diff options
Diffstat (limited to 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb')
-rw-r--r-- | activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb | 123 |
1 files changed, 106 insertions, 17 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb index dd573ba569..f143fd348e 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -127,10 +127,7 @@ module ActiveRecord super(connection, logger) @connection_options, @config = connection_options, config @quoted_column_names, @quoted_table_names = {}, {} - end - - def self.visitor_for(pool) # :nodoc: - Arel::Visitors::MySQL.new(pool) + @visitor = Arel::Visitors::MySQL.new self end def adapter_name #:nodoc: @@ -155,6 +152,12 @@ module ActiveRecord true end + # Technically MySQL allows to create indexes with the sort order syntax + # but at the moment (5.5) it doesn't yet implement them + def supports_index_sort_order? + true + end + def native_database_types NATIVE_DATABASE_TYPES end @@ -222,6 +225,80 @@ module ActiveRecord # DATABASE STATEMENTS ====================================== + def explain(arel) + sql = "EXPLAIN #{to_sql(arel)}" + start = Time.now + result = exec_query(sql, 'EXPLAIN') + elapsed = Time.now - start + + ExplainPrettyPrinter.new.pp(result, elapsed) + end + + class ExplainPrettyPrinter # :nodoc: + # Pretty prints the result of a EXPLAIN in a way that resembles the output of the + # MySQL shell: + # + # +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ + # | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | + # +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ + # | 1 | SIMPLE | users | const | PRIMARY | PRIMARY | 4 | const | 1 | | + # | 1 | SIMPLE | posts | ALL | NULL | NULL | NULL | NULL | 1 | Using where | + # +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ + # 2 rows in set (0.00 sec) + # + # This is an exercise in Ruby hyperrealism :). + def pp(result, elapsed) + widths = compute_column_widths(result) + separator = build_separator(widths) + + pp = [] + + pp << separator + pp << build_cells(result.columns, widths) + pp << separator + + result.rows.each do |row| + pp << build_cells(row, widths) + end + + pp << separator + pp << build_footer(result.rows.length, elapsed) + + pp.join("\n") + "\n" + end + + private + + def compute_column_widths(result) + [].tap do |widths| + result.columns.each_with_index do |column, i| + cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? 'NULL' : r[i].to_s} + widths << cells_in_column.map(&:length).max + end + end + end + + def build_separator(widths) + padding = 1 + '+' + widths.map {|w| '-' * (w + (padding*2))}.join('+') + '+' + end + + def build_cells(items, widths) + cells = [] + items.each_with_index do |item, i| + item = 'NULL' if item.nil? + justifier = item.is_a?(Numeric) ? 'rjust' : 'ljust' + cells << item.to_s.send(justifier, widths[i]) + end + '| ' + cells.join(' | ') + ' |' + end + + def build_footer(nrows, elapsed) + rows_label = nrows == 1 ? 'row' : 'rows' + "#{nrows} #{rows_label} in set (%.2f sec)" % elapsed + end + end + # Executes the SQL statement in the context of this connection. def execute(sql, name = nil) if name == :skip_logging @@ -309,11 +386,11 @@ module ActiveRecord sql = "SHOW TABLES" end - select_all(sql).map do |table| + select_all(sql).map { |table| table.delete('Table_type') sql = "SHOW CREATE TABLE #{quote_table_name(table.to_a.first.last)}" exec_without_stmt(sql).first['Create Table'] + ";\n\n" - end.join("") + }.join end # Drops the database specified on the +name+ attribute @@ -496,8 +573,8 @@ module ActiveRecord # Returns a table's primary key and belonging sequence. def pk_and_sequence_for(table) - execute_and_free("DESCRIBE #{quote_table_name(table)}", 'SCHEMA') do |result| - keys = each_hash(result).select { |row| row[:Key] == 'PRI' }.map { |row| row[:Field] } + execute_and_free("SHOW INDEX FROM #{quote_table_name(table)} WHERE Key_name = 'PRIMARY'", 'SCHEMA') do |result| + keys = each_hash(result).map { |row| row[:Column_name] } keys.length == 1 ? [keys.first, nil] : nil end end @@ -526,17 +603,29 @@ module ActiveRecord protected + def add_index_length(option_strings, column_names, options = {}) + if options.is_a?(Hash) && length = options[:length] + case length + when Hash + column_names.each {|name| option_strings[name] += "(#{length[name]})" if length.has_key?(name)} + when Fixnum + column_names.each {|name| option_strings[name] += "(#{length})"} + end + end + + return option_strings + end + def quoted_columns_for_index(column_names, options = {}) - length = options[:length] if options.is_a?(Hash) + option_strings = Hash[column_names.map {|name| [name, '']}] - case length - when Hash - column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) } - when Fixnum - column_names.map {|name| "#{quote_column_name(name)}(#{length})"} - else - column_names.map {|name| quote_column_name(name) } - end + # add index length + option_strings = add_index_length(option_strings, column_names, options) + + # add index sort order + option_strings = add_index_sort_order(option_strings, column_names, options) + + column_names.map {|name| quote_column_name(name) + option_strings[name]} end def translate_exception(exception, message) |