Clustered index by default

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minijebu asked Sep 11, '15

Clustered index by default

In the below T-sql code, CREATE TABLE PERSON ( PERSON_ID INT NOT NULL PRIMARY KEY CLUSTERED, FIRST_NAME VARCHAR(255) NOT NULL, LAST_NAME VARCHAR(255) NOT NULL); Go If i dont specify the word CLUSTERED,wont sql engine still create a clustered index on PERSON_ID since Primary key is defined on it ?

clustered-index

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Answer 1 · 2015-09-11T16:05:16Z

JohnM answered Sep 11, '15

That is correct. As per the documentation, https://msdn.microsoft.com/en-us/library/ms174979.aspx, a primary key contraint will default to clustered and a unique constraint will default to non-clustered. Hope that helps!

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Grant Fritchey ♦♦ commented · Sep 11, 2015 at 07:56 PM

100% agreement. I'd just add that it's important to know that you have the choice. The primary key isn't always the best choice for the clustered index.

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minijebu commented · Sep 12, 2015 at 04:13 PM

Thanks JohnM and Thank you Grant Fritchey.

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