C++實(shí)現(xiàn)PyMysql的基本功能實(shí)例詳解
用C++實(shí)現(xiàn)一個(gè)Thmysql類,實(shí)現(xiàn)Python標(biāo)準(zhǔn)庫PyMysql的基本功能,并提供與PyMysql類似的API,并用pybind11將Thmysql封裝為Python庫。
| PyMysql | Thmysql(C++) | Thmysql(Python) |
|---|---|---|
| connect | connect | connect |
| cursor | —— | —— |
| execute | execute | execute |
| fetchone | fetchone | fetchone |
| fetchall | fetchall | fetchall |
| close | close | close |
一.開發(fā)環(huán)境
- Windows64位操作系統(tǒng);
- mysql 5.5.28 for Win64(x86);
- pycharm 2019.1.1。
二.PyMysql數(shù)據(jù)庫查詢
#文件名:python_test.py
import pymysql
# 連接database
conn = pymysql.connect(host="localhost",user="root",password="123456",
database="test",charset="utf8")
# 得到一個(gè)可以執(zhí)行SQL語句的光標(biāo)對(duì)象
cursor = conn.cursor() # 執(zhí)行完畢返回的結(jié)果集默認(rèn)以元組顯示
# 執(zhí)行SQL語句
cursor.execute("use information_schema")
cursor.execute("select version();")
first_line = cursor.fetchone()
print(first_line)
cursor.execute("select * from character_sets;")
res = cursor.fetchall()
print(res)
# 關(guān)閉光標(biāo)對(duì)象
cursor.close()
# 關(guān)閉數(shù)據(jù)庫連接
conn.close()

三.開發(fā)步驟
- 將mysql安裝目錄下的include和lib文件夾拷到project目錄中;
- 將lib文件夾中的libmysql.dll文件拷到system32路徑下;
- 定義MysqlInfo結(jié)構(gòu)體,實(shí)現(xiàn)C++版的Thmysql類;
- 編寫封裝函數(shù);
- 通過setuptools將C++代碼編譯為Python庫。
四.代碼實(shí)現(xiàn)
// 文件名:thmysql.h
#include <Windows.h>
#include "mysql.h"
#include <iostream>
#include <string>
#include <vector>
#pragma comment(lib, "lib/libmysql.lib")
using namespace std;
typedef struct MysqlInfo{
string m_host;
string m_user;
string m_passwd;
string m_db;
unsigned int m_port;
string m_unix_socket;
unsigned long m_client_flag;
MysqlInfo(){}
MysqlInfo(string host, string user, string passwd, string db, unsigned int port,
string unix_socket, unsigned long client_flag){
m_host = host;
m_user = user;
m_passwd = passwd;
m_db = db;
m_port = port;
m_unix_socket = unix_socket;
m_client_flag = client_flag;
}
}MysqlInfo;
class Thmysql{
public:
Thmysql();
void connect(MysqlInfo&);
void execute(string);
vector<vector<string>> fetchall();
vector<string> fetchone();
void close();
private:
MYSQL mysql;
MYSQL_RES * mysql_res;
MYSQL_FIELD * mysql_field;
MYSQL_ROW mysql_row;
int columns;
vector<vector<string>> mysql_data;
vector<string> first_line;
};
// 文件名:thmysql.cpp
#include <iostream>
#include "thmysql.h"
Thmysql::Thmysql(){
if(mysql_library_init(0, NULL, NULL) != 0){
cout << "MySQL library initialization failed" << endl;
}
if(mysql_init(&mysql) == NULL){
cout << "Connection handle initialization failed" << endl;
}
}
void Thmysql::connect(MysqlInfo& msInfo){
string host = msInfo.m_host;
string user = msInfo.m_user;
string passwd = msInfo.m_passwd;
string db = msInfo.m_db;
unsigned int port = msInfo.m_port;
string unix_socket = msInfo.m_unix_socket;
unsigned long client_flag = msInfo.m_client_flag;
if(mysql_real_connect(&mysql, host.c_str(), user.c_str(), passwd.c_str(), db.c_str(),
port, unix_socket.c_str(), client_flag) == NULL){
cout << "Unable to connect to MySQL" << endl;
}
}
void Thmysql::execute(string sqlcmd){
mysql_query(&mysql, sqlcmd.c_str());
if(mysql_errno(&mysql) != 0){
cout << "error: " << mysql_error(&mysql) << endl;
}
}
vector<vector<string>> Thmysql::fetchall(){
// 獲取 sql 指令的執(zhí)行結(jié)果
mysql_res = mysql_use_result(&mysql);
// 獲取查詢到的結(jié)果的列數(shù)
columns = mysql_num_fields(mysql_res);
// 獲取所有的列名
mysql_field = mysql_fetch_fields(mysql_res);
mysql_data.clear();
while(mysql_row = mysql_fetch_row(mysql_res)){
vector<string> row_data;
for(int i = 0; i < columns; i++){
if(mysql_row[i] == nullptr){
row_data.push_back("None");
}else{
row_data.push_back(mysql_row[i]);
}
}
mysql_data.push_back(row_data);
}
// 沒有mysql_free_result會(huì)造成內(nèi)存泄漏:Commands out of sync; you can't run this command now
mysql_free_result(mysql_res);
return mysql_data;
}
vector<string> Thmysql::fetchone(){
// 獲取 sql 指令的執(zhí)行結(jié)果
mysql_res = mysql_use_result(&mysql);
// 獲取查詢到的結(jié)果的列數(shù)
columns = mysql_num_fields(mysql_res);
// 獲取所有的列名
mysql_field = mysql_fetch_fields(mysql_res);
first_line.clear();
mysql_row = mysql_fetch_row(mysql_res);
for(int i = 0; i < columns; i++){
if(mysql_row[i] == nullptr){
first_line.push_back("None");
}else{
first_line.push_back(mysql_row[i]);
}
}
mysql_free_result(mysql_res);
return first_line;
}
void Thmysql::close(){
mysql_close(&mysql);
mysql_library_end();
}
// 文件名:thmysql_wrapper.cpp
#include "pybind11/pybind11.h"
#include "pybind11/stl.h"
#include "thmysql.h"
namespace py = pybind11;
PYBIND11_MODULE(thmysql, m){
m.doc() = "C++操作Mysql";
py::class_<MysqlInfo>(m, "MysqlInfo")
.def(py::init())
.def(py::init<string, string, string, string, unsigned int, string, unsigned long>(),
py::arg("host"), py::arg("user"), py::arg("passwd"), py::arg("db"),py::arg("port"),
py::arg("unix_socket") = "NULL", py::arg("client_flag")=0)
.def_readwrite("host", &MysqlInfo::m_host)
.def_readwrite("user", &MysqlInfo::m_user)
.def_readwrite("passwd", &MysqlInfo::m_passwd)
.def_readwrite("db", &MysqlInfo::m_db)
.def_readwrite("port", &MysqlInfo::m_port)
.def_readwrite("unix_socket", &MysqlInfo::m_unix_socket)
.def_readwrite("client_flag", &MysqlInfo::m_client_flag);
py::class_<Thmysql>(m, "Thmysql")
.def(py::init())
.def("connect", &Thmysql::connect)
.def("execute", &Thmysql::execute, py::arg("sql_cmd"))
.def("fetchall", &Thmysql::fetchall)
.def("fetchone", &Thmysql::fetchone)
.def("close", &Thmysql::close);
}
#文件名:setup.py
from setuptools import setup, Extension
functions_module = Extension(
name='thmysql',
sources=['thmysql.cpp', 'thmysql_wrapper.cpp'],
include_dirs=[r'D:\software\pybind11-master\include',
r'D:\software\Anaconda\include',
r'D:\project\thmysql\include'],
)
setup(ext_modules=[functions_module])
五.Thmysql數(shù)據(jù)庫查詢
#文件名:test.py
from thmysql import Thmysql, MysqlInfo
info = MysqlInfo("localhost", "root", "123456", "", 3306)
conn = Thmysql()
# 連接database
conn.connect(info)
# 執(zhí)行SQL語句
conn.execute("use information_schema")
conn.execute("select version();")
first_line = conn.fetchone()
print(first_line)
conn.execute("select * from character_sets;")
res = conn.fetchall()
print(res)
# 關(guān)閉數(shù)據(jù)庫連接
conn.close()

總結(jié)
到此這篇關(guān)于C++實(shí)現(xiàn)PyMysql的基本功能的文章就介紹到這了,更多相關(guān)c++ pymysql內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家!
相關(guān)文章
C++實(shí)現(xiàn)高性能轉(zhuǎn)換大小寫算法示例
大小寫轉(zhuǎn)換是我們作為一名程序員經(jīng)常會(huì)遇到,也必須要會(huì)的一個(gè)功能,下面這篇文章主要給大家介紹了關(guān)于C++實(shí)現(xiàn)高性能轉(zhuǎn)換大小寫算法的相關(guān)資料,文中通過示例代碼介紹的非常詳細(xì),需要的朋友可以參考借鑒,下面來一起看看吧。2018-01-01
C++?拷貝構(gòu)造函數(shù)與賦值的區(qū)別
拷貝構(gòu)造函數(shù)和賦值函數(shù)非常容易混淆,本文主要介紹了C++?拷貝構(gòu)造函數(shù)與賦值的區(qū)別,具有一定的參考價(jià)值,感興趣的可以了解一下2024-04-04
c++基礎(chǔ)學(xué)習(xí)之如何區(qū)分引用和指針
C語言中只有指針,C++加入了引用,能夠起到跟指針類似的作用,下面這篇文章主要給大家介紹了關(guān)于c++基礎(chǔ)學(xué)習(xí)之區(qū)分引用和指針的相關(guān)資料,文中通過示例代碼介紹的非常詳細(xì),需要的朋友可以參考下2021-08-08
詳解設(shè)計(jì)模式中的中介者模式在C++編程中的運(yùn)用
這篇文章主要介紹了設(shè)計(jì)模式中的中介者模式在C++編程中的運(yùn)用,中介者模式將對(duì)象間的通信封裝到一個(gè)類中,將多對(duì)多的通信轉(zhuǎn)化為一對(duì)多的通信,降低了系統(tǒng)的復(fù)雜性,需要的朋友可以參考下2016-03-03
DSP中浮點(diǎn)轉(zhuǎn)定點(diǎn)運(yùn)算--舉例及編程中的心得
本文主要講解DSP浮點(diǎn)轉(zhuǎn)定點(diǎn)運(yùn)算舉例及編程中的心得 ,具有參考價(jià)值,需要的朋友可以參考一下。2016-06-06

