CODEWITHSUNDEEP
postgresqlclojure
rbb
rbb

Reputation: 999

Clojure - Postgres No Suitable driver found

I have defined my postgres database as 

(def db {:subprotocol "postgresql"
         :subname "//localhost:5432/mydb"
         :user "admin"
         :password "password"})

I have also defined a function 

(defn get-users []
  (sql/query db ["select * from users"]))

where sql is [clojure.java.jdbc :as sql]

If I run (get-users) I get the error

SQLException No suitable driver found for jdbc:postgresql://127.0.0.1:5432/mydb  java.sql.DriverManager.getConnection (DriverManager.java:689)

I've seen from other Java posts that I need to load the driver using Class.forName("org.postgresql.Driver");

1) What does this mean?

2) How do I do this/solve my error in Clojure?

Upvotes: 2

Views: 2264

Answers (2)

Josh
Josh

Reputation: 4816

The solution is to add this to your :dependencies in your project.clj:

[org.postgresql/postgresql "42.1.4"]

Also, while your db definition is fine, instead of the concatenated string for :subname, you can also separately define the host, port, and db name, which makes it more modular and composable in case any one of them changes:

(def db {:dbtype "postgresql"
         :dbname "mydb"
         :host "localhost"
         :port 5432
         :user "userrole"
         :password "password"})

Upvotes: 7

Chris Murphy
Chris Murphy

Reputation: 6509

This means that the JVM needs to have loaded the Postgres driver class before the driver can be used. The sql/query call uses the driver. Usually in Java classes are instantiated, so the class is automatically loaded. But notice that your code has no new, nor is a static factory (constructor) method called. With the call to sql/query you are in fact directly calling the function java.sql.DriverManager.getConnection, without the class DriverManager ever having been loaded. Presumably loading Driver loads DriverManager.

From http://clojure-doc.org/articles/language/interop.html I found this:

(Class/forName "java.util.Date")

So you could try:

(Class/forName "org.postgresql.Driver")

Upvotes: 1

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