Re: SQL DESCRIBE was( SQLRPGLE - Dynamic selection)

Frank,

Depends on how you prepared the SQL statement and do the FETCH SQL function. 
You can use the SQLDA datastructure to retireve the resultset, but also host 
variables.

With the SQLDA datastructure you tell the SQL engine how many columns to 
retrieve with a FETCH. For each column you define an array element within the 
SQLDA datastructure; two of those subfields in that array are pointers to 
programme variables, where the actual value (contents) of the column can be 
found and an indicator if the column contains a null value.

It is possible to write a generic SQL programme, that can run almost any SQL 
statement using the SQLDA as receiver variable.

This may sound simplistic or too vague. For an explanation of the QSQPRCED AP, 
look at www.mcpressonline.com; there you can find an article, "Power up SQL 
performance with QSQPRCED" by Jim Denton. This API relies heavily on the SQLDA.

Regards,
Carel Teijgeler



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On 26-2-03 at 9:26 Frank.Kolmann@xxxxxxxxxx wrote:

>Yet again my mind boggles as I try to grasp the implications.
>Perhaps it is possible to not even know the file structure that the SQL 
>operates on, then from the info in SQLDA get the
>file layout information.
>Once the file layout is known what does the FETCH fetch into? I usually use a 
>set of fields or a DS.  Can I FETCH into an
>unformatted space then parse the data according to the SQLDA.
>
>DESCRIBE  would have to be some sort of generic SQL that can read any file. I 
>have once done something similiar in RPG before
>vary and float field types.
>
>I dont see many applications for DESCRIBE, or am I completely off the scent. 
>(mind unwarping from the 4th dimension, what a relief)
>(gee the last Star Trek movie was such a dissapointment)