Groups > comp.databases.postgresql > #866

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

From	John-Paul Stewart <jpstewart@sympatico.ca>
Newsgroups	comp.databases.postgresql
Subject	Re: Table with a variable number of elements in a column
Date	2019-04-27 17:10 -0400
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>

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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.

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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

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