Question

我遇到了麻烦，我有两个具有Node StartNode属性的Route entite 第二个节点是StartNode。起始节点和结束节点应该与Route有关系，但是当我尝试这样做时，我得到了一个例外：Cannot create a relationship between 'Node.Route' and 'Route.EndNode', because there already is a relationship between 'Node.Route' and 'Route.StartNode'. Navigation properties can only participate in a single relationship.

路径实体有两个对象Node，分别代表起点和终点：

public class Route
{
    public Guid DailyRouteId { get; set; }
    public DailyRoute DailyRoute { get; set; }
    public Node StartNode { get; protected set; }
    public Node EndNode { get; protected set; }
    public Guid EndNodeId { get; set; }
    public Guid StartNodeId { get; set; }
}

Node实体：

public class Node
{
    [Key]
    public Guid Id { get; set; }
    public string Address { get; protected set; }
    public double Longitude { get; protected set; }
    public double Latitude { get; protected set; }
    public DateTime UpdatedAt { get; protected set; }

    public Route Route { get; set; }
}

这是模型构建器：

modelBuilder.Entity<Route>()
            .HasOne(x => x.StartNode)
            .WithOne(x => x.Route)
            .HasForeignKey<Route>(x => x.StartNodeId)
            .OnDelete(DeleteBehavior.Restrict);

        modelBuilder.Entity<Route>()
            .HasOne(x => x.EndNode)
            .WithOne(x => x.Route)
            .HasForeignKey<Route>(x => x.EndNodeId)
            .OnDelete(DeleteBehavior.Restrict);

Answer 1

您需要为每个关系创建一个导航属性：

public class Node
{
    [Key]
    public Guid Id { get; set; }
    public string Address { get; protected set; }
    public double Longitude { get; protected set; }
    public double Latitude { get; protected set; }
    public DateTime UpdatedAt { get; protected set; }

    public Route StartRoute { get; set; }
    public Route EndRoute { get; set; }
}

modelBuilder.Entity<Route>()
        .HasOne(x => x.StartNode)
        .WithOne(x => x.StartRoute)
        .HasForeignKey<Route>(x => x.StartNodeId)
        .OnDelete(DeleteBehavior.Restrict);

    modelBuilder.Entity<Route>()
        .HasOne(x => x.EndNode)
        .WithOne(x => x.EndRoute)
        .HasForeignKey<Route>(x => x.EndNodeId)
        .OnDelete(DeleteBehavior.Restrict);

实体之间的净核心ef多重关系

1 个答案: