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Is unique key a primary key?

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  1. Is unique key same as primary key?
  2. Is primary key always unique?
A Primary key is a unique key. Each table must have at most ONE primary key but it can have multiple unique key. A primary key is used to uniquely identify a table row. A primary key cannot be NULL since NULL is not a value. 22 сент. 2014 г.


Is unique key same as primary key?

Primary Key is a column that is used to uniquely identify each tuple of the table. It is used to add integrity constraints to the table. ... Difference between Primary Key and Unique Key.Primary KeyUnique KeySelection using primary key creates clustered indexSelection using unique key creates non-clustered index

Is primary key always unique?

Primary key is always unique in every SQL. You dont have to explicitly define it as UNIQUE. On a side note: You can only have onePrimary key in a table and it never allows null values.

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