Update Domain-Driven-Design-Implementation-Guide.md

docs/en/Domain-Driven-Design-Implementation-Guide.md

@@ -208,6 +208,12 @@ If you think such features are **important** for you and you **will never move a
 
 #### Presentation Technology Agnostic
 
-The presentation technology (UI Framework) is one of the most changed parts of a real world application. It is very important to design the **Domain and Application Layers** to be completely **unaware** of the presentation technology/framework.
+The presentation technology (UI Framework) is one of the most changed parts of a real world application. It is very important to design the **Domain and Application Layers** to be completely **unaware** of the presentation technology/framework. This principle is relatively easy to implement and ABP's startup template makes it even easier.
 
-This principle is relatively easy to implement and ABP's startup template makes it even easier.
+In some cases, you may need to have **duplicate logic** in the application and presentation layers. For example, you may need to duplicate the **validation** and **authorization** checks in both layers. The checks in the UI layer is mostly for **user experience** while checks in the application and domain layers are for **security and data integrity**. That's perfectly normal and necessary.
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+#### Focus on the State Changes, Not Reporting
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+DDD focuses on how the domain objects **changes and interactions**; How to create an entity and change its properties by preserving the data **integrity/validity** and implementing the **business rules**.
+
+DDD **ignores reporting** and mass querying. That doesn't mean they are not important. If your application doesn't have fancy dashboards and reports, who would use it? However, reporting is another topic. You typically want to use the full power of the SQL Server or even use a separate data source (like ElasticSearch) for reporting purpose. You will write optimized queries, create indexes and even stored procedures(!). You are free to do all as long as you don't mix all these into your business logic.