Can A column defined as PRIMARY KEY can have NULL values ?
Answer Posted / parul chaudhary
No,a coloum defined as PRIMARY KEY can't have NULL values,
because when we assign a coloum as a PRIMARY KEY that mean
its a unique coloum by which whole the table have to be
accessed.
| Is This Answer Correct ? | 5 Yes | 0 No |
Post New Answer View All Answers
Write down the differences between nosql and rdbms?
Explain environment of openedge?
How do you notify dbpak about stored procedure?
Why is maintaining a database important?
Explain dml (data manipulation language)?
What is database write application of database?
Explain a checkpoint and when does it occur?
1. Tell me about your self? 2. Latest Project Introduction? 3. Difference between server jobs and parallel jobs? 4. Seq-Seq Explain its behavior and execution mode and which parallelism technique is used? 5. What is padding characters? 6. Seq-Seq, Seq-Copy-Seq which one is the best and efficient? 7. How many reject links do we have to a transformer? 8. How many reject links to join stage? 9. Difference between join and lookup? 10. How to design PX routine? 11. How can we call job in another job? 12. Difference between batch and sequencer? 13. Which Database is used? 14. What is change capture? Give briefing of that? 15. What is change Code? Explain? 16. How you call UNIX in Ds? 17. How do you call JCL in UNIX? 18. How do you pass the job status of one job to another job? Have designed any job sequencer? 19. How do you find a file in existed directory? 20. How can you call parallel jobs in transformer? 21. Execution of jobs in command line? 22. Tuning of sql queries? 23. What is orchestrating metadata? 24. What are junk dimension? 25. What are the third party tools you are used? 26. What are the system variables you have used?
What is openedge abl in terms of taking the perspective of the developer?
What are the main features of a database?
What is data sparsity and how it effect on aggregation?
What are types of dbms?
What are the integrity rules in dbms?
What are five advantages of a database?
Explain atomicity and aggregation?