What is the use of CASCADE CONSTRAINTS?

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What is the use of CASCADE CONSTRAINTS?..

Answer / naresh

If you specify this option, later when you delete a row in
the parent table, the database server also deletes any rows
associated with that row (foreign keys) in a child table.
The principal advantage to the cascading-deletes feature is
that it allows you to reduce the quantity of SQL statements
you need to perform delete actions.

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What is the use of CASCADE CONSTRAINTS?..

Answer / kunal sain

to drop the constraint from child table when dropping the
constraint from parent table.

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What is the use of CASCADE CONSTRAINTS?..

Answer / nitesh

It is mainly used in referential integrity constraints.

When you use primary key/candidate key of one relation(say,
r1) as foreign key in other relation(say, r2), you want
changes made to primary key/candidate key of r1 must reflect
in foreign key of r2. And this can be achieved by CASCADE
constraint.
eg. consider two relations account, branch(with primary key
branch_name)

create table account(.....
foreign key branch_name references branch
on delete cascade
on update cascade
..........)

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