Interested to Buy Any Domain ? << Click Here >> for more details...
If a table column has is UNIQUE and has NOT NULL, is it
equivalent to a PRIMARY KEY column?
- 7 Answers
- 10795 Views
- IBM, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / murugananthan
NO, UNIQUE +NOT NULL != PRIMARY KEY
it cant refer someother table column
| Is This Answer Correct ? | 12 Yes | 2 No |
Answer / yuva
No. It can be at table level, but this will get failed
while referencing in another table.
| Is This Answer Correct ? | 13 Yes | 5 No |
Answer / kuldeep singh
Primary Key=Unique+Not Null+Sorting+Cluster Index
So
UNIQUE +NOT NULL != PRIMARY KEY
it cant refer someother table column
| Is This Answer Correct ? | 2 Yes | 0 No |
No. Generally Primary Key contains Unique + NotNull values.
If we are not defined a column as Primay Key and we defined
as Unique + NotNull, then, the behavior of that particular
column in that particular table looks like primary key. but
this cannot be referenced in any other table as we have not
defined as primary key..So, Primary Key column is different
from the column which have Unique + Not Null qualities.
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / ananta pilaka
Primary key is only one and it is clustered index.
Unique key cannot be referred as foreign key contraint of
another table.
| Is This Answer Correct ? | 2 Yes | 2 No |
no. bcoz we can insert null values in the column which
contains the combination of constraints as
UNIQUE+ NOT NULL
but in case of primary key we can't use null values in that
primary key column
| Is This Answer Correct ? | 2 Yes | 8 No |
How do I limit the number of rows returned by an oracle query after ordering?
how many types of index?
How i can handle exception in large code like 1000 line without distrubing the code or without exception handler sction?
What happens if the imported table already exists?
What are the various oracle database objects?
types of indexes and the rationale behind choosing a particular index for a situation.
What SQL query from v$session can you run to show how many sessions are logged in as a particular user account?
How can I convert single byte kana characters into multi byte kana characters and vice-versa.
select * from emp what happened internally when we write this query in the sql prompt?
What is the difference between "as" and "is" in an oracle stored procedure?
definition of cluster and non-clustered index?
How to convert times to characters in oracle?
Oracle General 
