copy_table_contents

# File activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb, line 580
        def copy_table_contents(from, to, columns, rename = {}) #:nodoc:
          column_mappings = Hash[columns.map {|name| [name, name]}]
          rename.each { |a| column_mappings[a.last] = a.first }
          from_columns = columns(from).collect {|col| col.name}
          columns = columns.find_all{|col| from_columns.include?(column_mappings[col])}
          quoted_columns = columns.map { |col| quote_column_name(col) } * ','

          quoted_to = quote_table_name(to)

          raw_column_mappings = Hash[columns(from).map { |c| [c.name, c] }]

          exec_query("SELECT * FROM #{quote_table_name(from)}").each do |row|
            sql = "INSERT INTO #{quoted_to} (#{quoted_columns}) VALUES ("

            column_values = columns.map do |col|
              quote(row[column_mappings[col]], raw_column_mappings[col])
            end

            sql << column_values * ', '
            sql << ')'
            exec_query sql
          end
        end