I was first introduced to the world of relational databases some 15 years ago, while developing geographic information systems (GIS) at Monolit. At that time GIS were just making a transition from storing attribute information in flat files to storing them in relational databases, while relational databases just started their expansion from the world of accounting and financial applications to other application domains. Oracle was especially aggressive in the field of GIS, so we've ended up using it. The world of relational databases has since commoditized, but Oracle somehow managed to keep his price very high. Therefore later in my career the free and open-sourced PostgreSQL has increasingly become a viable option in my projects. Except for missing a few very useful features (e.g. partitions), PostgreSQL didn't feel much different than Oracle, so my concept of a relational database didn't change a lot. My perception of relational databases was eventually shattered when I joined Zemanta and I started using MySQL. Deceived by having SQL in its name, I thought MySQL is yet another open-source implementation of trimmed-down Oracle, just like PostgreSQL is. Quite to my surprise I've found out that except for the common SQL interface MySQL has very little in common with Oracle and other traditional databases. MySQL is really only about performance, while reliability and consistency, the essence of traditional relational databases, aren't such a big concern. Consequently, it took me quite a while to acknowledge MySQL for what it is and adjust my perception of relational databases accordingly.
- Scaling PostgreSQL at Braintree: Four Years of Evolution (braintreepayments.com)
- PostgreSQL vs MySQL: an apples to oranges comparison (ledgersmbdev.blogspot.co.uk)
- Genealogy of Relational Databases (i-programmer.info)