解说mysql数据库_Mysql数据库的api介绍讲解-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_32762235/article/details/113554700

本文详细介绍了MySQL数据库的API用法，包括基本的SQL查询、预处理语句的使用，以及事务处理。预处理语句能够防止SQL注入并提高效率，文章通过示例代码展示了如何进行插入和查询的预处理。同时，还讲解了事务的开启、提交和回滚操作，以确保数据的一致性和完整性。

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Mysql数据库的api介绍讲解

; //读取client输入的sql字符串 read(STDIN_FILENO, strsql, sizeof(strsql)); //退出的处理 if (strncasecmp(strsql, "quit", 4) == 0) { printf("client 退出处理\n"); break; } //输入sql的 ret = mysql_query(mysql, strsql); if (ret) { printf("mysql_query error\n"); continue; } res = mysql_store_result(mysql); //有结果集的处理 if (res != NULL) { show_information(res, mysql); } else { //显示受影响的行数 printf(" Query OK, %ld row affected\n",(long) mysql_affected_rows(mysql)); } } // char sqlstr[] = "select *from emp"; // //查询语句int mysql_query(MYSQL *mysql, const char *query) // ret = mysql_query(mysql, sqlstr); // if (ret) { // printf("mysql_query error\n"); // return -1; // } // // //查询的结果集MYSQL_RES *mysql_store_result(MYSQL *mysql) // res = mysql_store_result(mysql); //MYSQL_ROW mysql_fetch_row(MYSQL_RES *result) // if ( res != NULL) { // show_information(res); // // 数据的长度unsigned int mysql_num_fields(MYSQL_RES *result) // num_fields = mysql_num_fields(res); // //返回列长unsigned long *mysql_fetch_lengths(MYSQL_RES *result) // //lengths = mysql_fetch_lengths(res); // printf("num_fields = [%d]\n", num_fields); // //字段名 // for (i = 0; i < num_fields, field = mysql_fetch_field(res); i++) { // printf(" %s\t", field->name); // } // printf("\n"); // while (row = mysql_fetch_row(res)) { // // for (i = 0; i < num_fields; i++) { // printf("%s \t", row[i]); // } // printf("\n"); // } // //释放结果集 // mysql_free_result(res); // } //关闭mysql mysql_close(mysql); return 0; }

</unistd.h>

</mysql.h>

</string.h>

</stdlib.h>

</stdio.h></pre>

<h3 id="二sql预处理-防止注入和增加效率">二，SQL预处理防止注入和增加效率</h3>

<h4 id="1插入预处理">1,插入预处理</h4>

<h5 id="①api介绍">①api介绍</h5>

<h6 id="1预处理初始化"> 1，预处理初始化</h6>

<p>MYSQL_STMT *mysql_stmt_init(MYSQL *mysql)</p>

</blockquote>

<p>创建MYSQL_STMT句柄。对于该句柄，应使用mysql_stmt_close(MYSQL_STMT *)释放。</p>

<p>成功时，返回指向MYSQL_STMT结构的指针。如果内存溢出，返回NULL。</p>

<h6 id="2插入预处理语句"> 2,插入预处理语句</h6>

<p>int mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, unsigned long length)</p>

</blockquote>

<p>给定mysql_stmt_init()返回的语句句柄，准备字符串查询指向的SQL语句，并返回状态值。字符串长度应由“length”参量给出。字符串必须包含1条SQL语句。不应为语句添加终结用分号(‘;’)或\g。</p>

<p>通过将问号字符“?”嵌入到SQL字符串的恰当位置，应用程序可包含SQL语句中的一个或多个参数标记符。</p>

<p>标记符仅在SQL语句中的特定位置时才是合法的。例如，它可以在INSERT语句的VALUES()列表中(为行指定列值)，或与WHERE子句中某列的比较部分(用以指定比较值)。但是，对于ID(例如表名或列名)，不允许使用它们，不允许指定二进制操作符(如等于号“=”)的操作数。后一个限制是有必要的，原因在于，无法确定参数类型。一般而言，参数仅在DML(数据操作语言)语句中才是合法的，在DDL(数据定义语言)语句中不合法。</p>

<p>执行语句之前，必须使用mysql_stmt_bind_param()，将参数标记符与应用程序变量绑定在一起。</p>

<p>如果成功处理了语句，返回0。如果出现错误，返回非0值。</p>

<p>unsigned long mysql_stmt_param_count(MYSQL_STMT *stmt)</p>

</blockquote>

<p>返回预处理语句中参数标记符的数目。</p>

<p>表示语句中参数数目的无符号长整数。</p>

<h6 id="4参数的绑定"> 4,参数的绑定</h6>

<p>my_bool mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *bind)</p>

</blockquote>

<p>mysql_stmt_bind_param()用于为SQL语句中的参数标记符绑定数据，以传递给mysql_stmt_prepare()。它使用MYSQL_BIND结构来提供数据。“bind”是MYSQL_BIND结构的某一数组的地址。按照客户端库的预期，对于查询中出现的每个“?”参数标记符，数组中均包含1个元素。</p>

<p>假定你准备了下述语句：</p>

<p>INSERT INTO mytbl VALUES(?,?,?)<br /> 绑定参数时，MYSQL_BIND结构的数组包含3个元素，并能声明如下：</p>

<p>MYSQL_BIND bind[3];</p>

<h6 id="5预处理执行"> 5,预处理执行</h6>

<p>int mysql_stmt_execute(MYSQL_STMT *stmt)</p>

</blockquote>

<p>mysql_stmt_execute()执行与语句句柄相关的预处理查询。在该调用期间，将当前绑定的参数标记符的值发送到服务器，服务器用新提供的数据替换标记符。</p>

<p>如果语句是UPDATE、DELETE或INSERT，通过调用mysql_stmt_affected_rows()，可发现更改、删除或插入的总行数。如果这是诸如SELECT等能生成结果集的语句，调用任何其他能导致查询处理的函数之前，必须调用mysql_stmt_fetch()来获取数据。关于如何获取结果的更多信息，请参见25.2.7.11节，“mysql_stmt_fetch()”。</p>

<p>对于生成结果集的语句，执行语句之前，可通过调用mysql_stmt_attr_set()，请求mysql_stmt_execute()为语句打开光标。如果多次执行某一语句，在打开新的光标前，mysql_stmt_execute()将关闭任何已打开的光标。</p>

<p>如果执行成功，返回0。如果出现错误，返回非0值。</p>

<h6 id="6返回预处理的行数"> 6,返回预处理的行数</h6>

<p>my_ulonglong mysql_stmt_affected_rows(MYSQL_STMT *stmt)</p>

</blockquote>

<p>返回上次执行语句更改、删除或插入的总行数。对于UPDATE、DELETE或INSERT语句，可在mysql_stmt_execute()之后立刻调用它们。对于SELECT语句，mysql_stmt_affected_rows()的工作方式类似于mysql_num_rows()。</p>

<p>大于0的整数指明了受影响或检索的行数。对于UPDATE语句，“0”表明未更新任何记录，在查询中没有与WHERE子句匹配的行，或尚未执行任何查询。“-1”表明返回了错误，或对SELECT查询，在调用mysql_stmt_store_result()之前调用了mysql_stmt_affected_rows()。由于mysql_stmt_affected_rows()返回无符号值，可通过比较返回值和“(my_ulonglong)-1”(或等效的“(my_ulonglong)~0”)，检查“-1”。</p>

//预处理方式api处理 -- insert

#include

<stdio.h>

#include "mysql.h"

#include

<stdlib.h>

#include

<string.h>

#define _HOST_ "localhost" //主机 #define _USER_ "root" //mysql用户,非主机 #define _PASSWD_ "123" //密码 #define _DBNAME_ "scott" //库名 #define STRING_SIZE 50 #define DROP_SAMPLE_TABLE "DROP TABLE IF EXISTS test_table" // if EXISTS 好处是如果表不存在,执行不会报错 #define CREATE_SAMPLE_TABLE "CREATE TABLE test_table(col1 INT,\ col2 VARCHAR(40),\ col3 SMALLINT,\ col4 TIMESTAMP)" #define INSERT_SAMPLE "INSERT INTO test_table(col1,col2,col3) VALUES(?,?,?)" void prepare_insert(MYSQL *mysql); int main() { //1.初始化 MYSQL * mysql = NULL; mysql = mysql_init(NULL) ; if(mysql == NULL ) { printf("mysql init err\n"); exit(1); } //2.连接 mysql = mysql_real_connect(mysql, _HOST_,_USER_, _PASSWD_,_DBNAME_, 0, NULL,0); if(mysql == NULL) { printf("mysql_real_connect connect err\n"); exit(1); } printf("welcome to mysql \n"); prepare_insert(mysql); //3.关闭 mysql_close(mysql); return 0; } void prepare_insert(MYSQL *mysql) { MYSQL_STMT *stmt;//预处理的句柄 -- 标识进程内唯一的一个预处理的sql MYSQL_BIND bind[3];//绑定变量 my_ulonglong affected_rows; int param_count; short small_data; int int_data; char str_data[STRING_SIZE]; unsigned long str_length; my_bool is_null; if (mysql_query(mysql, DROP_SAMPLE_TABLE))//删除表 { fprintf(stderr, " DROP TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } if (mysql_query(mysql, CREATE_SAMPLE_TABLE))//创建表 { fprintf(stderr, " CREATE TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } /* Prepare an INSERT query with 3 parameters */ /* (the TIMESTAMP column is not named; the server */ /* sets it to the current date and time) */ stmt = mysql_stmt_init(mysql); //预处理的初始化 if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } if (mysql_stmt_prepare(stmt, INSERT_SAMPLE, strlen(INSERT_SAMPLE))) //insert 语句的预处理 { fprintf(stderr, " mysql_stmt_prepare(), INSERT failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } fprintf(stdout, " prepare, INSERT successful\n"); /* Get the parameter count from the statement */ param_count= mysql_stmt_param_count(stmt);//获得参数个数 fprintf(stdout, " total parameters in INSERT: %d\n", param_count); if (param_count != 3) /* validate parameter count */ { fprintf(stderr, " invalid parameter count returned by MySQL\n"); exit(0); } /* Bind the data for all 3 parameters */ memset(bind, 0, sizeof(bind)); /* INTEGER PARAM */ /* This is a number type, so there is no need to specify buffer_length */ bind[0].buffer_type= MYSQL_TYPE_LONG;//对应int类型 bind[0].buffer= (char *)&int_data;//内存地址的映射 bind[0].is_null= 0; bind[0].length= 0; /* STRING PARAM */ bind[1].buffer_type= MYSQL_TYPE_STRING; bind[1].buffer= (char *)str_data;//char 100 bind[1].buffer_length= STRING_SIZE; bind[1].is_null= 0; bind[1].length= &str_length; /* SMALLINT PARAM */ bind[2].buffer_type= MYSQL_TYPE_SHORT; bind[2].buffer= (char *)&small_data; bind[2].is_null= &is_null;//是否为null的指示器 bind[2].length= 0; /* Bind the buffers */ if (mysql_stmt_bind_param(stmt, bind)) //绑定变量参数绑定 { fprintf(stderr, " mysql_stmt_bind_param() failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } //第一波赋值 int_data= 10; /* integer */ strncpy(str_data, "MySQL", STRING_SIZE); /* string */ str_length= strlen(str_data); //INSERT INTO test_table(col1,col2,col3) VALUES(10,'MySQL',null) /* INSERT SMALLINT data as NULL */ is_null= 1;//指示插入的第三个字段是否为null //insert into test_table(col1,col2,col3) values(10,'MySQL',null); /* Execute the INSERT statement - 1*/ if (mysql_stmt_execute(stmt)) //预处理的执行,第一次执行 { fprintf(stderr, " mysql_stmt_execute(), 1 failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Get the total number of affected rows */ affected_rows= mysql_stmt_affected_rows(stmt);//预处理的影响条数 fprintf(stdout, " total affected rows(insert 1): %lu\n", (unsigned long) affected_rows); if (affected_rows != 1) /* validate affected rows */ { fprintf(stderr, " invalid affected rows by MySQL\n"); exit(0); } //第二波赋值 int_data= 1000; strncpy(str_data, "The most popular Open Source database", STRING_SIZE); str_length= strlen(str_data); small_data= 1000; /* smallint */ is_null= 1; /* reset */ //INSERT INTO test_table(col1,col2,col3) VALUES(1000,'The most popular Open Source database',1000) //insert into test_table(col1,col2,col3) values(1000,'The most popular Open Source database',1000); /* Execute the INSERT statement - 2*/ if (mysql_stmt_execute(stmt))//第二次执行 { fprintf(stderr, " mysql_stmt_execute, 2 failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } /* Get the total rows affected */ affected_rows= mysql_stmt_affected_rows(stmt); fprintf(stdout, " total affected rows(insert 2): %lu\n", (unsigned long) affected_rows); if (affected_rows != 1) /* validate affected rows */ { fprintf(stderr, " invalid affected rows by MySQL\n"); exit(0); } /* Close the statement */ if (mysql_stmt_close(stmt)) { fprintf(stderr, " failed while closing the statement\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } }

</string.h>

</stdlib.h>

</stdio.h></pre>

<h4 id="2-查询预处理">2, 查询预处理</h4>

<h5 id="api介绍">api介绍</h5>

<p>MYSQL_RES *mysql_stmt_param_metadata(MYSQL_STMT *stmt)</p>

</blockquote>

<p>提前指定结果集的操作</p>

//select *from dept; 查询语句的使用

#include

<stdio.h>

#include

<stdlib.h>

#include

<string.h>

#include

<mysql.h>

#define _USER_ "root" //用户名 #define _HOST_ "127.0.0.1" //host #define _PASSWD_ "123" //root 用户名密码 #define _DB_ "scott" //库名 #define _PORT_ 3306 //port //============================stmt ====================================== #define STRING_SIZE 50 //mysql 查询语句 #define SELECT_SAMPLE "SELECT deptno, dname, loc FROM dept" void seach_information(MYSQL *mysql){ int i, count = 0;; MYSQL_STMT *stmt; // MYSQL_BIND bind[3]; //条件变量 MYSQL_RES *prepare_meta_result; //结果集 unsigned long length[3]; int param_count, column_count, row_count; int int_data; //序号 char str_name[STRING_SIZE]; //姓名 char str_loc[STRING_SIZE]; my_bool is_null[3]; //参数的控制 my_ulonglong row_unm; //===========================init start========================= //初始化sql预处理语句 stmt = mysql_stmt_init(mysql); if (!stmt) { fprintf(stderr, " mysql_stmt_init(), out of memory\n"); exit(0); } //绑定参数my_bool mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *bind) //mysql_stmt_bind_param(stmt, bind); if (mysql_stmt_prepare(stmt, SELECT_SAMPLE, strlen(SELECT_SAMPLE))) { fprintf(stderr, " mysql_stmt_prepare(), SELECT failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } fprintf(stdout, " prepare, SELECT successful\n"); fprintf(stdout, " total parameters in SELECT: %d\n", param_count); param_count = mysql_stmt_param_count(stmt); if (param_count != 0) /* validate parameter count */ { fprintf(stderr, " invalid parameter count returned by MySQL\n"); exit(0); } prepare_meta_result = mysql_stmt_result_metadata(stmt); if (!prepare_meta_result) { fprintf(stderr, " mysql_stmt_result_metadata(), returned no meta information\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } column_count= mysql_num_fields(prepare_meta_result); fprintf(stdout, " total columns in SELECT statement: %d\n", column_count); if (column_count != 3) /* validate column count */ { fprintf(stderr, " invalid column count returned by MySQL\n"); exit(0); } //mysql_stmt_execute(stmt); //发送占位符到mysql数据库上？？？？ if (mysql_stmt_execute(stmt)) { fprintf(stderr, " mysql_stmt_execute(), failed\n"); fprintf(stderr, " %s\n", mysql_stmt_error(stmt)); exit(0); } //初始化参数 memset(bind, 0, sizeof(bind)); /* INTEGER COLUMN */ bind[0].buffer_type= MYSQL_TYPE_LONG; bind[0].buffer= (char *)&int_data; bind[0].is_null= &is_null[0]; bind[0].length= &length[0]; //varchar -- MYSQL_TYPE_VAR_STRING /* name COLUMN */ bind[1].buffer_type= MYSQL_TYPE_VAR_STRING; bind[1].buffer= (char *)str_name; bind[1].buffer_length = STRING_SIZE; bind[1].is_null = &is_null[1]; bind[1].length = &length[1]; /* loc COLUMN */ bind[2].buffer_type= MYSQL_TYPE_VAR_STRING; bind[2].buffer= (char *)&str_loc; bind[2].buffer_length = STRING_SIZE; bind[2].is_null = &is_null[2]; bind[2].length = &length[2]; //绑定数据 mysql_stmt_bind_result(stmt, bind); mysql_stmt_store_result(stmt);// //init row row_count= 0; //查询的结果 row_unm = mysql_stmt_num_rows(stmt); //打印数据 //mysql_stmt_fetch(stmt); //mysql_stmt_fetch(stmt); printf("row_unm = %ld\n", row_unm); for (i = 0; i < row_unm; i++) { mysql_stmt_fetch(stmt); row_count++; fprintf(stdout, " row %d\n", row_count); /* column 1 */ fprintf(stdout, " column1 (integer) : "); if (is_null[0]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %d(%ld)\n", int_data, length[0]); /* column 2 */ fprintf(stdout, " column2 (string) : "); if (is_null[1]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %s(%ld)\n", str_name, length[1]); /* column 3 */ fprintf(stdout, " column3 (string) : "); if (is_null[2]) fprintf(stdout, " NULL\n"); else fprintf(stdout, " %s(%ld)\n", str_loc, length[2]); fprintf(stdout, "\n"); //break; } //释放内存 /* Validate rows fetched */ if (row_count != 10) { fprintf(stderr, " MySQL failed to return all rows\n"); exit(0); } /* Free the prepared result metadata */ mysql_free_result(prepare_meta_result); /* Close the statement */ mysql_stmt_close(stmt); } //===================================================================== int main(int argc, char *argv[]) { int ret, i; MYSQL *mysql; MYSQL_RES * res; MYSQL_ROW row; // //unsigned long *lengths; unsigned int num_fields; MYSQL_FIELD *field; //字段名 //1，mysql_init 初始化 mysql = mysql_init(NULL); if (mysql == NULL) { printf("mysql_init error\n"); return -1; } //2，mysql_real_connect链接 mysql = mysql_real_connect(mysql, _HOST_, _USER_, _PASSWD_, _DB_, 0, NULL, 0); if (mysql == NULL) { printf("mysql_real_connect error\n"); return -1; } printf("connect mysql ok\n"); //设置一下字符编码utf8 if (mysql_set_character_set(mysql, "utf8")) { printf(" mysql_set_character_set error\n"); return -1; } seach_information(mysql); // char sqlstr[] = "select *from emp"; // //查询语句int mysql_query(MYSQL *mysql, const char *query) // ret = mysql_query(mysql, sqlstr); // if (ret) { // printf("mysql_query error\n"); // return -1; // } // // //查询的结果集MYSQL_RES *mysql_store_result(MYSQL *mysql) // res = mysql_store_result(mysql); // // //MYSQL_ROW mysql_fetch_row(MYSQL_RES *result) // if ( res != NULL) { // // 数据的长度unsigned int mysql_num_fields(MYSQL_RES *result) // num_fields = mysql_num_fields(res); // //返回列长unsigned long *mysql_fetch_lengths(MYSQL_RES *result) // //lengths = mysql_fetch_lengths(res); // printf("num_fields = [%d]\n", num_fields); // //字段名 // for (i = 0; i < num_fields, field = mysql_fetch_field(res); i++) { // printf(" %s\t", field->name); // } // printf("\n"); // while (row = mysql_fetch_row(res)) { // // for (i = 0; i < num_fields; i++) { // printf("%s \t", row[i]); // } // printf("\n"); // } // //释放结果集 // mysql_free_result(res); // } //关闭mysql mysql_close(mysql); return 0; }

</mysql.h>

</string.h>

</stdlib.h>

</stdio.h></pre>

<h3 id="事物的介绍">事物的介绍</h3>

//mysql中的事务

#include

<stdio.h>

#include

<stdlib.h>

#include

<string.h>

#include "mysql.h" #define SET_TRAN "SET AUTOCOMMIT=0" //手动commit ————手动commit #define UNSET_TRAN "SET AUTOCOMMIT=1" //自动commit #define _HOST_ "127.0.0.1" #define _USER_ "root" #define _PASSWD_ "123" #define _DBNAME_ "scott" //设置事务为手动提交 int mysql_OperationTran(MYSQL *mysql) { //--开启事务 int ret = mysql_query(mysql, "start transaction"); //开启一次事务 start transaction if (ret != 0) { printf("mysql_OperationTran query start err: %s\n", mysql_error(mysql)); return ret; } //--设置事务为手动提交 ret = mysql_query(mysql, SET_TRAN); //set　autocommmit = 0 if (ret != 0) { printf("mysql_OperationTran query set err: %s\n", mysql_error(mysql)); return ret; } return ret; } //设置事务为自动提交 int mysql_AutoTran(MYSQL *mysql) { //--开启事务 int ret = mysql_query(mysql, "start transaction"); if (ret != 0) { printf("mysql_AutoTran query start err: %s\n", mysql_error(mysql)); return ret; } //--设置事务为自动提交 ret = mysql_query(mysql, UNSET_TRAN); //"set autocommit = 1" if (ret != 0) { printf("mysql_AutoTran query set err: %s\n", mysql_error(mysql)); return ret; } return ret; } //执行commit，手动提交事务 int mysql_Commit(MYSQL *mysql) { int ret = mysql_query(mysql, "COMMIT"); //提交 if (ret != 0) { printf("commit err: %s\n", mysql_error(mysql)); return ret; } return ret; } //执行rollback，回滚事务 int mysql_Rollback(MYSQL *mysql) { int ret = mysql_query(mysql, "ROLLBACK"); if (ret != 0) { printf("rollback err: %s\n", mysql_error(mysql)); return ret; } return ret; } #define DROP_SAMPLE_TABLE "DROP TABLE IF EXISTS test_table" #define CREATE_SAMPLE_TABLE "CREATE TABLE test_table(col1 INT,\ col2 VARCHAR(10),\ col3 VARCHAR(10))" #define sql01 "INSERT INTO test_table(col1,col2,col3) VALUES(10, 'AAA', 'A1')" #define sql02 "INSERT INTO test_table(col1,col2,col3) VALUES(20, 'BBB', 'B2')" #define sql03 "INSERT INTO test_table(col1,col2,col3) VALUES(30, 'CCC', 'C3')" #define sql04 "INSERT INTO test_table(col1,col2,col3) VALUES(40, 'DDD', 'D4')" int main(void) { int ret = 0; MYSQL *mysql = mysql_init(NULL); mysql = mysql_real_connect(mysql, _HOST_, _USER_, _PASSWD_, _DBNAME_, 0, NULL, 0); if (mysql == NULL) { ret = mysql_errno(mysql); printf("func mysql_real_connect() err：%d\n", ret); return ret; } printf(" --- connect ok......\n"); //执行删除表 if (mysql_query(mysql, DROP_SAMPLE_TABLE)) { fprintf(stderr, " DROP TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } //执行创建表 if (mysql_query(mysql, CREATE_SAMPLE_TABLE)) { fprintf(stderr, " CREATE TABLE failed\n"); fprintf(stderr, " %s\n", mysql_error(mysql)); exit(0); } ret = mysql_OperationTran(mysql); //开启事务，并修改事务属性为手动commit if (ret != 0) { printf("mysql_OperationTran() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql01); //向表中插入第一行数据 ‘AAA’ if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql02); //向表中插入第二行数据 ‘BBB’ if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_Commit(mysql); //手动提交事务 if (ret != 0) { printf("mysql_Commit() err:%d\n", ret); return ret; } //AAA BBB 进去了。 #if 1 ret = mysql_AutoTran(mysql); // =再次= 修改事务属性为【自动】commit if (ret != 0) { printf("mysql_OperationTran() err:%d\n", ret); return ret; } #else ret = mysql_OperationTran(mysql); // =再次= 修改事务属性为【手动】commit if (ret != 0) { printf("mysql_OperationTran() err:%d\n", ret); return ret; } #endif ret = mysql_query(mysql, sql03); //向表中插入第三行数据 ‘CCC’ if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_query(mysql, sql04); //向表中插入第四行数据 ‘DDD’ if (ret != 0) { printf("mysql_query() err:%d\n", ret); return ret; } ret = mysql_Rollback(mysql); //直接rollback操作 if (ret != 0) { printf("mysql_Rollback() err:%d\n", ret); return ret; } //rollback操作是否能回退掉CCC、DDD的值，取决于事务属性。 mysql_close(mysql); return 0; }

</string.h>

</stdlib.h>

</stdio.h></pre>

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