MySQL入门之一次函数调用执行多条语句

黄舟 2017-01-19 00:00:00 次阅读

 支持在单个字符串中指定的多语句的执行。要想与给定的连接一起使用该功能，打开连接时，必须将标志参数中的client_multi_statements选项指定给mysql_real_connect()。也可以通过调用mysql_set_server_option(mysql_option_multi_statements_on)，为已有的连接设置它。

常用套路：

/* 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));

具体看代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
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; i0 = error, 0 = yes (keep looping) */
        if ((status = mysql_next_result(mysql)) > 0)
                printf("Could not execute statement\n");
    } while (status == 0);
    mysql_close(mysql);
}