Python之mysql数据库更新表数据接口实现

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。

先码为敬~~~~~~~

 # -*- 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("")
     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~~~~~~

有不足之处，希望指正，共同进步~~~~~~~