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超轻量级php框架startmvc

Python实现mysql数据库更新表数据接口的功能

更新时间:2020-05-11 09:48:01 作者:startmvc
前言昨天,因为项目需求要添加表的更新接口,来存储预测模型训练的数据,所以自己写了

前言

昨天,因为项目需求要添加表的更新接口,来存储预测模型训练的数据,所以自己写了一段代码实现了该功能,在开始之前,给大家分享python 操作mysql数据库基础:


#coding=utf-8
import MySQLdb

conn= MySQLdb.connect(
 host='localhost',
 port = 3306,
 user='root',
 passwd='123456',
 db ='test',
 )
cur = conn.cursor()

#创建数据表
#cur.execute("create table student(id int ,name varchar(20),class varchar(30),age varchar(10))")

#插入一条数据
#cur.execute("insert into student values('2','Tom','3 year 2 class','9')")


#修改查询条件的数据
#cur.execute("update student set class='3 year 1 class' where name = 'Tom'")

#删除查询条件的数据
#cur.execute("delete from student where age='9'")

cur.close()
conn.commit()
conn.close()

>>> conn = MySQLdb.connect(host='localhost',port = 3306,user='root', passwd='123456',db ='test',)

Connect() 方法用于创建数据库的连接,里面可以指定参数:用户名,密码,主机等信息。

这只是连接到了数据库,要想操作数据库需要创建游标。

>>> cur = conn.cursor()

通过获取到的数据库连接conn下的cursor()方法来创建游标。

>>> cur.execute("create table student(id int ,name varchar(20),class varchar(30),age varchar(10))")

通过游标cur 操作execute()方法可以写入纯sql语句。通过execute()方法中写如sql语句来对数据进行操作。

>>>cur.close()

cur.close() 关闭游标

>>>conn.commit()

conn.commit()方法在提交事物,在向数据库插入一条数据时必须要有这个方法,否则数据不会被真正的插入。

>>>conn.close()

Conn.close()关闭数据库连接

下面开始本文的正文:

Python实现mysql更新表数据接口

示例代码


# -*- coding: utf-8 -*-
import pymysql
import settings

class mysql(object):
 def __init__(self):
 self.db = None

 def connect(self):

 self.db = pymysql.connect(host=settings.ip, port=settings.port, user=settings.mysql_user, passwd=settings.mysql_passwd, db=settings.database, )
 # print("connect is ok")
 # return 1
 def disconnect(self):
 self.db.close()
 # return -1

 def create_table(self, tablename, columns, spec='time'):
 """
 :param tablename:
 :param spec:
 :param columns: 列表[]
 :return:
 """

 type_data = ['int', 'double(10,3)']
 cursor = self.db.cursor()
 sql="create table %s("%(tablename,)
 sqls=[]
 for col in columns:
 #判断是否time_num
 if col==spec:
 sqls.append('%s %s primary key'%(col,type_data[0]))
 else:
 sqls.append('%s %s'%(col,type_data[1]))

 sqlStr = ','.join(sqls)
 sql+=sqlStr+')'
 try:
 cursor.execute(sql)
 print("Table %s is created"%tablename)
 except:
 self.db.rollback()

 def is_table_exist(self, tablename,dbname):
 cursor=self.db.cursor()
 sql="select table_name from information_schema.TABLES where table_schema='%s' and table_name = '%s'"%(dbname,tablename)
 #results="error:Thie table is not exit"
 try:
 cursor.execute(sql)

 results = cursor.fetchall() #接受全部返回行
 except:
 #不存在这张表返回错误提示
 raise Exception('This table does not exist')
 if not results:
 return None
 else :
 return results
 # print datas
 def insert_mysql_with_json(self, tablename, datas):
 """

 :param tablename:
 :param datas:字典{(key: value),.....}
 :return:
 """
 # keys = datas[0]
 keys = datas[0].keys()
 keys = str(tuple(keys))
 keys = ''.join(keys.split("'")) # 用' 隔开
 print(keys)
 ret = []
 for dt in datas:
 values = dt.values() ## ‘str' object has no attribute#
 sql = "insert into %s" % tablename + keys
 sql = sql + " values" + str(tuple(values))
 ret.append(sql)
 # print("1")
 # print keys insert into %tablename dat[i] values str[i]

 self.insert_into_sql(ret)
 print("1")
 def insert_into_sql(self,sqls):
 cursor = self.db.cursor()
 for sql in sqls:
 # 执行sql语句
 try:
 cursor.execute(sql)
 self.db.commit()
 # print("insert %s" % sql, "success.")
 except:
 # Rollback in case there is any error
 self.db.rollback()
 #找列名
 def find_columns(self, tablename):
 sql = "select COLUMN_NAME from information_schema.columns where table_name='%s'" % tablename
 cursor = self.db.cursor()
 try:
 cursor.execute(sql)
 results = cursor.fetchall()
 except:
 raise Exception('hello')
 return tuple(map(lambda x: x[0], results))

 def find(self, tablename, start_time, end_time, fieldName=None):
 """
 :param tablename: test_scale1015
 :param fieldName: None or (columns1010, columns1011, columns1012, columns1013, time)
 :return:
 """
 cursor = self.db.cursor()
 sql = ''
 if fieldName==None:
 fieldName = self.find_columns(tablename)
 sql = "select * from %s where time between %s and %s" % (tablename, str(start_time), str(end_time))
 # print('None')
 else:
 fieldNameStr = ','.join(fieldName)
 sql = "select %s from %s where time between %s and %s" % (
 fieldNameStr, tablename, str(start_time), str(end_time))
 # print('sm')
 try:
 cursor.execute(sql)
 results = cursor.fetchall()
 except:
 raise Exception('hello')
 return fieldName, results,
 
 #样例 data = [{'time':123321,'predict':1.222},{'time':123322,'predict':1.223},{'time':123324,'predict':1.213}]
 def updata(self,datas, tablename):
 cursor = self.db.cursor()
 columns = []
 for data in datas:
 for i in data.keys():
 columns.append(i)
 # print(columns)
 break
 # columns_2=columns[:]
 db.connect()
 if db.is_table_exist(settings.tablename_2, settings.database):
 # exists
 # pass
 for col in columns:
 if col != 'time':
 sql = "alter table %s add column %s double(10,3);" % (settings.tablename_2, col)
 try:
 cursor.execute(sql)
 print("%s is altered ok" % (col))
 except:
 print("alter is failed")
 

 ret = []
 for i in datas:
 col = []
 for ii in i.keys():
 col.append(ii)
 #time = col[0] and predict = col[1]
 time_data = i[col[0]]
 predic_data = i[col[1]]
 sql = "update %s set %s='%s'where %s=%s"%(settings.tablename_2,col[1],predic_data,col[0],time_data)
 ret.append(sql)
 self.insert_into_sql(ret)

 # db.insert_mysql_with_json(tablename, datas)


 else:
 # no exists
 db.create_table(settings.tablename_2, columns)
 db.insert_mysql_with_json(settings.tablename_2, datas)

db = mysql()

其中update()函数,是新添加的接口:

传入的data的样例 data = [{'time':123321,'predict':1.222},{'time':123322,'predict':1.223},{'time':123324,'predict':1.213}] 这样子的。

一个列表里有多个字典,每个字典有time和predict。如果需要存predict_2,predict_3的时候,则实现更新操作,否则,只进行创表和插入数据的操作~~~~~~

看起来是不是很简单~~~~~~

这个接口还没有进行优化等操作,很冗余~~~~

毕竟项目还在测试阶段,等先跑通了,在考虑优化吧~~~~~~

总结

以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作具有一定的参考学习价值,如果有疑问大家可以留言交流,谢谢大家对脚本之家的支持。

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