How to update one table in MySQL after insertion in another table - mysql

Question

I have two table first is "employee_details" second is "attendance_rule"
employee_details
e_code | e_name | e_type
01 | Ram | Regular
02 | Shyam | Contract
03 | Mohan | Regular
attendance_rule
e_code | e_type | casual_leaves
01 | Regular | 7
02 | Contract | 6
03 | Regular | 7
I have manually insert values in "attendance_rule".
Now the problem is that when the attendance rule changes in the organisation. The user has to manually update the casual_leave coloumn for all the employees.
What I want is that when an employee details are added in employee_details table , the entry in the attendance_rule table should be automatically made having e_code and e_type same as e_code and e_type of employee_details table and casual_leaves equals to the casual_leaves of the same type of employee.
I think that a trigger should be used here.
but I dont know how to use trigger for this condition i.e. for the entry of casual leaves.
Please help me...how should I do that? Is there a way to do it other that trigger?

Answer 1

It sounds like you don't need a separate entry in attendance_rule for every employee, just for every employee type, so you don't need a trigger at all.
Create employee_details like you suggested:
e_code | e_name | e_type
01 | Ram | Regular
02 | Shyam | Contract
03 | Mohan | Regular
But create attendance_rule with only the rules for each type:
e_type | casual_leaves
Regular | 7
Contract | 6
If you need to find the number of casual leaves for a particular employee, join the two tables:
select
e.e_code,
e.e_name,
e.e_type,
a.casual_leaves
from employee_details e
inner join attendance_rule a on e.e_type = a.e_type
to get
e_code | e_name | e_type | casual_leaves
01 | Ram | Regular | 7
02 | Shyam | Contract | 6
03 | Mohan | Regular | 7
And if you want to make it as easy to use as a table, you can create a view:
create view emp_all_details as
select
e.e_code,
e.e_name,
e.e_type,
a.casual_leaves
from employee_details e
inner join attendance_rule a on e.e_type = a.e_type
Now you can simply say: select * from emp_all_details to get:
e_code | e_name | e_type | casual_leaves
01 | Ram | Regular | 7
02 | Shyam | Contract | 6
03 | Mohan | Regular | 7