Re: R: feature proposal ...

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От Joshua D. Drake
Тема Re: R: feature proposal ...
Дата
Msg-id 4331809E.40504@commandprompt.com
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Ответ на Re: R: feature proposal ...  (Hans-Jürgen Schönig <postgres@cybertec.at>)
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Hans-Jürgen Schönig wrote:

> no because a new is not a heap ...

Why not use a function with a temporary table?

That way you can pass a table parameter that
is the temporary table with a select statement
that you can populate the temp table with.

Sincerely,

Joshua D. Drake



>
> em=# create view x as select * from pg_class;
> CREATE VIEW
>
> em=# copy x to '/tmp/x';
> ERROR:  cannot copy from view "x"
>
>     best regards,
>
>         hans
>
>
>
> Paolo Magnoli wrote:
>
>> Can't you just use a view?
>>
>> -----Messaggio originale-----
>> Da: pgsql-hackers-owner@postgresql.org
>> [mailto:pgsql-hackers-owner@postgresql.org]Per conto di Hans-Jürgen
>> Schönig
>> Inviato: mercoledì 21 settembre 2005 15.30
>> A: pgsql-hackers@postgresql.org; eg@cybertec.at
>> Oggetto: [HACKERS] feature proposal ...
>>
>>
>> hackers,
>>
>> currently we have to hack tons of export scripts for various customers.
>> the problem is: if tables can be exported straight forward COPY will
>> give you all you need but when data has to be transformed while
>> exporting things start becoming a bit more complex. usually people want
>> to have CSV file (excel-ify data) which is supported by COPY.
>>
>> the problem is: COPY can write data returned by a SELECT statement to a
>> file. our idea is to implement precisely that.
>>
>> example:
>>
>> COPY TO file_name USING some_select_statement;
>>
>> the advantage would be that COPY would then be able to export data and
>> transform it on the fly. this would save many people a lot of work
>> because complex data extractors could in many cases be replaced by
>> simple SQL scripts.
>>
>> how we plan to implement that:
>> currently copy simply opens a table and loops through the tuples (see
>> command/copy.c starting at line 1115).
>> to implement the desired feature we just had to add some SPI code to the
>> scenery (SPI will also return HeapTuples so it should fit in there).
>>
>> Any comments?
>>
>>     Best regards,
>>
>>         Hans
>>
>>
>> -- 
>> Cybertec Geschwinde & Schönig GmbH
>> Schöngrabern 134; A-2020 Hollabrunn
>> Tel: +43/1/205 10 35 / 340
>> www.postgresql.at, www.cybertec.at
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 6: explain analyze is your friend
>>
>
>


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