C#•3y ago•

10 replies

❔ DDD: How to apply a Domain specification on a Infrastructure EF Core?

Hello everyone,

I'm currently working on an app utilizing

DDD (Domain Driven Design)

DDD (Domain Driven Design)

and

Microservices

Microservices

. One key element in DDD that I'm focusing on is Specifications. Specifically, I'm dealing with the

ExpenseService

ExpenseService

, consisting of 5 projects:

ExpenseService.API

ExpenseService.API

ExpenseService.Application

ExpenseService.Application

ExpenseService.Domain.Shared

ExpenseService.Domain.Shared

ExpenseService.Domain

ExpenseService.Domain

ExpenseService.Infrastructure

ExpenseService.Infrastructure

Normally, Specifications are defined and implemented within the

Domain

Domain

layer. In this context, I have a foundational class named Specification:

namespace ExpenseService.Domain.Specifications;

public abstract class Specification<T> : ISpecification<T> where T : class
{
    public abstract Expression<Func<T, bool>> ToExpression();

    public bool IsSatisfiedBy(T entity)
    {
        var predicate = ToExpression().Compile();
        return predicate(entity);
    }
}

namespace ExpenseService.Domain.Specifications;

public abstract class Specification<T> : ISpecification<T> where T : class
{
    public abstract Expression<Func<T, bool>> ToExpression();

    public bool IsSatisfiedBy(T entity)
    {
        var predicate = ToExpression().Compile();
        return predicate(entity);
    }
}

Furthermore, I've crafted a specific Specification for a

Domain

Domain

Entity known as

Expense

Expense

namespace ExpenseService.Domain.Specifications;

public class ValidExpenseSpecification : Specification<Expense>
{
    public override Expression<Func<Expense, bool>> ToExpression()
    {
        return expense => expense.Amount > 0
            && expense.Date > DateTime.MinValue 
            && !string.IsNullOrEmpty(expense.Description);
    }
}

namespace ExpenseService.Domain.Specifications;

public class ValidExpenseSpecification : Specification<Expense>
{
    public override Expression<Func<Expense, bool>> ToExpression()
    {
        return expense => expense.Amount > 0
            && expense.Date > DateTime.MinValue 
            && !string.IsNullOrEmpty(expense.Description);
    }
}

The Challenge:
The challenge I'm facing arises from the separation of

Domain

Domain

entities from their

Infrastructure

Infrastructure

counterparts. For instance, while I employ

EF Core

EF Core

and

PostgreSQL

PostgreSQL

in the I

nfrastructure

nfrastructure

to manage entities, I've created equivalent

Domain

Domain

entities in the

Infrastructure

Infrastructure

layer (e.g., ExpenseEntity corresponding to the Expense domain entity). Consequently, the

ToExpression()

ToExpression()

method exclusively targets

Domain

Domain

entities and doesn't function with their

Infrastructure

Infrastructure

equivalents.

I'm seeking suggestions on how to tackle this.

I mean, How to make the
Domain
Domain
specifications to be applied on the
Infrastructure
Infrastructure

EF Core
EF Core
entities ?

❔ DDD: How to apply a Domain specification on a Infrastructure EF Core?

Hello everyone,

I'm currently working on an app utilizing

DDD (Domain Driven Design)

DDD (Domain Driven Design)

and

Microservices

Microservices

. One key element in DDD that I'm focusing on is Specifications. Specifically, I'm dealing with the

ExpenseService

ExpenseService

, consisting of 5 projects:

ExpenseService.API

ExpenseService.API

ExpenseService.Application

ExpenseService.Application

ExpenseService.Domain.Shared

ExpenseService.Domain.Shared

ExpenseService.Domain

ExpenseService.Domain

ExpenseService.Infrastructure

ExpenseService.Infrastructure

Normally, Specifications are defined and implemented within the

Domain

Domain

layer. In this context, I have a foundational class named Specification:

namespace ExpenseService.Domain.Specifications;

public abstract class Specification<T> : ISpecification<T> where T : class
{
    public abstract Expression<Func<T, bool>> ToExpression();

    public bool IsSatisfiedBy(T entity)
    {
        var predicate = ToExpression().Compile();
        return predicate(entity);
    }
}

namespace ExpenseService.Domain.Specifications;

public abstract class Specification<T> : ISpecification<T> where T : class
{
    public abstract Expression<Func<T, bool>> ToExpression();

    public bool IsSatisfiedBy(T entity)
    {
        var predicate = ToExpression().Compile();
        return predicate(entity);
    }
}

Furthermore, I've crafted a specific Specification for a

Domain

Domain

Entity known as

Expense

Expense

namespace ExpenseService.Domain.Specifications;

public class ValidExpenseSpecification : Specification<Expense>
{
    public override Expression<Func<Expense, bool>> ToExpression()
    {
        return expense => expense.Amount > 0
            && expense.Date > DateTime.MinValue 
            && !string.IsNullOrEmpty(expense.Description);
    }
}

namespace ExpenseService.Domain.Specifications;

public class ValidExpenseSpecification : Specification<Expense>
{
    public override Expression<Func<Expense, bool>> ToExpression()
    {
        return expense => expense.Amount > 0
            && expense.Date > DateTime.MinValue 
            && !string.IsNullOrEmpty(expense.Description);
    }
}

The Challenge:
The challenge I'm facing arises from the separation of

Domain

Domain

entities from their

Infrastructure

Infrastructure

counterparts. For instance, while I employ

EF Core

EF Core

and

PostgreSQL

PostgreSQL

in the I

nfrastructure

nfrastructure

to manage entities, I've created equivalent

Domain

Domain

entities in the

Infrastructure

Infrastructure

layer (e.g., ExpenseEntity corresponding to the Expense domain entity). Consequently, the

ToExpression()

ToExpression()

method exclusively targets

Domain

Domain

entities and doesn't function with their

Infrastructure

Infrastructure

❔ DDD: How to apply a Domain specification on a Infrastructure EF Core?

❔ DDD: How to apply a Domain specification on a Infrastructure EF Core?

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