How to initialize the SQLite3 JDBC driver in JRuby?

Question

How do you access SQLite3 via JDBC without using active record?

Answer 1

Here's an example that works with JRuby 1.6.6 (in Ruby 1.8 compat mode) with jdbc-sqlite3 3.7.2.

require 'rubygems'
require 'jdbc/sqlite3'
require 'java'

org.sqlite.JDBC                 # load the driver so DriverManager detects it 
#Java::OrgSqlite::JDBC          # alternate means of same

connection = java.sql.DriverManager.getConnection 'jdbc:sqlite:test.sqlite3'
begin
  statement = connection.createStatement
  begin
    statement.executeUpdate("create table user (name varchar, pass varchar)")
    statement.executeUpdate("insert into user values ('alice', 1234)")
    statement.executeUpdate("insert into user values ('bob', 5678)")
    statement.executeUpdate("insert into user values ('charlie', 'asdf')")

    rs = statement.executeQuery("select * from user")
    begin
      puts "user\tpass"
      while rs.next
        puts ["#{rs.getString(1)}",
              "#{rs.getString(2)}"].join("\t")
      end
    ensure
      rs.close
    end

  ensure
    statement.close
  end
ensure
  connection.close
end

Output:

$ rm -f test.sqlite3; ruby sql.rb
user    pass
------------
alice   1234
bob     5678
charlie asdf

Answer 2

Install the jdbc-sqlite3 gem

Then, in your jruby script:

require 'jdbc/sqlite3'
url = "jdbc:sqlite:path.to.your.db"
begin        
    Java::org.sqlite.JDBC #initialize the driver
    connection = JavaLang::DriverManager.getConnection(url) #grab your connection
rescue => error      
    #handle error
end