Question

我正在使用实体框架，我在其他实体中有一个Employee实体。我希望Employee拥有的一个导航属性是此Employee管理的Employees列表。这是Employee类（它实际上使用了EF前缀，但我在没有前缀的情况下引用它，以减少它的混乱）：

/// <summary>
/// The Class model for the Employee Entity
/// </summary>
[Table("employee_entity")]
public class EFEmployee : EFBusinessEntity
{
    /// <summary>
    /// The hire date of the employee
    /// </summary>
    [Column("hire_date")]
    public DateTime HireDate { get; set; }

    /// <summary>
    /// The list of jobtitles for the employee
    /// </summary>
    [Column("job_title")]
    [Required]
    public byte[] JobTitle { get; set; }

    /// <summary>
    /// The Employee's salary (note: not attached to jobtitle necessarily)
    /// </summary>
    [Column("salary")]
    public int Salary { get; set; }

    /// <summary>
    /// List of Certifications for the employee
    /// </summary>
    [Column("certifications")]
    public byte[] Certifications { get; set; }

    /// <summary>
    /// Employee's stored up vacation time
    /// </summary>
    [Column("vacation_time")]
    public int VacationTime { get; set; }

    /// <summary>
    /// Employee's stored up sick time
    /// </summary>
    [Column("sick_time")]
    public int SickTime { get; set; }

    /// <summary>
    /// Maps the employee entity to the office entity
    /// </summary>
    [ForeignKey("office_entity")]
    public virtual EFOffice Office { get; set; }

    /// <summary>
    /// Maps the employee entity to the person entity
    /// </summary>
    public virtual EFPerson Identity { get; set; }

    /// <summary>
    /// Maps the employee entity to another employee entity
    /// </summary>
    public virtual EFEmployee ReportingTo { get; set; }

    /// <summary>
    /// Maps the employee entity to a collection of employee entites
    /// </summary>
    public virtual ICollection<EFEmployee> Managing { get; set; }

    /// <summary>
    /// Constructor for an Entity. Only requires the properties that cannot be null.
    /// </summary>
    /// <param name="Id"></param>
    /// <param name="TenantId"></param>
    /// <param name="hire"></param>
    /// <param name="titles"></param>
    /// <param name="salary"></param>
    /// <param name="certifications"></param>
    /// <param name="vacationTime"></param>
    /// <param name="sickTime"></param>
    public EFEmployee(Guid Id, Guid TenantId, DateTime hire, byte[] titles, int salary, byte[] certifications, int vacationTime, int sickTime)
    {
        this.HireDate = hire;
        this.JobTitle = titles;
        this.Salary = salary;
        this.Certifications = certifications;
        this.SickTime = sickTime;
        this.VacationTime = vacationTime;
    }
}

如您所见，员工的导航属性之一是

public virtual ICollection<EFEmployee> Managing { get; set; }

我有一个EmployeeMap类，它使用Fluent API建立Employee实体和其他实体之间的关系。它现在还不完整，但这就是它的样子：

public partial class EmployeeMap : EntityTypeConfiguration<EFEmployee>
{
    public EmployeeMap()
    {
        // Relations
        HasRequired(t => t.Office).WithMany(u => u.Employees);
        HasMany(t => t.Managing).WithRequired(u => u.Employees);
    }
}

与办公室和员工的第一个关系是有效的，因为每个Office实体都有许多Employee实体。但是，我收到了第二个关系映射的错误。具体来说，＆＃39;员工＆＃39;最后给出了一个错误说

员工不包含＆＃39;员工＆＃39;的定义。没有扩展方法等......

很明显，为什么我会收到这个错误。我还没有在Employee for Employees中宣布财产，我也不知道为什么会这样做。但是，如何在同一类型的两个实体之间建立关系？如果你回顾我的Employee实体类，我也有导航属性：

public virtual EFEmployee ReportingTo { get; set; }

我在这里也试图建立一个员工与另一个员工之间的关系，但我不知道这是如何工作的，因为在实体数据模型中，Employee实体只表示为一个表与其属性。有谁知道我在谈论什么以及如何绕过它？

Answer 1

当您定义关系时，您使用的属性需要彼此相反。在Managing的情况下，我认为您正在寻找的是：

HasMany(t => t.Managing).WithRequired(t => t.ReportingTo);

因为我猜你想要：

someEmployee.ReportingTo.Managing.Contains(someEmployee) == true

并且您希望EFEmployee中的每个someManager.Managing都拥有ReportingTo == someManager。

如果您实际上没有定义反向属性，则不需要在模型配置中有一个：

// someEmployee can possibly have many other EFEmployees with 
// ReportingTo == someEmployee, but no collection property on someEmployee to 
// represent that relationship!
HasRequired(t => t.ReportingTo).WithMany();

如何在Employee实体和ICollection <employee>之间使用Fluent API设置关系？

1 个答案: