Since Position is a custom object, it has a suffix '__c'. In the next line, we defined a constructor which fetches the value to be shown in the VisualForce Page. The controller for the VisualForce page is positionController which is a class defined with same name as positionController. For Standard relation. First one is for Account (Parent) - Contact (Child) relationship. Below screen, we have opened the Lookup field present on contact (child object). We also call it soql relationship query. Here is the screen that you will see after clicking on the look-up/Master-detail field name that is present on child object.