Refactoring Core Models: Improving Data Integrity in Nebula

Improving Data Consistency

In the Nebula project, we recently focused on refactoring the core financial tracking module. As our application grows, maintaining a clean separation of concerns within our domain models is vital for long-term scalability and bug prevention.

The Challenge

The original implementation of the daily record model had become tightly coupled with database-specific logic. This made unit testing difficult and created friction when attempting to extend the model to support new operational requirements. We identified the need to decouple our domain representation from the infrastructure layer.

The Solution

We transitioned to a cleaner domain-driven design, ensuring the model acts as a pure representation of the business logic rather than a direct database mapping. By implementing a more structured approach to property management, we ensure that state transitions remain predictable.

public class DailyRecord
{
    public Guid Id { get; private set; }
    public decimal StartingBalance { get; private set; }
    public DateTime EntryDate { get; private set; }

    public DailyRecord(decimal startingBalance)
    {
        Id = Guid.NewGuid();
        StartingBalance = startingBalance;
        EntryDate = DateTime.UtcNow;
    }

    public void UpdateBalance(decimal newBalance)
    {
        // Domain logic for balance validation
        StartingBalance = newBalance;
    }
}

Key Decisions

1. Encapsulation: Moving logic inside the domain entity prevents invalid states from being set from external services.
2. Immutable Identity: Protecting the object's identity ensures that reference tracking remains stable across the application lifecycle.
3. Separation of Concerns: By stripping out persistence logic, we can easily swap data providers or implement repository patterns without modifying the domain model itself.

Results

• Improved readability of business logic within the core services.
• Facilitated easier unit testing for financial calculations.
• Reduced the surface area for side-effect-related bugs during database migrations.

Lessons Learned

Refactoring is not just about cleaning up code—it is about refining the language of the application. By focusing on domain integrity, we make the system easier to reason about, even as the underlying complexity increases. Take the time to audit your core models regularly; identifying tightly coupled logic early saves significant development effort down the road.

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