CharField 继承自具有构造函数的 Field 类
class Field(RegisterLookupMixin):
"""Base class for all field types"""
# <some more code>
def __init__(self, verbose_name=None, name=None, primary_key=False,
max_length=None, unique=False, blank=False, null=False,
db_index=False, rel=None, default=NOT_PROVIDED, editable=True,
serialize=True, unique_for_date=None, unique_for_month=None,
unique_for_year=None, choices=None, help_text='', db_column=None,
db_tablespace=None, auto_created=False, validators=[],
error_messages=None):
字符字段构造函数
class CharField(Field):
description = _("String (up to %(max_length)s)")
def __init__(self, *args, **kwargs):
super(CharField, self).__init__(*args, **kwargs)
self.validators.append(validators.MaxLengthValidator(self.max_length))
charfield 构造函数基本上将参数(关键字和普通参数)传递给字段构造函数,并添加一个 maxlength 验证器。
因此 CharField('name',max_length=100 中的参数 'name' 被分配给 verbose_name
看到这个
https://github.com/django/django/blob/master/django/db/models/fields/__init__.py https://github.com/django/django/blob/master/django/db/models/fields/__init__.py