design-patterns

问题 I've seen a few answers that get in the general area of this question, but none that directly gets at what I'm seeing. I've inherited a recent code base with a charter to make the code run faster. It looks to me like each of the tables in the database (one database) is given its own dbcontext. These tables are highly relational and the major issue I keep seeing is that decisions need to be made based on foreign key relationships between tables. With this design approach, every time two tables

问题 I need to create automated tests for several related apps and faced one problem with test data management between tests. The problem is that same data must be shared between several apps and/or different APIs. Now I have next structure with pytest that working good for me but I doubt that use test data managment in conftest.py is correct approach: Overall structure looks like: tests/ conftest.py app1/ conftest.py test_1.py test_2.py app2/ conftest.py test_1.py test_2.py test_data/ test_data

问题 According to the MySQL documentation: As a general rule, you should never assign a value to a user variable and read the value within the same statement. You might get the results you expect, but this is not guaranteed. http://dev.mysql.com/doc/refman/5.6/en/user-variables.html However, in the book High Perfomance MySQL there are a couple of examples of using this tactic to improve query performance anyway. Is the following an anti-pattern and if so is there a better way to write the query

问题 I see occational references to delegation, or the delegation design pattern in Julia. What is this? E.g. I see it mentioned in This file in DataStructures.jl 回答1: This is a form of polymorphism via composition (rather than inheritance) Say one has a wrapper type, wrapping some instance of a concrete subtype of AbstractT where the wrapper itself is intended to be a subtype of AbstractT (Not nesc always true, but in general). To add all the methods one exacts such a subtype of AbstractT to have

问题 I see occational references to delegation, or the delegation design pattern in Julia. What is this? E.g. I see it mentioned in This file in DataStructures.jl 回答1: This is a form of polymorphism via composition (rather than inheritance) Say one has a wrapper type, wrapping some instance of a concrete subtype of AbstractT where the wrapper itself is intended to be a subtype of AbstractT (Not nesc always true, but in general). To add all the methods one exacts such a subtype of AbstractT to have

问题 In a scenario like below where an object needs to be intantiated based on some conditional logic, can the factory method pattern help to avoid client code getting cluttered due to number of if/elseif conditions (which would also be a maintenance nightmare if more and more products needs to get created due to different variations of logics). Or else is there a any other design pattern that could come to rescue? public interface IProduct { void Method1(); } public class ProductA : IProduct {

问题 Is MFC is based on any design pattern,if so which design pattern?? 回答1: MFC and Design Patterns As we all know, MFC is one of the popular class libraries used by C++ programmers. The success story behind MFC is its class architecture and design principles adopted by the developers of MFC, which makes it one of the popularly reused library. The main focus is to show how patterns are used in MFC. We will be seeing the usage of three patterns in MFC library. Creational : Singleton Pattern First

问题 Is MFC is based on any design pattern,if so which design pattern?? 回答1: MFC and Design Patterns As we all know, MFC is one of the popular class libraries used by C++ programmers. The success story behind MFC is its class architecture and design principles adopted by the developers of MFC, which makes it one of the popularly reused library. The main focus is to show how patterns are used in MFC. We will be seeing the usage of three patterns in MFC library. Creational : Singleton Pattern First

问题 Note: This is a Visual Studio 2015 feature only, as far as I know... How can I edit the Implement interface with Disposable Pattern option? This is NOT a question on how to Implement the Dispose Pattern and its variations, but how to edit the option "Implement interface with Disposable Pattern" I would like to remove some comments and add some code on the Disposable Pattern, but I want it to be saved and every time I click " Implement interface with Disposable Pattern ", it implements my code

问题 Note: This is a Visual Studio 2015 feature only, as far as I know... How can I edit the Implement interface with Disposable Pattern option? This is NOT a question on how to Implement the Dispose Pattern and its variations, but how to edit the option "Implement interface with Disposable Pattern" I would like to remove some comments and add some code on the Disposable Pattern, but I want it to be saved and every time I click " Implement interface with Disposable Pattern ", it implements my code