I have a C to postgres question.
От | Jay G. Scott |
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Тема | I have a C to postgres question. |
Дата | |
Msg-id | 200301301613.h0UGDVF27650@csdsun1.arlut.utexas.edu обсуждение исходный текст |
Ответы |
Re: I have a C to postgres question.
|
Список | pgsql-novice |
I'm hoping it's okay to post this kind of thing here. There's no newsgroup, cruising the FAQs didn't turn up anything--or I missed it. The database has 4 values; I can see them when I get into the d.b. via: psql test and, using (cut and paste) the string the C program uses to select, from "psql test" I see the four values. The string, I suppose, must be okay. Furthermore, if I turn on tracing in the C program, I believe I see the four values being printed. That makes me think the select statement syntax is correct. However, my C program thinks it got 0 rows. And I can't retrieve anything. So I think the problem is in my C code. I printed the online man pages, it looks okay to me. Here's the code fragment: /*-----------------------------------------------*/ sprintf(select_stmt, "SELECT m_id FROM machines WHERE hostname = '%s'", node); fprintf(stderr,"trying this: %s\n", select_stmt); /*____________________________________________________________________________*/ igot = PQsendQuery(conn_to_db,select_stmt); fprintf(stderr,"igot from query is %d\n", igot ); seek_m_id = PQgetResult(conn_to_db); estgot = PQresultStatus( seek_m_id ); fprintf(stderr,"estgot from PQgetResult is %d\n", estgot ); while( seek_m_id != NULL ) { fprintf(stderr,"seek_m_id != NULL\n"); seek_m_id = PQgetResult(conn_to_db); estgot = PQresultStatus( seek_m_id ); tmwh( estgot ); /* i suppose nrows could keep coming back as 1 */ nrows = PQntuples( seek_m_id ); fprintf(stderr,"nrows = %d\n", nrows ); for(jj=0;jj<nrows;jj++) { cgot = PQgetvalue( seek_m_id, jj, 0 ); machine_id = atoi( cgot ); fprintf(stderr,"machine_id = %d\n", machine_id ); } PQclear(seek_m_id); } /*____________________________________________________________________________*/ -- Jay Scott 512-835-3553 gl@arlut.utexas.edu Head of Sun Support, Sr. Operating Systems Specialist Applied Research Labs, Computer Science Div. S224 University of Texas at Austin
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