Base: Manipulate PostgreSQL table records

This is a base class that can be used to wrap the access to records of tables in PostgreSQL databases.

The class can query the information about the fields of a given table to be able to store and retrieve the values of the fields of the table records.

It can create new records from scratch or retrieve the record field values into class variables given the record primary key identifier value.

It can also update a loaded record with new values or delete it from the database table.