bom_lines (parent_part, child_part, qty_per_parent) is a bill of materials: making one parent_part uses qty_per_parent of child_part. A child can be an assembly with lines of its own, and the same subassembly can be used in more than one place.
A raw part is one with no lines of its own — nothing is assembled into it. Purchasing needs the total quantity of every raw part required to build 10 `BIKE`s. BOMs in the hidden data are deeper than this sample.
Columns: part, qty_needed. Sort by part.