Update pgeasy for missing files.

This commit is contained in:
Bruce Momjian 1999-10-12 14:06:49 +00:00
parent 5a2085392c
commit 3c44a132ea
3 changed files with 380 additions and 0 deletions

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.\" This is -*-nroff-*-
.\" XXX standard disclaimer belongs here....
.\" $Header: /cvsroot/pgsql/src/interfaces/libpgeasy/Attic/libpgeasy.3,v 1.1 1999/10/12 14:06:49 momjian Exp $
.TH PGEASY INTRO 08/08/98 PostgreSQL PostgreSQL
.SH DESCRIPTION
Pgeasy allows you to cleanly interface to the libpq library,
more like a 4gl SQL interface.
.PP
It consists of set of simplified C functions that encapsulate the
functionality of libpq.
The functions are:
.nf
PGresult *doquery(char *query);
PGconn *connectdb();
void disconnectdb();
int fetch(void *param,...);
int fetchwithnulls(void *param,...);
void reset_fetch();
void on_error_continue();
void on_error_stop();
PGresult *get_result();
void set_result(PGresult *newres);
void unset_result(PGresult *oldres);
.fi
.PP
Many functions return a structure or value, so you can do more work
with the result if required.
.PP
You basically connect to the database with
.BR connectdb ,
issue your query with
.BR doquery ,
fetch the results with
.BR fetch ,
and finish with
.BR disconnectdb .
.PP
For
.IR select
queries,
.BR fetch
allows you to pass pointers as parameters, and on return the variables
are filled with data from the binary cursor you opened. These binary
cursors can not be used if you are running the
.BR pgeasy
client on a system with a different architecture than the database
server. If you pass a NULL pointer parameter, the column is skipped.
.BR fetchwithnulls
allows you to retieve the
.IR null
status of the field by passing an
.IR int*
after each result pointer, which returns true or false if the field is null.
You can always use libpq functions on the PGresult pointer returned by
.BR doquery .
.BR reset_fetch
starts the fetch back at the beginning.
.PP
.BR get_result ,
.BR set_result ,
and
.BR unset_result
allow you to handle multiple result sets at the same time.
.PP
There are a variety of demonstration programs in the
.BR pgeasy
source directory.

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/*
* pgeasy.c
*
*/
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <libpq-fe.h>
#include "halt.h"
#include "libpgeasy.h"
#define NUL '\0'
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
/* GLOBAL VARIABLES */
static PGconn *conn;
static PGresult *res = NULL;
#define ON_ERROR_STOP 0
#define ON_ERROR_CONTINUE 1
static int on_error_state = ON_ERROR_STOP;
static in_result_block = FALSE;
static was_get_unset_result = FALSE;
/* LOCAL VARIABLES */
static int tuple;
/*
**
** connectdb - returns PGconn structure
**
*/
PGconn *
connectdb(char *dbName,
char *pghost,
char *pgport,
char *pgoptions,
char *pgtty)
{
/* make a connection to the database */
conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);
if (PQstatus(conn) == CONNECTION_BAD)
halt("Connection to database '%s' failed.\n%s\n", dbName,
PQerrorMessage(conn));
return conn;
}
/*
**
** disconnectdb
**
*/
void
disconnectdb()
{
PQfinish(conn);
}
/*
**
** doquery - returns PGresult structure
**
*/
PGresult *
doquery(char *query)
{
if (res != NULL && in_result_block == FALSE && was_get_unset_result == FALSE)
PQclear(res);
was_get_unset_result = FALSE;
res = PQexec(conn, query);
if (on_error_state == ON_ERROR_STOP &&
(res == NULL ||
PQresultStatus(res) == PGRES_BAD_RESPONSE ||
PQresultStatus(res) == PGRES_NONFATAL_ERROR ||
PQresultStatus(res) == PGRES_FATAL_ERROR))
{
if (res != NULL)
fprintf(stderr, "query error: %s\n", PQcmdStatus(res));
else
fprintf(stderr, "connection error: %s\n", PQerrorMessage(conn));
PQfinish(conn);
halt("failed request: %s\n", query);
}
tuple = 0;
return res;
}
/*
**
** fetch - returns tuple number (starts at 0), or the value END_OF_TUPLES
** NULL pointers are skipped
**
*/
int
fetch(void *param,...)
{
va_list ap;
int arg,
num_fields;
num_fields = PQnfields(res);
if (tuple >= PQntuples(res))
return END_OF_TUPLES;
va_start(ap, param);
for (arg = 0; arg < num_fields; arg++)
{
if (param != NULL)
{
if (PQfsize(res, arg) == -1)
{
memcpy(param, PQgetvalue(res, tuple, arg), PQgetlength(res, tuple, arg));
((char *) param)[PQgetlength(res, tuple, arg)] = NUL;
}
else
memcpy(param, PQgetvalue(res, tuple, arg), PQfsize(res, arg));
}
param = va_arg(ap, char *);
}
va_end(ap);
return tuple++;
}
/*
**
** fetchwithnulls - returns tuple number (starts at 0),
** or the value END_OF_TUPLES
** Returns TRUE or FALSE into null indicator variables
** NULL pointers are skipped
*/
int
fetchwithnulls(void *param,...)
{
va_list ap;
int arg,
num_fields;
num_fields = PQnfields(res);
if (tuple >= PQntuples(res))
return END_OF_TUPLES;
va_start(ap, param);
for (arg = 0; arg < num_fields; arg++)
{
if (param != NULL)
{
if (PQfsize(res, arg) == -1)
{
memcpy(param, PQgetvalue(res, tuple, arg), PQgetlength(res, tuple, arg));
((char *) param)[PQgetlength(res, tuple, arg)] = NUL;
}
else
memcpy(param, PQgetvalue(res, tuple, arg), PQfsize(res, arg));
}
param = va_arg(ap, char *);
if (PQgetisnull(res, tuple, arg) != 0)
*(int *) param = 1;
else
*(int *) param = 0;
param = va_arg(ap, char *);
}
va_end(ap);
return tuple++;
}
/*
**
** on_error_stop
**
*/
void
on_error_stop()
{
on_error_state = ON_ERROR_STOP;
}
/*
**
** on_error_continue
**
*/
void
on_error_continue()
{
on_error_state = ON_ERROR_CONTINUE;
}
/*
**
** get_result
**
*/
PGresult *
get_result()
{
char *cmdstatus = PQcmdStatus(res);
was_get_unset_result = TRUE;
/* we have to store the fetch location somewhere */
cmdstatus[0] = NUL;
memcpy(&cmdstatus[1], &tuple, sizeof(tuple));
return res;
}
/*
**
** set_result
**
*/
void
set_result(PGresult *newres)
{
char *cmdstatus = PQcmdStatus(res);
if (newres == NULL)
halt("set_result called with null result pointer\n");
if (res != NULL && was_get_unset_result == FALSE)
if (in_result_block == FALSE)
PQclear(res);
else
{
cmdstatus[0] = NUL;
memcpy(&cmdstatus[1], &tuple, sizeof(tuple));
}
in_result_block = TRUE;
was_get_unset_result = FALSE;
cmdstatus = PQcmdStatus(newres);
memcpy(&tuple, &cmdstatus[1], sizeof(tuple));
res = newres;
}
/*
**
** unset_result
**
*/
void
unset_result(PGresult *oldres)
{
char *cmdstatus = PQcmdStatus(oldres);
if (oldres == NULL)
halt("unset_result called with null result pointer\n");
if (in_result_block == FALSE)
halt("Unset of result without being set.\n");
was_get_unset_result = TRUE;
cmdstatus[0] = NUL;
memcpy(&cmdstatus[1], &tuple, sizeof(tuple));
in_result_block = FALSE;
}
/*
**
** reset_fetch
**
*/
void
reset_fetch()
{
tuple = 0;
}

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/*
* pglib.h
*
*/
PGresult *doquery(char *query);
PGconn *connectdb(char *dbName,
char *pghost,
char *pgport,
char *pgoptions,
char *pgtty);
void disconnectdb(void);
int fetch(void *param,...);
int fetchwithnulls(void *param,...);
void on_error_continue(void);
void on_error_stop(void);
PGresult *get_result(void);
void set_result(PGresult *newres);
void unset_result(PGresult *oldres);
void reset_fetch(void);
#define END_OF_TUPLES (-1)