Python--ZODB

zodb是python自带的对象数据库，以kv的形式存放对象状态。可以存放简单类型与复杂类型。例子：

from persistent import Persistent

from ZODB import FileStorage, DB

import transaction

from elec_rate_server.data.measurepoint import MeasurePoint

from elec_rate_server.electools.meterpowertype import MeterPowerType

class DescHandler(object):

    def __init__(self, info_path):

        self.info_path = info_path

       

    def zodb_init(self):

       '''数据库初始化'''

        self.storage = FileStorage.FileStorage(self.info_path)

        self.db = DB(self.storage)

        self.connection = self.db.open()

        self.dbroot = self.connection.root()

   

    def zodb_finit(self):

        '''数据库关闭'''

        self.connection.close()

        self.db.close()

        self.storage.close()

    def save_desc_info(self, func_index, users, transgroups, relations):

        '''存放对象'''

        self.zodb_init()

       

        result_mps = list()

        for user in users:

            for mp in user.get_measure_pos_list():

                result_mps.append(mp)

       '''对象可以是list'''

        self.dbroot[func_index] = result_mps

        transaction.commit()

       

        self.zodb_finit()

   

    def get_desc_info(self):

        '''获取对象数据'''

        self.zodb_init()

       

        for key in self.dbroot.keys():

            proc_results = self.dbroot[key]

            if isinstance(proc_results, list):

                print(str(key)+' 打印中间结果：')

                for mp in proc_results:

                    if isinstance(mp, MeasurePoint):

                        print("group_no:", mp.group_no)

                        if isinstance(mp.get_write_power(), MeterPowerType):

                            print("  power:", mp.get_write_power().get_e())

       

        self.zodb_finit()