mysqli executes multiple statements in batches and executes multiple statements in one function call

This article mainly shares with you the methods of mysqli batch execution of multiple statements and one function call to execute multiple statements. I hope you can have your own ideas through the examples in this article.

Supports the execution of multiple statements specified in a single string. To use this feature with a given connection, you must specify the CLIENT_MULTI_STATEMENTS option in the flags parameter to mysql_real_connect() when opening the connection. It can also be set for an existing connection by calling mysql_set_server_option(MYSQL_OPTION_MULTI_STATEMENTS_ON).

Commonly used routines:

   
/* Connect to server with option CLIENT_MULTI_STATEMENTS */
mysql_real_connect(..., CLIENT_MULTI_STATEMENTS);
/* Now execute multiple queries */
mysql_query(mysql,"DROP TABLE IF EXISTS test_table;\
                   CREATE TABLE test_table(id INT);\
                   INSERT INTO test_table VALUES(10);\
                   UPDATE test_table SET id=20 WHERE id=10;\
                   SELECT * FROM test_table;\
                   DROP TABLE test_table");
do
{
  /* Process all results */
  ...
  printf("total affected rows: %lld", mysql_affected_rows(mysql));
  ...
  if (!(result= mysql_store_result(mysql)))
  {
     printf(stderr, "Got fatal error processing query\n");
     exit(1);
  }
  process_result_set(result); /* client function */
  mysql_free_result(result);
} while (!mysql_next_result(mysql));

Look at the code specifically:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <mysql/mysql.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <termios.h>
#include <mysql/mysql.h>
void process_result_set(MYSQL       *mysql, MYSQL_RES *result)
{
        int i =0;
        unsigned int fieldnum;
        //从结果集，获取表头信息
        MYSQL_FIELD *fields = mysql_fetch_fields(result);
        fieldnum = mysql_field_count(mysql);
        for (i=0; i<fieldnum; i++)
        {
            printf("%s\t", fields[i].name);
        }
        printf("\n");
        //从结果集， 按照行获取信息信息
        MYSQL_ROW row = NULL;
        //从结果集中一行一行的获取数据
        while (  row = mysql_fetch_row(result))
        {
            fieldnum = mysql_field_count(mysql);
            //优化，我的行有多少列。。。。查找这样的api函数
            for (i=0; i<fieldnum; i++) //经过测试 发现 不是以0结尾的指针数组。。
            {
                printf("%s\t", row[i]);
            }
            printf("\n");
        }
}
int main()
{
    int         ret = 0, status = 0;
    MYSQL       *mysql;
    MYSQL_RES   *result;
    MYSQL_ROW   row;
    char        *query;
    mysql = mysql_init(NULL);
    mysql =mysql_real_connect(mysql, "localhost", "root", "123456", "mydb2", 0, NULL, CLIENT_MULTI_STATEMENTS);
    if (mysql == NULL)
    {
        ret = mysql_errno(mysql);
        printf("func mysql_real_connect() err\n");
        return ret;
    }
    else
    {
        printf(" ok......\n");
    }
    /* execute multiple statements */
status = mysql_query(mysql,
"DROP TABLE IF EXISTS test_table;\
CREATE TABLE test_table(id INT);\
INSERT INTO test_table VALUES(10);\
UPDATE test_table SET id=20 WHERE id=10;\
SELECT * FROM test_table;\
DROP TABLE test_table");
    if (status)
    {
        printf("Could not execute statement(s)");
        mysql_close(mysql);
        exit(0);
    }
    /* process each statement result */
    do {
            /* did current statement return data? */
            result = mysql_store_result(mysql);
            if (result)
            {
                /* yes; process rows and free the result set */
                process_result_set(mysql, result);
                mysql_free_result(result);
            }
            else /* no result set or error */
            {
                if (mysql_field_count(mysql) == 0)
                {
                    printf("%lld rows affected\n",
                    mysql_affected_rows(mysql));
                }
                else /* some error occurred */
                {
                    printf("Could not retrieve result set\n");
                    break;
                }
            }
        /* more results? -1 = no, >0 = error, 0 = yes (keep looping) */
        if ((status = mysql_next_result(mysql)) > 0)
                printf("Could not execute statement\n");
    } while (status == 0);
    mysql_close(mysql);
}

The above is the content of the MySQL entry to execute multiple statements in one function call.

Next, we mainly introduce the method of PHP to implement mysqli to execute multiple statements in batches, and analyze the related operating skills of PHP to connect to mysqli and execute multiple statements in batches in the form of examples.

The details are as follows :

You can perform multiple operations or retrieve multiple result sets at one time.

Example:

<?php
$mysqli = new mysqli("localhost", "root", "111111", "test");
/* check connection */
if (mysqli_connect_errno()) {
  printf("Connect failed: %s\n", mysqli_connect_error());
  exit();
}
/* multi_query执行一个或多个针对数据库的查询。多个查询用分号进行分隔。 */
$query = "SELECT * from test where id = 1;";
$query .= "SELECT name FROM test";
/* 批量执行查询 ，如果第一个查询失败则返回 FALSE。*/
if ($mysqli->multi_query($query)) {
  do {
    /* 获取第一个结果集 */
    if ($result = $mysqli->store_result()) {
      while ($row = $result->fetch_row()) {
        printf("%s\n", $row[0]);
      }
      $result->free();
    }
    /* 检查一个多查询是否有更多的结果 */
    if ($mysqli->more_results()) {
      printf("-----------------\n");
    }
    //准备下一个结果集
  } while ($mysqli->next_result());
}
/* close connection */
$mysqli->close();
?>

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MySQL implementation of executing multiple statements at one time and common problems

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