Entity Framework (EF) is an ORM (Object-Relational Mapper) that simplifies database interactions by allowing you to work with data as strongly-typed objects.
Setting Up Entity Framework:
Install the Microsoft.EntityFrameworkCore and Microsoft.EntityFrameworkCore.SqlServer packages.
Create a model class and a DbContext.
Example:
using System;
using Microsoft.EntityFrameworkCore;
namespace NationalParks
{
public class Park
{
public int Id { get; set; }
public string Name { get; set; }
public int YearEstablished { get; set; }
}
public class ParkContext : DbContext
{
public DbSet<Park> Parks { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("your_connection_string_here");
}
}
class Program
{
static void Main(string[] args)
{
using (var context = new ParkContext())
{
context.Database.EnsureCreated();
context.Parks.Add(new Park { Name = "Yellowstone", YearEstablished = 1872 });
context.SaveChanges();
foreach (var park in context.Parks)
{
Console.WriteLine($"Park: {park.Name}, Established: {park.YearEstablished}");
}
}
}
}
}
CRUD Operations:
Create: Add new records to the database.
Read: Retrieve records from the database.
Update: Modify existing records.
Delete: Remove records from the database.
Example:
using System;
using Microsoft.EntityFrameworkCore;
using System.Linq;
namespace NationalParks
{
public class Park
{
public int Id { get; set; }
public string Name { get; set; }
public int YearEstablished { get; set; }
}
public class ParkContext : DbContext
{
public DbSet<Park> Parks { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("your_connection_string_here");
}
}
class Program
{
static void Main(string[] args)
{
using (var context = new ParkContext())
{
// Create
var newPark = new Park { Name = "Great Smoky Mountains", YearEstablished = 1934 };
context.Parks.Add(newPark);
context.SaveChanges();
// Read
var parks = context.Parks.ToList();
foreach (var park in parks)
{
Console.WriteLine($"Park: {park.Name}, Established: {park.YearEstablished}");
}
// Update
var yellowstone = context.Parks.First(p => p.Name == "Yellowstone");
yellowstone.YearEstablished = 1872;
context.SaveChanges();
// Delete
var zion = context.Parks.FirstOrDefault(p => p.Name == "Zion");
if (zion != null)
{
context.Parks.Remove(zion);
context.SaveChanges();
}
}
}
}
}
Async File I/O:
using System;
using System.IO;
using System.Threading.Tasks;
namespace NationalParks
{
class Program
{
static async Task Main(string[] args)
{
string path = "parks.txt";
string content = "Yellowstone\nYosemite\nZion\nGrand Canyon";
// Writing to file asynchronously
await File.WriteAllTextAsync(path, content);
Console.WriteLine("File written asynchronously.");
// Reading from file asynchronously
string result = await File.ReadAllTextAsync(path);
Console.WriteLine("File content:\n" + result);
}
}
}
Async Serialization:
using System;
using System.IO;
using System.Text.Json;
using System.Threading.Tasks;
namespace NationalParks
{
public class Park
{
public string Name { get; set; }
public int YearEstablished { get; set; }
}
class Program
{
static async Task Main(string[] args)
{
Park park = new Park { Name = "Yellowstone", YearEstablished = 1872 };
// Serialize to JSON asynchronously
string json = JsonSerializer.Serialize(park);
await File.WriteAllTextAsync("park.json", json);
Console.WriteLine("JSON written asynchronously.");
// Deserialize from JSON asynchronously
string jsonData = await File.ReadAllTextAsync("park.json");
Park deserializedPark = JsonSerializer.Deserialize<Park>(jsonData);
Console.WriteLine($"Park: {deserializedPark.Name}, Established: {deserializedPark.YearEstablished}");
}
}
}
Async Database Operations with Entity Framework:
using System;
using Microsoft.EntityFrameworkCore;
using System.Linq;
using System.Threading.Tasks;
namespace NationalParks
{
public class Park
{
public int Id { get; set; }
public string Name { get; set; }
public int YearEstablished { get; set; }
}
public class ParkContext : DbContext
{
public DbSet<Park> Parks { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("your_connection_string_here");
}
}
class Program
{
static async Task Main(string[] args)
{
using (var context = new ParkContext())
{
// Create
var newPark = new Park { Name = "Great Smoky Mountains", YearEstablished = 1934 };
await context.Parks.AddAsync(newPark);
await context.SaveChangesAsync();
// Read
var parks = await context.Parks.ToListAsync();
foreach (var park in parks)
{
Console.WriteLine($"Park: {park.Name}, Established: {park.YearEstablished}");
}
// Update
var yellowstone = await context.Parks.FirstAsync(p => p.Name == "Yellowstone");
yellowstone.YearEstablished = 1872;
await context.SaveChangesAsync();
// Delete
var zion = await context.Parks.FirstOrDefaultAsync(p => p.Name == "Zion");
if (zion != null)
{
context.Parks.Remove(zion);
await context.SaveChangesAsync();
}
}
}
}
}
Performance and Resource Management
When working with data, especially in large-scale applications, it's important to consider performance and resource management. Asynchronous programming can significantly enhance performance by allowing concurrent execution of tasks without blocking the main thread.
Performance Tips:
Use async I/O operations to keep the UI responsive.
Leverage caching mechanisms to avoid repetitive data fetching.
Optimize database queries and use efficient data structures.
Profile and benchmark your code to identify bottlenecks and optimize resource usage.
Benchmarking Example (Hypothetical):
Comparing synchronous vs. asynchronous database operations:
Operation Type
Execution Time (ms)
Memory Usage (MB)
Synchronous
2000
50
Asynchronous
1200
45
In summary, mastering File I/O, serialization, and database operations with Entity Framework, combined with effective asynchronous programming, can lead to robust, efficient, and scalable applications. Always aim to write clean, maintainable code and be mindful of resource management to ensure optimal application performance.