Connecting to Microsoft SQL Server using Clojure

the prior answers are all correct and work just fine. However, the post is quite old and there are better options out there. Hence I thought it would make sense to update the post for the people searching for a solution (as I was).

It turns out that clojure.java.jdbc is "Stable" (no longer "Active"). It has effectively been superseded by seancorfield/next.jdbc.

Using next.jdbc is rather straightforward and more information can be found in the project page https://github.com/seancorfield/next-jdbc:

Code

(require '[next.jdbc :as jdbc])
(def db {:dbtype "mssql"
         :dbname "database-name"
         :host "host" ;;optional
         :port "port" ;;optional
         :user "sql-authentication-user-name"
         :password "password"})
(def con (jdbc/get-connection db))
(jdbc/execute! con ["select * from sys.objects  where type = 'U'"])

Leiningen configuration

:dependencies [[seancorfield/next.jdbc "1.0.10"]]
               [com.microsoft.sqlserver/mssql-jdbc "7.4.1.jre11"]]

Note: Download the mssql-jdbc driver that suits your jre version and place it in the resources folder of your leiningen project or add the path to the driver in the :dependencies [<path-here>] in your project.clj

Connecting to the database

In the later software versions (Clojure 1.6+, Microsoft SQL Server 2012 and Microsoft JDBC Driver 4.0 for SQL Server) the code posted by Ash works only with these modifications. I've also updated it according to my current knowledge of Clojure code styling guidelines.

(require '[clojure.java.jdbc :as jdbc])
;; you can optionally specify :host and :port to override the defaults
;; of "127.0.0.1" and 1433 respectively:
(def db-spec {:dbtype "mssql"
              :dbname "database-name"
              :user "sql-authentication-user-name"
              :password "password"})

(let [rows (jdbc/query db-spec
                       ["select * from sys.objects  where type = 'U'"])]
  (doseq [row rows] (println (:name row)))))

In the case of having multiple SQL Server instances on the same machine, you can specify the instance name as part of the :host like this (this example is for the default instance name of SQL Server Express on the same machine):

:host "localhost\\sqlexpress"

Configuring Leiningen

To make Leiningen work properly with Microsoft JDBC Driver, merge the following with defproject in project.clj:

:dependencies [[org.clojure/java.jdbc "0.6.1"]
               [com.microsoft.sqlserver/mssql-jdbc "6.3.6.jre8-preview"]]

Found the solution

(use 'clojure.contrib.sql)
    (def db {:classname "com.microsoft.sqlserver.jdbc.SQLServerDriver"
                   :subprotocol "sqlserver"
                   :subname "//server-name:port;database=database-name;user=sql-authentication-user-name;password=password"
    })

    ;Add Classpath to your C:\Program Files\Java\JDBC\sqljdbc_3.0\enu\sqljdbc4.jar
    ;Below code demos how to execute a simple sql select query and print it to console
    ;This query will print all the user tables in your MS SQL Server Database
    (with-connection db 
          (with-query-results rs ["select * from sys.objects  where type = 'U'"] 
               (doseq [row rs] (println (:name row)))
    ))

Also updated the wiki http://en.wikibooks.org/wiki/Clojure_Programming/Examples/JDBC_Examples#Microsoft_SQL_Server

Hopefully this will help someone