Database

Introduction

The database that will hold all of the details concerning the images for the Image Processing Application will be defined in a few tables.

Master Image Table

The master image table will contain all of the meta data concerning each image. There will only ever be one instance

Instance Table

The instance table will record and keep track of each instance of an image. There will always be at least one instance of any image because there will always be the master copy but there could be numerous other copies of an image such as a copy for Piwigo or another copy that is being used on the main website or a copy for some other reason.

Directory State Tables

We will need to have a semi permanent state table for each file system or server. This table will only describe the state of the individual hard drives. So it will need to have a reference to the file instance and then record the file meta data, using this state table it should be possible to know if the file is a new instance or has been changed.

Temporary state table

The temporary state table will be purely in memory. It will be a complete list of the meta data of each and every file that can be used to build the semi permanent Directory state table.