PQparamSendQueryPrepared (3)

#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);

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.

On success, a non-zero value is returned. On error, zero is returned and PQgeterror(3) will contain an error message.

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.

A contribution of eSilo, LLC. for the PostgreSQL Database Management System. Written by Andrew Chernow and Merlin Moncure.

Report bugs to <[email protected]>.

Copyright (c) 2011 eSilo, LLC. All rights reserved.

This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

PQparamCreate(3), PQgeterror(3), PQparamExec(3), PQparamExecPrepared(3)