Comments on: PostgreSQL is Powerful, Confuses Newbies http://alexhochberger.com/2009/08/12/postgresql-is-powerful-confuses-newbies/ Using Technology in Business Communications Mon, 31 Jan 2011 15:29:58 +0000 hourly 1 http://wordpress.com/ By: alexhochberger http://alexhochberger.com/2009/08/12/postgresql-is-powerful-confuses-newbies/#comment-140 Mon, 31 Jan 2011 15:29:58 +0000 http://alexhochberger.com/?p=96#comment-140 Because removing row 2 doesn’t create a reason to eliminate row 3. The only rule is that the numbers are unique.

If you had 15 Billion lines in a table, and you removed one of them, you want the database to renumber 15 billion lines?

If you want to know the number of rows, do, SELECT count(*) FROM tablename; and you’ll get the count. If you want the last inserted one that isn’t deleted, you do SELECT max(no) FROM tablename, and those results may not be the same.

]]> By: Afrihar http://alexhochberger.com/2009/08/12/postgresql-is-powerful-confuses-newbies/#comment-120 Thu, 16 Dec 2010 09:50:17 +0000 http://alexhochberger.com/?p=96#comment-120 I have a question, why if I delete a row, then auto_increment (serial) not re-number,

example :

no | name
_________
1 | jack
2 | smith
3 | less

then I delete row number 2, why column no became like this :

no | name
_________
1 | jack
3 | less

thanks

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