.NET Core - Data Retrieval issue

Pratham Jain 221

Hi All,

I am developing an application in .NET Core with Angular. I have a scenario where I am returning all the Employee data by EmployeeId from several Employee database tables using .NET Core WebAPI. I am using DbContext in Repository class to fetch all the data from Employee tables which is fetched in employee DB entities.

Now my concern is that should I return these DB entities directly to client or should I create a new Model/ViewModel in WebAPI to return data to Angular client.

Note: I also have few additional properties which are calculated from returned entities properties from DB.

Please advise me the best way to achieve the same.

Thanks and Regards,

Pratham

AgaveJoe 28,031 Reputation points

2023-03-21T10:53:42.75+00:00

Now my concern is that should I return these DB entities directly

Of course not. Entity are used to model tables not the user interface and found in your data access layer. It would be very unusual that your user interface exactly matches the database schema and contains the same validations. Usually the user interface is made up of several sets of data from several tables that are specific to a page. This is especially true for an SPA.

or should I create a new Model/ViewModel in WebAPI to return data to Angular client.

View model are in the UI, the angular application. Web API returns a DTO which is a logical group of data. How you decide to build the DTO depends on design.

Also, implementing a repository on top of Entity Framework typically causes problems (anti-pattern) unless you know what you're doing. Entity Framework is already a unit of work and repository pattern.

Accepted answer

Zhi Lv - MSFT 32,141 Reputation points Microsoft Vendor

2023-03-22T05:55:52.7633333+00:00

Hi @Pratham Jain

Now my concern is that should I return these DB entities directly to client or should I create a new Model/ViewModel in WebAPI to return data to Angular client. Note: I also have few additional properties which are calculated from returned entities properties from DB.

I prefer to the create a new Model/ViewModel in WebAPI to return data to Angular client.

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Best regards,

Dillion
Please sign in to rate this answer.
Pratham Jain 221 Reputation points

2023-03-22T07:37:46.75+00:00

Hi @Zhi Lv - MSFT Many thanks for your suggestion! Any working sample in same direction would be highly appreciated. Thank you. Regards, Pratham

Zhi Lv - MSFT 32,141 Reputation points Microsoft Vendor

2023-03-22T09:19:01.19+00:00

Hi @Pratham Jain

Any working sample in same direction would be highly appreciated.

In the API application, you can create a ViewModel, then when use LINQ query statement to query the database, use the new key word to create the ViewModel instance based on the DB entities. After that return the ViewModel to the client.

For example, the DB entity Employee contains FirstName and LastName properties, the EmployeeViewModel contains the FullName property, the query statement like this:

var result = (from emp in _dbContext.Employees select new EmployeeViewModel() { FullName = emp.FirstName +" " + emp.LastName }).ToList();

Besides, you can also create the ViewModel in a class library and then add the class library reference in the API project.
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Share via

.NET Core - Data Retrieval issue

0 additional answers

Your answer