SQL

From APIDesign

Revision as of 09:30, 23 August 2010

SQL is a DSL used to manipulate and especially query relational databases. The mathematical roots of SQL are based on relational algebra. SQL seems to be one of the most often used programming languages in software engineering, althrough these days it may be slightly over its zenith.

History

The SQL raised in seventies and eighties driven by the (for example Sybase) vision to unify all data available and represent them in one big database. These data should have been collected from various other (non-relational) databases which many businesses used to have at that time (and still continue to maintain even now). Over the night a snapshot of such data had been converted into various SQL tables. Next morning, the management could then effectively perform various queries and find out more precisely than ever what is the state of the business.

In this scenario the SQL database is not the primary source of the data. It is more or less reporting tool. There is nothing wrong on that! Compared to previous age where one had to ask a programmer to write some code to traverse various graphs and nets of data to find out an answer to some question few weeks later it has been asked and probably also few weeks later when the answer mattered, now with SQL queries everything was much more simplified. All the data available to a simple SELECT. Coding of a query does not require orchestration of a various languages and systems. Cluelessness par excellence! Even non-programmers could perform or modify queries and they could see the results almost instantly (sometimes), much faster than in the previous era.

SQL was well suited for this reporting job. I can imagine companies using it becoming much more effective. Maybe the increase of effectiveness was so rapid, that SQL become synonymy for a database.

TBD: What is SQL good for and why. Why it is not good for internet age...