具有许多一对零或一对一关系的实体框架

Question

我想在一个实体中实现许多一对零或一的关系，但是在使它工作然后为它生成迁移方面遇到问题。

public class Invoice
{
    public int Id { get; set; }
    public int? MorningExpenseId { get; set; }
    public int? EveningExpenseId { get; set; }
    public Expense MorningExpense { get; set; }
    public Expense EveningExpense { get; set; }
}

public class Expense
{
    public int Id { get; set; }
    public int InvoiceId { get; set; }
    public Invoice Invoice { get; set; }
}
modelBuilder.Entity<Invoice>()
    .HasOptional<Expense>(p => p.MorningExpense)
    .WithRequired(g => g.Invoice);

modelBuilder.Entity<Invoice>()
    .HasOptional<Expense>(p => p.EveningExpense)
    .WithRequired(g => g.Invoice);

但是我收到一个错误的Schema specified is not valid. Errors: The relationship '...' was not loaded because the type '...' is not available.的错误Schema specified is not valid. Errors: The relationship '...' was not loaded because the type '...' is not available. Schema specified is not valid. Errors: The relationship '...' was not loaded because the type '...' is not available. 。 我还尝试在“ Expense”类中使用主组合键，例如：

public enum ExpenseType { Morning, Evening };
public class Expense
{
    public int Id { get; set; }
    public ExpenseType ExpenseType { get; set; }
    public Invoice Invoice { get; set; }
}

但要使其正常工作也就没有运气。 应该如何使用Fluent API来实现？

Answer 1

在实体框架中，应用程序类型必须与数据库类型匹配。 关系必须具有虚拟键。

您必须像这样编码

public class Invoice
{
    public int Id { get; set; }
    public int MorningExpenseId { get; set; }
    public int EveningExpenseId { get; set; }
    public virtual Expense MorningExpense { get; set; }
    public virtual Expense EveningExpense { get; set; }
}

public class Expense
{
    public int Id { get; set; }
    public int InvoiceId { get; set; }
    public virtual Invoice Invoice { get; set; }
}