There are several types of 5c Moreno items:

Each of the types listed above is a table in the database. Some of these types can be included in others, and I discuss here why in some cases it makes sense, and it others, it does not. "Sense" here means "compact," and "easy to use." The minimal number of tables is ONE table, but it would have many columns with a large number of empty spaces. Each of the types listed above, however, are candidates for a database table that would minimize the number of empty cells by grouping types. The number of perfin singles, for example, is small in comparison to the number of not perfined singles. Including a column in the singles table for perfin would mean many empty cells. Even though this database is intended for one value of the Argentina 1935-51 Definitives, I am assuming that it may be expanded to the entire series.

Each table here describes an entity, using database terminology, and each entity has attributes that describe it. For example, a mint stamp may or may not have gum (attribute), while used singles, such as the two shown here, may have a specific type of postmark, and the postmark may be readable. There is much more about entities, attributes, and relationships (how different entities are related to each other) in the pages describing each of the tables.