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Is a Primary Key an index?


Is a Primary Key an index?

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Phil Factor
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Comments posted to this topic are about the item Is a Primary Key an index?


Best wishes,

Phil Factor
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TomThomson
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Irritating because over-pedantic. Good question nevertheless.

Tom

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Question didn't really make an adequate distinction between the logical and the physical:
Does the logical definition of a Primary Key imply the presence of an index? No
In SQL Server, does the presence of a Primary Key imply some kind of index is also present? Yes
pmadhavapeddi22
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This is my understanding. primary key is a constraint not an index, but it creates an index automatically by default, but primary key is called a constraint not an index though. so I got it correct (though I had to think little bit)

Good question :-)
Raghavendra Mudugal
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Thank you for the post, simply good one. (for me the question was simple enough)

ww; Raghu
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Raghavendra Mudugal
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pmadhavapeddi22 (7/15/2014)
This is my understanding. primary key is a constraint not an index, but it creates an index automatically by default, but primary key is called a constraint not an index though. so I got it correct (though I had to think little bit)

Good question :-)


+1

ww; Raghu
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The first and the hardest SQL statement I have wrote- "select * from customers" - and I was happy and felt smart.
Koen Verbeeck
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I remembered that it is sometimes called a "primary key constraint", so the question was easy enough.
Still I expect some flaming in this topic :-)



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I got it wrong because I misinterpreted this line:

When you specify a PRIMARY KEY constraint for a table, the Database Engine enforces data uniqueness by creating a unique index for the primary key columns.


It creates an index but doesn't use the PRIMARY KEY as that index. Annoying, but my fault.


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twin.devil
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Koen Verbeeck (7/16/2014)
I remembered that it is sometimes called a "primary key constraint", so the question was easy enough.
Still I expect some flaming in this topic :-)


+1, Nice question
Stewart "Arturius" Campbell
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TomThomson (7/15/2014)
Irritating because over-pedantic. Good question nevertheless.

+1

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