what is the difference between rollback & commit?
can a foreign key has null value?
Answer Posted / ashu_deepu
rollback is used to revert back the changes which we have made in the databases.when we do the rollback we return back to the last commit point which we have made.
commit is use to make the changes in the databases permanently. the values of the variables are written to the databases or disk.
FK can have null value but primary key can't have null value.
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