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.

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...

Answer / dhanashree

Unique Key can be NULL
But
Primary Key can not be NULL

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).

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.

Answer / nagurthilak

Through Unique key we cant establish the relation between to
two tables but from primary key it is possible

Answer / l..l.n.reddy

PRIMARY KEY:- only one primary key in a table.

UNIQUE KEY:- One or more unique key in a table.

What are the attributes of SQL*PLUS ?

2 Answers   Dream Careers, Oracle,

How to convert lowercase letters to uppercase and uppercase letters to lowercase in a string. (ex, AbcdEfG should convert as aBCDeFg)

3 Answers   TCS,

i declare 4 procedure in package specification but in package body i write only 3 procedure. is it complie??//w

4 Answers   Scope International,

What is java sql connection?

0 Answers  

What is %rowtype in pl sql?

0 Answers  

What are local and global Indexes and where they are useful.

0 Answers  

How do you use collections in procedure to return the resultset?

0 Answers  

Do we need commit after truncate?

0 Answers  

table :- city name country code abc 11 bcd 22 cde 232 def 33 write a procedure , so that when we give a phone no. eg - 1123456789 - o/p sud be city name = abc if phone no. - 2322345897 , o/p sud be =cde note - bcd and cde city name sud be diff. as dey diff only with th last no. Pls ans. this questnion.

1 Answers  

Table name: T1, it has only one column. col1 ------ c b a b b b b d s a a t s Requirement: I need the following output from the above base table by using SQL query. col1 Cnt ----- ------- a 3 b 5 Others 5 Please help. Thanks Guru v.gurus@in.com

11 Answers  

What are the different types of dbmss?

0 Answers  

What is a schema? How is it useful in sql servers?

0 Answers