将 FOREIGN KEY 约束 'FK_dbo.Employees_dbo.Admins_AdminID' 引入表 'Employees' 可能会导致循环或多重级联路径。请指定 ON DELETE

来源：互联网发布：加工中心圆怎么编程编辑：程序博客网时间：2024/06/06 04:54

       [Required]
        public virtual ICollection<Permanents> Permanents { get; set; }//导航属性
        [Required]
        public virtual ICollection<Dimissions> Dimissions { get; set; }//导航属性

    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TL.DAL
{
    /// <summary>
    /// 转正信息
    /// </summary>
    public class Permanents
    {
        [Key]
        public int PerID { get; set; }//转正信息编号
        [Required]
        public int EmpID { get; set; }//员工编号
        [Required]
        public int AdminID { get; set; }//创建人
        public PerType PerType { get; set; }//转正类型
        [Column("PerDate", TypeName = "date")]
        public DateTime PerDate { get; set; }//转正日期
        [MaxLength(500)]
        [Column("PerReMark", TypeName = "nvarchar")]
        public string PerReMark { get; set; }//转正备注
        [Required]
        [Column("PerCreateDate", TypeName = "datetime")]
        public DateTime PerCreateDate { get; set; }//创建时间
        [Required]
        public virtual Employees Employees { get; set; }
        [Required]
        public virtual Admins Admins { get; set; }
    }
    public enum PerType
    {
        正常转正 = 1,
        提前转正,
        推迟转正
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TL.DAL
{
    /// <summary>
    /// 职位表
    /// </summary>
    public class Dutys
    {
        [Key]
        public int DutyID { get; set; }//职位编号
        [MaxLength(20)]
        [Column("DutyName",TypeName="nvarchar")]
        public string DutyName { get; set; }//职位名称
        [Required]
        public virtual ICollection<Employees> Employees { get; set; }

    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TL.DAL
{
    /// <summary>
    /// 离职信息
    /// </summary>
    public class Dimissions
    {
        [Key]
        public int DimID { get; set; }//离职信息编号
        [Required]
        public int EmpID { get; set; }//员工编号
        [Column("DimDate", TypeName = "date")]
        public DateTime DimDate { get; set; }//离职时间
        public DimType DimType { get; set; }//离职类型
        public DimCause DimCause { get; set; }//离职原因
        [Column("DimCreateDate", TypeName = "datetime")]
        public DateTime DimCreateDate { get; set; }//创建时间
        [Required]
        public int AdminID { get; set; }//创建人编号
        [Required]
        public virtual Employees Employees { get; set; }
        [Required]
        public virtual Admins Admins { get; set; }
    }
    public enum DimType
    {
        离职 = 1,
        劝退,
        辞退,
        自离
    }
    public enum DimCause
    {
        薪酬福利 = 1,
        身体原因,
        人际关系,
        家庭原因,
        发展空间,
        上级主管,
        能力欠缺,
        出差原因,
        其他
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TL.DAL
{
    /// <summary>
    /// 部门表
    /// </summary>
    public class Departs
    {
        [Key]
        public int DepID { get; set; }//部门编号
        [MaxLength(20)]
        [Column("DepName", TypeName = "nvarchar")]
        public string DepName { get; set; }//部门名称
        [Required]
        public virtual ICollection<Employees> Employees { get; set; }
    }
}

namespace TL.DAL

{
    using System;
    using System.Data.Entity;
    using System.Linq;
    using TL.DAL;

    public class MyContext : DbContext
    {
        public MyContext() : base("dbcon") { }
        public virtual DbSet<Dutys> Dutys { get; set; }
        public virtual DbSet<Departs> Departs { get; set; }
        public virtual DbSet<Admins> Admins { get; set; }
        public virtual DbSet<Contracts> Contracts { get; set; }
        public virtual DbSet<Dimissions> Dimissions { get; set; }
        public virtual DbSet<Permanents> Permanents { get; set; }
        public virtual DbSet<Employees> Employees { get; set; }
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Employees>().HasRequired(u => u.Admins)
                .WithMany(d => d.Employees)
                .HasForeignKey(c => c.AdminID)
                .WillCascadeOnDelete(false);
        }
    }

}

上面代码是能成功建库，并新增数据的最终版。

1、去掉OnModelCreating重载方法

　　报错：

将 FOREIGN KEY 约束 'FK_dbo.Employees_dbo.Admins_AdminID' 引入表 'Employees' 可能会导致循环或多重级联路径。请指定 ON DELETE NO ACTION 或 ON UPDATE NO ACTION，或修改其他 FOREIGN KEY 约束。
无法创建约束。请参阅前面的错误消息。

或

SqlException: Introducing FOREIGN KEY constraint 'FK_dbo.Employees_dbo.Admins_AdminID' on table 'Employees' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.Could not create constraint. See previous errors.

　分析原因：EF创建的FK默认是带级联

　　因为SqlServer并不是真正运行去校验是否循环或多重级联，而是通过一个级联路径(可能与Name有关系)

　　如果主键列不叫ID，也没有问题，但这样EF在建库时，会自动创建一列外键列(如Admins_AdminID在代码中看不到)

0 0