Supporting a recursive relationship—like you find in a typical bill of materials (BOM)—is one of the hardest problems to solve in relational databases. A BOM is a hierarchical structure that describes relationships among components. For example, a car is made up of components such as a steering wheel, a frame, and tires. The car frame is made up of additional smaller components such as side rails, cross rails, and bolts. Traditional database tables store all the components together and link them in recursive one-to-many (1:M) relationships, as Table 1 shows.

But...