What is the purpose of each database table class?
The generic table class contains code which is common to every database table, but it cannot be instantiated into an object because it does not contain such details as database name, table name, table structure, validation rules, et cetera. This type of class is known as an abstract class, and it needs the addition of a subclass before it can be instantiated into a usable object. The implementation details for each individual database table are therefore supplied in separate database table classes (subclasses) which extend the generic table class (superclass) and combine with the generic code through the process of inheritance. All the knowledge required to access a database table is contained or ‘encapsulated’ within its database table class. Whenever a component needs to communicate with a database table all it need do is create an object from that table’s class and then call one of the standard methods and everything is handled within that object, either by the generic code within t
