EF Core 代码首先自行创建附加属性

Question

我先在随机示例上练习代码，这是我的代码：

public class Employee
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int SectionId { get; set; }
    public string SpecializationName { get; set; }
    public virtual Section Section { get; set; }
    public virtual Specialization Specialization { get; set; }
}

public class Specialization
{
    public string SpecializationName { get; set; }
}

public class EmployeeConfiguration : IEntityTypeConfiguration<Employee>
{
    public void Configure(EntityTypeBuilder<Employee> builder)
    {
        builder.ToTable("Employees");
        builder.Property(x => x.Name).IsRequired().HasMaxLength(100);

        builder.HasOne(x => x.Section);
        builder.HasOne(x => x.Specialization);
    }
}

public class SpecializationConfiguration : IEntityTypeConfiguration<Specialization>
{
    public void Configure(EntityTypeBuilder<Specialization> builder)
    {
        builder.ToTable("Specializations");
        builder.HasKey(x => x.SpecializationName);

        builder.Property(x => x.SpecializationName).IsRequired().HasMaxLength(20);
    }
}

一切正常，除了在更新迁移后出现一个新属性 - SpecializationName1 in Employees table。加一个是FK，原来不是，更奇怪。我完全不知道如何修复它，因为它几乎是自己做的，我从来没有在代码中输入 SpecializationName1 。

Answer 1

有趣，您似乎遇到了 EF Core 3.x 错误。

Employee 中的属性名称 SpecializationName 似乎不符合任何 EF Core FK 名称约定

If the dependent entity contains a property with a name matching one of these patterns then it will be configured as the foreign key:

<navigation property name><principal key property name>

<navigation property name>Id

<principal entity name><principal key property name>

<principal entity name>Id

所以它被丢弃了，但是不知何故默认生成的 FK 是相同的，并且由于它是 "reserved"，EF 在末尾附加后缀“1”。

像往常一样，当 EF Core 约定不起作用时，解决方案是使用显式映射，例如在 EmployeeConfiguration

builder.HasOne(x => x.Specialization)
    .WithMany()
    .HasForeignKey(x => x.SpecializationName);

EF Core 代码首先自行创建附加属性

EF Core code first creates additional attribute on its own

c#

entity-framework-core

ef-core-3.0