What is the cleanest and clearest way to validate entities using the Entity Framework

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What is the cleanest and clearest way to validate entities using the Entity Framework

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I'm using the Entity Framework for data manipulation. The project is divided into 2, one containing the domain entities and the other Fluent Api mappings). I need a clean and clear way to validate entities without polluting entities with DataAnnotations, knowing that I am using Fluent Api to configure them. Should I use DataAnnotations? What is the best way to validate them?

c# entity-framework dataannotations fluent-api

asked by anonymous 02.02.2017 / 00:00

2 answers

1

If this "clear" and "clean" form is a correct way.

If your application is intended for the user interface:

• Create DTOs (View Models) and apply the Data Annotations attributes to it.

Soon after this, use the Assertion Concern Pattern to validate data integrity (if you need an example: link ).

• And to validate a business rule, you can use the Specification Pattern ( link )

This is a validated and segmented form of validation.

EDIT : It should be noted that the Assertion Concern Pattern and Specification Pattern must be and refer to the domain entities.

02.02.2017 / 00:12

What is the need to inform the "Order" parameter in the object of type IndexAnnotation? Sort DateTime field of a DataTable

score 6 · Accepted Answer

I need a clean and clear way to validate entities without polluting entities with DataAnnotations, knowing that I am using Fluent Api to configure them.

What do you mean by "polluting entities"?

The best way to work with validation is by decorating by attributes ( belonging to namespace System.ComponentModel.DataAnnotations ). With it, Model becomes a complete representation of a record in a database, with support for validation and description of relationships with other entities.

It's okay to use the Fluent API to decorate the data elements of each entity, but of course this work gets bigger for the following reasons:

Attribute designation does not stay with the class that represents the entity. It can stay in the Entity Framework context initialization (event OnModelCreating ") or in a separate class (which inherits EntityMappingConfiguration<T> );

The statement is more verbose and not all possible modifiers are in the Fluent API , causing the programmer to have to write extra code to make an equivalent effort, such as using the Index attribute with Fluent API .

Should I use DataAnnotations?

Yes.

What is the best way to validate them?

Attributes work by themselves. You do not need to do anything.

If you want, you can write your own validation attributes , herdando ValidationAttribute .

Or, implement IValidatableObject in Model . This interface forces the programmer to implement a Validate method with business rules involving entity data. Here does not exactly involve the Entity Framework: you are more involved with business rules.

In this way, the validation is done natively in two steps: one in the framework you are working on (such as ASP.NET MVC, for example, or ASP.NET Data Controls ) and another at the database level. The only job the programmer has is to collect the exception messages when submitting the context modifications. This question has an answer on how this can be done .