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Candidate key vs composite primary key Posted Date: 28 Sep 2009      Posted By:: Ameer     Member Level: Silver    Member Rank: 1204     Points: 1   Responses: 6
Can any one tell the exact difference between Candidate key vs Composite primary key. for me it resembles the same. Tweet
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#427657    Author: Kritika Yadav      Member Level: Gold      Member Rank: 0     Date: 28/Sep/2009   Rating:     Points: 2 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. 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. Happy Programming Kritika Yadav   #427677    Author: ABitSmart      Member Level: Gold      Member Rank: 21     Date: 28/Sep/2009   Rating:     Points: 2 Candidate key is not a primary key. Primary key is a candidate key. (Composite primary key is just a primary key with multiple columns. It is no different from a primary key. The name is just to signify multiple columns) Kind regards, ABitSmart DNS Web-master, DNS MVM My blog Thoughts.exe   #427680    Author: Ameer      Member Level: Silver      Member Rank: 1204     Date: 28/Sep/2009   Rating:     Points: 2 it means that composite primary key will have only two columns or more than two columns.   #428569    Author: David Portas      Member Level: Bronze      Member Rank: 0     Date: 30/Sep/2009   Rating:     Points: 2 There is no difference. A primary key is any candidate key. The term "primary key" is in fact superfluous and could easily be dispensed with.   #428596    Author: Abhisek Panda      Member Level: Gold      Member Rank: 214     Date: 30/Sep/2009   Rating:     Points: 2 Attribute that uniquely identifies a row in a table is called candidate key for that table. We have to select one of the candidate key as Primary key which has a most unique value than other candidate keys. Rest of all candidate keys which are not chosen as primary key are called Alternate keys. Composite key have more than one attribute. When a composite key becomes primary key it is called as composite primary key. --------------- Regards, Abhisek Panda DNS EDITOR Be Happy And Make Others Happy. Go Green and Save Your Future. Get websites at only Rs.2000!   #431557    Author: kaleeswaran      Member Level: Gold      Member Rank: 0     Date: 09/Oct/2009   Rating:     Points: 2 candidate key is not a primary key... Regards, Kaleeswaran, http://4xchange.blogspot.com Regards, Kaleeswaran Vist this site fisrt If u go for investment...
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