what is the difference between rollback & commit?
can a foreign key has null value?
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Answer / ven
Commit made changes permenant to the database.
Rollback made undo the changes.
Yes, FK has null values.
| Is This Answer Correct ? | 23 Yes | 2 No |
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.
| Is This Answer Correct ? | 9 Yes | 1 No |
Answer / anjani kumar
Commits and Rollback both complete our transaction cycle.
we use commit to store the DML changes into DB but Rollback
performs undo to our DML transaction
| Is This Answer Correct ? | 5 Yes | 1 No |
Answer / komal
Roll back Undoes whatever add, delete update transactions
we do.
Commit saves the add,delete update transactions
permanenetly in the database.
However a DML statement if fired in between a transaction
commits the complete list of add, delete update statements
above.
| Is This Answer Correct ? | 3 Yes | 1 No |
Answer / aditi
commit save the transactions done after the last commit and rollback undo all transactions after last commit
Yes foreign key can have null value
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / 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.
| Is This Answer Correct ? | 1 Yes | 1 No |
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