
Primary Key:
--> uniquely identifies a row in a table
--> May use one or more columns
--> values can be modified
Surrogate key:
--> Must use only one column
--> Values are uniquely generated
--> cannot be modified
A surrogate key is a primary key. Paul meant that a surrogate key is one kind of primary key. All surrogate keys are primary keys. Not all primary keys are surrogate keys.
A surrogate key is somthing that has no meaning other than uniquely identifying the row.
Because it has no meaning, there will never be any reason to change it, which is a very desirable quality in a primary key.
surrogate keys are integers that are assigned sequentially as needed to populate a dimension table.
refer
http://blog.sojib2bd.com/oracle-10g/what-is-the-difference-between-natural-key-and-surrogate-key.xhtml Mark This Response as Answer
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Chandu
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