Interested to Buy Any Domain ? << Click Here >> for more details...
"primary key=unique+null" is equal,reson?not,reason?
- 5 Answers
- 7282 Views
- I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / prashant
Primary Key = unique + Not null
Because primary key is used to uniquely identify each row
of the table.
| Is This Answer Correct ? | 9 Yes | 0 No |
Answer / karunakar reddy s
primary key = unique and not null in a table
because primary key act as foreign key in other table, and
we can identify the records using this key. If pk has null
value how can we identify the records in the first table
| Is This Answer Correct ? | 8 Yes | 0 No |
Answer / devaraja.m
Primary key should be Unique + not null. hence
Primary key = unique+ Not null.
primary having the best role in al table, without PK we
cont identify the table itself. because it should be only
one & should not be zero.
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / sajeda
primary key = unique+ null
Because the primary key identyfi uniqe value that does not
contain nll values.
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / s.rama devi
if we create pk for any column in table. That column dont
allow the duplicate values and also not null values
| Is This Answer Correct ? | 0 Yes | 1 No |
What is literal?
what are corelated subqueries
what is the maximum number of indexes i can create for a table? What happens if i create indexes for all the columns of a table? Will it slow down the speed of retrieval
Explain oracle instance.
What is meant by recursive hints ?
How to generate query output in html format?
How would you design a database for an e-commerce website?
How to use null as conditions in oracle?
What are the built-in functions used for sending Parameters to forms ?
Assuming today is Monday, how would you use the DBMS_JOB package to schedule the execution of a given procedure owned by SCOTT to start Wednesday at 9AM and to run subsequently every other day at 2AM.
what is candidate key & super key
How to export data with a field delimiter?
Oracle General 
