List of fixed data that, unlike databases relate them, they are flat and have two inputs and a single possibility of entry for access to a desired value. For example, a table of a health system could have a line of heading of the following columns REGION, city, inhabitants, over 60, adults, children, infants 0-2, hospitals, CONSULTORIS, clinics, consultations, C major, C adult S, CONSULTATIONS C INFANTS, CHILDREN, DEATHS, HIGH. The lines will have the first column filled with the names of the regions. The intersection of a vertical fixed variable against a horizontal allows to find the searched value. Two entries is because you can search from a specific region (line) or from a column (fourth region and adults for example. There are 3 entrances, rare volumetric tables
