set maximum value to a column

Question

I have a table with a column (int type) called age. This column should hold maximun value 50. If it exceeds then it shouldn\'t update that row.

Means this column sho

Answer 1

Try this:

CREATE TRIGGER check_trigger
  BEFORE INSERT
  ON table
  FOR EACH ROW
BEGIN
  IF NEW.age<0 OR NEW.age>50 THEN
    CALL `Error: Wrong values for age`; -- this trick will throw an error
  END IF;
END

Answer 2

You could use CHECK constraint:

CREATE TABLE person (
Name VARCHAR(80), 
Age  INT CHECK (Age BETWEEN 5 and 50));

Answer 3

create table test (
age tinyint not null ) engine = myisam;

delimiter //
drop trigger if exists max_num//
create trigger max_num before insert on test
for each row 
begin
if new.age < 0 or new.age > 50 then
set new.age = null;
end if;
end//
delimiter ;

insert into test (age) values (100);

Make the same thing for update.