Let’s look at a small sample from the table where I currently track changes.

The 2 pages listed here are for Romanian Air Mails from 1961. As of today, those are pages 539 & 540 of the Romanian stamp album, but as other pages are inserted, these numbers will necessarily changes. The columns are as follows:

• PageID: Immutable unique identifier
• ChangeDate: Date of change
• ChangeType: Either “Added” or “Revised”
• ChangeDesc: A text field describing the changes

I’m writing about these 2 pages today, because I am making some changes that the current system cannot handle. The PK for this table is the first 3 fields. As originally designed, the PK consisted of only the first 2 fields, but the third was added so I could distinguish between creating a page and adding stamps to a page – in this case, specifically the addition of actual stamp images as opposed to empty spaces for stamps yet to be added. Until this change was made, I had only added pages where all the images were actual stamps, not place-holders. After the change was made, I could track the addition of stamps and the addition of pages, but the actual problem is a little more complex. Let’s start by considering changes that can occur on a page:

• A new page is added to an albu.m
• All the images are place-holders.
• Some of the images are place-holders, while others are scanned stamps.
• All the images are scanned stamp.s
• A page is assigned a new number, usually because of the insertion of other pages. Currently, this information can be inferred from existing records, but is not explicitly stored.
• A place-holder is added to a page (currently not explicitly tracked).
• A stamp is added to a page (tracked indirectly via the ChangeDesc column).
• A stamp (or placeholder) is removed from a page. (Currently not tracked, but sometimes can be inferred. A few instances of this can be re-constructed from existing data.)
• A stamp image is revised because a better quality stamp has been added to the collection (tracked indirectly via the ChangeDesc column).

In this case, we are going to move some placeholders and some stamp images between these two pages, moving the imperforate Winter Sports place-holders to the same page as the perforated variety, and moving the Vostok 1 and Solar Eclipse stamps and/or placeholders to the page from which the imperforate Winter Sports stamps are coming. Also, all the stamp references in the descriptions are to the Scott catalog numbers, but as the Romanian collection grows, the number of issued stamps not listed by Scott is increasing, so references to the catalog numbers will have to be replaced by individual stamp descriptions.

When these changes are implemented, I’m hoping the new data will look something like this:

Updated set of changes