python uses pymysql to operate mysql

pymsql is a module in Python that operates MySQL. Its usage is almost the same as MySQLdb. But currently pymysql supports python3.x and the latter does not support version 3.x.

Applicable environment

python version>=2.6 or 3.3

mysql version>=4.1

Installation

You can use pip to install or manually download and install.

Use pip to install, execute the following command on the command line:

pip install PyMySQL

To install manually, please download first. Download address: https://github.com/PyMySQL/PyMySQL/tarball/pymysql-X.X.

X.X is the version (the latest version currently available is 0.6.6).

After downloading, unzip the compressed package. Enter the decompressed directory on the command line and execute the following instructions:

python setup.py install

It is recommended to use pip to install.

Usage example

Connect to the database as follows:

import pymysql.cursors
  
# Connect to the database
connection = pymysql.connect(host='127.0.0.1',
               port=3306,
               user='root',
               password='zhyea.com',
               db='employees',
               charset='utf8mb4',
               cursorclass=pymysql.cursors.DictCursor)

You can also use a dictionary to manage connection parameters. I think this is more elegant:

import pymysql.cursors
  
config = {
     'host':'127.0.0.1',
     'port':3306,
     'user':'root',
     'password':'zhyea.com',
     'db':'employees',
     'charset':'utf8mb4',
     'cursorclass':pymysql.cursors.DictCursor,
     }
  
# Connect to the database
connection = pymysql.connect(**config)

Insert data:

You need to obtain the cursor before executing the sql statement. Because the configuration is automatically submitted by default, you need to actively commit after executing the sql statement. Finally, do not Forgot to close the connection:

from datetime import date, datetime, timedelta
import pymysql.cursors
  
#连接配置信息
config = {
     'host':'127.0.0.1',
     'port':3306,
     'user':'root',
     'password':'zhyea.com',
     'db':'employees',
     'charset':'utf8mb4',
     'cursorclass':pymysql.cursors.DictCursor,
     }
# 创建连接
connection = pymysql.connect(**config)
  
# 获取明天的时间
tomorrow = datetime.now().date() + timedelta(days=1)
  
# 执行sql语句
try:
  with connection.cursor() as cursor:
    # 执行sql语句，插入记录
    sql = 'INSERT INTO employees (first_name, last_name, hire_date, gender, birth_date) VALUES (%s, %s, %s, %s, %s)'
    cursor.execute(sql, ('Robin', 'Zhyea', tomorrow, 'M', date(1989, 6, 14)));
  # 没有设置默认自动提交，需要主动提交，以保存所执行的语句
  connection.commit()
  
finally:
  connection.close();

Execute query:

import datetime
import pymysql.cursors
  
#连接配置信息
config = {
     'host':'127.0.0.1',
     'port':3306,
     'user':'root',
     'password':'zhyea.com',
     'db':'employees',
     'charset':'utf8mb4',
     'cursorclass':pymysql.cursors.DictCursor,
     }
# 创建连接
connection = pymysql.connect(**config)
  
# 获取雇佣日期
hire_start = datetime.date(1999, 1, 1)
hire_end = datetime.date(2016, 12, 31)
  
# 执行sql语句
try:
  with connection.cursor() as cursor:
    # 执行sql语句，进行查询
    sql = 'SELECT first_name, last_name, hire_date FROM employees WHERE hire_date BETWEEN %s AND %s'
    cursor.execute(sql, (hire_start, hire_end))
    # 获取查询结果
    result = cursor.fetchone()
    print(result)
  # 没有设置默认自动提交，需要主动提交，以保存所执行的语句
  connection.commit()
  
finally:
  connection.close();

The query here retrieves a query result. The query result Return in the form of a dictionary:

To obtain the specified number of records from the result set, you can use the fetchmany method:

result = cursor.fetchmany(2)

However, this is not recommended To use, it is best to set the total number of records queried in the sql statement.

To obtain all result sets, you can use the fetchall method:

result = cursor.fetchall()

Because there are only two records, the two query methods mentioned above The results found are the same:

[{'last_name': 'Vanderkelen', 'hire_date': datetime.date(2015, 8, 12), 'first_name': 'Geert'}, {'last_name': 'Zhyea', 'hire_date': datetime.date(2015, 8, 21), 'first_name': 'Robin'}]

Used in django

Used in django is the original purpose of my search for this. Currently, it is not easy to find a database backend that supports both python3.4 and django1.8. This is the best one I've found so far.

Setting DATABASES is no different from the officially recommended MySQLdb setting:

DATABASES = {
'default': {
'ENGINE': 'django.db.backends. mysql',
'NAME': 'mytest',
'USER': 'root',
'PASSWORD': 'zhyea.com',
'HOST': '127.0.0.1' ,
       'PORT': '3306',
   }
}

The key is here: we also need to add the following content to the __init__.py file of the site:

import pymysql
pymysql.install_as_MySQLdb()

Finally, I attach the code for pymysql to implement addition, deletion, modification and query. I hope you can like it

#!/usr/bin/python
#coding:gbk
import pymysql
from builtins import int
 
#将MysqlHelper的几个函数写出来
 
def connDB():               #连接数据库
  conn=pymysql.connect(host="localhost",user="root",passwd="zx69728537",db="student");
  cur=conn.cursor();
  return (conn,cur);
 
def exeUpdate(conn,cur,sql):        #更新或插入操作
  sta=cur.execute(sql);
  conn.commit();
  return (sta);
 
def exeDelete(conn,cur,IDs):        #删除操作
  sta=0;
  for eachID in IDs.split(' '):
    sta+=cur.execute("delete from students where Id=%d"%(int(eachID)));
  conn.commit();
  return (sta);
     
def exeQuery(cur,sql):           #查找操作
  cur.execute(sql);
  return (cur);
   
def connClose(conn,cur):          #关闭连接，释放资源
  cur.close();
  conn.close();
 
result=True;
print("请选择以上四个操作：1、修改记录，2、增加记录，3、查询记录，4、删除记录.(按q为退出)");
conn,cur=connDB();
number=input();
while(result):
  if(number=='q'):
    print("结束操作");
    break;
  elif(int(number)==1):
    sql=input("请输入更新语句：");
    try:
      exeUpdate(conn, cur, sql);
      print("更新成功");
    except Exception:
      print("更新失败");
      raise;
  elif(int(number)==2):
      sql=input("请输入新增语句:");
      try:
        exeUpdate(conn, cur, sql);
        print("新增成功");
      except Exception:
        print("新增失败");
        raise;
  elif(int(number)==3):
    sql=input("请输入查询语句：");
    try:
      cur=exeQuery(cur, sql);
      for item in cur:
        print("Id="+str(item[0])+" name="+item[1]);
    except Exception:
      print("查询出错");
      raise;
  elif(int(number)==4):
    Ids=input("请输入Id，并用空格隔开");
    try:
      exeDelete(conn, cur, Ids);
      print("删除成功");
    except Exception:
      print("删除失败");
      raise;
  else:
    print("非法输入，将结束操作!");
    result=False;
    break;
  print("请选择以上四个操作：1、修改记录，2、增加记录，3、查询记录，4、删除记录.(按q为退出)");
  number=input("请选择操作");

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