Entity Framework Change Tracking

Introduction

In this article, we will learn about Entity Framework Change Tracking.

Before we start, please take a look at my last article on Entity Framework.

• Handle Entity Framework Transactions

Now, like get started.

Understanding Change Tracking

Change tracking is a mechanism that allows EF Core to keep track of changes to your entities. This helps EF Core determine what SQL commands need to be executed to persist changes to the database.

Example

using (var context = new AppDbContext())
  {
	  var employee = context.Employees.FirstOrDefault(e => e.EmployeeId == 101);
	  employee.City = "Mumbai";
	  
	  // EF Core tracks the change in the City property.
  }

Managing the State of Entities

EF Core tracks the state of each entity (Added, Unchanged, Modified, Deleted) to determine the operations to be performed during SaveChanges.

using (var context = new AppDbContext())
  {
	  var employee = context.Employees.FirstOrDefault(e => e.EmployeeId == 101);
	  context.Entry(employee).State = EntityState.Modified;
      context.SaveChanges();
	  
	  // The state is set to Modified, prompting and UPDATE command
  }

Using No-Tracking Queries

No-tracking queries improve performance for read-only operations by not tracking the entities in the context. This reduces memory usage and speeds up query execution.

using (var context = new AppDbContext())
  {
	  var employees = context.Employees.AsNoTracking().ToList();
	  
	  // No change tracking is performed, ideal for read-only operations
  }

Benefits of No-Tracking Queries

• Performance: Faster queries and lower memory footprint.
• Scalability: Better for large-scale read operations.
• Simplicity: Reduces overhead when changes to entities are not needed

using (var context = new AppDbContext())
  {
	  var employees = context.Employees.AsNoTracking().FirstOrDefault(e => e.EmployeeId == 101);
	  
	  // Efficiently retrieves the post without tracking it's state
  }

Summary

• Change Tracking: Tracks changes to determine necessary database operations.
• Entity State Management: Manages entity states for accurate database updates.
• No-Tracking Queries: Optimizes performance for read-only operations.

In this article, I have tried to cover how to handle Entity Framework Change Tracking.