更改列的 IDENTITY 属性，需要删除并重新创建该列 [英] Change the IDENTITY property of a column, the column needs to be dropped and recreated

问题描述

我使用的是 EF Core 2.1

这是我最初的模型定义.

This was my initial model definition.

public class Customer //Parent
{
    public int Id { get; set; }

    public string Name { get; set; }

    public string Email { get; set; }

    public BankAccount BankAccount { get; set; }

}


public class BankAccount
{
    public int Id { get; set; }

    public string Branch { get; set; }

    public string AcntNumber { get; set; }

    public DateTime CreatedDate { get; set; }

    public int CustomerId { get; set; }

    public Customer Customer { get; set; }

}

但我意识到有 Id &CustomerId 两者都是一对一关系的开销，我可以如下更新我的 BankAccount 模型定义.

But I realized having Id & CustomerId both is overhead as its One-to-One relation, I can update my BankAccount model definition as below.

public class BankAccount
{
    public int Id { get; set; }

    public string Branch { get; set; }

    public string AcntNumber { get; set; }

    public DateTime CreatedDate { get; set; }

    public Customer Customer { get; set; }

}

虽然在 DbContext 类中定义了主体实体，如下所示.

While in DbContext class defined the principal entity as below.

HasOne(b => b.Customer).WithOne(c => c.BankAccount).HasForeignKey<BankAccount>(f => f.Id);

在运行 update-database 时，我收到以下错误.

While running the update-database I am getting the below error.

System.InvalidOperationException:要更改列的 IDENTITY 属性，需要删除并重新创建该列.

System.InvalidOperationException: To change the IDENTITY property of a column, the column needs to be dropped and recreated.

但是，理想情况下，我不应该只是摆脱这个错误，我删除了列、约束和表，然后还删除了完整的数据库.但还是一样的错误.

However, ideally I should not but just get rid of this error, I deleted the column, constraints and as well table and then the complete database as well. But still the same error.

推荐答案

遇到了同样的问题，通过两步两迁移解决了:

I ran into the same problem, and I solved it by two steps and two migrations:

第一步

1. 删除标识列.
2. 注释 BankAccount 中的 ID 并添加一个新 ID(即 BankAccountId as
   身份，添加迁移和更新 - 这会删除 id).
3. 添加一个新列作为标识.

第 2 步

1. 删除新添加的列并重新添加上一列.评论 BankAccountId 和取消评论 ID.
2. 添加迁移和更新(这会删除 BankAccountId 并添加 Id 作为身份).

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