text: Oracle was the first relational database management system.  Previous to that data was physically stored in a way, often complex, that would facilitate retrieval.\nSome examples are indexed sequential files or a 'network' database, in which linkage files would be created by the database administrator to allow two files to be combined in a single retrieval.\nA RDBMS stores data simply in lists in no particular order, but runs processes that use advanced algorithms to combine any bits of data of the various files into single retrievals.\nThe complexity is in the software and not in the storage of the data.