在Web Api中更新实体的最佳实践

Question

I'm researching best practice for updating entity from action that called by client. There are several ways to do that but none of them seem best practice.

1- Getting datas that will be updated via reflection from request model and update entity with these properties. But reflection doesn't recommended to use in web api.

2- Sending all datas of entity to client and getting it's updated version from request. It seems make unnecessary traffic.

3- Getting datas that will be updated and check them with if else conditions for getting which ones changed. It's so basic and not generic, seems so unprofessionally.

Request Model that i talked about is clone of entity model.

Answer 1

First off, don't use Reflection. It's slow as hell and makes your code extra fragile.

When it comes to EF, usually there are 3 possible solutions:

1; The client sends the whole updated entity, and only the updated entity. In this case, you simply have to attach the entity to the corresponding entityset and mark the entity state as Modified.

2; The client sends both the original entity and the updated entity. You attach the original and set the currentvalues to the the update entity.

3; The client only sends the modified properties, not the whole entity. In this case you have to query the original entity from the db and set the properties either one by one or again override the currentvalues.

The 3 approaches differ in their bandwith requirement and the number of queries they make.

1; If we take this as the baseline, it has a bandwith requirement of sending one entity from the client to the server, and then sending this one entity from the server to the db. This makes 1 db query altogehter (attaching does not require querying, so only the saving changes part initiates the query).

2; This has a bandwith of sending two entities from the client to the server. Here you have to send less data from the server to the db, because the changed properties are calculated when you set the currentvalues. Again, just 1 query (attaching and setting currentvalues don't initiate queries, so only the saving changes part creates a query).

3; This has the least bandwith requirement both from the client to the server and from the server to the db (both times only the changed properties are sent). However, this does need one more query besides saving, because you have to query the original values from the db, before setting the changes.

I ususally find the the first approach is a good trade-off between the other two. It does send more data than the third, but still less than the second, and it only initiates the one query for saving data. Also I like to minimize the traffic between the client and the server even if it means there is more traffic between the server and the db. The clients (for me at least) are usually mobile, so no guaranteed bandwith, no guaranteed battery lifetime. The server and the db are much "closer" and they don't have these restrictions. But of course this can be different for your application.