What Goes Around Comes Around... And Around...

Abstract

Two decades ago, one of us co-authored a paper commenting on the previous 40 years of data modelling research and development [188]. That paper demonstrated that the relational model (RM) and SQL are the prevailing choice for database management systems (DBMSs), despite efforts to replace either them. Instead, SQL absorbed the best ideas from these alternative approaches. We revisit this issue and argue that this same evolution has continued since 2005. Once again there have been repeated efforts to replace either SQL or the RM. But the RM continues to be the dominant data model and SQL has been extended to capture the good ideas from others. As such, we expect more of the same in the future, namely the continued evolution of SQL and relational DBMSs (RDBMSs). We also discuss DBMS implementations and argue that the major advancements have been in the RM systems, primarily driven by changing hardware characteristics.