PTools::SDF Overview is an overview of the PTools::SDF API.
This document describes the class hierarchy used to implement the 'SDF DB' abstraction layer. This discussion covers most, but not all, of the modules in the suite of SDF (Simple Data File) classes.
The classes used to define this simple 'DBMS' are based on a suite of 'Simple Data File' (SDF) classes that have evolved over several years to provide an object interface to several common types of data files.
The format used here is a flat ascii file consting of records containing fields delimited by an arbitrary character (usually a colon ':').
The classes described below provide access to the data structure(s) defined using a simple 'schema' format, and provide a layer allowing for consistency checks and data entry edits across 'data sets.'
The 'data set' relationships are defined in the 'schema' format. This schema is simply a Perl data structure consisting of multiple nested hash and array references.
The class hierarchy may appear complex at first, but each layer builds logically upon the prior layers to provide the necessary methods to access data. Simple projects can get by with simple functionality and, as project complexity increases, greater functionality is available.