Question

我想创建两个表，其中一个表包含两个引用另一个表的列，并且遇到一些问题。所以，我的模型中有一个Employee类：

public class Employee
{
    public Guid Id { get; set; }
    [ForeignKey("EmployeeId")]
    public virtual ICollection<EmployeeRequest> EmployeeRequests { get; set; }
}

每个员工都可以创建EmployeeRequest，因此我们有一个导航属性。 EmployeeRequest看起来像这样：

public class EmployeeRequest
{
    public Guid Id { get; set; }

    public Guid ManagerId { get; set; }
    public virtual Employee Manager { get; set; }

    public Guid EmployeeId { get; set; }
    public virtual Employee Employee { get; set; }
}

除了EmployeeId，EmployeeRequest还必须有ManagerId。经理也是员工和必填字段。迁移代码如下：

public partial class employee_request : DbMigration
{
    public override void Up()
    {
        CreateTable(
            "dbo.EmployeeRequest",
            c => new
                {
                    Id = c.Guid(nullable: false),
                    ManagerId = c.Guid(nullable: false),
                    EmployeeId = c.Guid(nullable: false),
                })
            .PrimaryKey(t => t.Id)
            .ForeignKey("dbo.Employee", t => t.EmployeeId, cascadeDelete: true)
            .ForeignKey("dbo.Employee", t => t.ManagerId, cascadeDelete: true)
            .Index(t => t.ManagerId)
            .Index(t => t.EmployeeId);

        CreateTable(
            "dbo.Employee",
            c => new
                {
                    Id = c.Guid(nullable: false),
                })
            .PrimaryKey(t => t.Id);

    }

    public override void Down()
    {
        DropForeignKey("dbo.EmployeeRequest", "ManagerId", "dbo.Employee");
        DropForeignKey("dbo.EmployeeRequest", "EmployeeId", "dbo.Employee");
        DropIndex("dbo.EmployeeRequest", new[] { "EmployeeId" });
        DropIndex("dbo.EmployeeRequest", new[] { "ManagerId" });
        DropTable("dbo.Employee");
        DropTable("dbo.EmployeeRequest");
    }
}

但是在尝试更新数据库时，我收到以下错误：

引入FOREIGN KEY约束＆＃39; FK_dbo.EmployeeRequest_dbo.Employee_ManagerId＆＃39;桌子上＆＃39; EmployeeRequest＆＃39;可能会导致循环或多个级联路径。指定 ON DELETE NO ACTION或ON UPDATE NO ACTION，或修改其他FOREIGN 关键约束。无法创建约束。查看以前的错误。

有人可以解释一下如何配置上下文以便它可以使用这样的配置吗？

实体框架CF：由于循环或多个级联路径，无法创建外键约束

0 个答案: