Getting Clojure/Leiningen to talk to Oracle

06 Sep 2013 →

I’ve just started learning Clojure and have been trying desperately to get my Leiningen project to talk to an Oracle database. All of my enterprise’s data is wrapped up in Oracle, so to do anyting useful or interesting with Clojure, I had to first overcome this step.

The following is surely a no-brainer for experienced Java developers, but I come from Ruby and am new to both Java and Clojure. I hope this helps others coming into Clojure from this angle.

Download Oracle JDBC driver

If you don’t already have an Oracle JDBC driver (ojdbc5.jar, ojdbc6.jar, ojdbc14.jar), you’ll want to download it from Oracle first.

Install ojdbc jar to local Maven repository

Install your JDBC driver to your local Maven repo with this command:

mvn install:install-file -X -DgroupId=local -DartifactId=ojdbc6 -Dversion=11.2.0.3 -Dpackaging=jar -Dfile=/opt/oracle/instantclient/ojdbc6.jar -DgeneratePom=true

Note a few things here:

groupId, which would normally be something like com.oracle is replaced with local. This can be anything you want; self or poo would work just as well.
Make sure version matches the version you downloaded from Oracle.
file needs to point to an absolute path to your jar file. Relative paths don’t seem to work.

Reference your local respository in project.clj

In your project.clj file, you can now specify your proprietary library as you would any other dependency. Just be sure to prefix it with the value you used for groupId in your maven command; local in this case:

  :dependencies [[org.clojure/clojure "1.5.1"]
                 [org.clojure/java.jdbc "0.3.0-alpha4"]
                 [local/ojdbc6 "11.2.0.3"]

Trying it out

Huzzah! My cheesy query now returns results:

(require '[clojure.java.jdbc :as j]
         '[clojure.java.jdbc.sql :as s])

(def db {:classname "oracle.jdbc.driver.OracleDriver"
         :subprotocol "oracle"
         :subname "thin:@somehost:1521/some_service"
         :user "some_user"
         :password "some_pass"})

(j/query db (s/select * :dual))

Returns the familiar ol’:

({:dummy "X"})