Relational databases get their information from a single source.
Related files extract this data whenever it is needed. As a result, informational reports produced by a relational system are always up to date. Records in flat files, like those in TLC Version 1, also get their data from a single source. But each flat file stores this data within its own records. This means that the same data may be repeated over and over, thus using up substantial space on the hard drive or network server.