| From: | Teodor Macicas <teodor(dot)macicas(at)epfl(dot)ch> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Luca Ferrari <fluca1978(at)infinito(dot)it>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: what is the meaning of Datum? |
| Date: | 2010-06-23 15:22:19 |
| Message-ID: | 4C2226AB.8080500@epfl.ch |
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| Lists: | pgsql-general |
Tom Lane wrote:
> Luca Ferrari <fluca1978(at)infinito(dot)it> writes:
>
>> ok this is a silly question, but I've got a doubt: what is the exact meaning
>> of Datum?
>>
>
> It's the backend-internal representation of a single value of any SQL
> data type. The code using the Datum has to know which type it is,
> since the Datum itself doesn't contain that information. Usually,
> C code will work with a value in a "native" representation, and then
> convert to or from Datum in order to pass the value through
> data-type-independent interfaces.
>
> regards, tom lane
>
>
And how this convertions will be made ?
Are there internal functions to do this ?
Thanks.
-Tedy
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