c# - EF 代码优先 : separate creation of objects in db with TFT inheritance

Question

用例示例

用户已在网站上注册(向用户表添加记录)。然后转到电子邮件并确认注册。确认链接重定向到人员编辑表单页面，用户填写表单并提交(向人员表添加记录)。

技术说明

我在 EF 模型中定义了一个简单的 2 对象表类型继承。

实体

public class User
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
}

public class Person : User
{
    public string FirstName { get; set; }
    public string MiddleName { get; set; }
    public string LastName { get; set; }
}

数据库

public class MainDataContext : DbContext
{
    public DbSet<User> Users { get; set; }
    public DbSet<Person> Persons { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        var configs = modelBuilder.Configurations;
        configs.Add(new UserConfiguration());
        configs.Add(new PersonConfiguration());
    }
}

配置

internal class UserConfiguration : EntityTypeConfiguration<User>
{
    internal UserConfiguration()
    {
        ToTable("Users");

        HasKey(x => x.Id);

        Property(x => x.Id)
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        Property(x => x.Name)
            .IsRequired()
            .HasMaxLength(128);
        Property(x => x.Password)
            .IsRequired()
            .HasMaxLength(128);
        Property(x => x.Email)
            .IsRequired()
            .HasMaxLength(128);
    }
}
internal class PersonConfiguration : EntityTypeConfiguration<Person>
{
    internal PersonConfiguration()
    {
        ToTable("Persons");

        Property(x => x.FirstName)
            .IsRequired()
            .HasMaxLength(16);
        Property(x => x.MiddleName)
            .IsOptional()
            .HasMaxLength(16);
        Property(x => x.LastName)
            .IsRequired()
            .HasMaxLength(16);
    }
}

需要在 DbSet 中一致地创建链接 (FK) 对象，如下所示:

    var db = new MainDataContext();
    var user = new User
    {
        Name = "someUser",
        Password = "somePassword",
        Email = "someEmail"
    };
    db.Users.Add(user);
    db.SaveChanges();
    // After some time in other some place
    var person = new Person
    {
        Id = user.Id,
        FirstName = "someFirstName",
        LastName = "someLastName"
    };
    db.Persons.Add(person);
    db.SaveChanges();

在最后一次 SaveChanges DbEntityValidationError 被捕获后:“一个或多个实体的验证失败。有关更多详细信息，请参阅‘EntityValidationErrors’属性。”必填用户字段存在 3 个验证错误。

如何在FK(继承)关联的DbSets中单独添加条目？

更新

我找到了一个解决方案。但是为此您必须删除旧用户。我想在不删除的情况下执行此操作，因为如果 Users 表与其他表相关联，那么它将无法删除。

    var db = new MainDataContext();
    var user = new User
    {
        Name = "someUser",
        Password = "somePassword",
        Email = "someEmail"
    };
    db.Users.Add(user);
    db.SaveChanges();
    // After some time in other some place
    var person = new Person
    {
        Id = user.Id,
        Name = user.Name,
        Password = user.Password,
        Email = user.Email,
        FirstName = "someFirstName",
        LastName = "someLastName"
    };
    db.Users.Remove(user);
    db.Persons.Add(person);
    db.SaveChanges();

但是还有另一个问题 - 为 person 对象生成了一个新的 Guid。

如何在不删除用户旧记录的情况下解决问题？

Answer 1

包含用例更新后:

你不应该在这里使用继承。您应该在实体之间使用组合和一对一关系:

public class User
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
    public virtual UserInfo Information{get;set;}
}

internal class UserConfiguration : EntityTypeConfiguration<User>
{
    internal UserConfiguration()
    {
        ToTable("Users");

        HasKey(x => x.Id);

        Property(x => x.Id)
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        Property(x => x.Name)
            .IsRequired()
            .HasMaxLength(128);
        Property(x => x.Password)
            .IsRequired()
            .HasMaxLength(128);
        Property(x => x.Email)
            .IsRequired()
            .HasMaxLength(128);        
    }
}

public class UserInfo
{
    [ForeignKey("InfosUser")]
    [Key]
    public UserId {get;set;}
    public string FirstName { get; set; }
    public string MiddleName { get; set; }
    public string LastName { get; set; }
    public virtual User InfosUser {get;set;}
}

internal class UserInfoConfiguration : EntityTypeConfiguration<UserInfo>
{
    internal UserInfoConfiguration()
    {
        ToTable("Persons");

        Property(x => x.FirstName)
            .IsRequired()
            .HasMaxLength(16);
        Property(x => x.MiddleName)
            .IsOptional()
            .HasMaxLength(16);
        Property(x => x.LastName)
            .IsRequired()
            .HasMaxLength(16);
        HasRequired(ui=>ui.InfosUser).WithOptional(u=>u.Information)
    }
}

并使用它:

    var db = new MainDataContext();
    var user = new User
    {
        Name = "someUser",
        Password = "somePassword",
        Email = "someEmail"
    };
    db.Users.Add(user);
    db.SaveChanges();
    // After some time in other some place
    var user = db.GetPersonFromDb(Id);// Get early saved person from db
    var information = new UserInfo
    {
         FirstName = "someFirstName",
         LastName = "someLastName",
    }
    user.Information = information;
    db.SaveChanges();