datapersistance

问题 It's possible for room to have Recursive relations? I have an Entity that can be nested in a Parent/Childs structures something like this Category1 |_________Category2 |_________Category3 | |_________Category4 |_________Category5` I'm copying this structure from a json that is obtained from a WebService. This is my current Entity: @Entity(tableName = "categories") public class Category { @PrimaryKey @NonNull private String code; private String name; private String parentCode; @Relation

问题 What is the is the best approach to implement data persistence using database tables over several wizard steps in ASP.NET MVC? At the moment we are using a session to persist alot of data across several wizard steps/views. We are experiencing an issue and we suspect that session timeouts are to blame. For this reason we have decided to replace sessions with database tables. So far we've established that we need the following: When the user hits the first page a unique id/token (possibly

问题 I would like to create a web application where a user can drag and drop images and text onto a div or similar container. Then, when the user clicks a save button, the application would be able to save the content of the dropped items, as well as the positional information for those items. Ultimately the user should be able to come back, open then application, and have the images and text back in the exact same places as when they were saved. If anyone knows a methodology or framework that

问题 As part of a new project we need a service which can generate monotonically increasing integers. Requirements for the service are: service does not need to produce contiguous integer as long as it produces monotonically increasing integers it should be fine It should produce 64 bit integer the service should be highly available services should be resilient to failure (or restarts) I was planing to use redis ( INCR ) as a back-end store with replication enable but the issue is if the master

问题 How do I persist the data that has been parsed from the server using Retrofit library. So that users can view it when there is no internet connection. final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.post_recycler_view); recyclerView.setLayoutManager(new LinearLayoutManager(this)); ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class); Call<ArrayList<Post>> call = apiService.getAllPosts(); call.enqueue(new Callback<ArrayList<Post>>() { @Override public

问题 I'm a java developer. I'm using spring 4.0.1 and hibernate 4.2.21. I have a class as follow: @Entity @Inheritance(...) public abstract class Feature{ @Id @GeneratedValue protected Long id; ... } Now I have some many class as follow: Label.java class: @Entity public class Label extends Feature{ protected String str; ... } Point.java class: @Entity public class Point extends Feature{ protected Integer intg; ... } I have more than 20 Entity class that extends from Feature class. Is there any way