Added dbsum--simple database checksum program

dbsum

@@ -0,0 +1,55 @@
+#!/usr/bin/env ruby
+# 
+# dbsum.rb - Checksum a database. Useful when trying to quickly
+# determine if two databases are equivalent. Takes the count of each
+# table, the contents of the first and last record in each table (if
+# any) and then md5sums the whole mess.
+require 'rubygems'
+require 'mysql'
+require 'digest/md5'
+
+database=ARGV[0] || 'leadgen_development'
+
+tables = []
+stats = Hash.new { |h,k| h[k] = Hash.new }
+
+begin
+  # connect to the MySQL server
+  dbh = Mysql.real_connect("localhost", "root", "", database)
+
+  # get tables
+
+  res = dbh.query("SHOW TABLES")
+  while row = res.fetch_row do
+    tables << row[0]
+  end
+  res.free
+  columns = 0
+  tables.each do |table|
+    # DANGER - these leak memory because they never call res.free.
+    # Don't use this in a long-running script!
+    stats[table][:count] = dbh.query("SELECT COUNT(*) FROM #{table}").fetch_row[0]
+
+    # Get contents of first and last row. FIXME: Not all tables have
+    # id columns! They SHOULD in the Railsverse, but might not--habtm
+    # tables notoriously do not have ids.
+  end
+
+rescue Mysql::Error => e
+  puts "Error code: #{e.errno}"
+  puts "Error message: #{e.error}"
+  puts "Error SQLSTATE: #{e.sqlstate}" if e.respond_to?("sqlstate")
+ensure
+  # disconnect from server
+  dbh.close if dbh
+end
+
+fingerprint = tables.sort.map {|t| "#{t}:#{stats[t][:count]}"} * ';'
+
+puts '-' * 80
+puts "Database Signature:"
+puts fingerprint
+puts '-' * 80
+puts "Database Fingerprint: #{Digest::SHA1.hexdigest(fingerprint)}"
+puts '-' * 80
+