Author: Written by Bruce Momjian (
<pgman@candle.pha.pa.us>
) and last updated 2000-03-30
pgeasy allows you to cleanly interface to the libpq library, more like a 4GL SQL interface. Refer to Chapter 1 for more information about libpq
It consists of set of simplified C functions that encapsulate the functionality of libpq. The functions are:
PGresult *doquery(char *query);
PGconn *connectdb(char *options);
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);
Many functions return a structure or value, so you can do more work with the result if required.
You basically connect to the database with connectdb
, issue your query with doquery
, fetch the results with fetch
, and finish with disconnectdb
.
For SELECT queries, 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 cannot be used
if you are running the pgeasy
client on a system with a different architecture than the
database server. If you pass a NULL pointer parameter, the column
is skipped. fetchwithnulls
allows
you to retrieve the NULL status of the field by passing an
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
doquery
. reset_fetch
starts the fetch back at the
beginning.
get_result
, set_result
, and unset_result
allow you to handle multiple
result sets at the same time.
There are several demonstration programs in the source directory.