django修改models重建數據庫的操作

第二次修改models.py以后再次

python manage.py makemigrations

提示如下

You are trying to add a non-nullable field 'address' to xc_users without a default; we can't do that (the database needs something to populate existing rows). Please select a fix: 1) Provide a one-off default now (will be set on all existing rows) 2) Qu

于是刪除數據庫表，繼續報相同的錯誤

makemigration需要指定名稱，然后migrate才能識別兩次<span >makemigrations的不同</span>

python manage.py makemigrations --name sqlname

然后再執行：

python manage.py migrate

成功解決問題！

補充知識：django rest framework如何一次性序列化同一個數據庫下多個model表數據在一個json頁面下

在django項目中，首先我們要安裝django-rest-mutiple-models

pip install django-rest-multiple-models

然后在setting配置中配置一下APP

INSTALLED_APPS = (
 ....
 'drf_multiple_model',
)

在我們的views視圖函數下引入

from drf_multiple_model.views import ObjectMultipleModelAPIView

如下兩個模型

class Play(models.Model):
 genre = models.CharField(max_length=100)
 title = models.CharField(max_length=200)
 pages = models.IntegerField()
 
class Poem(models.Model):
 title = models.CharField(max_length=200)
 style = models.CharField(max_length=100)
 lines = models.IntegerField()
 stanzas = models.IntegerField()

序列化如下

class PlaySerializer(serializers.ModelSerializer):
 class Meta:
 model = Play
 fields = ('genre','title','pages')
 
class PoemSerializer(serializers.ModelSerializer):
 class Meta:
 model = Poem
 fields = ('title','stanzas')

views中我們可以這么寫，繼承一個ObjectMutipleModelAPIView

from drf_multiple_model.views import ObjectMultipleModelAPIView
 
class TextAPIView(ObjectMultipleModelAPIView):
 querylist = [
 {'queryset': Play.objects.all(), 'serializer_class': PlaySerializer},
 {'queryset': Poem.objects.filter(style='Sonnet'), 'serializer_class': PoemSerializer},
 ....
 ]

如果我們使用的url是router，那這里我們就應該繼承ObjectMutipleModelAPIViewset

具體的引入

from drf_multiple_model.viewsets import ObjectMultipleModelAPIViewSet

DRF頁面的顯示效果如下

{
 "Play" : [
 {"genre": "Comedy", "title": "A Midsummer Night"s Dream", "pages": 350},
 {"genre": "Tragedy", "title": "Romeo and Juliet", "pages": 300},
 ....
 ],
 "Poem" : [
 {"title": "Shall I compare thee to a summer"s day", "stanzas": 1},
 {"title": "As a decrepit father takes delight", "stanzas": 1},
 ....
 ],
}

效果就是能在一個json頁面下序列化出多個不同的model數據

我們還可以對每個表的數據進行分頁

from drf_multiple_model.pagination import MultipleModelLimitOffsetPagination

views下可以這么寫

class LimitPagination(MultipleModelLimitOffsetPagination):
default_limit = 10

意思是每個model默認顯示前十條數據

如果前端需要，url上可以加上limit=5，自定義默認顯示前五條數據

更多詳細內容，github搜索DjangoRestMultipleModels

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