What is the difference between primary key & unique index ?
- 6 Answers
- 25189 Views
- Patni, Temenos, I also Faced
- E-Mail Answers
Answer Posted / uddipto banerji
1. Primary Key is a column or a set of columns that uniquely identifies a row.Its purpose RECORD UNIQUENESS
2. Primary Key will not allow duplicate values.
3. Primary Key will not allow null.
4. Primary Key is not compulsory but recommended.
5. Primary Key helps to identify one record from another.
6. Only One Primary Key is allowed per table.
7. Unique Indexes is created automatically if there is Primary Key.
8. One table can combine upto 16 columns in a Composite Primary Key.
9. A table can have more than one Unique Key which is not possible in a Primary Key.
| Is This Answer Correct ? | 10 Yes | 2 No |
Post New Answer View All Answers
Is db2 a mainframe?
Are view updateable?
What is precompiler in db2?
What do you mean by between and in? Is between inclusive of specified range values?
What is innodb buffer pool?
What is the difference between oracle and db2?
Highlight all the advantages that are attached to a package.
What is package in cobol db2?
List down the types of triggers in the db2 database?
What is deadlock in db2?
How can we read records for specific member in CL? AND rpg?
What is nvl in db2?
How do you concatenate the firstname and lastname from emp table to give a complete name?
Is it possible to create an Instance in DB2 using DB2 Control Center ?
List some fields from sqlca?
