Data has been collected ever since the first businesses opened their doors, governments began conducting censuses, and organizations tried to learn more about their members or the people they served. But the emergence of large mainframe computers in the 1950s, the creation of the first database management system by Charles Bachman at General Electric in 1961, the invention of the first relational database by Edgar Codd of IBM in 1969, the introduction of personal computers in the late 1970s and early 1980s, the emergence of the World Wide Web in 1989, and the development of the Internet of Things (everyday objects with sensors that allow them to connect to the Internet and automatically record, report, and receive data) in the late 1990s fueled a massive increase in the amount of data that was collected and the sophistication of the digital databases and warehouses that were used to store this information. As a result, demand has grown for skilled specialists to design, develop, and manage data warehouses. The need for data warehousing specialists is expected to continue as the amount of data that is collected grows at jaw-dropping rates. In fact, the global market intelligence firm IDC reports that the amount of data on the planet is expected to grow 10-fold from 2014 to 2020—increasing from 4.4 zettabytes to 44 zettabytes. (One zetabyte is the equivalent of 180 million Libraries of Congress; the Library of Congress holds about 29 million volumes.)