How Unit of Work and Repository Pattern Save Your Code

One time I had a disaster … I was working on an e-commerce project, and the user placed a new order .
I wanted to add it quickly… and suddenly
Here’s where you’ll understand why Unit of Work and Repository Pattern make your code cleaner and smarter .

Why is this important?​

Because they save you a lot of confusion when dealing with the database, and make any future changes way easier .​

Imagine this

• You need to add the Order to the Orders table.
• Decrease the quantity in the Products table .
• Record the payment in the Payments table .

If just one step fails (for example, the order gets saved but the quantity doesn’t decrease), your data is corrupted .

Here comes the hero : Unit of Work
The idea

• It groups all operations as one single transaction .
• Either everything is executed successfully … or everything is rolled back as if nothing happened.
• Your database always stays consistent.

But how does it know what to add or update?
That’s where its best friend comes in : Repository Pattern.

The Repository is the mediator :

• Instead of writing queries everywhere, you use clean objects like UserRepository or ProductRepository.
• The business logic doesn’t need to know what kind of database is behind the scenes . Whether it’s SQL Server, MongoDB, or even a text file-it doesn’t matter.

The big advantage: your code becomes decoupled.
Tomorrow, if you want to switch ORM or database type → you just change the Repositories. Your business logic stays untouched .

How do they work together?

1. Your business logic calls the UnitOfWork.
2. From the UnitOfWork, you request the Repository you need.
3. You use the Repository to add or modify.
4. At the end, you call just one command: Complete() .

This way, all operations are executed together in a single transaction.

But doesn’t DbContext in EF Core already do this?
Yes, exactly … but if you use it directly, you’re tying yourself to Entity Framework forever .
Want to run unit tests without a real database? Almost impossible.
This abstraction separates the what (business logic: “add user”) from the how (implementation: “save in SQL Server”).