一个Mysql C API小型封装

主要用于维护C结构的查询和返回。




#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);        }}