# File lib/active_record/connection_adapters/abstract/schema_statements.rb, line 255 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 else index_type = options end quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ") execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{quoted_column_names})" end