Artificial Intelligence Research: The Utility and Design of a Relational Database System

Although many researchers talk about a “patient database,” they typically are not referring to a database at all, but instead to a spreadsheet of curated facts about a cohort of patients. This article describes relational database systems and how they differ from spreadsheets. At their core, spreadsheets are only capable of describing one-to-one (1:1) relationships. However, this article demonstrates that clinical medical data encapsulate numerous one-to-many relationships. Consequently, spreadsheets are very inefficient relative to relational database systems, which gracefully manage such data. Databases provide other advantages, in that the data fields are “typed” (that is, they contain specific kinds of data). This prevents users from entering spurious data during data import. Because each record contains a “key,” it becomes impossible to add duplicate information (ie, add the same patient twice). Databases store data in very efficient ways, minimizing space and memory requirements on the host system. Likewise, databases can be queried or manipulated using a highly complex language called SQL. Consequently, it becomes trivial to cull large amounts of data from a vast number of data fields on very precise subsets of patients. Databases can be quite large (terabytes or more in size), yet still are highly efficient to query. Consequently, with the explosion of data available in electronic health records and other data sources, databases become increasingly important to contain or order these data. Ultimately, this will enable the clinical researcher to perform artificial intelligence analyses across vast amounts of clinical data in a way heretofore impossible. This article provides initial guidance in terms of creating a relational database system.