insert_records.rb

# INSERT RECORDS INTO A DB
# Use case: To insert millions of records into a local db to test scripts.
#           Testing scripts that affect millions of records on a remote db is very time consuming.
require('mysql2')

class Table
  # @params cur_index [The id to start the insertion at]
  # @params num_records [Number of records to insert starting at the id above]
  def insert_records(cur_index, num_records)
    end_index = cur_index + num_records
    while cur_index < end_index  do
      client.query("INSERT into emails VALUES('#{cur_index}', 'address #{cur_index}')")
      cur_index += 1
      if cur_index % 100000 == 0
        puts "At index: #{cur_index}"
      end
    end

  end

  def client
    @client ||= Mysql2::Client.new(:host => "localhost", :username => "root", :database => "test_emails")
  end

end

Table.new.insert_records(1,1000000)