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I have to wonder why a relation algebra language isn't actually algebraic. What about projections in the form of something like c := a x b etc? Nooo, they had t
by jakub_h 10y ago
I have to wonder why a relation algebra language isn't actually algebraic. What about projections in the form of something like c := a x b etc? Nooo, they had to make it look like COBOL.
- tiglionabbit 10y agoI have seen it taught with operators like that.
- SapphireSun 10y agoIn databases class, they used Pi for projection, bowtie for natural join, and sigma for row filtration. They added conditions on the operators with subscripts. SQL is just the standardized version of that.
- jakub_h 10y ago"Standardized"...and without the legibility of symbolic notation and the option to use intermediate named relvars?
- zenexer 10y agoIt's designed to be "natural", meaning that technical symbols were largely avoided. Someone who knows little about formal notation but a decent amount about databases can usually figure out what's going on. It's also easier to type, seeing how most of the relevant symbols aren't on your average keyboard.
- deleted 10y ago[deleted]
- Sanddancer 10y agoBecause one of SEQUEL, and thus SQL's design goals was to create a language that's usable by non-programmers of various levels of computer and math fluency. Having to remember a set of symbols just to get a jobs report would be a huge turn-off to a huge subsection of people that the language was intended for.