Thread: counting columns

counting columns

From
pere roca
Date:

hi!

I want different users to insert data and perform different analysis which
will be inserted in an interactively created new column. The name of this
new column should follow a logic name such as: fxanalysis_1 for the first
user that perform the analysis called fx, fxanalysis_2 for the second...
To get it, I think I should construct a function that counts how many
columns have their name starting with fxanalysis.
   If count >=1, then alter table adding a new column with name fxanalysis_2
   and so on...
   One of the questions: how to COUNT COLUMNS? I can rename, add, alter
columns... but count?

Thanks in advance,
Pere
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Re: counting columns

From
Ron Johnson
Date:
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On 08/28/07 10:46, pere roca wrote:
> hi!
>
> I want different users to insert data and perform different analysis which
> will be inserted in an interactively created new column. The name of this
> new column should follow a logic name such as: fxanalysis_1 for the first
> user that perform the analysis called fx, fxanalysis_2 for the second...
> To get it, I think I should construct a function that counts how many
> columns have their name starting with fxanalysis.
>    If count >=1, then alter table adding a new column with name fxanalysis_2
>    and so on...
>    One of the questions: how to COUNT COLUMNS? I can rename, add, alter
> columns... but count?

You'll need to go into the catalog.

Your idea, though, is poor.  You should make a second table, where
the key is the same as the master table, plus a "sequence number".

If you want to do it your way, though, PostgreSQL supports array types.

- --
Ron Johnson, Jr.
Jefferson LA  USA

Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!

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