Hierarchical refers to systems that are organized in the shape of a pyramid, with each row of objects linked to objects directly beneath it. Hierarchical systems pervade everyday life. The army, for example, which has generals at the top of the pyramid and privates at the bottom, is a hierarchical system.Hierarchical systems are as popular in computer systems as they are in other walks of life. The most obvious example of a hierarchical system in computers is a file system, in which directories have files and subdirectories beneath them. Such a file organization is, in fact, called a hierarchical file system .
A relational database matches data by using common characteristics found within the data set. The resulting groups of data are organized and are much easier for people to understand.