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IDK, what about indexes? what about atomic transactions which add/update/delete rows to/from/from multiple tables?
by HillaryBriss 7y ago
IDK, what about indexes? what about atomic transactions which add/update/delete rows to/from/from multiple tables?
- PaulHoule 7y agoIt's more accurate to say that you can implement the relational algebra via the Unix command line https://en.wikipedia.org/wiki/Relational_algebra https://en.wikipedia.org/wiki/Relational_algebra
- HillaryBriss 7y agook. yeah. pursuing that, i'm wondering if there's a simple way to convince someone that this is true. one idea I saw somewhere was that because awk is part of a Turing complete language, it can be used to implement the relational algebra. though I don't know how to prove that myself, except by actual construction: implementing each part of the relational algebra definition. looking over the definition of relational algebra, at first I wondered: what about a theta join? it's not directly built into the CLI "join" command. but then the article points out that if you can obtain a Cartesian product of two tables then you can use a Select to filter out the rows that do not meet the criteria of your theta join. and then there's division, which I can only guess would depend heavily on some careful awk scripting. and so it goes. IDK. it seems a bit laborious to prove it all by construction.