foreign-keys

问题 My models.py class Order(models.Model): user = models.ForeignKey(User, blank=True, null=True, on_delete=models.PROTECT) customer_email = models.EmailField(blank=True, null=True, default=None) customer_name = models.CharField(max_length = 64, blank=True, null=True, default=None) customer_phone = models.CharField(max_length = 48, blank=True, null=True, default=None) customer_address = models.CharField(max_length = 128, blank=True, null=True, default=None) total_price = models.DecimalField(max

问题 I am building a simple ASP.NET MVC app with Entity Framework Database First that allows a user to edit tables in a database. One table has a foreign key to another table. I want the user to be able to change the foreign key value. My question: How do I choose which column from the "foreign" table is displayed to the user in the view? I scaffolded the view out, but it is displaying the wrong column. The foreign key is in the DealerAuto table, which has columns: DealerAutoID, DealerID,

问题 Just curious, if I have this table: CREATE TABLE "post" ( "id" SERIAL, "revision" INTEGER NOT NULL DEFAULT 0, "summary" CHARACTER VARYING NOT NULL, "description" TEXT NOT NULL, "user_id" INTEGER NOT NULL REFERENCES "user" ("id") MATCH FULL ON UPDATE CASCADE ON DELETE RESTRICT, "post_type_id" INTEGER NOT NULL REFERENCES "post_type" ("id") MATCH FULL ON UPDATE CASCADE ON DELETE RESTRICT, "ctime" TIMESTAMP WITH TIME ZONE DEFAULT NOW(), PRIMARY KEY("id", "revision") ); to store posts, and this

问题 i want to get the images form the image model in the template. class Products(models.Model): category = models.ForeignKey(Category) name= models.CharField(max_length=120, unique=True) slug = models.SlugField(unique = True) price = models.IntegerField(default=100) class Image(models.Model): property = models.ForeignKey(Products, related_name='images') image = models.ImageField(upload_to='static/images/home',blank=True,null=True) views.py def index(request): queryset = Products.objects.all()

问题 I have created the following 3 tables using the following code. CREATE TABLE BUILDING( BUILDINGNO CHAR(2), BUILDINGWING VARCHAR2(15), BUILDINGLANE VARCHAR2(15), CONSTRAINT BUILDING_PK PRIMARY KEY(BUILDINGNO)); CREATE TABLE ROOM( BUILDINGNO CHAR(2), ROOMNO CHAR(2), ROOMCAPACITY NUMBER(3), CONSTRAINT ROOM_PK PRIMARY KEY(BUILDINGNO,ROOMNO), CONSTRAINT ROOM_FK1 FOREIGN KEY(BUILDINGNO) REFERENCES BUILDING(BUILDINGNO)); CREATE TABLE SPEAKER( SPEAKERID CHAR(2), SPEAKERNAME VARCHAR2(20),

问题 I think my title is pretty self explainitory, however I will outline what I am doing below. A person is connected to a town. This town is connected to a county. The county is connected to a country. There are many counties in one country. Also there are many towns in a county. That being said many people can be from the same town. In my database I have a separate table for people, towns, counties and countries. To get a full user record I LEFT JOIN the tables on a record set. This is a

问题 I have a chat table with fields admin TINYINT owner_id INTEGER The goal is to have two relations in Yii: 'admin'=>array( self::BELONGS_TO, 'Admin', 'owner_id', 'condition'=>'admin=1', ), 'user'=>array( self::BELONGS_TO, 'User', 'owner_id', 'condition'=>'admin=0', ), However, I got General error: 1 no such column: admin , and could manage only by adding all_ones and all_zeros columns to Admin table, so I could write 'admin'=>array( self::BELONGS_TO, 'Admin', array('owner_id' => 'id', 'admin' =

问题 I am using Django Rest Framework in my app, and I need to create new model instances which contain foreign keys. These refer to existing objects in another table, so I don't want new instances of these foreign objects to be created. Also I cannot access these objects via their primary keys, as that information is not submitted (I need to filter on certain fields which are included in the POST request). How do I do this? This question seems to address the same issue, though it's not clear to

问题 I'm trying to upload files for an article model. Since an object can have multiple images, I'm using a foreign-key from file model to my article model. However, I want all the files to have unique titles. Herez the code snippet. class Article(models.Model): name = models.CharField(max_length=64) class Files(models.Model): title = models.CharField(max_length=64) file = models.FileField(upload_to="files/%Y/%m/%d/") article = models.ForeignKey(Article) Now when I upload the files, I want the

问题 I have an h2 database with two tables with foreign keys like CREATE TABLE master (masterId INT PRIMARY KEY, slaveId INT); CREATE TABLE slave (slaveId INT PRIMARY KEY, something INT, CONSTRAINT fk FOREIGN KEY (slaveId) REFERENCES master(slaveId)); and need something like DELETE master, slave FROM master m JOIN slave s ON m.slaveId = s.slaveId WHERE something = 43; i.e., delete from both tables (which AFAIK works in MySql). Because of the FOREIGN KEY I can't delete from the master first. When I