1. An apparatus for visualizing data, comprising: a single-data collecting unit to collect plural single-data having a first format and having a second format; a first multi-data generating unit to generate first multi-data from a first source using plural first single-data, wherein the plural first single-data is obtained from the collected plural single-data having the first format; a second multi-data generating unit to generate second multi-data from a second source using at least one of the plural first single-data, plural second single-data, and the generated plural first multi-data, wherein the plural second single-data has a second format different from the first format; and a data visualizer to visualize at least one of the collected plural single-data, the first multi-data generated from the first source, and the second multi-data generated from the second source, wherein the first multi-data generating unit comprises: a first data extracting unit to extract only plural single-data having any one format from among the collected plural single-data; a first data relationship prescribing unit to prescribe a relationship between the extracted plural single-data by sorting the extracted plural single-data based on a predetermined criterion comprising a selected predetermined attribute or field, or comprising only an extracted field including only a predetermined word; and a first data normalizing unit to generate the first multi-data by normalizing the relation-prescribed plural single-data.