如何用外键插入数据？

Question

用外键插入数据最好（我的意思是最快和最简单）的方法是什么？

我的模型：

public class Package
{
    public Int PackId { get; set; }
    // some fields

    // list with other models! 
    public ICollection<Shipment> shipments { get; set; }
}

public class Shipment
{
    Int Id { get; set; }
    // some fields

    [ForeignKey]
    Int PackId { get; set; }
    Package package { get; set; }
}

我需要在一个请求中创建一个Package 和一些Shipments（数据来自表单）。我是这样做的：

[HttpPost]
public void ControllerMethod(MyViewModel form)
{
    transaction
    {
        // empty list,method from 
        var pack_id = _packageRepository(some_fields_here, new List<Shipment>());

        // repo returns id
        var package = _packageRepository.GetSpecific(pack_id);

        var ls_shipments = new List<Shipment>();

        foreach(var x in form.ListOfShipments)
        {
            var ship = _shipRepository.Add(some_fields_here, pack_id, package);
            ls_shipments.Add(ship);
        }

        // replace empty list with list filled in foreach above
        package.shipments = ls_shipments; 

        _context.SaveChanges();
    }
    catch (Exception e)
    {
        // some actions here
    }
}

看起来很奇怪，但我需要一次创建包裹和许多货物。此外，我添加了新的Package，然后从数据库中获取它——这是最简单的方法吗？

Answer 1

您不需要为主表和详细表使用单独的存储库。将您的视图模型字段映射到主实体和详细实体并调用主 Add 方法，它只会跟踪子项本身。如果 PackId 是自动编号，那么您不需要做任何事情。如果不是把pkgid的主键赋给出货的外键

var _Package = new Package();
// Assign fields of packages from viewmdoel to entity
foreach(var item in form.shipments)
{
var _Shipment = new Shipment();
//Assign shipment fields from your view models to shipment entity
_Package.shipments.Add(_Shipment)
}

using (var dbCtx = new yourDBEntities())
{
    //add package entity into  entitySet
    dbCtx.Package.Add(_Package);
    //Save whole entity graph to the database
    dbCtx.SaveChanges();
}

或者你从包中调用你的 repo 方法来添加/保存

可以看简单教程here