From: Abhishek <abhisheksgumadi_at_gmail.com>
Date: 21 Feb 2006 03:45:59 -0800
Message-ID: <1140522359.762187.213930_at_o13g2000cwo.googlegroups.com>
Hi,
Can anybody tell me the differences between the above mentioned terms? Also please tell me if one can be the other and vice versa..please elaborate with the helpof a table if possible. Also please tellme if the below statement by me is correct..
a) Any attribute or a collection of attributes which uniquely identifies the tuples in a relation is called a canditate key.this candidate key thus can contain a single attribute or a collection of attributes.
b) one of the attributes is chosen by the DBMS to identify the tuples uniquely and this attribute is called the primary key. c) A primarykey is a candidate key.all candidate keys cannot be a primary key.
Now,,,what is the superkey? Received on Tue Feb 21 2006 - 12:45:59 CET
Date: 21 Feb 2006 03:45:59 -0800
Message-ID: <1140522359.762187.213930_at_o13g2000cwo.googlegroups.com>
Hi,
Can anybody tell me the differences between the above mentioned terms? Also please tell me if one can be the other and vice versa..please elaborate with the helpof a table if possible. Also please tellme if the below statement by me is correct..
a) Any attribute or a collection of attributes which uniquely identifies the tuples in a relation is called a canditate key.this candidate key thus can contain a single attribute or a collection of attributes.
b) one of the attributes is chosen by the DBMS to identify the tuples uniquely and this attribute is called the primary key. c) A primarykey is a candidate key.all candidate keys cannot be a primary key.
Now,,,what is the superkey? Received on Tue Feb 21 2006 - 12:45:59 CET