Groups > comp.databases.postgresql > #866

Re: Table with a variable number of elements in a column

Path	csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From	John-Paul Stewart <jpstewart@sympatico.ca>
Newsgroups	comp.databases.postgresql
Subject	Re: Table with a variable number of elements in a column
Date	Sat, 27 Apr 2019 17:10:16 -0400
Lines	24
Message-ID	<gijuppF7slsU1@mid.individual.net> (permalink)
References	<gijn3vF68nnU1@mid.individual.net> <gijpelF6n73U1@mid.individual.net> <gijpvpF6sfbU1@mid.individual.net> <gijqqoF71obU1@mid.individual.net> <gijsdrF7d5iU1@mid.individual.net>
Mime-Version	1.0
Content-Type	text/plain; charset=utf-8
Content-Transfer-Encoding	8bit
X-Trace	individual.net mycx1X5RFdeeZrZNh8AYGgwBD3h/edOCWNgn/xOZduvlDKFPCF
Cancel-Lock	sha1:fa5P5ygt9QT8PutOo/tmow0aRv4=
User-Agent	Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1
In-Reply-To	<gijsdrF7d5iU1@mid.individual.net>
Content-Language	en-CA
Xref	csiph.com comp.databases.postgresql:866

Show key headers only | View raw

On 2019-04-27 4:29 p.m., Bill Gunshannon wrote:
> On 4/27/19 4:02 PM, John-Paul Stewart wrote:
>> On 2019-04-27 3:48 p.m., Bill Gunshannon wrote:
>>>
>>> But if I understand this correctly I would need a separate table for
>>> every album resulting in, potentially, thousands of tables. (OK, in
>>> my case hundreds but others may like this idea, too, when I finish
>>> the whole project.)
>>
>> No, it's only one "tracks" table.  That's why there's an album id column
>> in it:  so that each track is associated with one album.  There'd be
>> (album 1, track 1), (album 1, track 2), (album 2, track 1), and so
>> on....  Each (album, track) tuple would have to be unique.  But you'd
>> keep all the tracks for all the albums in one table.
> 
> I got that now.
> But I guess I am still stuck with how I define how many tracks columns
> there has to be for each album.  I think I have been away from this for
> too long.  I am missing something that is probably both simple and very
> apparent.

By using a tracks table, it's no longer a question of "how many tracks
columns" but "how many tracks rows" instead. And the answer is "however
many you populate with the same album id".  That's the beauty of it.

Back to comp.databases.postgresql | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Table with a variable number of elements in a column Bill Gunshannon <bill.gunshannon@gmail.com> - 2019-04-27 14:59 -0400
  Re: Table with a variable number of elements in a column John-Paul Stewart <jpstewart@sympatico.ca> - 2019-04-27 15:39 -0400
    Re: Table with a variable number of elements in a column Bill Gunshannon <bill.gunshannon@gmail.com> - 2019-04-27 15:48 -0400
      Re: Table with a variable number of elements in a column John-Paul Stewart <jpstewart@sympatico.ca> - 2019-04-27 16:02 -0400
        Re: Table with a variable number of elements in a column Bill Gunshannon <bill.gunshannon@gmail.com> - 2019-04-27 16:29 -0400
          Re: Table with a variable number of elements in a column John-Paul Stewart <jpstewart@sympatico.ca> - 2019-04-27 17:10 -0400
            Re: Table with a variable number of elements in a column Bill Gunshannon <bill.gunshannon@gmail.com> - 2019-04-27 18:40 -0400
              Re: Table with a variable number of elements in a column John-Paul Stewart <jpstewart@sympatico.ca> - 2019-04-27 19:26 -0400
  Re: Table with a variable number of elements in a column alexander.d.mills@gmail.com - 2020-02-21 14:02 -0800
    Re: Table with a variable number of elements in a column Christian Barthel <bch@online.de> - 2020-02-22 09:15 +0100

csiph-web