PQparamSendQuery3
Executes an asynchronous paramertized query using the parameters in a pgparam.
Usage
#include <libpqtypes.h>
int PQparamSendQuery(PGconn *conn, PGparam *param,
const char *command, int resultFormat);
int PQparamSendQueryPrepared(PGconn *conn, PGparam *param,
const char *stmtName, int resultFormat);
Overview
The PQparamSendQuery() and PQparamSendQueryPrepared() functions execute an asynchronous paramertized query using the parameters in a PGparam. The only difference between these functions is that PQparamSendQuery() expects a parameterized command string while PQparamSendQueryPrepared() expects a stmtName previously prepared via PQprepare().
Both functions take a param argument, which must contain the same number of parameters as either the command string or previously prepared stmtName. Internally, the param is transformed into parallel arrays that are supplied to a PQsendQueryParams() or PQsendQueryPrepared() call.
The resultFormat argument indicates if text or binary results are desired; a value of zero or one respectively. PQgetf supports both text and binary result formats, with the exclusion of arrays and composites which only support binary.
After successfully calling PQparamSendQuery() or PQparamSendQueryPrepared(), call libpq´s PQgetResult() one or more times to obtain the results.
Return value
On success, a non-zero value is returned. On error, zero is returned and PQgeterror(3) will contain an error message.
Examples
Using PQparamSendQuery
The example uses PQparamSendQuery() to execute a query using a PGparam.
PGparam *param = PQparamCreate(conn);
if(!PQputf(param, "%text %int4", "ACTIVE", CAT_CAR)) {
fprintf(stderr, "PQputf: %s\n", PQgeterror()); } else {
int success = PQparamSendQuery(conn, param,
"SELECT * FROM t WHERE status=$1 AND category=$2", 1);
if(!success)
fprintf(stderr, "PQparamSendQuery: %s\n", PQgeterror());
else
get_and_print_results(conn); /* calls PQgetResult() */ }
PQparamClear(param);
Using PQparamSendQueryPrepared
PQparamSendQueryPrepared() is behaves identically to PQparamSendQuery(), except PQparamSendQueryPrepared() requires that a statement has been previously prepared via PQprepare(). Also, a stmtName is supplied rather than a parameterized command string.
Releases
Unchanged in 5 releases since Debian 8 (Jessie).