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.

Is This Answer Correct ?    1 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What suggestions do you have to reduce the network traffic?

746


What are the restrictions in a oracle read only transaction?

797


How would you edit your CRONTAB to schedule the running of /test/test.sh to run every other day at 2PM?

1682


How does oracle handle read consistency?

900


hello friends Im doing my final year engineering in B.Tech.. one of uncle said he can provide job in his company if im good in database management. but i have only basic knowledge about database, so like to join database management course in good intuition. so friends kindly help me to get good intuition because its my future.

2030


what is the difference between functional dependecy and multilevel dependency?

2246


Explain the different normalization forms?

834


What happens to the data files if a tablespace is dropped?

826


What is an anonymous block?

930


What is the difference difference between $ORACLE_HOME and $ORACLE_BASE.

900


Describe an oracle table?

818


How many categories of data types?

778


List the various oracle database objects?

835


Is insert autocommit in oracle?

821


What is the data pump import utility?

799