Entity Framework Core: How to add related data to a Db without querying the top object

To add related data to a database using Entity Framework Core without querying the top object, you can use the Add method of the DbSet class.

Here is an example of how you can use this method to add related data to a database:

Copy codeusing (var context = new MyDbContext())
{
    // Create a new object and set its navigation properties
    var relatedObject = new RelatedObject
    {
        TopObject = new TopObject { Id = 1 },
        Name = "Related Object"
    };

    // Add the related object to the context
    context.RelatedObjects.Add(relatedObject);

    // Save the changes to the database
    context.SaveChanges();
}

In this example, TopObject is the top object that the related object is related to, and RelatedObject is the related object that you want to add to the database.

By setting the TopObject navigation property of the RelatedObject object, you can specify which top object the related object should be related to. When you call the SaveChanges method, Entity Framework Core will automatically add both the top object and the related object to the database, if they do not already exist.