A tuple is a fixed fixed-length list containing elements that need not have the same type. It can be, and often is, used as a key-value pair. A row (sometimes called a record) is the set of fields within a table that are relevant to a specific entity.
The stem wall on a concrete foundation is essentially the supporting wall that joins the foundation of a building to the vertical walls of the structure that is constructed atop the foundation.
Slab Foundations. The two basic types of slab foundations are the monolith and the stem wall. Monolithic foundations are poured as a single form, with the outside edge, about the width of the wall, being 10 to 12 inches deep and the center of the slab typically 4 to 6 inches deep. A stem wall foundation is poured in multiple parts.