C# Databases

MS SQL Server & Entity Framework Core — SoftUni Course Repository

From raw SQL queries and database design to full ORM mastery with Entity Framework Core —
plus real-world competitive SQL problems from HackerRank.

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📖 About

This repository contains my coursework and solutions for the C# Databases track at SoftUni, covering two major pillars of modern data-driven .NET development:

• MS SQL Server — relational database design, T-SQL querying, stored procedures, functions, triggers, transactions, and performance optimization.
• Entity Framework Core — the leading ORM for .NET: code-first modeling, migrations, LINQ queries, relationships, and advanced EF Core patterns.

Additionally, the repo includes a bonus collection of competitive SQL problems solved on HackerRank.

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🗂️ Repository Structure

🗄️ 01 — MS SQL Problems

Mastering relational databases and T-SQL from the ground up.

A comprehensive collection of SQL exercises covering:

• Database design & normalization (1NF, 2NF, 3NF)
• DDL — creating tables, constraints, indexes
• DML — SELECT, INSERT, UPDATE, DELETE
• Joins, subqueries, CTEs, and window functions
• Stored procedures, user-defined functions & triggers
• Transactions and error handling
• Performance tuning & execution plans

📁 Browse module →

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⚙️ 02 — Entity Framework Core

Working with databases the .NET way — code-first, type-safe, and productive.

In-depth EF Core coverage including:

• Code-First approach & database migrations
• DbContext, DbSet, and model configuration (Fluent API & Data Annotations)
• One-to-one, one-to-many, and many-to-many relationships
• LINQ queries — filtering, projection, grouping, aggregation
• Eager, lazy, and explicit loading
• Transactions & concurrency handling
• AutoMapper integration & DTOs
• JSON processing with EF Core

📁 Browse module →

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🏆 HackerRank — MS SQL Server Problems

Competitive SQL problem solving on a real-world judge platform.

A curated set of HackerRank SQL challenges solved in T-SQL — ranging from basic queries to advanced analytical problems.

📁 Browse solutions →

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🛠️ Tech Stack

Layer	Technologies
Database	Microsoft SQL Server (MSSQL)
Query Language	T-SQL
ORM	Entity Framework Core
Language	C# (.NET)
IDE	Visual Studio / SSMS
Platform	SoftUni · HackerRank

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🚀 Getting Started

1. Clone the repository

   git clone https://github.com/georgidelchev/CSharp-Databases.git
   cd CSharp-Databases

2. For SQL scripts — open any .sql file in SQL Server Management Studio (SSMS) or Azure Data Studio and execute against your local MSSQL instance.

3. For EF Core projects — open the .sln file in Visual Studio, then apply migrations:

   dotnet restore
   dotnet ef database update
   dotnet run

Prerequisites: SQL Server (2019+), .NET SDK, Visual Studio or Rider.

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👤 Author

Georgi Delchev

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📄 License

This project is licensed under the MIT License.

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_{Made with ☕ and determination · SoftUni}