prestogres_jdbc_example.rb

# prestogres jdbc
require "java"
java_import java.util.Properties
require "./postgresql-9.4-1203.jdbc41.jar"
Java::org.postgresql.Driver

db_url = "jdbc:postgresql://localhost:5439/hive"
props = Properties.new
props.set_property "protocolVersion", "2"
props.set_property "user","presto"
props.set_property "password",""
#props.set_property "ssl","true"
#props.set_property "loglevel", "1"
def print_row rs
  puts "%20s%60s%20s%20s" % [rs.get_object("code"), rs.get_object("description"), 
    rs.get_object("total_emp"), rs.get_object("salary")]
end

conn = java.sql.DriverManager.get_connection db_url, props
stmt = conn.create_statement
query = "SELECT code, description, total_emp, salary FROM sample_07 limit 20"
puts query, "%20s%60s%20s%20s" % ["CODE", "DESCRIPTION", "TOTAL_EMP" , "SALARY"]
rs = stmt.execute_query query
while rs.next do
  print_row rs
end

prep_query = "SELECT code, description, total_emp, salary FROM sample_07 where salary > ? order by salary desc limit 20"
prep = conn.prepare_statement prep_query
prep.set_int 1, 100000
puts prep_query, "%20s%60s%20s%20s" % ["CODE", "DESCRIPTION", "TOTAL_EMP" , "SALARY"]
rs = prep.execute_query
while rs.next do
  print_row rs
end