SQL and management of external data

In late 2000, work was completed on yet another part of the SQL standard [1], to which we introduced our readers in an earlier edition of this column [2].Although SQL database systems manage an enormous amount of data, it certainly has no monopoly on that task. Tremendous amounts of data remain in ordinary operating system files, in network and hierarchical databases, and in other repositories. The need to query and manipulate that data alongside SQL data continues to grow. Database system vendors have developed many approaches to providing such integrated access.In this (partly guested) article, SQL's new part, Management of External Data (SQL/MED), is explored to give readers a better notion of just how applications can use standard SQL to concurrently access their SQL data and their non-SQL data.