Can you explain what a change tracking mechanism in data is?

Change tracking mechanism allows automatically recording changes in objects or collections, for example, to synchronize them with a database or update the UI.

In C#, this is often implemented through the interfaces INotifyPropertyChanged and INotifyCollectionChanged.

• INotifyPropertyChanged notifies when a property of an object changes.
• INotifyCollectionChanged notifies about changes in a collection (adding, removing items).

Example implementation of INotifyPropertyChanged:

using System.ComponentModel;

public class Person : INotifyPropertyChanged
{
    private string name;
    public string Name
    {
        get => name;
        set
        {
            if (name != value)
            {
                name = value;
                OnPropertyChanged("Name");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

Thus, when the Name property changes, subscribers will be notified and can react to the changes.