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一个Mysql C API小型封装

#include typedef        std::string        string;struct        mysql_parm{

string        host;

string        user;

string        password;

string        database;

string        unixsock;

};

class        DBSTMT;

class        DBMysql;class        DBSTMT{

DBSTMT(const DBSTMT&);

DBSTMT&        operator=(const DBSTMT&);

MYSQL_STMT*        stmt_;

public:

DBSTMT(pcsz_t        query,DBMysql&        mysql);

void        execute(){

if(mysql_stmt_execute(stmt_))

throw        mysql_stmt_error(stmt_);

}        void        execute(MYSQL_BIND* bind){

if(mysql_stmt_execute(stmt_))

throw        mysql_stmt_error(stmt_);

if(mysql_stmt_bind_result(stmt_,bind)){

throw        mysql_stmt_error(stmt_);

}

if(mysql_stmt_store_result(stmt_))

throw        mysql_stmt_error(stmt_);

}        //void        execute(){

//        if(mysql_stmt_execute(stmt_))

//                throw        mysql_stmt_error(stmt_);

//}        void        bind(MYSQL_BIND* bind){

if(mysql_stmt_bind_param(stmt_,bind) )

throw        mysql_stmt_error(stmt_);

}        int        fetch(){

return        mysql_stmt_fetch(stmt_)==0;

}

~DBSTMT(){

if(stmt_){

mysql_stmt_close(stmt_);

}

}};

class        DBMysql{

DBMysql(const DBMysql&);

DBMysql&operator=(const DBMysql&);

MYSQL        *        mysqlPtr_;        uint32_t        errno_;

protected:

friend        class        DBSTMT;

MYSQL_STMT*        _createSTMT(){

MYSQL_STMT        *ret=mysql_stmt_init(mysqlPtr_);

if(ret)

return        ret;

errno_=mysql_errno(mysqlPtr_);

throw        mysql_error(mysqlPtr_);

}

public:

const        char*        strerr(){

return        mysql_error(mysqlPtr_);

}

DBMysql():mysqlPtr_(NULL){

mysqlPtr_=mysql_init(NULL);

if(NULL== mysqlPtr_)

throw        "Mysql :outof memory";

}

void        open(const        mysql_parm& parm){

if(!mysql_real_connect(mysqlPtr_,

parm.host.c_str(),

parm.user.c_str(),

parm.password.c_str(),

parm.database.c_str(),

0,

parm.unixsock.c_str(),

0        ))

{

errno_=mysql_errno(mysqlPtr_);

throw(mysql_error(mysqlPtr_));

}

}        void        close(){

if(mysqlPtr_)

{

mysql_close(mysqlPtr_);

mysqlPtr_=NULL;

}

}};

DBSTMT::DBSTMT(pcsz_t        query,DBMysql&        mysql):stmt_(NULL){

stmt_=mysql._createSTMT();

if(!stmt_)

throw        mysql.strerr();

if( mysql_stmt_prepare(stmt_,query,strlen(query)) )

{

//const char*        err=                throw        mysql_stmt_error(stmt_);

}}#define        DECL_BIND(h,n)\

class bind_##h:public        h{\

typedef        h        parent;\

MYSQL_BIND                _bind[n];\

my_bool                        _is_null[n];\

unsigned        long        _length[n];\

public:\

bind_##h(){\

int        i=0;\

bzero(_bind,sizeof(_bind));

#define        BIND_BIN(x,l)\

_bind[i].buffer_type= MYSQL_TYPE_STRING;\

_bind[i].buffer= (char *)&(parent::x);\

_bind[i].buffer_length= l;\

_bind[i].is_null= _is_null+i;\

_bind[i].length= _length+i;\

++i;#define        BIND_INT(x)\

_bind[i].buffer_type= MYSQL_TYPE_LONG;\

_bind[i].buffer= (char *)&(parent::x);\

_bind[i].buffer_length= 0;\

_bind[i].is_null= _is_null+i;\

_bind[i].length= _length+i;\

++i;#define        END_BIND(h)                }\

operator        MYSQL_BIND*(){\

return        _bind;\

}\

};  使用方法;例如想查询的内容具有以下结构

struct account{

char        user[36];

byte        password[16];

uint32_t        status;

uint32_t        id;

};//声明查询bind 结构account,参数4个

DECL_BIND(account,4)

BIND_BIN(user,32)

BIND_BIN(password,16)

BIND_INT(status)

BIND_INT(id)

END_BIND(account)int main(){        try{

DBMysql        mysql;

mysql_parm        parm;

parm.host="localhost";

parm.user="root";

parm.password="test";

parm.unixsock="/var/lib/mysql/mysql.sock";

parm.database="testdb";

mysql.open(parm);//打开数据库

DBSTMT          smt("select user,password,status,id from account",mysql);  //生成一个查询语法

DBSTMT          smt1("insert into account(user,password,status) value(?,?,?)",mysql);  //另外一个

//

bind_account        acc;

smt.execute(acc);//执行查询，并bind返回结果到account结构

while(smt.fetch()){

printf("%s %d %d\n",acc.user,acc.status,acc.id);

};                smt1.bind(acc);//bind查询参数

smt1.execute();//执行

}catch(const char* err){

printf("error:%s\n",err);

}}

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