使用C++操作mysql数据库
2016-05-15 11:49
477 查看
话不多说,直接进入主题。
一.环境搭建
本文所述是在32位win7,VS2013,mysql5.5下的实验情况,其它环境应该也是大同小异。
首先,需要安装VS2013和mysql数据库。
然后,打开VS2013开始配置mysql使用环境。
1、新建win32控制台程序,此处就不多说了。
2、在VS2013的菜单栏选择“项目——>属性”
![](http://img.blog.csdn.net/20160515115013480?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
3、配置属性——>VC++目录——>包含目录(Include),选择MySQL安装路径下的“include”文件夹
——>库目录(Lib),选择MySQL安装目录下的lib文件夹
![](http://img.blog.csdn.net/20160515115127919?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
“包含目录”在mysql安装路径的截图如下:
![](http://img.blog.csdn.net/20160515115233576?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
“库目录”的截图如下:
![](http://img.blog.csdn.net/20160515115336965?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
4、配置属性——>链接器——>输入——>附加依赖项,添加“libmysql.lib”
![](http://img.blog.csdn.net/20160515115448734?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
5、把\MySQL\MySQLServer
5.5\lib下的libmysql.dll复制并拷贝到C:\Windows\System32下。(这步如果不设置,运行时会报错)。
![](http://img.blog.csdn.net/20160515115616655?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
![](http://img.blog.csdn.net/20160515115636422?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
此时环境就配置好了!
二.Mysql.h头文件中常用类型简介
下面就看一下MYSQL_RES,MYSQL ,MYSQL_ROW ,MYSQL_FIELD 的定义:
typedef struct
st_mysql_res {
my_ulonglong row_count;
MYSQL_FIELD *fields;
MYSQL_DATA *data;
MYSQL_ROWS *data_cursor;
unsigned long *lengths;
/*column lengths of current row */
MYSQL *handle;
/* for unbuffered reads */
const struct
st_mysql_methods *methods;
MYSQL_ROW row;
/* If unbuffered read */
MYSQL_ROW current_row;
/* buffer to current row */
MEM_ROOT field_alloc;
unsigned int field_count,current_field;
my_bool eof;
/* Used by mysql_fetch_row */
/* mysql_stmt_close() had to cancel thisresult */
my_bool unbuffered_fetch_cancelled;
void *extension;
} MYSQL_RES;
用于保存执行结果的结构体。
typedef struct
st_mysql
{
NET net;
/* Communication parameters */
unsigned char *connector_fd;
/* ConnectorFd for SSL */
char *host,*user,*passwd,*unix_socket,*server_version,*host_info;
char *info, *db;
struct charset_info_st *charset;
MYSQL_FIELD *fields;
MEM_ROOT field_alloc;
my_ulonglong affected_rows;
my_ulonglong insert_id;
/* id if insert on table with NEXTNR */
my_ulonglong extra_info;
/* Not used */
unsigned long thread_id;
/*Id for connection in server */
unsigned long packet_length;
unsigned int port;
unsigned long client_flag,server_capabilities;
unsigned int protocol_version;
unsigned int field_count;
unsigned int server_status;
unsigned int server_language;
unsigned int warning_count;
struct st_mysql_options options;
enum mysql_status status;
my_bool free_me;
/* If free in mysql_close */
my_bool reconnect;
/* set to 1 if automatic reconnect */
/* session-wide random string */
char scramble[SCRAMBLE_LENGTH+1];
my_bool unused1;
void *unused2, *unused3, *unused4, *unused5;
LIST *stmts;
/* list of all statements */
const struct
st_mysql_methods *methods;
void *thd;
/*
Points toboolean flag in MYSQL_RES or MYSQL_STMT.We set this flag
frommysql_stmt_close if close had to cancel result set of this object.
*/
my_bool *unbuffered_fetch_owner;
/* needed for embedded server - no netbuffer to store the 'info' */
char *info_buffer;
void *extension;
} MYSQL;
用于保存数据库连接的结构体。
typedef char **MYSQL_ROW;
/* return data as array of strings */
用于保存某一行返回结果的值。
typedef struct
st_mysql_field {
char *name;
/* Name of column */
char *org_name;
/* Original column name, if an alias */
char *table;
/* Table of column if column was a field */
char *org_table;
/* Org table name, if table was an alias */
char *db;
/* Database for table */
char *catalog;
/* Catalog for table */
char *def;
/* Default value (set by mysql_list_fields) */
unsigned long length;
/* Width of column (create length) */
unsigned long max_length;
/* Max width for selected set */
unsigned int name_length;
unsigned int org_name_length;
unsigned int table_length;
unsigned int org_table_length;
unsigned int db_length;
unsigned int catalog_length;
unsigned int def_length;
unsigned int flags;
/* Div flags */
unsigned int decimals;
/* Number of decimals in field */
unsigned int charsetnr;
/* Character set */
enum enum_field_types type;
/* Type of field. See mysql_com.h for types */
void *extension;
} MYSQL_FIELD;
包含字段信息的结构,例如字段名、类型和大小。
内容较多就不一一解释了,感兴趣的自己探索,或在网上搜相应的说明。
三.函数调用流程及简介
1. 连接mysql数据库
MYSQL *
STDCALL mysql_real_connect(MYSQL *mysql,
const char *host,
const
char *user,
const
char *passwd,
const
char *db,
unsigned
int port,
const
char *unix_socket,
unsigned
long clientflag);
2. 执行sql语句
int
STDCALL mysql_query(MYSQL *mysql,
const char *q);
3. 获取执行结果
MYSQL_RES * STDCALL mysql_store_result(MYSQL *mysql);
保存结果集到一个变量。
my_ulonglong
STDCALL mysql_num_rows(MYSQL_RES *res);
typedef unsigned
long my_ulonglong;
获得数据的行数
unsigned intSTDCALL mysql_num_fields(MYSQL_RES *res);
获得一行数据中字段的数目。
MYSQL_FIELD *
STDCALL mysql_fetch_field(MYSQL_RES *result);
通过重复调用mysql_fetch_field() 可以对每一列获得MYSQL_FIELD 结构
MYSQL_ROW
STDCALL mysql_fetch_row(MYSQL_RES *result);
typedef char **MYSQL_ROW;
/* return data as array of strings */
从结果集中获取某一行的内容,可以取到每一行的内容。
4. 释放资源
void
STDCALL mysql_free_result(MYSQL_RES *result);
释放结果集
void STDCALL mysql_close(MYSQL *sock);
关闭数据库连接。
四.简单应用举例
在第一步建好的工程中加入一个cpp文件,并添加如下代码:
#include <stdio.h>
#include <windows.h>
#include <mysql.h>
#include <iostream>
#include <iomanip>
using namespace std;
//全局变量
int res = 0;
MYSQL_RES *result =
NULL;
MYSQL mysql;
MYSQL_ROW sql_row;
MYSQL_FIELD *fd =
NULL;
char column[20][20] = { 0 };
//用于查询数据
int selectData(char * SQL,
char * Msg);
int main()
{
mysql_init(&mysql); //初始化mysql结构
if(!mysql_real_connect(&mysql,
"localhost", "用户名",
"密码",
"数据库名", 3306,
NULL, 0))
{
cout << "连接数据库时发生错误!"<< endl;
}
else
{
cout << "连接数据库成功!" << endl;
//设置编码格式,否则在cmd下无法显示中文;并且插入的中文也会显示乱码
mysql_query(&mysql, "SET NAMES GBK");
char *msg =
NULL;
//查询数据
char select[] =
"select * from user";
if (selectData(select, msg) != 0)
{
cout << msg << endl;
}
}
if(result !=
NULL)mysql_free_result(result);//释放结果资源
mysql_close(&mysql); //释放数据库
system("pause");
return0;
}
//查询数据实现
int selectData(char *
SQL, char *
Msg)
{
res = mysql_query(&mysql, SQL);//查询
if(!res)
{
result = mysql_store_result(&mysql);//保存查询到的数据到result
if (result)
{
int i, j;
cout << "number of result:"<< (unsigned
long)mysql_num_rows(result)<< endl;
//获取列名
for (i = 0; fd = mysql_fetch_field(result); i++)
{
strcpy(column[i], fd->name);
}
j = mysql_num_fields(result);
//输出列名
for (i = 0; i<j; i++)
{
cout << setw(10) <<setiosflags(ios::left) <<column[i];
//printf("%s\t", column[i]);
}
cout << endl;
//获取具体的数据
while (sql_row = mysql_fetch_row(result))
{
for (i = 0; i<j; i++)
{
cout << setw(10) <<setiosflags(ios::left) <<sql_row[i];
//printf("%s\t",sql_row[i]);
}
cout << endl;
}
}
return 0;
}
else
{
Msg =
"query sqlfailed!";
}
return1;
}
执行结果如下图所示:
![](http://img.blog.csdn.net/20160515120514097?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
说明:我所连接的数据库中相应数据表的数据如下:
![](http://img.blog.csdn.net/20160515120545019?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
相信小伙伴们应该都学会了吧!
一.环境搭建
本文所述是在32位win7,VS2013,mysql5.5下的实验情况,其它环境应该也是大同小异。
首先,需要安装VS2013和mysql数据库。
然后,打开VS2013开始配置mysql使用环境。
1、新建win32控制台程序,此处就不多说了。
2、在VS2013的菜单栏选择“项目——>属性”
3、配置属性——>VC++目录——>包含目录(Include),选择MySQL安装路径下的“include”文件夹
——>库目录(Lib),选择MySQL安装目录下的lib文件夹
“包含目录”在mysql安装路径的截图如下:
“库目录”的截图如下:
4、配置属性——>链接器——>输入——>附加依赖项,添加“libmysql.lib”
5、把\MySQL\MySQLServer
5.5\lib下的libmysql.dll复制并拷贝到C:\Windows\System32下。(这步如果不设置,运行时会报错)。
此时环境就配置好了!
二.Mysql.h头文件中常用类型简介
下面就看一下MYSQL_RES,MYSQL ,MYSQL_ROW ,MYSQL_FIELD 的定义:
typedef struct
st_mysql_res {
my_ulonglong row_count;
MYSQL_FIELD *fields;
MYSQL_DATA *data;
MYSQL_ROWS *data_cursor;
unsigned long *lengths;
/*column lengths of current row */
MYSQL *handle;
/* for unbuffered reads */
const struct
st_mysql_methods *methods;
MYSQL_ROW row;
/* If unbuffered read */
MYSQL_ROW current_row;
/* buffer to current row */
MEM_ROOT field_alloc;
unsigned int field_count,current_field;
my_bool eof;
/* Used by mysql_fetch_row */
/* mysql_stmt_close() had to cancel thisresult */
my_bool unbuffered_fetch_cancelled;
void *extension;
} MYSQL_RES;
用于保存执行结果的结构体。
typedef struct
st_mysql
{
NET net;
/* Communication parameters */
unsigned char *connector_fd;
/* ConnectorFd for SSL */
char *host,*user,*passwd,*unix_socket,*server_version,*host_info;
char *info, *db;
struct charset_info_st *charset;
MYSQL_FIELD *fields;
MEM_ROOT field_alloc;
my_ulonglong affected_rows;
my_ulonglong insert_id;
/* id if insert on table with NEXTNR */
my_ulonglong extra_info;
/* Not used */
unsigned long thread_id;
/*Id for connection in server */
unsigned long packet_length;
unsigned int port;
unsigned long client_flag,server_capabilities;
unsigned int protocol_version;
unsigned int field_count;
unsigned int server_status;
unsigned int server_language;
unsigned int warning_count;
struct st_mysql_options options;
enum mysql_status status;
my_bool free_me;
/* If free in mysql_close */
my_bool reconnect;
/* set to 1 if automatic reconnect */
/* session-wide random string */
char scramble[SCRAMBLE_LENGTH+1];
my_bool unused1;
void *unused2, *unused3, *unused4, *unused5;
LIST *stmts;
/* list of all statements */
const struct
st_mysql_methods *methods;
void *thd;
/*
Points toboolean flag in MYSQL_RES or MYSQL_STMT.We set this flag
frommysql_stmt_close if close had to cancel result set of this object.
*/
my_bool *unbuffered_fetch_owner;
/* needed for embedded server - no netbuffer to store the 'info' */
char *info_buffer;
void *extension;
} MYSQL;
用于保存数据库连接的结构体。
typedef char **MYSQL_ROW;
/* return data as array of strings */
用于保存某一行返回结果的值。
typedef struct
st_mysql_field {
char *name;
/* Name of column */
char *org_name;
/* Original column name, if an alias */
char *table;
/* Table of column if column was a field */
char *org_table;
/* Org table name, if table was an alias */
char *db;
/* Database for table */
char *catalog;
/* Catalog for table */
char *def;
/* Default value (set by mysql_list_fields) */
unsigned long length;
/* Width of column (create length) */
unsigned long max_length;
/* Max width for selected set */
unsigned int name_length;
unsigned int org_name_length;
unsigned int table_length;
unsigned int org_table_length;
unsigned int db_length;
unsigned int catalog_length;
unsigned int def_length;
unsigned int flags;
/* Div flags */
unsigned int decimals;
/* Number of decimals in field */
unsigned int charsetnr;
/* Character set */
enum enum_field_types type;
/* Type of field. See mysql_com.h for types */
void *extension;
} MYSQL_FIELD;
包含字段信息的结构,例如字段名、类型和大小。
内容较多就不一一解释了,感兴趣的自己探索,或在网上搜相应的说明。
三.函数调用流程及简介
1. 连接mysql数据库
MYSQL *
STDCALL mysql_real_connect(MYSQL *mysql,
const char *host,
const
char *user,
const
char *passwd,
const
char *db,
unsigned
int port,
const
char *unix_socket,
unsigned
long clientflag);
2. 执行sql语句
int
STDCALL mysql_query(MYSQL *mysql,
const char *q);
3. 获取执行结果
MYSQL_RES * STDCALL mysql_store_result(MYSQL *mysql);
保存结果集到一个变量。
my_ulonglong
STDCALL mysql_num_rows(MYSQL_RES *res);
typedef unsigned
long my_ulonglong;
获得数据的行数
unsigned intSTDCALL mysql_num_fields(MYSQL_RES *res);
获得一行数据中字段的数目。
MYSQL_FIELD *
STDCALL mysql_fetch_field(MYSQL_RES *result);
通过重复调用mysql_fetch_field() 可以对每一列获得MYSQL_FIELD 结构
MYSQL_ROW
STDCALL mysql_fetch_row(MYSQL_RES *result);
typedef char **MYSQL_ROW;
/* return data as array of strings */
从结果集中获取某一行的内容,可以取到每一行的内容。
4. 释放资源
void
STDCALL mysql_free_result(MYSQL_RES *result);
释放结果集
void STDCALL mysql_close(MYSQL *sock);
关闭数据库连接。
四.简单应用举例
在第一步建好的工程中加入一个cpp文件,并添加如下代码:
#include <stdio.h>
#include <windows.h>
#include <mysql.h>
#include <iostream>
#include <iomanip>
using namespace std;
//全局变量
int res = 0;
MYSQL_RES *result =
NULL;
MYSQL mysql;
MYSQL_ROW sql_row;
MYSQL_FIELD *fd =
NULL;
char column[20][20] = { 0 };
//用于查询数据
int selectData(char * SQL,
char * Msg);
int main()
{
mysql_init(&mysql); //初始化mysql结构
if(!mysql_real_connect(&mysql,
"localhost", "用户名",
"密码",
"数据库名", 3306,
NULL, 0))
{
cout << "连接数据库时发生错误!"<< endl;
}
else
{
cout << "连接数据库成功!" << endl;
//设置编码格式,否则在cmd下无法显示中文;并且插入的中文也会显示乱码
mysql_query(&mysql, "SET NAMES GBK");
char *msg =
NULL;
//查询数据
char select[] =
"select * from user";
if (selectData(select, msg) != 0)
{
cout << msg << endl;
}
}
if(result !=
NULL)mysql_free_result(result);//释放结果资源
mysql_close(&mysql); //释放数据库
system("pause");
return0;
}
//查询数据实现
int selectData(char *
SQL, char *
Msg)
{
res = mysql_query(&mysql, SQL);//查询
if(!res)
{
result = mysql_store_result(&mysql);//保存查询到的数据到result
if (result)
{
int i, j;
cout << "number of result:"<< (unsigned
long)mysql_num_rows(result)<< endl;
//获取列名
for (i = 0; fd = mysql_fetch_field(result); i++)
{
strcpy(column[i], fd->name);
}
j = mysql_num_fields(result);
//输出列名
for (i = 0; i<j; i++)
{
cout << setw(10) <<setiosflags(ios::left) <<column[i];
//printf("%s\t", column[i]);
}
cout << endl;
//获取具体的数据
while (sql_row = mysql_fetch_row(result))
{
for (i = 0; i<j; i++)
{
cout << setw(10) <<setiosflags(ios::left) <<sql_row[i];
//printf("%s\t",sql_row[i]);
}
cout << endl;
}
}
return 0;
}
else
{
Msg =
"query sqlfailed!";
}
return1;
}
执行结果如下图所示:
说明:我所连接的数据库中相应数据表的数据如下:
相信小伙伴们应该都学会了吧!
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