Lazy loading, eager loading and explicit loading

Lazy loading

• virtual properties are only loaded when they are required to be used

• This is controlled by an option that you set - you can make lazy loading the default way to load properties

• Has an N+1 loading problem. If you have a foreach statement which needs to access a virtual property, then you will make a database call each time you iterate through that loop

Eager loading

• Use the .Include and tell SQL to go and include that virtual property when the first database call is made

• It will populate that virtual property for ALL the elements in your database call

• Very easy, one SQL call upfront

Explicit loading

• When you need more fine grained control than eager loading

• So let's say you don't need every single row to have its virtual property loaded. You only care about one particular row

• With explicit loading, you can specify that level of loading, just for that one row

• It will always have a second SQL call, where you specify what you want to be explicitly loaded, and how you want to do it