Thread: SPI_execute (result of a select statement)

Hi,

While using SPI_execute for a select statement, how do we store the result returned by select statement (say a C variable)?
SPI_execute returns different values for success or failure only as per the postgres manual.

Thanks,
Jas

On Fri, Sep 01, 2006 at 02:24:32AM -0400, Jasbinder Bali wrote:
> Hi,
>
> While using SPI_execute for a select statement, how do we store the result
> returned by select statement (say a C variable)?
> SPI_execute returns different values for success or failure only as per the
> postgres manual.

Did you read the whole page?

http://www.postgresql.org/docs/8.1/interactive/spi-spi-execute.html

Especially the bit where it says:

  If the return value of the function is SPI_OK_SELECT then you may use
  the global pointer SPITupleTable *SPI_tuptable to access the result
  rows.

From there you can get the data. There's also the helper functions like
SPI_getvalue().

http://www.postgresql.org/docs/8.1/interactive/spi-interface-support.html

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

The structure SPITupleTable is defined thus:

typedef struct
{
    MemoryContext tuptabcxt;    /* memory context of result table */
    uint32      alloced;        /* number of alloced vals */

    uint32      free;           /* number of free vals */
    TupleDesc   tupdesc;        /* row descriptor */
    HeapTuple  *vals;           /* rows */
} SPITupleTable;

If the select query returns 10 rows (say),
how to access the result of each row separately?

Can you please help me with the syntax of the same?

Regards,

~Jas

On Fri, Sep 01, 2006 at 03:41:12AM -0400, Jasbinder Bali wrote:
> The structure SPITupleTable is defined thus:

<snip>

> If the select query returns 10 rows (say),
> how to access the result of each row separately?

<snip>

Read this:

> >http://www.postgresql.org/docs/8.1/interactive/spi-interface-support.html

I would say that the example should clear up most of your questions:

http://www.postgresql.org/docs/8.1/interactive/spi-examples.html

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.