Python架构师：Django

Python，架构师

§Python架构师：Django

一、问题记录

§1、执行python manage.py makemigration MySQL数据迁移时报错：query = query.decode(errors='replace')

具体报错如下：

Traceback (most recent call last):
  File "manage.py", line 21, in 
    main()
  File "manage.py", line 17, in main
    execute_from_command_line(sys.argv)
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/software/anaconda3/lib/python3.7/site-packages/django/core/management/commands/makemigrations.py", line 101, in handle
    loader.check_consistent_history(connection)
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/migrations/loader.py", line 283, in check_consistent_history
    applied = recorder.applied_migrations()
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/migrations/recorder.py", line 73, in applied_migrations
    if self.has_table():
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/migrations/recorder.py", line 56, in has_table
    return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/base/base.py", line 256, in cursor
    return self._cursor()
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/base/base.py", line 233, in _cursor
    self.ensure_connection()
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/base/base.py", line 217, in ensure_connection
    self.connect()
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/base/base.py", line 197, in connect
    self.init_connection_state()
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/mysql/base.py", line 231, in init_connection_state
    if self.features.is_sql_auto_is_null_enabled:
  File "/software/anaconda3/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/mysql/features.py", line 82, in is_sql_auto_is_null_enabled
    cursor.execute('SELECT @@SQL_AUTO_IS_NULL')
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/utils.py", line 103, in execute
    sql = self.db.ops.last_executed_query(self.cursor, sql, params)
  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/mysql/operations.py", line 146, in last_executed_query
    query = query.decode(errors='replace')
AttributeError: 'str' object has no attribute 'decode'

直接看最后面的报错信息为：

  File "/software/anaconda3/lib/python3.7/site-packages/django/db/backends/mysql/operations.py", line 146, in last_executed_query
    query = query.decode(errors='replace')
AttributeError: 'str' object has no attribute 'decode'

解决方法：

将 anaconda3/lib/python3.7/site-packages/django/db/backends/mysql/operations.py 文件中第146行代码中的 decode 改成 encode就解决了！如下图：
说明：
由于 python3.和Python2.在套接字返回值解码上的区别
python在bytes和str两种类型转换，所需要的函数依次是encode(),decode()
str通过encode()方法可以编码为指定的bytes。反过来，当从网络或磁盘上读取了字节流，那么读到的数据就是bytes。要把bytes变为str，就需要用decode()方法。反之，则使用encode()方法即可！