what is the difference between rollback & commit?
can a foreign key has null value?
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Answer Posted / vaibhavi_dixit
With commit, all the changes, which are made using insert,
update or delete SQL statments, are save permanently in the
table(ie DB).Whereas, if one want to undo the changes made
by DML statments, then before issuing commit, one can use
rollback statment.Rollback statment has no effect, if used
after commit.
Yes foreign key can have null value.
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