Interested to Buy Any Domain ? << Click Here >> for more details...
What is differance unique key and primary key.
- 7 Answers
- 11383 Views
- EDS, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / rahul khanke
primary key : primary key dose not except null value
unique key : it accept null values.. if it set to not null
then it as good as primary key.
| Is This Answer Correct ? | 5 Yes | 0 No |
Answer / hema
Unique :: it does not allow duplicate values but allows
null values.
Primary:: Primary does not allow duplicate values as wel as
it dosnt allow null values.
unique+not null==Primary key...
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / dhanashree
Unique Key can be NULL
But
Primary Key can not be NULL
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / madhu
unique key:
1.unique key will accept more than one null value.
2.whenever u created a unique key, then internally one non-clustered index will be created(one table can have more than one Non-clustered index).
3.one table can have more than one unique key.
Primary key:
1.One table should have one primary key only.
2.primary key will not accept null values.
3.whenever u created a primary key then internally one clustered index will be created(one table can have only one clustered index).
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / gourvendra singh
Unique : One or more unique key in a table,
allow only one null in the field.
Primary :Only one primary key in a table and u cannot
insert null into it.
| Is This Answer Correct ? | 1 Yes | 2 No |
Answer / nagurthilak
Through Unique key we cant establish the relation between to
two tables but from primary key it is possible
| Is This Answer Correct ? | 3 Yes | 4 No |
Answer / l..l.n.reddy
PRIMARY KEY:- only one primary key in a table.
UNIQUE KEY:- One or more unique key in a table.
| Is This Answer Correct ? | 1 Yes | 3 No |
What are all types of user defined functions?
What are sql constraints?
What are the components of a PL/SQL block ?
Write a query to find five highest salaries from EMP table. (there is a column SALARY)
24 Answers Cap Gemini, iNautix,
What is a stored procedure in sql with example?
What is trigger and types?
What does count (*) do in sql?
how can you see all indexes defined for a table? : Sql dba
need to split a string into seperate values. eg. col1 col2 ---------- 100 - 'a,b,c' 200 - 'a,x,b,d,e' 300 - 'c' result: value count ------------- a - 2 b - 1 c - 2 etc.
what is the difference between primary key and unique key? : Sql dba
display your age in months?
What are some predefined exceptions in pl/sql?
-
Oracle (3259) - SQL Server (4518)
- MS Access (429)
- MySQL (1402)
- Postgre (483)
- Sybase (267)
- DB Architecture (141)
- DB Administration (291)
- DB Development (113)
- SQL PLSQL (3330)
- MongoDB (502)
- IBM Informix (50)
- Neo4j (82)
- InfluxDB (0)
- Apache CouchDB (44)
- Firebird (5)
- Database Management (1411)
- Databases AllOther (288)
