Re: Column order in multi column primary key - Mailing list pgsql-general

From David G. Johnston
Subject Re: Column order in multi column primary key
Date
Msg-id CAKFQuwa0Bso+3tDXJiHwBzNqg9PsFu0yD0yM=FW84z1=4Gab9A@mail.gmail.com
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In response to Re: Column order in multi column primary key  ("Craig Boucher" <craig@wesvic.com>)
List pgsql-general
On Mon, Aug 8, 2016 at 4:35 PM, Craig Boucher <craig@wesvic.com> wrote:

Thanks David.  I’ve thought about the hierarchy you mentioned but the hierarchy can change and I need to capture it as it was when the data was generated.

 

I should have pointed out in my last response that I was wondering if the performance of the pk index on work_session would be better if my primary key was (customer_id, work_session_id) or if (work_session_id,  customer_id) will be fine.  Customer_id will be repeated quite a bit in the table but work_session_id should be unique across the whole table.

 


​I answered that in the original response...for PKs to operate most efficiently the most selective attribute ​should come first.

David J.

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