django - Django South 迁移错误“包含空值”，带有 null=True 字段

Question

向模型添加简单缩略图字段时

easy_thumbnail = ThumbnailerImageField(
    null=True, blank=True, verbose_name=_("Easy_Thumbnails"),
    upload_to="easy_thumbnails",
    resize_source=dict(size=(100, 100), crop="smart"),
)

执行时./manage.py schemamigration test --auto，South 产生以下迁移：

def forwards(self, orm):
    # Adding field 'Test.easy_thumbnail'
    db.add_column('test_test', 'easy_thumbnail', self.gf('django.db.models.fields.files.ImageField')(), keep_default=False)
[...]
models = {
    'test.test': {
        'Meta': {'object_name': 'Test'},
        'easy_thumbnail': ('django.db.models.fields.files.ImageField', [], {}),

执行时./manage.py migrate test，出现此错误：

The error is `django.db.utils.IntegrityError: column "easy_thumbnail" contains null values`

Answer 1

修改迁移脚本如下解决问题：

• 在 db.add_column 中添加“null=True，blank=True”
• 在模型['test.test']['easy_thumbnail'] 中添加“'null': 'True', 'blank': 'True'”

编码：

def forwards(self, orm):
    # Adding field 'Test.easy_thumbnail'
    db.add_column('test_test', 'easy_thumbnail', self.gf('django.db.models.fields.files.ImageField')(null=True, blank=True), keep_default=False)
[...]
models = {
    'test.test': {
        'Meta': {'object_name': 'Test'},
        'easy_thumbnail': ('django.db.models.fields.files.ImageField', [], {'null': 'True', 'blank': 'True'}),