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existing.mdwn

Last time I created an abstract model, a mathematical one. Then I decided I want to examine existing query languages and see how they perform compared to my model. I would like to examine two kinds of languages:

1. Logical programming languages (query real-time in-memory data)
2. Database query languages (query potentially huge datasets stores on disk)

There’s one more special thing I want to learn, especially from logical programming: How to combine procedural programming with the logic. It is very important because some relations are realized as stored data (e.g. hasLicense for a SourceFile object mapped to its License object), others are computed from these (e.g. does a given file have a license specified) and others are predefined because they operate on primitive type (e.g. number comparison). Others may be more complicated, e.g. string lexicographical comparison or string concatenation.

This is where I should start:

• https://en.wikipedia.org/wiki/Logic_programming
• https://en.wikipedia.org/wiki/Query_language

Okay. I went over some Wikipedia articles, and now I want to consider the following:

• Read about Datalog and Prolog query syntax
• Go over sparql here: http://www.w3.org/TR/sparql11-query/
• Try to plan my own query language based on the model I defined, concentrating on abstract syntax first