Re: Sequences part 2 - Mailing list pgsql-general

From Thomas Kellerer
Subject Re: Sequences part 2
Date
Msg-id bd21060f-c6ce-8c1f-ebe2-e2b594edb60b@gmx.net
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In response to Sequences part 2  (Karl Martin Skoldebrand <KS0C77263@TechMahindra.com>)
Responses RE: Sequences part 2
List pgsql-general
Karl Martin Skoldebrand schrieb am 02.07.2019 um 12:44:
> Looking more at sequences, I have some sequences that start with ID 1, incrementing each record by 1.
> 
> So I have e.g. 1 Spain 2. Germany 3. France 4. Ireland 5. Norway
> 
> Now I want to insert more countries, between France and Ireland. 

That is a wrong assumption - there is no "between" for rows in a relational database. 

Why do you think you need that? 


A sequence is used to generate a unique number. The only job of that number is to be unique. 
You should never rely on PK values to be "gapless" nor should you rely on them defining any kind of ordering. 

If you need to sort your countries in a non-default way, add a specific sort_order column to your table which you can
usewhen selecting from the table.
 



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