prepare.c

// TAOS standard API example. The same syntax as MySQL, but only a subet 
// to compile: gcc -o prepare prepare.c -ltaos

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"


void taosMsleep(int mseconds);

int main(int argc, char *argv[])
{
  TAOS     *taos;
  TAOS_RES *result;
  int      code;
  TAOS_STMT *stmt;

  // connect to server
  if (argc < 2) {
    printf("please input server ip \n");
    return 0;
  }

  taos = taos_connect(argv[1], "root", "taosdata", NULL, 0);
  if (taos == NULL) {
    printf("failed to connect to db, reason:%s\n", taos_errstr(taos));
    exit(1);
  }   

  result = taos_query(taos, "drop database demo"); 
  taos_free_result(result);

  result = taos_query(taos, "create database demo");
  code = taos_errno(result);
  if (code != 0) {
    printf("failed to create database, reason:%s\n", taos_errstr(result));
    taos_free_result(result);
    exit(1);
  }
  taos_free_result(result);

  result = taos_query(taos, "use demo");
  taos_free_result(result);

  // create table
  const char* sql = "create table m1 (ts timestamp, b bool, v1 tinyint, v2 smallint, v4 int, v8 bigint, f4 float, f8 double, bin binary(40), blob nchar(10))";
  result = taos_query(taos, sql);
  code = taos_errno(result);
  if (code != 0) {
    printf("failed to create table, reason:%s\n", taos_errstr(result));
    taos_free_result(result);
    exit(1);
  }
  taos_free_result(result);

  // sleep for one second to make sure table is created on data node
  // taosMsleep(1000);

  // insert 10 records
  struct {
      int64_t ts;
      int8_t b;
      int8_t v1;
      int16_t v2;
      int32_t v4;
      int64_t v8;
      float f4;
      double f8;
      char bin[40];
      char blob[80];
  } v = {0};

  stmt = taos_stmt_init(taos);
  TAOS_BIND params[10];
  params[0].buffer_type = TSDB_DATA_TYPE_TIMESTAMP;
  params[0].buffer_length = sizeof(v.ts);
  params[0].buffer = &v.ts;
  params[0].length = &params[0].buffer_length;
  params[0].is_null = NULL;

  params[1].buffer_type = TSDB_DATA_TYPE_BOOL;
  params[1].buffer_length = sizeof(v.b);
  params[1].buffer = &v.b;
  params[1].length = &params[1].buffer_length;
  params[1].is_null = NULL;

  params[2].buffer_type = TSDB_DATA_TYPE_TINYINT;
  params[2].buffer_length = sizeof(v.v1);
  params[2].buffer = &v.v1;
  params[2].length = &params[2].buffer_length;
  params[2].is_null = NULL;

  params[3].buffer_type = TSDB_DATA_TYPE_SMALLINT;
  params[3].buffer_length = sizeof(v.v2);
  params[3].buffer = &v.v2;
  params[3].length = &params[3].buffer_length;
  params[3].is_null = NULL;

  params[4].buffer_type = TSDB_DATA_TYPE_INT;
  params[4].buffer_length = sizeof(v.v4);
  params[4].buffer = &v.v4;
  params[4].length = &params[4].buffer_length;
  params[4].is_null = NULL;

  params[5].buffer_type = TSDB_DATA_TYPE_BIGINT;
  params[5].buffer_length = sizeof(v.v8);
  params[5].buffer = &v.v8;
  params[5].length = &params[5].buffer_length;
  params[5].is_null = NULL;

  params[6].buffer_type = TSDB_DATA_TYPE_FLOAT;
  params[6].buffer_length = sizeof(v.f4);
  params[6].buffer = &v.f4;
  params[6].length = &params[6].buffer_length;
  params[6].is_null = NULL;

  params[7].buffer_type = TSDB_DATA_TYPE_DOUBLE;
  params[7].buffer_length = sizeof(v.f8);
  params[7].buffer = &v.f8;
  params[7].length = &params[7].buffer_length;
  params[7].is_null = NULL;

  params[8].buffer_type = TSDB_DATA_TYPE_BINARY;
  params[8].buffer_length = sizeof(v.bin);
  params[8].buffer = v.bin;
  params[8].length = &params[8].buffer_length;
  params[8].is_null = NULL;

  strcpy(v.blob, "一二三四五六七八九十");
  params[9].buffer_type = TSDB_DATA_TYPE_NCHAR;
  params[9].buffer_length = strlen(v.blob);
  params[9].buffer = v.blob;
  params[9].length = &params[9].buffer_length;
  params[9].is_null = NULL;

  int is_null = 1;

  sql = "insert into m1 values(?,?,?,?,?,?,?,?,?,?)";
  code = taos_stmt_prepare(stmt, sql, 0);
  if (code != 0){
    printf("failed to execute taos_stmt_prepare. code:0x%x\n", code);
  }
  v.ts = 1591060628000;
  for (int i = 0; i < 10; ++i) {
    v.ts += 1;
    for (int j = 1; j < 10; ++j) {
      params[j].is_null = ((i == j) ? &is_null : 0);
    }
    v.b = (int8_t)i % 2;
    v.v1 = (int8_t)i;
    v.v2 = (int16_t)(i * 2);
    v.v4 = (int32_t)(i * 4);
    v.v8 = (int64_t)(i * 8);
    v.f4 = (float)(i * 40);
    v.f8 = (double)(i * 80);
    for (int j = 0; j < sizeof(v.bin) - 1; ++j) {
      v.bin[j] = (char)(i + '0');
    }

    taos_stmt_bind_param(stmt, params);
    taos_stmt_add_batch(stmt);
  }
  if (taos_stmt_execute(stmt) != 0) {
    printf("failed to execute insert statement.\n");
    exit(1);
  }
  taos_stmt_close(stmt);

  // query the records
  stmt = taos_stmt_init(taos);
  taos_stmt_prepare(stmt, "SELECT * FROM m1 WHERE v1 > ? AND v2 < ?", 0);
  v.v1 = 5;
  v.v2 = 15;
  taos_stmt_bind_param(stmt, params + 2);
  if (taos_stmt_execute(stmt) != 0) {
    printf("failed to execute select statement.\n");
    exit(1);
  }

  result = taos_stmt_use_result(stmt);

  TAOS_ROW    row;
  int         rows = 0;
  int         num_fields = taos_num_fields(result);
  TAOS_FIELD *fields = taos_fetch_fields(result);
  char        temp[256];

  // fetch the records row by row
  while ((row = taos_fetch_row(result))) {
    rows++;
    taos_print_row(temp, row, fields, num_fields);
    printf("%s\n", temp);
  }
  if (rows == 2) {
    printf("two rows are fetched as expectation\n");
  } else {
    printf("expect two rows, but %d rows are fetched\n", rows);
  }

  taos_free_result(result);
  taos_stmt_close(stmt);

  return 0;
}