Question

在构建与实体框架的多对多关系时，我遇到了一些问题。我尝试通过ConnectionPointRoute在ConnectionPoint和Route之间建立多对多的关系。但是在执行数据库更新（运行种子）时，我收到消息“检测到冲突的更改。当尝试插入具有相同密钥的多个实体时，可能会发生这种情况。”我可能只是忽略了一些东西，但任何帮助表示赞赏！

public class ConnectionPoint
{
    public int ConnectionPointId { get; set; }
    public string ConnectionPointName { get; set; }
    public virtual Location Location { get; set; }
    public virtual ICollection<ConnectionPointRoute> ConnectionPointRoutes { get; set; }
    public virtual ICollection<Connection> Connections { get; set; }
}

public class Route
{
    public int RouteId { get; set; }
    public string RouteName { get; set; }
    public virtual ICollection<ConnectionPointRoute> ConnectionPointRoutes { get; set; }
}

public class ConnectionPointRoute
{
    public int ConnectionPointId { get; set; }
    public int RouteId { get; set; }
    public  int Position { get; set; }
    public virtual ICollection<ConnectionPoint> ConnectionPoints { get; set; }
    public virtual ICollection<Route> Routes { get; set; }
}
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();

        modelBuilder.Entity<ConnectionPointRoute>()
            .HasKey(c => new { c.ConnectionPointId, c.RouteId });

        modelBuilder.Entity<ConnectionPoint>()
            .HasMany(c => c.ConnectionPointRoutes)
            .WithRequired()
            .HasForeignKey(c => c.ConnectionPointId);

        modelBuilder.Entity<Route>()
            .HasMany(c => c.ConnectionPointRoutes)
            .WithRequired()
            .HasForeignKey(c => c.RouteId);
    }
        var ConnectionPointRoutes = new List<ConnectionPointRoute>
        {
            new ConnectionPointRoute { Routes = new List<Route>(), ConnectionPoints= new List<ConnectionPoint>(), Position = 1},
            new ConnectionPointRoute { Routes = new List<Route>(), ConnectionPoints= new List<ConnectionPoint>(), Position = 2},
            new ConnectionPointRoute { Routes = new List<Route>(), ConnectionPoints= new List<ConnectionPoint>(), Position = 2},
            new ConnectionPointRoute { Routes = new List<Route>(), ConnectionPoints= new List<ConnectionPoint>(), Position = 1}
        };
        ConnectionPointRoutes.ForEach(r => context.ConnectionPointRoutes.AddOrUpdate(r));
        context.SaveChanges();

Answer 1

您的ConnectionPointRoute有两个列表＆lt;＆gt;。您想要ConnectionPoint和ConnectionPointRoute之间的多对多，以及ConnectionPointRoute和Route之间的多对多（选项＃1）吗？

或者您是否尝试在ConnectionPoint和Route之间进行多对多，其中ConnectionPointRoute是连接表（选项＃2）？

我猜你想要选项＃2。它将配置如下：

public class ConnectionPointRoute
{
    public int ConnectionPointId { get; set; }

    public int RouteId { get; set; }

    public int Position { get; set; }

    public virtual ConnectionPoint ConnectionPoint { get; set; }

    public virtual Route Route { get; set; }
}

模型构建器：

modelBuilder.Entity<ConnectionPointRoute>()
    .HasKey(c => new { c.ConnectionPointId, c.RouteId });

modelBuilder.Entity<ConnectionPoint>()
    .HasMany(c => c.ConnectionPointRoutes)
    .WithRequired(x => x.ConnectionPoint)
    .HasForeignKey(c => c.ConnectionPointId);

modelBuilder.Entity<Route>()
    .HasMany(c => c.ConnectionPointRoutes)
    .WithRequired(x => x.Route)
    .HasForeignKey(c => c.RouteId);

并创建：

new ConnectionPointRoute { Route = new Route(), ConnectionPoint= new ConnectionPoint(), Position = 1}

检测到冲突的更改。许多与其他值的关系

1 个答案: