Explain Generic Repository Design Pattern

A generic repository is a software design pattern commonly used in object-oriented programming to provide a generic interface for accessing data from a database or other data sources. It abstracts the underlying data access code and provides a set of common operations that can be performed on entities within a data source.

The generic repository pattern typically consists of a generic interface, such as ‘IGenericRepository’, which defines common CRUD (Create, Read, Update, Delete) operations that can be performed on entities. It also includes a generic implementation of the repository interface, such as ‘GenericRepository<T>’, which provides the concrete implementation of those operations.

Here's an example of a generic repository interface:

public interface IGenericRepository<T>
{
    T GetById(int id);
    IEnumerable<T> GetAll();
    void Add(T entity);
    void Update(T entity);
    void Delete(T entity);
}
  

And here's an example of a generic repository implementation using Entity Framework in C#:

public class GenericRepository<T> : IGenericRepository<T> where T : class
{
    private readonly DbContext _context;
    private readonly DbSet<T> _dbSet;

    public GenericRepository(DbContext context)
    {
        _context = context;
        _dbSet = context.Set<T>();
    }

    public T GetById(int id)
    {
        return _dbSet.Find(id);
    }

    public IEnumerable<T> GetAll()
    {
        return _dbSet.ToList();
    }

    public void Add(T entity)
    {
        _dbSet.Add(entity);
        _context.SaveChanges();
    }

    public void Update(T entity)
    {
        _context.Entry(entity).State = EntityState.Modified;
        _context.SaveChanges();
    }

    public void Delete(T entity)
    {
        _dbSet.Remove(entity);
        _context.SaveChanges();
    }
}
  

By using a generic repository, you can avoid writing repetitive data access code for each entity in your application and promote code reusability. However, it's worth noting that the generic repository pattern may not be suitable for every scenario and should be evaluated based on the specific requirements and complexity of your application.