class Branch(EmbeddedDocument):
    ten_khoa = StringField()
    ten_nganh = StringField()

class Dissertation(Document):
    disser_name = StringField()
    post_day = DateTimeField()
    branch = EmbeddedDocumentField(Branch)

class User(Document):
    username = StringField()
    password = StringField()
    name = StringField()
    age = IntField()
    role = IntField()
    email = EmailField()
    branch = EmbeddedDocumentField(Branch)
    giao_vien_chu_nhiem = StringField()
    giang_vien_huong_dan = StringField()
    disser = ListField(ReferenceField(Dissertation,reverse_delete_rule=CASCADE))

class Exarminer(Document):
    maExarminer = StringField()
    name = StringField()
    list_thanhvien = ListField(ReferenceField(User,reverse_delete_rule=CASCADE))
    trongso = FloatField()