This library looks great! I've always liked ClojureQL much more than the other Clojure SQL libraries, exactly for its emphasis on composability and relational algebra.
At first looks - your library looks like it will be easier to extend for different database servers... I'd be interested in knowing some more about your approach compared to that of ClojureQL and the motivation behind it. Dan On Saturday, July 6, 2013 5:34:37 PM UTC+2, r0man wrote: > > You can do this with the second argument to the where function. I added an > example here: > > https://github.com/r0man/sqlingvo/blob/master/test/sqlingvo/test/core.clj#L24 > > On Saturday, July 6, 2013 4:02:23 PM UTC+2, Carlo wrote: >> >> This is a fairly restricted composition, though: >> >> (def triangles (compose (select [:color :num_sides] (from :shapes)) >> (where '(= :num_sides 3)))) >> (def green-triangles (compose triangles >> (where '(= :color "green")))) >> (sql green-triangles) >> ;=> ["SELECT color, num_sides FROM shapes WHERE (color = ?)" "green"] >> >> We've lost our `num_sides` selection, so now our query is wrong. "Last >> clause wins" means you have to be aware of the previous ones to ensure you >> don't obliterate them when "composing". >> >> The same example in `clojure-sql`: >> >> (def triangles (-> (table :shapes) >> (project [:color :num_sides]) >> (select '(= :num_sides 3)))) >> (def green-triangles (select triangles '(= :color :green))) >> (deref green-triangles) >> ;=> ["SELECT \"shapes2142\".\"color\" AS \"color\", >> \"shapes2142\".\"num_sides\" AS \"num_sides\" FROM \"shapes\" AS >> \"shapes2142\" WHERE ((\"shapes2142\".\"num_sides\" = 3) AND >> (\"shapes2142\".\"color\" = ?))" "green"] >> >> On 6 July 2013 22:37, r0man <roman....@burningswell.com> wrote: >> >>> Composing queries is done via "compose". >>> >>> Take a look here: >>> https://github.com/r0man/sqlingvo/blob/master/test/sqlingvo/test/core.clj#L16 >>> >>> >>> On Saturday, July 6, 2013 5:46:06 AM UTC+2, Carlo wrote: >>> >>>> Hey Roman, >>>> >>>> The issue that I see with `sqlingvo`, and the thing which I was trying >>>> to solve for myself, is that it doesn't compose well. Unless I'm missing >>>> something, you have to generate the entire query in the one `sql` form. To >>>> me, this is a big restriction and was the number one thing I was trying to >>>> fix with `clojure-sql`. >>>> >>>> The basic sort of thing I want to be able to do is this: >>>> >>>> (def users (-> (table :users) (project [:id :person :username]))) >>>> (def people (-> (table :people) (project [:id :first-name]))) >>>> >>>> (def combined-query (-> people >>>> (rename {:id :person}) >>>> (join users) >>>> (project [:username :first-name]))) >>>> >>>> So now in queries I can use `people`, `users` and `combined-query` in >>>> the same way. The only difference in terms of how I can compose them is >>>> that they expose different fields (`users` exposes [:id, :person, >>>> :username], `people` exposes [:id :first-name], `combined-query` exposes >>>> [:username :first-name]). In this example it's not completely obvious why >>>> this would be beneficial, but it means that I can change `users`, for >>>> instance, to also have a `(select '(= :deleted false)` in its definition >>>> and no other code has to change. They will all join/query against the >>>> users >>>> where `deleted` is false without any other modifications of code. >>>> >>>> This freedom of composition is what you have in relational algebra, and >>>> what I was trying to get in Clojure as well. All the naming of tables and >>>> field aliases and everything is handled by the library, so you only have >>>> to >>>> worry about constructing the queries. Unfortunately SQL provides a number >>>> of operations outside of the relational algebra model (grouping, sorting, >>>> take/drop), so they've been "tacked on" as a bit of an afterthought and >>>> could probably use some improvement. >>>> >>>> Looking at `sqlingvo` did show up a mistake that I made in how I was >>>> dealing with sorts, though, so thanks for that! I think our libraries just >>>> have fairly different concerns at the moment. >>>> >>>> Carlo >>>> >>>> >>>> On 5 July 2013 20:59, r0man <roman....@burningswell.**com> wrote: >>>> >>>>> Hi Carlo, >>>>> >>>>> if you'are looking for generating more complex SQL there's also: >>>>> >>>>> https://github.com/r0man/**sqlingvo<https://github.com/r0man/sqlingvo> >>>>> >>>>> Roman. >>>>> >>>>> On Wednesday, July 3, 2013 10:48:07 AM UTC+2, Carlo wrote: >>>>>> >>>>>> Hey guys! >>>>>> >>>>>> I've been working on a small library to make writing SQL queries a >>>>>> little bit easier. It's along the same lines as ClojureQL, but takes a >>>>>> different approach and compiles into quite different SQL in the end. >>>>>> >>>>>> At the moment it's quite immature, but it should be able to support >>>>>> any queries which can be expressed in relational algebra. There will be >>>>>> some SQL queries which can't be expressed in clojure-sql, but hopefully >>>>>> there won't be too many of those. A greater limitation is that at the >>>>>> moment the SQL generation is specific to the PostgresSQL database >>>>>> (although >>>>>> any contributions for other databases are welcome!). >>>>>> >>>>>> Dependency vector: [clojure-sql "0.1.0"] >>>>>> Repository: >>>>>> https://bitbucket.org/czan/**clo**jure-sql<https://bitbucket.org/czan/clojure-sql> >>>>>> Clojars link: >>>>>> https://clojars.org/clojure-**sq**l<https://clojars.org/clojure-sql> >>>>>> >>>>>> Let me know what you think! >>>>>> >>>>>> Carlo >>>>>> >>>>> -- >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Clojure" group. >>>>> To post to this group, send email to clo...@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+u...@**googlegroups.com >>>>> >>>>> For more options, visit this group at >>>>> http://groups.google.com/**group/clojure?hl=en<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+u...@**googlegroups.com. >>>>> >>>>> For more options, visit >>>>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> >>>>> . >>>>> >>>>> >>>>> >>>> >>>> -- >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To post to this group, send email to clo...@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+u...@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+u...@googlegroups.com. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >>> >> >> -- -- 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.
