+
+ def add_index(table_name, column_name, options = {})
+ column_names = Array(column_name)
+ index_name = index_name(table_name, :column => column_names)
+
+ if Hash === options # legacy support, since this param was a string
+ index_type = options[:unique] ? "UNIQUE" : ""
+ index_name = options[:name] || index_name
+ index_method = options[:method] || "BTREE"
+ else
+ index_type = options
+ end
+
+ quoted_column_names = column_names.map { |e| quote_column_name(e) }
+ if Hash === options and options[:lowercase]
+ quoted_column_names = quoted_column_names.map { |e| "LOWER(#{e})" }
+ end
+ quoted_column_names = quoted_column_names.join(", ")
+
+ execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} USING #{index_method} (#{quoted_column_names})"
+ end