Curriculum
Repository Pattern and Unit of Work in ASP.NET Core are two of the most commonly used design patterns in enterprise application development. Large-scale applications often require clean separation between business logic and data access logic. Without proper architecture, applications become tightly coupled to databases, difficult to maintain, and challenging to test.
Understanding Repository Pattern and Unit of Work in ASP.NET Core is essential because these patterns help developers build scalable, maintainable, testable, and enterprise-ready applications.
The Repository Pattern is a design pattern that abstracts data access logic from business logic.
Purpose:
Business Logic
↓
Repository
↓
DatabaseRepositories act as a bridge between the application and the database.
Without Repository Pattern:
Controller
↓
Database Code
↓
Business LogicProblems:
Tight Coupling
Poor Maintainability
Difficult TestingRepository Pattern solves these issues.
Separation Of Concerns
Testability
Maintainability
FlexibilityThese benefits are important for enterprise systems.
Controller
↓
Service
↓
Repository
↓
DatabaseEach layer has a specific responsibility.
Responsibilities:
Retrieve Data
Insert Data
Update Data
Delete DataRepositories handle data operations.
Examples:
Create
Read
Update
DeleteRepositories commonly implement CRUD functionality.
Example:
public interface
ICustomerRepository
{
}Interfaces define repository contracts.
Benefits:
Loose Coupling
Dependency Injection
TestabilityInterfaces are central to enterprise architecture.
Example:
public class
CustomerRepository :
ICustomerRepository
{
}The class contains actual database logic.
Controller
↓
Service
↓
Repository
↓
DatabaseBusiness logic remains isolated.
public class Customer
{
public int Id
{
get;
set;
}
public string Name
{
get;
set;
}
}Repositories operate on entities.
Examples:
GetAll()
GetById()
Add()
Update()
Delete()These methods support CRUD operations.
Task<
IEnumerable<Customer>>
GetAll();Returns all records.
Task<Customer>
GetById(
int id);Retrieves a specific record.
Task Add(
Customer customer);Creates a new record.
Task Update(
Customer customer);Modifies existing data.
Task Delete(
int id);Removes a record.
Repositories often use:
Entity Framework CoreEF Core performs database operations.
public class
ApplicationDbContext :
DbContext
{
}DbContext manages database communication.
Example:
private readonly
ApplicationDbContext
context;Repositories interact with the database through DbContext.
builder.Services
.AddScoped<
ICustomerRepository,
CustomerRepository>();Repositories are injected automatically.
Repositories allow:
Mock Repositories
Unit Testing
Independent TestingApplications become easier to test.
Unit of Work is a design pattern that manages multiple database operations as a single transaction.
Purpose:
Multiple Changes
↓
Single TransactionEnsures consistency.
Without Unit of Work:
Operation 1 Success
Operation 2 FailureResult:
Inconsistent DataUnit of Work prevents such situations.
Create Changes
↓
Track Changes
↓
Save Once
↓
Commit TransactionAll operations succeed or fail together.
Bank Transfer:
Withdraw Money
↓
Deposit Money
↓
CommitBoth operations must succeed.
Example:
public interface
IUnitOfWork
{
}Defines transaction-related operations.
Examples:
SaveChanges()
Commit()
Rollback()Used to manage transactions.
Task SaveChangesAsync();Persists all tracked changes.
Architecture:
Unit Of Work
↓
Repository A
Repository B
Repository CMultiple repositories share the same transaction.
Benefits:
Transaction Management
Consistency
MaintainabilityThey complement each other.
Direct DbContext:
Controller
↓
DbContextRepository Pattern:
Controller
↓
Repository
↓
DbContextRepositories add abstraction.
Purpose:
Reusable Data Access LogicSupports multiple entity types.
IRepository<T>A single repository can work with multiple entities.
Less Code
Consistency
ReusabilityPopular in enterprise projects.
Location:
Application Layer
↓
Interfaces
Infrastructure Layer
↓
ImplementationThis follows dependency inversion principles.
Repositories:
Customer Repository
Account Repository
Transaction RepositoryUnit of Work ensures transactional consistency.
Repositories:
Patient Repository
Doctor Repository
Appointment RepositoryData remains organized and manageable.
Repositories:
Product Repository
Order Repository
Customer RepositoryEnterprise systems commonly use these patterns.
Code remains organized.
Repositories can be mocked.
Business logic stays independent.
Unit of Work ensures consistency.
Supports large applications.
These advantages make the patterns valuable.
Violates separation of concerns.
Makes maintenance difficult.
Can create inconsistent data.
May reduce flexibility.
Reduces testability.
A design pattern that abstracts data access logic.
A design pattern that manages multiple operations within a single transaction.
To separate business logic from database logic.
To ensure data consistency.
A reusable repository implementation that works with multiple entity types.
They improve maintainability, testability, and transaction management.
The Repository Pattern separates data access logic from business logic.
Unit of Work manages multiple database operations within a single transaction.
Repositories improve maintainability, testability, and code organization.
A Generic Repository provides reusable data access functionality for multiple entity types.
Unit of Work ensures multiple repository operations succeed or fail together.
They help create scalable, maintainable, testable, and enterprise-ready applications.