我们现在已经知道如何使用Code First来定义简单的领域类,并且如何使用DbContext类来执行数据库操作。现在我们来看下数据库理论中的多样性关系,我们会使用Code First来实现下面的几种关系: 1、一对一关系: one to one 2、一对多关系: one to many 3、多对多关系::many to many 首先要明确关系的概念。关系就是定...
一、One-to-Many Relationship 创建Map映射类 在编写代码之前,我们先分析一下客户和订单的关系。一个客户可以有多个订单,但一个订单只能属于一个客户,所以我们用到了EF中的HasRequired,一个客户又存在多个订单,因此也使用到了WithMany,同时Order表中有CustomerId作为外键,因此我们用到了HasForeignKey。根据我们的分析,...
https://www.learnentityframeworkcore.com/configuration/many-to-many-relationship-configuration 目前无法使用 convention 来实现 many to many. 所以只能用 fluent api. entity design in ef core for many to many relationship: publicclassBook{publicintBookId {get;set; }publicstringTitle {get;set; }public...
According to your description,I don't understand your requirement clearly.You need many To many relationships in Entity Framework Core?If you need this,you could use ** the Fluent API**. If not,you could post your codes and tell us more details of requirements to us.It will help us to...
create automatically controllers and strong-typed view to perform basic CRUDL operations on our entities. Unfortunately ASP.NET MVC scaffolding doesn't handle many to many relationship. I think that the main reason is that there are too many kinds of many-to-many user interface creating/editing....
i have a problem with many to many relationship using entity framework how to perform CRUD Function and not using repository pattern for e.g. i have three table 1. Table 1 is for Posts which stores post id and other details 2. Table 2 is for tags which stores all tag id and tagname...
didn't work as well... i tried several ways to load data from table having Many To Many Relationship before removing data from it. But I don't know where am I going wrong. Is there any other way I can have Add and Remove Method for Many 2 Many Relationship table without using M2...
The entity type ‘CartItem’ requires a primary key to be defined. Right,CartItemdoesn’t have primary key. Since it’s a many-to-many relationship it should have composite key. Composite key is like a regular primary key but it is composed by two properties (columns) instead of one. ...
I tried to build a database with entity framework code first. When i run my project itsnot being able to create a new databaseat all and corresponding tables which are in many to many relationship. I do not get a clue what went wrong, please guys help me out with it. i am stucked...
EntityFramework Core映射关系详解 前言 Hello,开始回归开始每周更新一到两篇博客,本节我们回归下EF Core基础,来讲述EF Core中到底是如何映射的,废话少说,我们开始。 One-Many Relationship(一对多关系) 首先我们从最简单的一对多关系说起,我们给出需要映射的两个类,一个是Blog,另外一个则是Post,如下:...