Re: derive the sequence name of a column
От | Mel Jamero |
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Тема | Re: derive the sequence name of a column |
Дата | |
Msg-id | 004c01c39eb4$3d73d890$1b06a8c0@cmpmel обсуждение исходный текст |
Ответ на | Re: derive the sequence name of a column (Bruno Wolff III <bruno@wolff.to>) |
Ответы |
Re: derive the sequence name of a column
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Список | pgsql-novice |
Thank for the reply Bruno but I need more. =) Sorry, I have to send this again because I haven't figured out how to solve this. Can anyone please tell me exactly how the name of a sequence a field is using (manually created or generated by a serial) could be derived programmatically (using libpq or through SQL)? Thus: CREATE SEQUENCE an_unknown_sequence_name; CREATE TABLE test ( test_id integer default nextval('an_unknown_sequence_name'), useless_redundant_test_id serial ); How do I programmatically extract that column 'test_id' in table 'test' is using 'an_unknown_sequence_name' TIA! Mel -----Original Message----- From: pgsql-novice-owner@postgresql.org [mailto:pgsql-novice-owner@postgresql.org] On Behalf Of Bruno Wolff III Sent: Monday, October 27, 2003 11:45 AM To: Mel Jamero Cc: pgsql-novice@postgresql.org Subject: Re: [NOVICE] derive the sequence name of a column On Fri, Oct 24, 2003 at 15:41:00 +0800, Mel Jamero <mel@gmanmi.tv> wrote: > Hi! Please don't reply to messages to start new threads. > > Can anyone please tell me exactly how the name of a sequence a field is > using (manually created or generated by a serial) could be derived > programmatically (using libpq or through SQL)? When creating a sequence for a serial type, for short names the format is tablename underline columnname underline seq . If the resulting name is longer than 63 characters then something else is used so as to get a shorter name. If you have control over the table and column names than you can make sure the names are always short enough so that the simple algorithm is used. For manually created references to sequences, you will probably need to parse the default value. I don't know how to do this, but using the -E on pgsql and using \d sampletable should show you what query to use. > > Thus: > > CREATE SEQUENCE an_unknown_sequence_name; > CREATE TABLE test ( > test_id integer default nextval('an_unknown_sequence_name'), > useless_redundant_test_id serial > ); > > How do I programmatically extract that column 'test_id' in table 'test' > is using 'an_unknown_sequence_name' ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
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