在.Net Core/EF Core中设置多个相同类的外键 [英] Setting up multiple Foreign keys of same class in .Net Core / EF Core
问题描述
我正在构建.Net Core Web应用程序,以将旧的旧版Access ADP/ADE前端替换为项目管理SQL Server数据库.但是,原始数据库的构建者并未设置大量外键关系来支持在SQL视图中进行所有操作.我希望通过此应用程序进行补救.
I'm building a .Net Core web app to replace an old legacy Access ADP/ADE front end to a project management SQL Server database. However, the builder of the original DB didn't setup a whole lot of Foreign key relationships in favor of doing it all in SQL views. Something I'm hoping to remedy with this app.
我要确保在同一个类类型的外键设置时会束手无策.例如,我有以下课程.
I'm wanting to make sure I have my head wrapped around setting up foreign keys when they are of the same class type. For example, I've got the following classes.
Project.cs
Project.cs
using System;
using System.Collections.Generic;
namespace ProjectLogic.Models
{
public class Project
{
public int Id { get; set; };
public string Name { get; set; }
public int? PmEmployeeId { get; set; }
public int? CadEmployeeId { get; set; }
public int? SalesRepEmployeeId { get; set; }
...
}
}
Employee.cs
Employee.cs
using System;
using System.Collections.Generic;
namespace ProjectLogic.Models
{
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public string Title { get; set; }
...
}
}
我在Project Class末尾的按键会像这样吗?
Would my keys at the end of the Project Class look like this?
public Employee PmEmployee { get; set; }
public Employee CadEmployee { get; set; }
public Employee SalesRepEmployee { get; set; }
在员工类别中具有相应的声明
With corresponding declarations in Employee Class
public ICollection<Project> Projects { get; set; }
DbContext类中的模型构建器
And the Model Builder in my DbContext class
modelBuilder.Entity<Project>(entity =>
{
// Fluent API for column properties
...
entity.HasOne(d => d.PmEmployee)
.WithMany(p => p.Projects)
.HasForeignKey(d => d.PmEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_PM");
entity.HasOne(d => d.CadEmployee)
.WithMany(p => p.Projects)
.HasForeignKey(d => d.CadEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_CAD");
entity.HasOne(d => d.SalesRepEmployee)
.WithMany(p => p.Projects)
.HasForeignKey(d => d.SalesRepEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_SALES");
});
我想我最关心的/问题是Employee类如何处理与Project类的多个关系.我需要像public ICollection<Project> PmProjects { get; set; }
一样分别处理吗?
I guess my biggest concern/question is how the Employee class will handle multiple relationships with the Project Class. Do I need to handle those separately as well like public ICollection<Project> PmProjects { get; set; }
?
推荐答案
是的,您需要有单独的项目集合.
Yes, you need to have separate project collections.
在Employee中,您将:
In Employee, you would have:
public ICollection<Project> PmProjects { get; set; }
public ICollection<Project> CadProjects { get; set; }
public ICollection<Project> SalesProjects { get; set; }
在Project中,您将:
In Project, you would have:
public Employee PmEmployee { get; set; }
public Employee CadEmployee { get; set; }
public Employee SalesRepEmployee { get; set; }
生成器为:
modelBuilder.Entity<Project>(entity =>
{
// Fluent API for column properties
...
entity.HasOne(d => d.PmEmployee)
.WithMany(p => p.PmProjects)
.HasForeignKey(d => d.PmEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_PM");
entity.HasOne(d => d.CadEmployee)
.WithMany(p => p.CadProjects)
.HasForeignKey(d => d.CadEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_CAD");
entity.HasOne(d => d.SalesRepEmployee)
.WithMany(p => p.SalesProjects)
.HasForeignKey(d => d.SalesRepEmployeeId)
.OnDelete(DeleteBehavior.SetNull)
.HasConstraintName("FK_Project_Employee_SALES");
});
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