Can A column defined as PRIMARY KEY can have NULL values ?
- 2 Answers
- 4448 Views
- I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / 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 |
what is s/w lifecycle?
Define transaction and transaction isolation levels?
What is Restricted Mode of Instance Startup ?
What is structure of dbms?
What is executive plan?
1. How many nodes you are using project? 2. What is configuration file? 3. What is modules partition? How it is work in project? 4. What is Environment Variable? How it is use? 5. What is sequence? 6. How do you execute parallel jobs in projects? 7. If you run a job in job sequencer individually without any comments? 8. How many jobs did in your project? 9. How to schedule the job in Data stage 7.5 X2? 10. If you have 10 jobs in PX2, shall you run all jobs at a time? 11. I have 5 jobs (1-5), I connect with each other, but I want to run from 3-5 only how? 12. What is same partition? 13. If you have 40GB hard disk in I have 30GB data how I configure the nodes for partition? 14. Did you write any code for Data stage project? 15. Did you write any code for parallel job execution in your project? 16. Will you schedule all jobs at a time? 1. What are environment variable, job parameters? 2. What is the relationship between the tables in oracle? 3. How can u create the sequence? 4. What are the client components? 5. Tell me about the Data stage administrator? 6. Tell me about the Data stage Manager? 7. What is joining? 8. What is difference between grep command and fgrep command? 9. What is run time column propagation? 10. How to open the file? 11. How do you cleanse the data in your project? 1. Using which stage raw binary converted into dataset? 2. Which stage is used to read the data into external application? 3. Can we convert dataset into raw binary 4. XML path? 5. When we use the hash partition in aggregator stage? 6. How many reject links in transformer stage? 7. Data stage debugger available in which jobs? 8. Tell me two parts of data set? 9. What is the function used for null handling in modify stage? 10. Default execution mode for exception handler? 11. Maximum exception handler allowed in sequence?
What is the use of FILE option in IMP command ?
What is db context?
What is the use of CONSTRAINTS option in EXP command ?
What do you understand by ‘database’?
Explain the concepts of a primary key and foreign key.
How to do replication of firebird databases?
-
Oracle (3258) - SQL Server (4518)
- MS Access (429)
- MySQL (1402)
- Postgre (483)
- Sybase (267)
- DB Architecture (141)
- DB Administration (291)
- DB Development (113)
- SQL PLSQL (3328)
- MongoDB (502)
- IBM Informix (50)
- Neo4j (82)
- InfluxDB (0)
- Apache CouchDB (44)
- Firebird (5)
- Database Management (1411)
- Databases AllOther (288)
