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

142 lines
3.9 KiB
C

// compile with
// gcc -o stmt_example stmt_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
/**
* @brief execute sql only.
*
* @param taos
* @param sql
*/
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
/**
* @brief check return status and exit program when error occur.
*
* @param stmt
* @param code
* @param msg
*/
void checkErrorCode(TAOS_STMT *stmt, int code, const char* msg) {
if (code != 0) {
printf("%s. error: %s\n", msg, taos_stmt_errstr(stmt));
(void)taos_stmt_close(stmt);
exit(EXIT_FAILURE);
}
}
typedef struct {
int64_t ts;
float current;
int voltage;
float phase;
} Row;
/**
* @brief insert data using stmt API
*
* @param taos
*/
void insertData(TAOS *taos) {
// init
TAOS_STMT *stmt = taos_stmt_init(taos);
// prepare
const char *sql = "INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)";
int code = taos_stmt_prepare(stmt, sql, 0);
checkErrorCode(stmt, code, "failed to execute taos_stmt_prepare");
// bind table name and tags
TAOS_MULTI_BIND tags[2];
char* location = "California.SanFrancisco";
int groupId = 2;
tags[0].buffer_type = TSDB_DATA_TYPE_BINARY;
tags[0].buffer_length = strlen(location);
tags[0].length = &tags[0].buffer_length;
tags[0].buffer = location;
tags[0].is_null = NULL;
tags[1].buffer_type = TSDB_DATA_TYPE_INT;
tags[1].buffer_length = sizeof(int);
tags[1].length = &tags[1].buffer_length;
tags[1].buffer = &groupId;
tags[1].is_null = NULL;
code = taos_stmt_set_tbname_tags(stmt, "d1001", tags);
checkErrorCode(stmt, code, "failed to execute taos_stmt_set_tbname_tags");
// insert two rows
Row rows[2] = {
{1648432611249, 10.3, 219, 0.31},
{1648432611749, 12.6, 218, 0.33},
};
TAOS_MULTI_BIND values[4];
values[0].buffer_type = TSDB_DATA_TYPE_TIMESTAMP;
values[0].buffer_length = sizeof(int64_t);
values[0].length = &values[0].buffer_length;
values[0].is_null = NULL;
values[1].buffer_type = TSDB_DATA_TYPE_FLOAT;
values[1].buffer_length = sizeof(float);
values[1].length = &values[1].buffer_length;
values[1].is_null = NULL;
values[2].buffer_type = TSDB_DATA_TYPE_INT;
values[2].buffer_length = sizeof(int);
values[2].length = &values[2].buffer_length;
values[2].is_null = NULL;
values[3].buffer_type = TSDB_DATA_TYPE_FLOAT;
values[3].buffer_length = sizeof(float);
values[3].length = &values[3].buffer_length;
values[3].is_null = NULL;
for (int i = 0; i < 2; ++i) {
values[0].buffer = &rows[i].ts;
values[1].buffer = &rows[i].current;
values[2].buffer = &rows[i].voltage;
values[3].buffer = &rows[i].phase;
code = taos_stmt_bind_param(stmt, values); // bind param
checkErrorCode(stmt, code, "failed to execute taos_stmt_bind_param");
code = taos_stmt_add_batch(stmt); // add batch
checkErrorCode(stmt, code, "failed to execute taos_stmt_add_batch");
}
// execute
code = taos_stmt_execute(stmt);
checkErrorCode(stmt, code, "failed to execute taos_stmt_execute");
int affectedRows = taos_stmt_affected_rows(stmt);
printf("successfully inserted %d rows\n", affectedRows);
// close
(void)taos_stmt_close(stmt);
}
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", NULL, 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "CREATE DATABASE power");
executeSQL(taos, "USE power");
executeSQL(taos, "CREATE STABLE meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
insertData(taos);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 2 rows