MSDN Documentation

Database Access Tutorials

Welcome to the Database Access section of MSDN tutorials. This guide will walk you through various methods and best practices for connecting to, interacting with, and managing databases in your applications.

Introduction to Database Concepts

Before diving into specific technologies, it's essential to understand fundamental database concepts:

• Relational Databases (SQL) vs. NoSQL Databases
• Schemas, Tables, Rows, and Columns
• Primary Keys, Foreign Keys, and Relationships
• CRUD Operations (Create, Read, Update, Delete)

Working with SQL Databases

SQL databases are widely used for structured data storage. This section covers popular SQL databases and how to access them.

ADO.NET Fundamentals

ADO.NET is a set of .NET Framework classes for interacting with data sources. It provides a robust way to manage database connections and execute commands.

using System;
using System.Data;
using System.Data.SqlClient;

public class SqlExample
{
    public static void Main(string[] args)
    {
        string connectionString = "Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;";

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            try
            {
                connection.Open();
                Console.WriteLine("Connection opened successfully.");

                string query = "SELECT COUNT(*) FROM MyTable";
                using (SqlCommand command = new SqlCommand(query, connection))
                {
                    int count = (int)command.ExecuteScalar();
                    Console.WriteLine($"Number of records: {count}");
                }
            }
            catch (SqlException ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
            }
        }
    }
}
                

Entity Framework Core

Entity Framework Core (EF Core) is a modern, cross-platform Object-Relational Mapper (ORM) for .NET. It simplifies database interactions by allowing you to work with data as objects.

// Assuming YourDbContext and YourEntity are defined elsewhere
using (var context = new YourDbContext())
{
    var users = context.Users
                       .Where(u => u.IsActive)
                       .OrderBy(u => u.LastName)
                       .ToList();

    foreach (var user in users)
    {
        Console.WriteLine($"{user.FirstName} {user.LastName}");
    }
}
                

Working with NoSQL Databases

NoSQL databases offer flexible data models suitable for different types of applications.

Introduction to MongoDB

MongoDB is a popular document-oriented NoSQL database. Learn how to connect and perform basic operations.

using MongoDB.Driver;
using MongoDB.Bson;

public class MongoExample
{
    public static void Main(string[] args)
    {
        var client = new MongoClient("mongodb://localhost:27017");
        var database = client.GetDatabase("myMongoDatabase");
        var collection = database.GetCollection<BsonDocument>("myCollection");

        var document = new BsonDocument
        {
            { "name", "John Doe" },
            { "age", 30 },
            { "city", "New York" }
        };

        collection.InsertOne(document);
        Console.WriteLine("Document inserted.");
    }
}
                

Best Practices and Advanced Topics

• Security: Preventing SQL Injection
• Performance Tuning: Indexing and Query Optimization
• Connection Pooling
• Transactions
• Asynchronous Database Operations

Continue exploring the MSDN documentation for more in-depth guides on specific database technologies and programming languages.