EF Core OwnsOne 在保存时失败

Question

我有以下型号：

public class User
{
    public Guid Id {get;set;}
    public string Username {get;set;}
    public string Address Useraddress {get;set;}
}

public class Address
{
    public string Street {get;set;}
    public string Zipcode {get;set;}
}

我想把Useraddress中的数据保存到同一个Usertable中。所以我向上下文构建器添加了一个 OwnsOne 配置。

class UserEntityTypeConfiguration : IEntityTypeConfiguration<User>
{
    public void Configure(EntityTypeBuilder<User> builder)
    {
        builder.HasKey(x => x.Id);
        builder.OwnsOne(x => x.UserAddress);
    }
}

当我运行迁移工具时，一切似乎都很好。这是生成的迁移脚本的相关部分：

migrationBuilder.CreateTable(
    name: "Users",
    columns: table => new
    {
        Id = table.Column<Guid>(nullable: false),
        Username = table.Column<string>(nullable: false),
        Useraddress_Street = table.Column<string>(nullable: true),
        Useraddress_Zipcode = table.Column<string>(nullable: true)
    },
    constraints: table =>
    {
        table.PrimaryKey("PK_Users", x => x.Id);
    });

然后当我稍后尝试添加 User:

await _dbContext.Users.AddAsync(user);
await _dbContext.SaveChangesAsync();

然后我收到以下错误：

The entity of 'User' is sharing the table 'Users' with 'User.Useraddress#Address', but there is no entity of this type with the same key value that has been marked as 'Added'

我做错了什么吗？

PS。我正在使用 Entity Framework Core 2.0.

Answer 1

EF Core 2.0 默认为拥有的实体创建一个主键作为影子属性因为它支持 table 拆分，因此 UserAddress 属性在 User 实例中不能为 null，必须定义。

var user = new User
{
    Id = Guid.NewGuid(),
    Username = "...",
    UserAddress = new Address
    {
        Street = "...",
        Zipcode = "..."
    }
};

await _dbContext.Users.AddAsync(user);
await _dbContext.SaveChangesAsync();

如果您希望拥有的实体的值为空，则只需定义一个默认实例，即：

var user = new User
{
    Id = Guid.NewGuid(),
    Username = "...",
    UserAddress = new Address()
};

您可以在此处阅读有关自有实体隐式密钥的更多信息：https://docs.microsoft.com/en-us/ef/core/modeling/owned-entities#implicit-keys

Answer 2

所提供的解决方案在 EF Core 5.0 中对我不起作用。我已将构造函数添加到地址 class

public Address()
{
    Line1 = string.Empty;
}

（至少有一个字段不能为空）。

现在它适用于新的根实体。但我仍然修复数据库中的现有实体

UPDATE RootEntityTable SET Address_Line1 = '' WHERE Id IN (...)

EF Core OwnsOne 在保存时失败

EF Core OwnsOne fails when saving

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entity-framework-migrations

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