Perl.com: Short guide to DBI (The Perl Database Interface Module)

Relational databases started to get to be a big deal in the
1970’s, and they’re still a big deal today, which is a little
peculiar, because they’re a 1960’s technology.

“A relational database is a bunch of rectangular tables. Each
row of a table is a record about one person or thing; the record
contains several pieces of information called fields…”

“Sometimes this is a very silly way to store information. When
the information naturally has a tabular structure it’s fine. When
it doesn’t, you have to squeeze it into a table, and some of the
techniques for doing that are more successful than others.
Nevertheless, tables are simple and are easy to understand, and
most of the high-performance database systems you can buy today
operate under this 1960’s model.”