Answer / karunakar reddy

No,In the entire table,there will be only one primary key.
A primary key is nothing but a collection of one or more
coloumns used to identify a row in a table.

Answer / dev lamani

no a table can have only one primary key.
u can make one or column to have primary key
that is called a composite primary key


Dev
ddlamani@yahoo.com

Answer / suresh somayajula

A table can have Only One Primary key. But a table can have
composite Primary key. that means we can create composite
primary key
upto 16 columns only.

suresh.
suresh_somayajula@hotmail.com

Answer / sankar

yes any table has only one primary key.but the basic idea
of pk is ....primary key=NOTNULL+UNIQUE KEY.which we can
give any column to a table and act as primary key

Answer / vaibhavi_dixit

A table can have only one primary key constraint but it can
consist one or multiple columns.If a primary key is made up
of more than one columns then it is know as composite
primary key.

VD

Answer / sowmya

Hi
A table can have only one primary key.but a primary key can
have two column fields
Ex i have a employee table.and i have fields eno,ename,esal
i can declare primarykey(esal,ename)

let me know if i am wrong

Answer / satish reddy

Each table can have only one primary key; however, that key may consist of more than one column.

SQL> create table EMP(EMPNO Number(5),EMPNAME Varchar2(10),ADDRESS Varchar2(10),Constraint Multi_Constr
aint Primary Key(EMPNO,EMPNAME));

After creating table try to insert null value into EMPNAME Column, it will throw an error "cannot insert NULL into ("SCOTT"."EMP"."EMPNAME")"

Answer / rahul khanke

primary key is only and only one in a table.
it may be in more column in table means
In one table --one primary key and more than one column on
the same table

Answer / murugavel. u

ya..it's possible when, a table contains more than one
fields. we can able to set the primary for two or more..

thanks.,

Answer / anish kumar anand

create table emp
(empno varchar2(10) constraint empnopk primary key,
e_id varchar2(10) constraint eiduk unique not null);

Hi, Can anybody please explain me the flow of the below query. I am not able to understand how this query works. This query is for finding the Nth highest salary.. SELECT DISTINCT (a.sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.sal)) FROM EMP B WHERE a.sal<=b.sal); If N = 2 then second highest salary will be the o/p. If N = 3 then third highest salary will be the o/p. and so on.. Thanks, Nitin

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