Re: ECGP - varchar in struct?
От | Michael Meskes |
---|---|
Тема | Re: ECGP - varchar in struct? |
Дата | |
Msg-id | 20020813181056.GK8886@feivel.fam-meskes.de обсуждение исходный текст |
Ответ на | Re: ECGP - varchar in struct? ("William West" <wwest@csc.com>) |
Список | pgsql-interfaces |
On Mon, Aug 12, 2002 at 09:53:03PM -0400, William West wrote: > I really appreciate your time. I know a lot of what I am saying > must sound silly, due to how low on the learning curve I am. Actually it sounds very reasonable, I just don't fully understand it. > > exec sql typedef sf struct foo {...}; Oops. This is incorrect syntax, must read: exec sql type sf is struct foo {...}; > This looks promising for what I am trying to do. Is > 'exec sql typedef' ecpg specific? I do not remember seeing > it called out as anything special in the books I have looked at? Informix has it also. > exec sql typedef sf struct foo {int intOne; int intTwo}; > > and I get: > > ERROR: parse error, unexpected IDENT at or near "typedef" Sure. My fault. Should be "exec sql type ... is ...;" > Here is what I setup: > ... > exec sql insert into mytable values (:bar); Hmm, that should work. Could you please send me the complete file? > Pro*C would take this to mean to put the present values of > bar.col1 and bar.col2 into columns 1 and 2 of a new row > added to mytable. This builds cleanly in ecpg, seems to emit > a sensible ECPGdo() call, but gives "-201, too many arguments" > at run time. I can't figure out what the library wants ... ECPGdo() > is emitted with two vectors, one to each of the struct members? Yes, that should be the correct ECPGdo() call. > I then tried to figure out how to mention the struct members > individually in the values() clause: > > exec sql insert into mytable values (:bar.col1.arr, :bar.col2.arr); > > But this causes ecpg to issue the error "'bar.col1.arr' is not > declared". I can't figure out what ecpg would want, to be > able to refer to the individual members of the struct? To get them individually you have to use: exec sql insert into mytable values (:bar.col1, :bar.col2); > where 'ROWS' establishes the maximum batch size. The Pro*C > understanding of the meaning of a structure in the declare section > (as signifying a row) and its members (as signifying a column) is > fundamental to being able to declare space for batched operations > via C-Language array declaration syntax. You can use arrays of struct with ecpg as well. Please look into ecpg/test/*.pgc for some examples. > Lack of the "exec sql for :batchsize" capability is a big problem to > overcome, Hmm, looks like a good idea to implement in ecpg. > This fear of the effects on performance, along with the scope of > application-internal > interface changes that seem to be needed, is what is making me inclined to > consider, > much as I hate it, going to libpq and/ or libpqeasy directly. Of course there may be reasons to use libpq, but I will certainly work on minimizing these. As soon as I learn about a missing feature and find time I will implement it. Now that won't help you of course. :-) Michael -- Michael Meskes Michael@Fam-Meskes.De Go SF 49ers! Go Rhein Fire! Use Debian GNU/Linux! Use PostgreSQL!
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