Question

我有课程：

public class Company
{
    public int CompanyId { get; set; }

    public virtual ICollection<Employee> Employees { get; set; }
}

public class Employee
{
    public int EmployeeId { get; set; }
}

代码首次迁移会创建以下表格：

CreateTable(
    "dbo.Companies",
    c => new
        {
            CompanyId = c.Int(nullable: false, identity: true),
        })
    .PrimaryKey(t => t.CompanyId);

CreateTable(
    "dbo.Employees",
    c => new
        {
            EmployeeId = c.Int(nullable: false, identity: true),
            Company_CompanyId = c.Int(),
        })
    .PrimaryKey(t => t.EmployeeId)
    .ForeignKey("dbo.Companies", t => t.Company_CompanyId)
    .Index(t => t.Company_CompanyId);

现在我想将Company属性添加到Employee类：

public class Employee
{
    public int EmployeeId { get; set; }

    public int CompanyId { get; set; }

    public virtual Company Company { get; set; }
}

在不更改数据库架构的情况下，将新属性绑定到现有列的最佳方法是什么？

Answer 1

首先映射关联：

modelBuilder.Entity<Employee>()
            .HasRequired(e => e.Company)
            .WithMany(c => c.Employees)
            .HasForeignKey(e => e.CompanyId);

然后告诉EF将属性CompanyId映射到列Company_CompanyId：

modelBuilder.Entity<Employee>().Property(e => e.CompanyId)
            .HasColumnName("Company_CompanyId");

Answer 2

同意@GertArnold提出的解决方案。遵循相同的想法，您还可以使用Data annotations来解决同样的问题：

public class Employee
{
    public int EmployeeId { get; set; }

    [ForeignKey("Company"),Column("Company_CompanyId")]
    public int CompanyId { get; set; }

    public virtual Company Company { get; set; }
}

添加新导航属性时保持原始FK列

2 个答案: