Data Structures in Python

Python provides several built-in data structures that are commonly used in programming

Below is some helpful summary on Python Data Structures

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.

SQL Server Integration not working in VS2022

Here is what you need to do, you need to install SSIS Project for VS 2022

To install Analysis Services, Integration Services, and Reporting Services project support, run the SSDT standalone installer or direct download from here.

The installer lists available Visual Studio instances to add SSDT tools. If Visual Studio isn't already installed, selecting Install a new SQL Server Data Tools instance installs SSDT with a minimal version of Visual Studio, but for the best experience, we recommend using SSDT with the latest version of Visual Studio

Explain Unit of Work pattern

The Unit of Work pattern is a software design pattern that provides a way to manage transactions and coordinate the work of multiple repositories in an application. It helps maintain data consistency and integrity by ensuring that multiple operations are treated as a single unit of work and are either all committed or all rolled back.

The main purpose of the Unit of Work pattern is to abstract the underlying data access code and provide a high-level interface for managing transactions and coordinating changes to multiple entities. It ensures that all changes made within a unit of work are tracked and persisted consistently.

Here's a basic example of the Unit of Work pattern:

public interface IUnitOfWork : IDisposable
{
    void BeginTransaction();
    void Commit();
    void Rollback();
    void SaveChanges();
    IRepository<TEntity> GetRepository<TEntity>() where TEntity : class;
}

public class UnitOfWork : IUnitOfWork
{
    private readonly DbContext _context;
    private readonly Dictionary<Type, object> _repositories;
    private DbContextTransaction _transaction;

    public UnitOfWork(DbContext context)
    {
        _context = context;
        _repositories = new Dictionary<Type, object>();
    }

    public void BeginTransaction()
    {
        _transaction = _context.Database.BeginTransaction();
    }

    public void Commit()
    {
        _transaction.Commit();
        _transaction = null;
    }

    public void Rollback()
    {
        _transaction.Rollback();
        _transaction = null;
    }

    public void SaveChanges()
    {

        _context.SaveChanges();
    }

    public IRepository<TEntity> GetRepository<TEntity>() where TEntity : class
    {
        if (_repositories.ContainsKey(typeof(TEntity)))
        {
            return (IRepository<TEntity>)_repositories[typeof(TEntity)];
        }

        var repository = new Repository<TEntity>(_context);
        _repositories.Add(typeof(TEntity), repository);
        return repository;
    }

    public void Dispose()
    {
        _transaction?.Dispose();
        _context.Dispose();
    }
}
  

In this example, the IUnitOfWork interface defines the methods for beginning a transaction, committing or rolling back the transaction, saving changes, and retrieving repositories. The UnitOfWork class implements this interface and provides the concrete implementation.

The UnitOfWork class maintains an instance of the database context (DbContext) and a dictionary of repositories. The repositories are created lazily and stored in the dictionary to ensure that the same repository instance is used throughout the unit of work.

By using the Unit of Work pattern, you can ensure that multiple operations across different repositories are treated as a single unit of work. This allows you to maintain data consistency, perform atomic commits or rollbacks, and simplify the management of transactions in your application.

How to Find Tables that Contain a Specific Column in SQL Server?

Basic concept to understand about SQL Server is that of catalog views, which are effectively database tables (catalogs in this case) that display system-wide information about the SQL Server Database Engine.

All catalog views are accessed via a SELECT SQL statement FROM a specific catalog within the sys. namespace.
For example, the following statement can be used to view information about all database tables in the system via the sys.tables catalog

use mobility
go
select  
        s.[name]            'Schema',
        t.[name]            'Table',
        c.[name]            'Column',
        d.[name]            'Data Type',
        c.[max_length]      'Length',
        d.[max_length]      'Max Length',
        d.[precision]       'Precision',
        c.[is_identity]     'Is Id',
        c.[is_nullable]     'Is Nullable',
        c.[is_computed]     'Is Computed',
        d.[is_user_defined] 'Is UserDefined',
        t.[modify_date]     'Date Modified',
        t.[create_date]     'Date created'
from        sys.schemas s
inner join  sys.tables  t
on s.schema_id = t.schema_id
inner join  sys.columns c
on t.object_id = c.object_id
inner join  sys.types   d
on c.user_type_id = d.user_type_id
where c.name like '%ProjectManagerID%'
  

Hope this helps!!