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基于关系变化的实体框架迁移

relation entity-framework c#

bugrasitemkar · 技术社区 · 6 年前

我有两个模型

  public class Employee
    {
        public Employee()
        {
            Active = true;
        }

        [Key]
        public long Id { get; set; }

        public List<Service> Services { get; set; }

        public List<SubService> SubServices { get; set; }

        [NotMapped]
        public List<long> ServiceIds { get; set; }

        public bool IsSyncedToSP { get; set; }

        public Certificate Certificate { get; set; }

        [NotMapped]
        public List<long> SubServiceIds { get; set; }

        public List<long> GetServiceIds()
        {
            if (ServiceIds != null && ServiceIds.Count > 0)
            {
                return ServiceIds;
            }
            else if (Services != null && Services.Count > 0)
            {
                return Services.Select(s => s.Id).ToList();
            }
            return new List<long>();
        }

public class Certificate
{
    [Key]
    public long Id { get; set; }

    [Required]
    [UnsyncOnEdit(Unsync = true)]
    public string Title { get; set; }

    public bool IsSyncedToSP { get; set; }

    public List<Employee> Employees { get; set; }
}

当我试图添加 public List<Employee> Employees { get; set; } EF创建以下迁移

 public partial class empcert2 : DbMigration
    {
        public override void Up()
        {
            RenameTable(name: "dbo.ServiceClients", newName: "ClientServices");
            RenameTable(name: "dbo.EmployeeServices", newName: "ServiceEmployees");
            DropPrimaryKey("dbo.ClientServices");
            DropPrimaryKey("dbo.ServiceEmployees");
            AddPrimaryKey("dbo.ClientServices", new[] { "Client_Id", "Service_Id" });
            AddPrimaryKey("dbo.ServiceEmployees", new[] { "Service_Id", "Employee_Id" });
        }

        public override void Down()
        {
            DropPrimaryKey("dbo.ServiceEmployees");
            DropPrimaryKey("dbo.ClientServices");
            AddPrimaryKey("dbo.ServiceEmployees", new[] { "Employee_Id", "Service_Id" });
            AddPrimaryKey("dbo.ClientServices", new[] { "Service_Id", "Client_Id" });
            RenameTable(name: "dbo.ServiceEmployees", newName: "EmployeeServices");
            RenameTable(name: "dbo.ClientServices", newName: "ServiceClients");
        }
    }

public List<Employee>员工{get;set;} 这行从证书模型,奇怪的迁移不创建。

1 回复 | 直到 6 年前

Ivan Stoev 6 年前

问题是隐式连接表的多对多关系的EF映射是不确定的。由于所涉及的两个表在关系中的角色是相等的,所以认为“左”还是“右”完全取决于EF模型依赖顺序算法,该算法的唯一要求是确保在依赖表之前创建引用表。

和 正确的 多对多关系的隐式连接表中的角色。因此,您不应该让EF选择它们,而总是显式地指定via HasMany WithMany (右)fluent API。

要保留原始设计,请将以下内容添加到 OnModelCreating

modelBuilder.Entity<Service>().HasMany(e => e.Clients).WithMany(e => e.Services);
modelBuilder.Entity<Employee>().HasMany(e => e.Services).WithMany(e => e.Employees);