There is no Wikipedia entry for “workpiece”, so FourOh-LLC may freely describe the concept of a physical object that was manufactured or being manufactured. Things that are going to be manufactured sometime in the future are not workpieces, things on a blue print or on the computer screen are not workpieces.
This definition is simply a reference, as we are exploring the workpiece namespace. If you work with milk on a dairy farm, or with mixture of gases in a chemical plant your namespace has to be described, and the reference above going to expand.
The single most relevant property of a work piece is its weight. Its not always grams, it could be an area or volume. This is important as grams cannot be converted to square centimeters or cubic milimeters. For example, 3D printing filament are usually sold in 1 kg spools. If you need to calculate the lenght and the volume you need to use more than just one type of UoM for the same workpiece.
These are MySQL-specific templates, see SQLite, PostGRES and others for more.