Answer / manoj

primary key is a key which always accept unique value.

secondary key is a key which when you are making primary key
for more than one column as primary key for retrieving of
reords.
eg.
create table tnam
(ano number,
bno number,
bname char(12),
primary key(ano,bno))

In this bno is secondary key.

Answer / renu kakkar

PRIMARY REPRESENTS THE ROW/TUPPLE UNIQUELY WHEREAS
SECONDARY KEY REPRESENTS THE SET OF TUPPLES
EMPLOY_ID IS A PRIMARY KEY AND EMPLOY_DEPTT. IS A SECONDARY
KEY.

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