Q: What is ON DELETE CASCADE ?

genaraly on delete cascade commend is used to
delete records at time in parant and child
tables

i think on delete casecade commend is used remove table along
with date at time

on delete cascade means suppose we r having the tables student(s-id,cource,s-name,.......) ,library(s-id,books).student table having the primary key& related forien in library table.based on the forien key librarian issues books to the students.if u delete record in student table automatically corosponding record will be deleted in the library table .

on delete cascade means suppose we r having the tables student(s-id,cource,s-name,.......) ,library(s-id,books).student table having the primary key& related forien in library table.based on the forien key librarian issues books to the students.if u delete record in student table automatically corosponding record will be deleted in the library table .