如何使用Mongoengine删除嵌入式文档？

Question

我有一个具有EmbeddedDocumentField的集合.我无法找到如何从集合中删除嵌入文档的示例.有人能为我提供一个例子或参考吗？

以下是我的设置:

• Python 2.7.5
• Django 1.5.5
• MongoEngine 0.8.7

码:

class Merchant(Document):
    merchant_id = StringField(max_length=50)
    merchant_name = StringField(max_length=150)
    merchant_name_search_alias = StringField(max_length=150)
    website = StringField(max_length=150)
    location = ListField(EmbeddedDocumentField(Location))
    address = StringField(max_length=50)
    city = StringField(max_length=30)
    state = StringField(max_length=20)
    zipcode = IntField()
    phone_nummber = StringField(max_length=10)
    sub_lat = FloatField()
    sub_lng = FloatField()
    country = StringField(max_length=20)
    promotion = ListField(EmbeddedDocumentField(Promotion))


class Promotion(EmbeddedDocument):
    provider_name = StringField(max_length=50)
    provider_website = URLField()
    promo_name = StringField(max_length=300)
    promo_name_search_alias = StringField(max_length=100)
    retail_price = DecimalField(precision=2, force_string=True)
    discount_price = DecimalField(precision=2, force_string=True)
    deal_url = URLField()
    buy_url = URLField()
    deal_image_url = URLField()
    description = StringField(max_length=1000)
    start_at = DateTimeField()
    end_at = DateTimeField()
    category = StringField(max_length=50)
    dq_category = StringField(max_length=50)
    keywords = StringField(max_length=100)

Answer 1

您可以$unset使用MyDoc.objects.update(unset__myField=1) 或使用$pull从列表中删除单个值的字段,例如:MyDoc.objects.update(pull__myField=Value)

请参阅:http://docs.mongoengine.org/en/latest/guide/querying.html?highlight=unset#atomic-updates