当你设置null=true时，如果字段没有填充，它将在你的数据库中设置为空。如果 你设置blank=true，它不会为该字段设置任何值。

这就是ORM在Django 1.8中映射空白和空字段的方法

class Test(models.Model):
    charNull        = models.CharField(max_length=10, null=True)
    charBlank       = models.CharField(max_length=10, blank=True)
    charNullBlank   = models.CharField(max_length=10, null=True, blank=True)

    intNull         = models.IntegerField(null=True)
    intBlank        = models.IntegerField(blank=True)
    intNullBlank    = models.IntegerField(null=True, blank=True)

    dateNull        = models.DateTimeField(null=True)
    dateBlank       = models.DateTimeField(blank=True)
    dateNullBlank   = models.DateTimeField(null=True, blank=True)        

为PostgreSQL 9.4创建的数据库字段是:

CREATE TABLE Test (
  id              serial                    NOT NULL,

  "charNull"      character varying(10),
  "charBlank"     character varying(10)     NOT NULL,
  "charNullBlank" character varying(10),

  "intNull"       integer,
  "intBlank"      integer                   NOT NULL,
  "intNullBlank"  integer,

  "dateNull"      timestamp with time zone,
  "dateBlank"     timestamp with time zone  NOT NULL,
  "dateNullBlank" timestamp with time zone,
  CONSTRAINT Test_pkey PRIMARY KEY (id)
)

为MySQL 5.6创建的数据库字段是:

CREATE TABLE Test (
     `id`            INT(11)     NOT  NULL    AUTO_INCREMENT,

     `charNull`      VARCHAR(10) NULL DEFAULT NULL,
     `charBlank`     VARCHAR(10) NOT  NULL,
     `charNullBlank` VARCHAR(10) NULL DEFAULT NULL,

     `intNull`       INT(11)     NULL DEFAULT NULL,
     `intBlank`      INT(11)     NOT  NULL,
     `intNullBlank`  INT(11)     NULL DEFAULT NULL,

     `dateNull`      DATETIME    NULL DEFAULT NULL,
     `dateBlank`     DATETIME    NOT  NULL,
     `dateNullBlank` DATETIME    NULL DEFAULT NULL
)

当你说null=False时，这意味着数据必须传递到数据库保存。当你说空白=False时，这意味着数据必须从前端输入，反之亦然

null = True

意味着没有数据库对要填充的字段的约束，因此您可以有一个具有此选项的填充的空值对象。

blank = True

意味着在django表单中没有验证约束。所以当你为这个模型填写一个modelForm时，你可以不填这个选项。

简单地说，

Blank和null不同。

Null是纯粹与数据库相关的，而blank是与验证相关的(表单要求)。

如果null=True, Django将在数据库中存储空值为null。如果字段有blank=True，表单验证将允许输入空值。如果一个字段有blank=False，该字段将是必需的。

正如Django Model Field reference中所说:Link

Field options The following arguments are available to all field types. All are optional. null Field.null If True, Django will store empty values as NULL in the database. Default is False. Avoid using null on string-based fields such as CharField and TextField because empty string values will always be stored as empty strings, not as NULL. If a string-based field has null=True, that means it has two possible values for "no data": NULL, and the empty string. In most cases, it’s redundant to have two possible values for "no data"; the Django convention is to use the empty string, not NULL. For both string-based and non-string-based fields, you will also need to set blank=True if you wish to permit empty values in forms, as the null parameter only affects database storage (see blank). Note When using the Oracle database backend, the value NULL will be stored to denote the empty string regardless of this attribute blank Field.blank If True, the field is allowed to be blank. Default is False. Note that this is different than null. null is purely database-related, whereas blank is validation-related. If a field has blank=True, form validation will allow entry of an empty value. If a field has blank=False, the field will be required.