Domain Concepts

Domain concepts are concepts that are related to the domain at hand... i.e., comic books

Issue Number

The issue number can consist of multiple components. In its simplest form, it is just an integer, usually starting at 1. However sometimes an issue number 0 (zero) will be created, or even an issue number -1 (negative one). Additionally, sometimes a .1 (point one) is added to the issue number, e.g., 15.1

Lastly, when multiple variants exist an issue extension is used to identify the variant. Though this would normally be specified on the variant table an not the issue table.

Uncertain, Confirmed, None/No, NULL

When looking at the data model in use by the GCD, they have many tables with columns ending with _uncertain. Or they have column starting with no_. For example, page_count_uncertain or no_indicia_frequency.

This seems like a very interesting alternative to using a NULL value. Null typically infers that that there is no value for a given field for a specific record. However a value of NULL does not indicate for certain that there is no value, or if the value exists but has not been entered because it is not known at the moment or hasn't been looked up. So in addition to using NULL, the use of the no_ field clarifies that there is no value rather than the value is unknown.

Additionally, sometimes a value is left NULL because it's exact value is not 100% certain. With the use of _uncertain columns, instead of leaving a value NULL, a non-NULL value can be entered and the value can be marked as UNCERTAIN by setting the corresponding _uncertain field to TRUE. This way, queries can be executed later to find the various uncertain values and either confirm or update them to the correct values.

great concept number 2

poop....