foreign-key-relationship

问题 In my schema, I have a generic table Animal and an inherited table Dog . Before using doctrine, I used to implement this pattern with an inherited id referencing the generic id as foreign key. I can't reproduce the same with Doctrine, and I feel like something is missing. The schema I used to produce is the following : CREATE TABLE `animal` ( `id` INT UNSIGNED NOT NULL AUTO_INCREMENT, `color` VARCHAR(20) NOT NULL, PRIMARY KEY (`id`) ); CREATE TABLE `dog` ( `id` INT UNSIGNED NOT NULL, `breed`

问题 PROBLEM: I am trying to create a EF6 model using the database first approach. Simply speaking, I have 2 tables tblUser and tblMilkMan which have a foreign key relationship on the UserID column. But when I create a new EDMX diagram and add the 2 tables: I dont see the relationship No navigation properties are created Please tell me what Im doing wrong! DB Schema: Table Scripts: CREATE TABLE [dbo].[tblMilkMan] ( [RecordID] [INT] NOT NULL IDENTITY(1, 1) , [UserID] [INT] NOT NULL , [IsMyTurn]

问题 What are the ways to tell SubSonic about the relationship (only foreign keys? Or other methods too)? If I have (for example) a team object with related team members ** how do I access and update the team members from the team ** how do I update the team members? Does saving the team object saves the team members changes ** How do I add members to the team? Do I just create a new member, assign the team ID to the foreign key and save? Or is there a more object oriented way (e.g. team.Add

问题 I was having trouble with the syntax for the .Include() and this related question got me to the point where it both compiled and ran: MVC-EF Reverse Engineer Code first include another table I use: [ForeignKey("Id")] public OtherTableModel OtherTableModel {get; set;} Both tables have the exact same primary key: string id {get; set} In my controller the code is: ourList = db.Table1.Include(t => t.OtherTableModel) Unfortunately, though this works in the sense of compiling and even running,

问题 Having an issue when trying to use DateField of a model class as the ForeignKey for another model class, and using default set to today on both classes. The error message is: django.core.exceptions.ValidationError: ["'self.date' value has an invalid date format. It must be in YYYY-MM-DD format."] code: class DailyImage(models.Model): date = models.DateField(auto_now_add=True, unique=True) name = models.CharField(max_length = 1000) image = models.CharField(max_length = 1000) location = models

问题 I am quickly learning the ins and outs of database design (something that, as of a week ago, was new to me), but I am running across some questions that don't seem immediately obvious, so I was hoping to get some clarification. The question I have right is about foreign keys. As part of my design, I have a Company table. Originally, I had included address information directly within the table, but, as I was hoping to achieve 3NF, I broke out the address information into its own table, Address

问题 I did not found a solution to this, so I want to ask you. The whole thing is that I have 3 tables: Cities, Districts, Institutions. Districts have a relationship with Cities Now when I want to register an Institution, I have to choose a District from which the Institution belongs, but if that City doesn't have any district, I have to choose the City itself. So, the question is, how can I bind these tables for the given situation? P.S. the Districts and Cities must remain bind 回答1: Have 2

问题 I need 1:1 relationship between ApplicationUser and my own class in entity framework. I do this: public class ApplicationUser : IdentityUser { public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager) { var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie); return userIdentity; } /*Realations*/ public virtual ICollection<Comment> Comments { get; set; } public virtual Posts Post { get; set; } } public

问题 My Models: class Faculty(models.Model): name = models.CharField(max_length=30) class Program(models.Model): name = models.CharField(max_length=30) faculty = models.ForeignKey(Faculty) class Student(models.Model): name = models.CharField(max_length=30) faculty = models.ForeignKey(Faculty) program = models.ForeignKey(Program) Let I have Two Faculty: Science Management And I have 3 Programs in each: Science B. Computer B. Software B. Civil Management BBA BBS BBI And What I want is When A studen

问题 I have a similar database with two tables as follow: +----------------------+ +------------------------+ |Persons | |phones | +----------------------+ +------------------------+ |id int +-----+ |id int | |name varchar(100) | +---->+person_id int | |allowed tinyint(1) | |number int | +----------------------+ +------------------------+ One person could have as many phones as he wants but he has to be allowed to it (allowed > 0). So, I created both tables using CREATE TABLE `phones` ( `id` int