快捷導(dǎo)航

django修改models重建數(shù)據(jù)庫的操作

更新時(shí)間：2020年03月31日 10:25:07 作者：yue492008824

這篇文章主要介紹了django修改models重建數(shù)據(jù)庫的操作，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。一起跟隨小編過來看看吧

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(shù)據(jù)庫表，繼續(xù)報(bào)相同的錯(cuò)誤

makemigration需要指定名稱，然后migrate才能識(shí)別兩次<span style="font-family: Arial, Helvetica, sans-serif;">makemigrations的不同</span>

python manage.py makemigrations --name sqlname

然后再執(zhí)行：

python manage.py migrate

成功解決問題！

補(bǔ)充知識(shí)：django rest framework如何一次性序列化同一個(gè)數(shù)據(jù)庫下多個(gè)model表數(shù)據(jù)在一個(gè)json頁面下

在django項(xiàng)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(shù)下引入

from drf_multiple_model.views import ObjectMultipleModelAPIView

如下兩個(gè)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(gè)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(yīng)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(gè)json頁面下序列化出多個(gè)不同的model數(shù)據(jù)

我們還可以對(duì)每個(gè)表的數(shù)據(jù)進(jìn)行分頁