C# - Using Entity Framework With Existing Business Layer And Database?
Feb 2, 2011
I have an ASP.NET application with existing business classes and a database schema. (which I would like to keep) Currently I am using ADO.NET for the DAL, but I would like to switch to some advanced technology there for easier data retrieval.
Is EF applicable to my situation? Can I use it without splitting up my business classes and auto code generation? Can LINQ to SQL solve my problem better?
All I want to do is map my existing classes to the existing tables and dont have to handle details of the data retrieval myself.
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Sep 20, 2010
Lets assume that I have my own business layer containing my business objects and my business services. And I have decided to create a "SilverLight Business Application" (with SL v 4.0) and I want to use my already used Business Layer from the SL application I plan to develop.
I know that I cannot include a project which is not a SL project.
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Aug 2, 2010
In this website article http://aspalliance.com/1943_ASPNET_40_and_the_Entity_Framework_4__Part_4__A_3_Layered_Approach_to_the_Entit_Framework
Vince Varallo says this in his opening paragraphs. "it will introduce a pattern for developing the application as a three layered application. Notice that I didn't say three tiered application. A tier really means a logical and physical separation of the layers. A layer implies just a logical separation. For many applications that's all you need. I'm not one to advocate over-engineering a system.
I always follow the simpler, better approach as long as the developers working with you understand the pattern."
Question 1. Can some explain to me what is difference between a 3 layer application and a 3 tiered application?
Question 2. Also, can some give me a link to a simple 3 tiered tutorial for entity framework?
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Sep 2, 2010
As I began writing web applications with asp.net I started with small projects that used a Linq-To-SQL mapper for database access to a MSSQL Server. After gaining some expierence I switched into a classic 3 tier with Graphic Layer, Business Layer, Data Layer. The only function of the Data Layer was to provide methods insert/update/delete without any logic and logic the form of selection methods.
Over the time I realized that it would be better not to provide the database classes up to the GUI (took some time unfortunately). I switched into using Business classes in the BL that are used for all operations performed by the BL and display by the GUI in the form of getting List from the BL. A great advantage is that I can provide additional properties that are not represented by the database itself. However, I did that mapping inside the BL myself with methods that mapped the corresponding BL class to the database class.
I guess thats where O/R mapper come in handy? Until now I haven't realized their purpose, but I think I just found it. I've recently tried out using the new Entity Framework with .net framework 4, but I'm only using it like the Linq-To-SQL DataContext.
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Oct 26, 2010
I am new to this .NET what is the difference between N-Tier and 3- Tier Architecture. If they are same. How to pass the values from presentation layer to business logic layer.
For Example
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Jun 24, 2010
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public ProductBLL
{
public int GetProductName(string productId)
{
ProductDataSet.ProductDataTable prodData = Adapter.GetProductById(productId);
[code]...
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Feb 23, 2011
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Mar 7, 2011
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Jan 26, 2011
I'm trying to reevaluate our n-layer architecture and would love to get some based on your experiences. Here is our typical .NET n-layer (sometimes n-tier) design.
Project.UI
Project.Services
Project.Business
Project.Model
Project.DataAccess
DataAccess typically consists of Entity Framework 4 and Repository classes. I attempt to follow the Aggregate Root concept in order to avoid having a repository for table, easier said than done in my experience. I tend to have ~70% match between Repositories and Tables.
Model usually consists of my Entity Framework 4 entities, I've been using Self-Tracking EF entities with success.
Business is what I struggle with the most. I typically have a Manager class for every Repository. This class will contain methods like .Add() which will perform business validation before forwarding down to repository.Add().
Services, typically I will only implement this if in fact I am looking to create a web service based solution. This layer will be tasked with marshaling requests/responses between DTOs and entities. And most importantly provide the more coarse grained interface. For example a TradingService.SubmitTrade(), which is really a facade for a business transaction which might include AccountManager.ValidateCash(), OrderManager.SubmitOrder(), etc.
My business layer is very entity centric, really it's just the glue between the entities and the repository, with validation in between. I've seen many designs where the Service Layer is what holds a reference to the repositories (in essence skipping the "business layer"). In essence it serves the same purpose as my Business layer, it does the validation, however its' responsibility (and naming) is a higher level, more coarse grained business transaction. Using the example above the TradingService.submitTrade() will not delegate to any business manager classes, it would itself query the necessary repositories, perform all the validation etc.
I like my design in a sense that I can reuse a business layer method in multiple service calls, however I hate the fact that for every repository I have a matching business layer manager, creating tons of extra work. Maybe the solution is a different type of grouping at the Business Layer level? For example combine individual Manager classes like PhoneManager and EmailManager (note I have Phone entities and Email entities) into a logical Manager class such as ContactsManager (note I don't have a "Contact" entity type). With methods such as ContactManager.GetPhones() and ContactManager.GetEmail(), etc.
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Jun 3, 2010
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Oct 25, 2010
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Jan 25, 2011
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[code]....
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Name Add
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new
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Sep 28, 2010
I'm wondering how can I use LINQ in here?
Code:
public Northwind.ProductsDataTable GetProducts()
{
[Can I use Linq here?]
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}
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"The method 'doInsertCust' was not found on the interface/type 'My.Type, MyTypeLibrary, Version=1.0.2371.15203, Culture=neutral, PublicKeyToken=null'.".
Note that I have already build the Business layer and DAL and the respective DLL gets automatically refreshed.
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Aug 6, 2010
My application has a three tier architectute
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[Code]....
Here, when I set debugpoint I can see the DataTable is getting populated by the data so my
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[Code]....
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Mar 7, 2011
I have a application with a 3-tier architecture. Onclick event of a button, I am calling a method in my code behind file. This method is defined in the Interface( Interface resides in my Business layer) and the implemtation of this method is given in the Data access layer.
The business layer and DAL are on different projects. I have compiled the entire solution and it complies OK. Now when I try to click the button I get the error:
"The method 'doInsertCust' was not found on the interface/type 'My.Type, MyTypeLibrary, Version=1.0.2371.15203, Culture=neutral, PublicKeyToken=null'.".
Note that I have already build the Business layer and DAL and the respective DLL gets automatically refreshed.
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