On Tue, Sep 17, 2013 at 02:28:08AM -0700, Daniel Neal wrote: > I'd be interested in knowing some more about your approach compared to that > of ClojureQL and the motivation behind it.
Sure! The basic difference is that I tried to be a little bit more rigid in how queries must be constructed. I tried to ensure that the generated queries weren't just valid SQL, but that they were also sensible and unambiguous (or, if there isn't enough information to make a sensible, unambiguous, query, that it throws an exception). As an example, in ClojureQL you can create the following query, which will compile into a query without any issue: (join (table :users) (table :people) (where (= :uid :pid))) but the result of this query (or even the structure of the result) is difficult to determine by examining the code. Even worse, because the :uid and :pid aren't from either table explicitly, this could fail on the database if both tables have a :uid or :pid field. The equivalent query in clojure-sql, (join (table :users) (table :people) :on `(= :uid :pid)) will fail, telling you there's an ambiguous field :uid in the query. If you disambiguate :uid (by projecting :uid in either of the tables) then it will complain about :pid. My ideal is that you could treat a query as some opaque object about which you can only know two things: the "shape" of the data it specifies, and (after executing the query) the data that it specifies. You should then be able to arbitrarily apply clojure-sql functions to those queries to produce new opaque queries without any concern about how the subqueries were produced (with each of the functions causing a known, predictable, effect on the execution result). At the moment this should be true of all the relational operators (project/select/rename/join), the set operations (union/intersection) and some other operations (take/drop/sort) but it's not true of the grouping operations (group/having). Carlo -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
