EF Core – Many to Many 前言 Many to many 是 EF Core 5.0 才开始有的, 以前都用 2 个 1-n 来实现的. 由于它比 1-n 复杂, 所以有必要写一遍来记入一下. 参考: Relationships Property bag entity types Without Fluent API publicclassPost {publicintPostId {get;set; }publicstringTitle {get;set...
https://stackoverflow.com/questions/46184678/fluent-api-many-to-many-in-entity-framework-core/46184785#46184785 代码如下: publicclassPerson{publicintPersonId {get;set; }publicvirtualICollection<PersonClub> PersonClubs {get;set; } }publicclassClub{publicintClubId {get;set; }publicvirtualICollection<...
在EF中更新关联实体时,从数据库中获取实体,并快速加载您可能要更新的任何关联数据。你需要更加慎重地确定添加和删除哪些作者,而不是试图替换一个集合来反映当前状态。当您替换集合时,EF会期望您只是添加所有新的关联,而不知道需要删除任何关联记录。 执行插入时,您可以初始化集合,最好是通过构造函数,因为您不想在集...
首先模型: public class Book{publicintBookId{get;set;}public string Title{get;set;}public string Description{get;set;}public ICollection<BookAuthor>Authors{get;set;}}public class Author{publicintAuthorId{get;set;}public string Name{get;set;}public virtual ICollection<BookAuthor>Books{get;set;}}...
ef core many to manyhttps://stackoverflow.com/questions/46184678/fluent-api-many-to-many-in-entity-framework-core/46184785#46184785代码如下:public class Person { public int PersonId { get; set; } public virtual ICollection<PersonClub> PersonClubs { get; set; } } public class Club { public...
As is shown in the examples below, a many-to-many relationship can be mapped in this way--that is, with a .NET class for the join entity, and with both navigations for the two one-to-many relationships and skip navigations exposed on the entity types. However, EF can manage the ...
This is one of the building blocks for many-to-many. However, it is also more broadly useful than just many-to-many. Problem Consider a model typical for a many-to-many relationship: public class Post { public int PostId { get; set; } pu...
i have two tables 1-Employees (ID ,EmpName) 2- Project (ID,ProjectName) data is already inserted in boh tables ,there is many to many relationship between these two so middle table created in table i.e EmployeesProject now i want to insert data (keys of
This noniterative method, which requires the odds ratio from a prior logistic regression analysis, was then applied to a large contemporary sample of gay men. The results showed that roughly 1 gay man in 7 owes his sexual orientation to the fraternal birth order effect. They also showed that...
In this article, I will show one possible solution to implement many-to-many relationship using Linq to Sql.Let's begin with some definitions and what Linq to Sql offers.A“many to many” relationship between two entities defines a kind of bi-directional “one to many” relat...