If you need to do join like operations on database tables from different
sources that you can't join through SQL, there's a nice library called
table-utils<http://stackoverflow.com/questions/13009939/outer-join-in-clojure>that
you can use. Since it's not released on clojars there's some steps
you'd need to take to use it, but it's all explained in the link.
After you've put it in your project, you can use it by putting the result
sets in a map by just putting a doall over the result set, and join them
like you would in SQL. It has support for inner, outer and full joins.
(let [db2 (sql/with-connection db
(sql/with-query-results rs ["select fields from table"]
(doall rs)))
sql (sql/with-connection db
(sql/with-query-results rs ["select fields from table"]
(doall rs)))]
(left-outer-join db2 sql :db2field :sqlfield))
On Friday, May 24, 2013 4:55:17 PM UTC+2, Mond Ray wrote:
>
> I am starting out to use Clojure to combine and verify data between DB2 on
> a Mainframe, SQL Server and an Atom Feed. Yes, it's such fun working in a
> start-up ;-)
>
> Database wise, all is connecting OK after some Leiningen shenanigans and I
> am now stuck on the mapping part ;-)
>
> The code is below. I want to generate a set of maps that show the
> following:
>
> #({:a2pid 269, :uuid nil}
> {:a2pid 270, :uuid nil}
> {:a2pid 258, :uuid nil}
> {:a2pid 261, :uuid nil}
> {:a2pid 251, :uuid E7D4262C-62B3-4129-9CE4-B342DC1C39FC})
>
> The idea is to have a list of maps that can show where there are gaps
> between the two DBs and, coming next, the Atom feed.
>
> It is essentially a join operation - and maybe that's what I need but I
> cannot figure out where to plonk the magic words.
>
> (defn a2p-records-by-date [query from-date to-date dh-sub-query]
> (sql/with-connection db2
> (sql/with-query-results rs [query from-date to-date]
> (doseq [row rs] (println (str " " (:project_id row) (dh-sub-query
> (:project_id row))))))))
>
> (defn dh-records-by-a2p-id [query a2p-id]
> (sql/with-connection mssql
> (sql/with-query-results rs [query a2p-id]
> (dorun (map #(print (:project_uuid %)) rs)))))
>
> (defn dh-sub-query [a2p-id] (dh-records-by-a2p-id "select PROJECT_UUID
> from PROJECT where A2P_PROJECT_ID = ?" a2p-id))
>
> (a2p-records-by-date "select project_id from PROJECT where timestamp > ?
> and timestamp < ?" "2012-03-02" "2012-03-07" dh-sub-query)
>
> The output looks like this, so I am close!
>
> 269
> 270
> 258
> 261
> E7D4262C-62B3-4129-9CE4-B342DC1C39FC 251
>
> Can anyone help me out about how to generate the maps?
>
> This is just the start as I have many queries to run for many entities, so
> doubtless I will be back again ;-)
>
> Thanks in advance
>
> Ray
>
--
--
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.
