Question

我正尝试从数据处理应用程序的文本文件转储中，从Django向pgsql数据库添加约40-50k行

以下是我的职责

def populate_backup_db(dumpfile):
    sensordata=sensorrecords()  **** This is the Model
    start_time = time.time()
    file= open(dumpfile)
    filedata = file.readlines()
    endcount=len(filedata)
    i=0
    imagecount=0
    while i<endcount:
        lineitem = split_entry(filedata[i])
        if (lineitem[0]== "HEADER"):
            imagecount=imagecount+1
            sensordata.Sensor          = lineitem[1]
            sensordata.Date1           = lineitem[2]
            sensordata.Date2           = lineitem[3]
            sensordata.Version         = lineitem[4]  
            sensordata.Proxyclient     = lineitem[8]
            sensordata.Triggerdate     = ctodatetime(lineitem[13])
            sensordata.Compression     = lineitem[16]
            sensordata.Encryption      = lineitem[17]
            sensordata.Fragments       = lineitem[21]
            sensordata.Pbit            = lineitem[37]
            sensordata.BlockIntFT      = lineitem[38]
            sensordata.OriginServer   =  lineitem[56]
            sensordata.save()
        i=i+1
    elapsed_time = time.time() - start_time
    print(imagecount ,'entries saved to database from ',dumpfile,'. Time Taken is ',elapsed_time,' seconds.')
    file.close()

这大约需要2-3分钟才能将所有数据保存到数据库。此转储文件的大小可能会增加，如果要使用此功能，则可能需要几分钟才能将所有数据保存到数据库

如何从转储文件中提取所有数据，然后一次将所有数据保存到数据库中。

我看到了一个名为bulk_create（）的DJANGO方法

bulk_create()¶

    bulk_create(objs, batch_size=None, ignore_conflicts=False)¶

此方法可以高效地将提供的对象列表插入数据库（通常只有1个查询，无论有多少个对象）：

>>> Entry.objects.bulk_create([
...     Entry(headline='This is a test'),
...     Entry(headline='This is only a test'),
... ])

该示例似乎是手动添加条目，我正在使用的功能正在运行一个循环，直到获取所有条目为止，并保存了该过程。

如何在Loop中运行它？是否将sensordata.save()替换为some_list.append(sensordata)

，最后在循环结束后执行

sensordata.objects.bulk_create(some_list)

我编辑了代码以将对象追加到列表中，然后如下所示进行批量更新

def populate_backup_db(dumpfile):
    sensordata=sensorrecords()  **** This is the Model
    datalist =[]
    start_time = time.time()
    file= open(dumpfile)
    filedata = file.readlines()
    endcount=len(filedata)
    i=0
    imagecount=0
    while i<endcount:
        lineitem = split_entry(filedata[i])
        if (lineitem[0]== "HEADER"):
            imagecount=imagecount+1
            sensordata.Sensor          = lineitem[1]
            sensordata.Date1           = lineitem[2]
            sensordata.Date2           = lineitem[3]
            sensordata.Version         = lineitem[4]  
            sensordata.Proxyclient     = lineitem[8]
            sensordata.Triggerdate     = ctodatetime(lineitem[13])
            sensordata.Compression     = lineitem[16]
            sensordata.Encryption      = lineitem[17]
            sensordata.Fragments       = lineitem[21]
            sensordata.Pbit            = lineitem[37]
            sensordata.BlockIntFT      = lineitem[38]
            sensordata.OriginServer   =  lineitem[56]
            datalist.append(sensordata)
        i=i+1
    elapsed_time = time.time() - start_time
    print(imagecount ,'entries saved to database from ',dumpfile,'. Time Taken is ',elapsed_time,' seconds.')
sensordata.objects.bulk_create(datalist)    
file.close()

这会在下面引发错误

跟踪：

File "C:\Python\Python36\lib\site-packages\django\core\handlers\exception.py" in inner
  34.             response = get_response(request)

File "C:\Python\Python36\lib\site-packages\django\core\handlers\base.py" in _get_response
  126.                 response = self.process_exception_by_middleware(e, request)

File "C:\Python\Python36\lib\site-packages\django\core\handlers\base.py" in _get_response
  124.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "C:\Python\Python36\lib\site-packages\django\contrib\auth\decorators.py" in _wrapped_view
  21.                 return view_func(request, *args, **kwargs)

File "C:\Users\va\eclipse-workspace\prod\home\views.py" in process_data
  68.             get_backup_data()

File "C:\Users\va\eclipse-workspace\prod\home\process.py" in get_backup_data
  8.     populate_backup_db('c:\\users\\va\\desktop\\vsp\\backupdata_server.txt')

File "C:\Users\va\eclipse-workspace\prod\home\process.py" in populate_backup_db
  122.     sensordata.objects.bulk_create(datalist)

File "C:\Python\Python36\lib\site-packages\django\db\models\manager.py" in __get__
  176.             raise AttributeError("Manager isn't accessible via %s instances" % cls.__name__)

Exception Type: AttributeError at /process_data/
Exception Value: Manager isn't accessible via sensorrecords instances

Answer 1

像这样更新您的代码：

def populate_backup_db(dumpfile):
    datalist =[]
    start_time = time.time()
    file= open(dumpfile)
    filedata = file.readlines()
    endcount=len(filedata)
    i=0
    imagecount=0
    while i<endcount:
        lineitem = split_entry(filedata[i])
        if (lineitem[0]== "HEADER"):
            imagecount=imagecount+1
            sensordata = sensorrecords()  # initiating object here
            sensordata.Sensor          = lineitem[1]
            sensordata.Date1           = lineitem[2]
            sensordata.Date2           = lineitem[3]
            sensordata.Version         = lineitem[4]  
            sensordata.Proxyclient     = lineitem[8]
            sensordata.Triggerdate     = ctodatetime(lineitem[13])
            sensordata.Compression     = lineitem[16]
            sensordata.Encryption      = lineitem[17]
            sensordata.Fragments       = lineitem[21]
            sensordata.Pbit            = lineitem[37]
            sensordata.BlockIntFT      = lineitem[38]
            sensordata.OriginServer   =  lineitem[56]
            datalist.append(sensordata)
        i=i+1
    elapsed_time = time.time() - start_time
    print(imagecount ,'entries saved to database from ',dumpfile,'. Time Taken is ',elapsed_time,' seconds.')
    sensorrecords.objects.bulk_create(datalilist) # you need to access objects method via model class name   
    file.close()

如何使用Django批量添加到数据库功能

1 个答案: