In this article, I counter persistent claims of big data revolutionising managerial decision making, by tracing the technological and cultural origins of data-based management in the United States back to the 1970s and 1980s using historical source materials from the trade magazine Datamation. I argue that innovations in database technology within this period – database management systems and the relational database model – shaped and reinforced a data-based mindset. This mindset, I demonstrate, is manifested in four interlinked concepts of data: data as asset, data as raw, data as reality, and data as relatable. These concepts, I argue, provide a basis for current associations of big data with ideological values of objectivity and truthfulness. The article contributes to a growing body of work in media and communication studies that deconstructs the ideological discourses facilitating big data’s unquestioned integration in the business world.