Define candidate key, alternate key, composite key.




Answers were Sorted based on User's Feedback



Define candidate key, alternate key, composite key...

Answer / shruti singh

Any attribute that is uniquely identify a row in a table is
candidate key for the table. We select one of the candidate
key as Primary key. All candidate keys which are not chosen
as "primary key" are Alternate keys. The key which uniquely
identify the rows of the table and which is made up of
more than one attribute is called Composite key.
As for Example:In a class we have to select Class Monitor.
So A, B,C and D stand for that post. So A,B,C and D are
candidate for monitor so these are candidate key. We select
B as monitor so B is primary key and A,C and D can be
monitor but not selected as a monitor so they are
alternative choise. So A,C and D are alternate key.
When two students of class work together in a project than
they are composite key for the class.

I TRIED TO EXPLAIN THESE KEY, IF YOU LIKE PLEASE DO
RESPONSE. iF YOU LIKE TO ASK ANY OTHRE QUE RELATED TO SQL
SERVER YOU CAN..

Is This Answer Correct ?    541 Yes 28 No

Define candidate key, alternate key, composite key...

Answer / swapna

A candidate key is one that can identify each row of a
table uniquely. Generally a candidate key becomes the
primary key of the table. If the table has more than one
candidate key, one of them will become the primary key, and
the rest are called alternate keys.

A key formed by combining at least two or more columns is
called composite key.

Is This Answer Correct ?    348 Yes 54 No

Define candidate key, alternate key, composite key...

Answer / anvar shadath.a

Candidate key: If any unique data column(s)in table is
called candidate key. may be one or more unique data column
(s).We can select any one unique (candidate key column) as
a primary key.

Alternate key: If one table contains more then one
candidate keys, remining candidate keys column(s) which is
not selected as a primary key is called Alternate Key.

Composite key: One primary key Contains more then one
columns is called Composite key.

Is This Answer Correct ?    75 Yes 15 No




Define candidate key, alternate key, composite key...

Answer / raghuram

Candidate Key is a Key which identifies each row of a table
uniquely. Generally a Candidate Key becomes a Primary Key
of the table. If table has more than one Candidate Keys
then one is called Primary key and rest are called
Alternative Keys.
A key is formed by two or more columns is called Composite
Keys.

Is This Answer Correct ?    80 Yes 28 No

Define candidate key, alternate key, composite key...

Answer / amar

A candidate key is one that can identify each row of a
table uniquely. Generally a candidate key becomes the
primary key of the table. If the table has more than one
candidate key, one of them will become the primary key, and
the rest are called alternate keys. A key formed by
combining at least two or more columns is called composite
key.

Is This Answer Correct ?    42 Yes 14 No

Define candidate key, alternate key, composite key...

Answer / sunil choudhary "hanumangarh"(

candidate key is a single key of each tuple.
alternative key is secondary key . for example(A entity
STUDENT an attribute of NAME,CLASS,ROLL.ID)the roll no is
primary key but id is alternate key.

A key formed combined of to or more columns called comosite
key.

Is This Answer Correct ?    88 Yes 71 No

Define candidate key, alternate key, composite key...

Answer / tanaji

A candidate key is a combination of attributes that can be uniquely used to identify a database record without any extraneous data. Each table may have one or more candidate keys. One of these candidate keys is selected as the table primary key.

Is This Answer Correct ?    23 Yes 19 No

Define candidate key, alternate key, composite key...

Answer / sheharyar ali

Candidate Key
A coulmn in database table that can be used to uniquely identify each row in that table is said to be a Candidate Key
Primary Key
IF a Table has a coulmn or min Combination of Column(s) that can uniquley Identify each Row in that table then such a column or group of Column is said to be Primary Key

Alternate Key
A table may contain more than one Cadidate Column.Among these Candidate column the most appropiate one is genrally chosen as Primary Key While others that are left out are Said to be Alternate Keys.

Composite Key
Combination of more than One Column to uniquely identfiy all rows in a Table is said to be Composite Key

Is This Answer Correct ?    3 Yes 1 No

Define candidate key, alternate key, composite key...

Answer / jeevan kurmi

A candidate key is a combination of attributes that can be uniquely used to identify a database record without any extraneous data. Each table may have one or more candidate keys. One of these candidate keys is selected as the table primary key.

Is This Answer Correct ?    2 Yes 0 No

Define candidate key, alternate key, composite key...

Answer / kishore

A candidate key is one that can identify each row of a
table uniquely. Generally a candidate key becomes the
primary key of the table. If the table has more than one
candidate key, one of them will become the primary key, and
the rest are called alternate keys.

A key formed by combining at least two or more columns is
called composite key.

Is This Answer Correct ?    0 Yes 0 No

Post New Answer



More SQL Server Interview Questions

how many joins we can write if at all we have n no of tables

5 Answers   Tanla Solutions, TS,


Difference between Function and Stored Procedure?

9 Answers   C1 India,


How will you fine tune a stored procedure or what are the steps that should be taken to fine tune or optimize a stored procedure?

1 Answers   Mphasis, Logitech,


Can you give me some DBCC command options?(Database consistency check) - DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked.and DBCC CHECKALLOC - To check that all pages in a db are correctly allocated. DBCC SQLPERF - It gives report on current usage of transaction log in percentage. DBCC CHECKFILEGROUP - Checks all tables file group for any damage.

0 Answers   iSoft,


How to get number of days in a given year?

4 Answers   ADP,






how to find the particular row in table?(means suppose one table contain 10 rows , in these 10 rows how to find the particular row(example in 10 rows i want 5 row how)?

15 Answers   Accenture, IBM, Marlabs,


What is a job?

3 Answers  


How much memory that we are using in Logshipping Concept?

0 Answers  


What is best institute to Learn DotNET And SQL in chennai?

0 Answers  


What is difference between stored procedure and function?

3 Answers   L&T,


Explain the types of indexes.

0 Answers   Accenture,


Differences between functions and stored procedures?

8 Answers   Accenture, 247Customer,






Categories