homework-jianmu/docs/examples/c/with_reqid_demo.c

79 lines
2.4 KiB
C

/*
* Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
*
* This program is free software: you can use, redistribute, and/or modify
* it under the terms of the GNU Affero General Public License, version 3
* or later ("AGPL"), as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// TAOS standard API example. The same syntax as MySQL, but only a subset
// to compile: gcc -o with_reqid_demo with_reqid_demo.c -ltaos
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
static int DemoWithReqId() {
// ANCHOR: with_reqid
const char *host = "localhost";
const char *user = "root";
const char *password = "taosdata";
uint16_t port = 6030;
int code = 0;
// connect
TAOS *taos = taos_connect(host, user, password, NULL, port);
if (taos == NULL) {
fprintf(stderr, "Failed to connect to %s:%hu, ErrCode: 0x%x, ErrMessage: %s.\n", host, port, taos_errno(NULL),
taos_errstr(NULL));
taos_cleanup();
return -1;
}
const char *sql = "SELECT ts, current, location FROM power.meters limit 1";
// query data with reqid
long reqid = 3L;
TAOS_RES *result = taos_query_with_reqid(taos, sql, reqid);
code = taos_errno(result);
if (code != 0) {
fprintf(stderr, "Failed to execute sql withQID: %ld, ErrCode: 0x%x, ErrMessage: %s\n.", reqid, code,
taos_errstr(result));
taos_close(taos);
taos_cleanup();
return -1;
}
TAOS_ROW row = NULL;
int rows = 0;
int num_fields = taos_field_count(result);
TAOS_FIELD *fields = taos_fetch_fields(result);
fprintf(stdout, "query successfully, got %d fields, the sql is: %s.\n", num_fields, sql);
// fetch the records row by row
while ((row = taos_fetch_row(result))) {
// Add your data processing logic here
rows++;
}
fprintf(stdout, "total rows: %d\n", rows);
taos_free_result(result);
// close & clean
taos_close(taos);
taos_cleanup();
return 0;
// ANCHOR_END: with_reqid
}
int main(int argc, char *argv[]) { return DemoWithReqId(); }