[英]Entity framework : Recursive update Parent-Child gives me duplicates
鉴于以下表格(在屏幕截图中,从位置到客户的FK不可见,但它在那里,只是没有刷新......):
我的映射:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Customer>().ToTable("CUSTOMERS");
modelBuilder.Entity<Customer>().HasKey(c => c.Id).Property(c => c.Id).HasColumnName("CUSTNO");
modelBuilder.Entity<Customer>().Property(c => c.Name).HasColumnName("NAME");
modelBuilder.Entity<Customer>().HasMany(c => c.AllLocations).WithRequired(l => l.Customer).Map(x => x.MapKey("CUSTNO"));
modelBuilder.Entity<Customer>().Ignore(c => c.RootLocations);
modelBuilder.Entity<Location>().ToTable("LOCATIONS");
modelBuilder.Entity<Location>().HasKey(c => c.Id);
modelBuilder.Entity<Location>().Property(c => c.Id).HasColumnName("ID");
modelBuilder.Entity<Location>().Property(c => c.LocationCode).HasColumnName("LOCATION_CODE");
modelBuilder.Entity<Location>().HasMany(l => l.Children).WithOptional(ch => ch.Parent).Map(x => x.MapKey("PARENT_ID"));
modelBuilder.Entity<Product>().ToTable("PRODUCTS");
modelBuilder.Entity<Product>().HasKey(p => new { p.Partno, p.LocationId, p.Quantity, p.SellUnit });
modelBuilder.Entity<Product>().Property(p => p.Partno).HasColumnName("PARTNO");
modelBuilder.Entity<Product>().Property(p => p.LocationId).HasColumnName("LOCATION_ID");
modelBuilder.Entity<Product>().Property(p => p.PartDescription).HasColumnName("PART_DESCRIPTION");
modelBuilder.Entity<Product>().Property(p => p.Quantity).HasColumnName("QUANTITY");
modelBuilder.Entity<Product>().Property(p => p.SellUnit).HasColumnName("SELL_UNIT");
modelBuilder.Entity<Product>().HasRequired(p => p.Location).WithMany(l => l.Products).HasForeignKey(p => p.LocationId);
}
我的更新代码:
public void UpdateLocations(string customerId, IEnumerable<Location> locations)
{
using (var context = new CustomerWarehouseContext(connectionString))
{
foreach (var location in locations)
RecursiveUpdate(location, context);
context.SaveChanges();
}
}
private void RecursiveUpdate(Location location, CustomerWarehouseContext context)
{
if (location != null)
{
bool locationIsNew = location.Id.Equals(Guid.Empty);
if (locationIsNew)
{
location.Id = Guid.NewGuid();
context.Locations.Add(location);
}
else
{
context.Entry(context.Locations.Single(l => l.Id.Equals(location.Id))).CurrentValues.SetValues(location);
}
if (location.Children != null)
{
foreach (var childLocation in location.Children)
{
childLocation.Parent = location;
RecursiveUpdate(childLocation, context);
}
}
if (location.Products != null)
{
foreach (var product in location.Products)
{
if (locationIsNew)
{
location.Products.Add(product);
}
else
{
//How to update product when key is changed? I cannot use contex.Entry here?
}
}
}
}
}
我执行以下代码:
Customer customer = null;
using (var context = new AwesomeContext("myAwesomeConnectionString"))
{
customer = (from c in context.Customers.Include(c => c.AllLocations.Select(l => l.Products))
where c.Id.Equals("100100")
select c).FirstOrDefault();
}
Location locationToUpdate = customer.RootLocations.Single(l => l.Id.Equals(Guid.Parse("1a2ad52e-84cc-bf4c-b14d-dc57b6d229a6")));
locationToUpdate.LocationCode = "Parent " + DateTime.Now.Millisecond; //Goes OK
locationToUpdate.Children[0].LocationCode = "Child " + DateTime.Now.Millisecond; //Goes OK
locationToUpdate.Children[0].Products[0].Quantity = 200;
locationToUpdate.Children.Add(new Location() { LocationCode = "XXX", Customer = customer, Parent = locationToUpdate }); //Creates duplicates?
UpdateLocations(customer.Id, newList);
因此,我正在更改父级和子级的位置代码,更新子级位置中产品的产品数量。 数量是产品表密钥的一部分。 此外,我正在向父母添加新位置。
问题:
我该如何更新我的产品? 因为我改变了部分键,所以我不能使用context.Entry(...)来检索旧键。
您无法使用Entity Framework更改或更新实体的密钥。 如果需要这样做,则必须使用手写SQL命令:
context.Database.ExecuteSqlCommand("UPDATE...");
添加第二个子位置后,为什么我的上下文中有重复的客户/位置?
您将分离的对象图传递到UpdateLocations
。 如果将图形的任何节点添加到上下文中,则该节点的导航属性可访问的所有其他分离实体将添加到上下文中,并且它们都已Added
EntityState。 如果调用SaveChanges
,实体将插入到数据库中。 这发生在这里例如:
context.Locations.Add(location);
因为您的新位置具有对客户的引用,所以客户也将被置于已Added
状态,这将在数据库中复制客户。 您可以通过将客户首先附加到上下文来避免这种情况。 调用Attach
将实体置于Unchanged
状态并避免客户重复:
context.Customers.Attach(location.Customer);
context.Locations.Add(location);
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.