Interested to Buy Any Domain ? << Click Here >> for more details...
what is the difference between rollback & commit?
can a foreign key has null value?
- 6 Answers
- 14517 Views
- I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
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 |
What is TNS File
What are the set operators union, union all, minus & intersect meant to do?
how to i write the query 'NISHI' TO N I S H I
4 Answers Attra, Metric Stream,
Create table Employee ( Employee_Id varchar2(8) Constraint emp_id_pk primary key, FirstName varchar2(50), LastName varchar2(50), DeptID Number(5) Constraint dept_id_fk Foreign Key(DeptId) References Department(DeptId) ) Error I am getting: Constraint specification are not allowed here
Display the records between two range?
What are the differences between interval year to month and interval day to second?
How to write date and time interval literals in oracle?
i have a table and it has constraints and i want to get "ALTER TABLE table_name ADD CONSTRAINT constraint_name constraint type" this code must be in string type please help me if you want, i can give more explainings
Whether any commands are used for months calculation? If so, what are they?
What are the types of trigger in oracle?
What is Hash Index?
What is program global area (pga) in oracle?
Oracle General 
