overtime,0)
);
else
update contribution
set hrs = hrs + ifnull(new.hrs_normal,0) + ifnull(new.hrs_overtime,0)
where developerid = new.developerid and projectid = new.projectid;
end if;
update contribution
set contribution = (hrs / totalhours) * 100
where projectid = new.projectid;
end $$
delimiter ;
MariaDB [sandbox]> truncate table t;
Query OK, 0 rows affected (0.28 sec)
MariaDB [sandbox]> truncate table contribution;
Query OK, 0 rows affected (0.25 sec)
MariaDB [sandbox]> select * from t;
Empty set (0.00 sec)
MariaDB [sandbox]> select * from contribution;
Empty set (0.00 sec)
MariaDB [sandbox]>
MariaDB [sandbox]> insert into t (developerid , projectid ,hrs_normal , hrs_overtime )
-> values
-> (1,1,10,0);
Query OK, 1 row affected (0.02 sec)
MariaDB [sandbox]>
MariaDB [sandbox]> select * from t;
+----+-------------+-----------+------------+--------------+
| id | developerid | projectid | hrs_normal | hrs_overtime |
+----+-------------+-----------+------------+--------------+
| 1 | 1 | 1 | 10 | 0 |
+----+-------------+-----------+------------+--------------+
1 row in set (0.00 sec)
MariaDB [sandbox]> select * from contribution;
+----+-----------+-------------+------+--------------+
| id | projectid | developerid | hrs | contribution |
+----+-----------+-------------+------+--------------+
| 1 | 1 | 1 | 10 | 100.000 |
+----+-----------+-------------+------+--------------+
1 row in set (0.00 sec)
MariaDB [sandbox]>
MariaDB [sandbox]> insert into t (developerid , projectid ,hrs_normal , hrs_overtime )
-> values
-> (1,1,10,0),(2,1,30,10);
Query OK, 2 rows affected (0.05 sec)
Records: 2 Duplicates: 0 Warnings: 0
MariaDB [sandbox]>
MariaDB [sandbox]> select * from t;
+----+-------------+-----------+------------+--------------+
| id | developerid | projectid | hrs_normal | hrs_overtime |
+----+-------------+-----------+------------+--------------+
| 1 | 1 | 1 | 10 | 0 |
| 2 | 1 | 1 | 10 | 0 |
| 3 | 2 | 1 | 30 | 10 |
+----+-------------+-----------+------------+--------------+
3 rows in set (0.00 sec)
MariaDB [sandbox]> select * from contribution;
+----+-----------+-------------+------+--------------+
| id | projectid | developerid | hrs | contribution |
+----+-----------+-------------+------+--------------+
| 1 | 1 | 1 | 20 | 33.333 |
| 2 | 1 | 2 | 40 | 66.667 |
+----+-----------+-------------+------+--------------+
2 rows in set (0.00 sec)
MariaDB [sandbox]>
MariaDB [sandbox]> insert into t (developerid , projectid ,hrs_normal , hrs_overtime )
-> values
-> (1,1,10,0),(2,2,30,10);
Query OK, 2 rows affected (0.05 sec)
Records: 2 Duplicates: 0 Warnings: 0
MariaDB [sandbox]>
MariaDB [sandbox]> select * from t;
+----+-------------+-----------+------------+--------------+
| id | developerid | projectid | hrs_normal | hrs_overtime |
+----+-------------+-----------+------------+--------------+
| 1 | 1 | 1 | 10 | 0 |
| 2 | 1 | 1 | 10 | 0 |
| 3 | 2 | 1 | 30 | 10 |
| 4 | 1 | 1 | 10 | 0 |
| 5 | 2 | 2 | 30 | 10 |
+----+-------------+-----------+------------+--------------+
5 rows in set (0.00 sec)
MariaDB [sandbox]> select * from contribution;
+----+-----------+-------------+------+--------------+
| id | projectid | developerid | hrs | contribution |
+----+-----------+-------------+------+--------------+
| 1 | 1 | 1 | 30 | 42.857 |
| 2 | 1 | 2 | 40 | 57.143 |
| 3 | 2 | 2 | 40 | 100.000 |
+----+-----------+-------------+------+--------------+
3 rows in set (0.00 sec)
Note if the business rules are that a developers hours can amended in tasks you will also need and update trigger along the same lines.