it is Base class for a database Joomla Model. It acts as a Factory class for application specific objects and provides many supporting API functions.
The method adds a directory where Joomla should search for models. You may either pass a string or an array of directories.
It is a method to get a table object, load it if necessary.
It returns a Model object, always creating it.
It is a method to get the model name. By default, the model name is parsed using the classname or it can be set by passing a $config['name'] in the class constructor.
It is a method to get model state variables.
It is a method to load a row for editing from the version history table.