標籤:關聯表 java for ice 執行 let 反向 ast 操作
ORM: object relationship mapping關於資料庫的兩條命令:python manage.py makemigrationspython manage.py migrate資料庫第一次配置必須完成資料庫的遷移,執行上邊的兩條命令就好表單的記錄操作:1、添加obj = models.表名(**kwargs)obj.save()models.表名.objects.create(**kwargs)2、修改#方式一:obj = models.表名.objects.filter(name="python")[0]obj.name = "JAVA"obj.save#方式二 updatemodels.表名.objects.filter(name="python").update(**kwargs)3、刪除:models.表名.objects.filter(name="python").delete()4、查詢:QuerySet集合對象:models.表名.objects.all()models.表名.objects.filter(**kwargs)models.表名.objects.all().values(*args)models.表名.objects.all().values_list(*args)models.表名.objects.exclude(**kwargs)models.表名.objects.order_by(*args)models.表名.objects.distinct(*args) model對象:models.表名.objects.get(**kwargs)models.表名.objects.filter(**kwargs).first()models.表名.objects.filter(**kwargs).last()models.表名.objects.filter(**kwargs).count()models.表名.objects.filter(**kwargs).exist()關聯表記錄操作:表關係:1、一對一2、一對多3、多對一添加記錄:一對多:建立一對多:publish = models.Foreignkey("Publish",related_name="bookList")#添加記錄方式1:models.Book.objects.create(publish_id=1)#添加的記錄方式2:pubObj = models.Publish.objects.filter(name = "人民出版社")[0]models.Book.objects.create(publish=pubObj)多對多:建立多對多關係:authorlist = models.ManyToManyField("Author",related_name="bookList")多對多添加記錄:book_obj = models.Book.objects.create(title="追風的人",price=100,publishDate="2017-12-12",publish_id=2)alex_obj = models.Author.objects.filter(name="alex")[0]egon_obj = models.Author.objects.filter(name="egon")[0]查詢記錄:正向查詢:一對多:linux_obj = models.Book.objects.filter(title="linux").first()print(linux_obj.publish.name) #與這本書對象關聯的出版社的對象的名字多對多:linux_obj = models.Book.objects.filter(title="linux").first()print(linux_obj.authorlist.all()) #與這本書關聯的所有的作者的對象集合反向查詢:一對多:eg:尋找人民出版社出版過的書籍的名字publist_obj = models.Publish.objects.filter(name="人民出版社")[0]print(publist_obj.bookList.all()) #出版社書籍對象集合多對多:eg:尋找yuan出版過的素有書籍的名字和價格author_yuan = models.Author.objects.get(name="yuan")print(author_yuan.bookList.all())與該作者關聯的所有書籍的對象的集合
ORM: object relationship mapping