I have a database into which i enter values through an application. To be specific ,i enter certain value in a text-box and click on save Button which handles the task of saving it into the database. The problem that i'm facing is even when i don't enter any value in the text-box and click on save button the value gets saved into the database( A case which i should have handled in the code ). Now i want to write a SQL-script so that it blocks the entry of the blank values into the database .
for example lets say ..books be the table which contains columns author_name , price , year
so if a try to enter a blank author name and try saving it, it should not be saved
I tried this:
CREATE TRIGGER test AFTER INSERT ON books
FOR EACH ROW BEGIN
IF NEW.author_name= '' THEN
delete from books where author_name= '';
can anyone tell me how to do this , is there any other method to achieve this ?