如何在 Entity Framework 6 中使用 Fluent API 映射没有外键属性的一对多对象列表？

Question

我有以下类（我无法更新、添加属性或添加注释）：

public class ApprovalRuleset
{
    public Guid Id { get; set; }
    public List<ApprovalRule> ApprovalRules { get; protected internal set; }
}

public class ApprovalRule
{
    public Guid Id { get; set; }
    public string Value { get; protected internal set; }
}

我正在尝试使用 Entity Framework 6 编写一些 Fluent API 代码以将它们映射到两个表。

这是 ApprovalRule 配置：

public class ApprovalRuleEntityConfiguration : EntityTypeConfiguration<ApprovalRule>
{
    public ApprovalRuleEntityConfiguration()
    {
        HasKey(x => x.Id);
        Property(x => x.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        Property(x => x.Value).IsRequired().HasMaxLength(450);
    }
}

到目前为止，我得到了：

public class ApprovalRulesetEntityConfiguration : EntityTypeConfiguration<ApprovalRuleset>
{
    public ApprovalRulesetEntityConfiguration()
    {
        HasKey(x => x.Id);
        Property(x => x.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        HasMany(x => x.ApprovalRules);
    }
}

表“ApprovalRules”上的外键与列 无法创建“ApprovalRuleset_Id”，因为主键 无法确定列。使用 AddForeignKey fluent API 完全指定外键。

public class ApprovalRulesetEntityConfiguration : EntityTypeConfiguration<ApprovalRuleset>
{
    public ApprovalRulesetEntityConfiguration()
    {
        HasKey(x => x.Id);
        Property(x => x.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        HasRequired(x => x.ApprovalRules)
            .WithMany()
            .HasForeignKey(x => x.Id);
    }
}

Multiplicity 与 Role 中的引用约束冲突 关系中的“ApprovalRuleset_ApprovalRules_Target” 'ApprovalRuleset_ApprovalRules'。因为所有的属性在 依赖角色是不可为空的，主要角色的多重性 必须是“1”。

我错过了什么？我花了很长时间搜索堆栈溢出和谷歌。

Answer 1

您需要在 ApprovalRule 类中添加两个属性。那么映射将是这样的 -

public class ApprovalRuleset
{
    public Guid Id { get; set; }
    public List<ApprovalRule> ApprovalRules { get; protected internal set; }
}

public class ApprovalRule
{
    public Guid Id { get; set; }
    public string Value { get; protected internal set; }

    public int ApprovalRulesetId { get; set; }
    public virtual ApprovalRuleset ApprovalRuleset { get; set; }
}

public class ApprovalRulesetEntityConfiguration : EntityTypeConfiguration<ApprovalRuleset>
{
    public ApprovalRulesetEntityConfiguration()
    {
        HasKey(t => t.Id);
    }
}

public class ApprovalRuleEntityConfiguration : EntityTypeConfiguration<ApprovalRule>
{
    public ApprovalRuleEntityConfiguration()
    {
        HasKey(t => t.Id);

        /*Property(t => t.Value)
            .HasMaxLength(100);*/

        HasRequired(t => t.ApprovalRuleset)
            .WithMany(t => t.ApprovalRules)
            .HasForeignKey(d => d.ApprovalRulesetId);
    }
}