entity framework可以使用单个SaveChanges（）添加许多相关实体吗？

我正在向数据库编写许多（20多个）父子数据集，并且EF要求我在每个集合之间保存更改，否则它会抱怨无法找出主键。 是否可以将数据刷新到SQL Server，以便EF可以从身份中获取主键，并在写入所有更改结束时发送SaveChanges？

foreach (var itemCount in itemCounts) { var addItemTracking = new ItemTracking { availabilityStatusID = availabilityStatusId, itemBatchId = itemCount.ItemBatchId, locationID = locationId, serialNumber = serialNumber, trackingQuantityOnHand = itemCount.CycleQuantity }; _context.ItemTrackings.Add(addItemTracking); _context.SaveChanges(); var addInventoryTransaction = new InventoryTransaction { activityHistoryID = newInventoryTransaction.activityHistoryID, itemTrackingID = addItemTracking.ItemTrackingID, personID = newInventoryTransaction.personID, usageTransactionTypeId = newInventoryTransaction.usageTransactionTypeId, transactionDate = newInventoryTransaction.transactionDate, usageQuantity = usageMultiplier * itemCount.CycleQuantity }; _context.InventoryTransactions.Add(addInventoryTransaction); _context.SaveChanges(); } 

我想在大循环结束时只做一次我的SaveChanges。

Answer 1

如果您使用对象引用新创建的对象而不是ID，则不需要每次都保存更改：

 var addItemTracking = new ItemTracking { ... } _context.ItemTrackings.Add(addItemTracking); var addInventoryTransaction = new InventoryTransaction { itemTracking = addItemTracking, ... }; _context.InventoryTransactions.Add(addInventoryTransaction); ... _context.SaveChanges(); 

Answer 2

因为它们都是新物品而不是

 itemTrackingID = addItemTracking.ItemTrackingID, 

你可以去

 addItemTracking.InventoryTransaction = addInventoryTransaction; 

（或任何相关的导航属性）并将_context.SaveChanges（）完全拉出循环。 当一切都是新的时，Entity Framework非常擅长插入对象图。 保存包含新项目和现有项目的对象图表时，设置关联的ID始终更安全。

Answer 3

怎么样：

 var trackingItems = itemCounts .Select(i => new ItemTracking { availabilityStatusID = availabilityStatusId, itemBatchId = i.ItemBatchId, locationID = locationId, serialNumber = serialNumber, trackingQuantityOnHand = i.CycleQuantity }); _context.ItemTrackings.AddRange(trackingItems); _context.SaveChanges(); var inventoryTransactions = trackingItems .Select(t => new InventoryTransaction { activityHistoryID = newInventoryTransaction.activityHistoryID, itemTrackingID = t.ItemTrackingID, personID = newInventoryTransaction.personID, usageTransactionTypeId = newInventoryTransaction.usageTransactionTypeId, transactionDate = newInventoryTransaction.transactionDate, usageQuantity = usageMultiplier * t.trackingQuantityOnHand }); _context.InventoryTransactions.AddRange(inventoryTransactions); _context.SaveChanges(); 

但是我已经有很长一段时间没用EF了，上面的代码是用记事本写的，所以我不能保证