класс ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 228
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 232
def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 616
def case_sensitive_comparison(table, attribute, column, value)
  if !value.nil? && column.collation && !column.case_sensitive?
    table[attribute].eq(Arel::Nodes::Bin.new(Arel::Nodes::BindParam.new))
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 300
def charset
  show_variable 'character_set_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 198
def clear_cache!
  reload_type_map
  @statements.clear
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 305
def collation
  show_variable 'collation_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 279
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')} COLLATE #{quote_table_name(options[:collation])}"
  else
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')}"
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 295
def current_database
  select_value 'SELECT DATABASE() as db'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 347
def data_source_exists?(table_name)
  return false unless table_name.present?

  schema, name = extract_schema_qualified_name(table_name)

  sql = "SELECT table_name FROM information_schema.tables "
  sql << "WHERE table_schema = #{schema} AND table_name = #{name}"

  select_values(sql, 'SCHEMA').any?
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 325
def data_sources
  sql = "SELECT table_name FROM information_schema.tables "
  sql << "WHERE table_schema = DATABASE()"

  select_values(sql, 'SCHEMA')
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 465
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 257
def empty_insert_statement_value
  "VALUES ()"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 217
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 207
def explain(arel, binds = [])
  sql     = "EXPLAIN #{to_sql(arel, binds)}"
  start   = Time.now
  result  = exec_query(sql, 'EXPLAIN', binds)
  elapsed = Time.now - start

  MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 515
      def foreign_keys(table_name)
        raise ArgumentError unless table_name.present?

        schema, name = extract_schema_qualified_name(table_name)

        fk_info = select_all("          SELECT fk.referenced_table_name AS 'to_table',
                 fk.referenced_column_name AS 'primary_key',
                 fk.column_name AS 'column',
                 fk.constraint_name AS 'name',
                 rc.update_rule AS 'on_update',
                 rc.delete_rule AS 'on_delete'
          FROM information_schema.key_column_usage fk
          JOIN information_schema.referential_constraints rc
          USING (constraint_schema, constraint_name)
          WHERE fk.referenced_column_name IS NOT NULL
            AND fk.table_schema = #{schema}
            AND fk.table_name = #{name}
            AND rc.table_name = #{name}
".strip_heredoc, 'SCHEMA')

        fk_info.map do |row|
          options = {
            column: row['column'],
            name: row['name'],
            primary_key: row['primary_key']
          }

          options[:on_update] = extract_foreign_key_action(row['on_update'])
          options[:on_delete] = extract_foreign_key_action(row['on_delete'])

          ForeignKeyDefinition.new(table_name, row['to_table'], options)
        end
      end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 160
def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 156
def native_database_types
  NATIVE_DATABASE_TYPES
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 265
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 469
def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    validate_index_length!(table_name, new_name)

    execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 445
def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 595
def show_variable(name)
  select_value("SELECT @@#{name}", 'SCHEMA')
rescue ActiveRecord::StatementInvalid
  nil
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 644
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 144
def supports_advisory_locks?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 136
def supports_datetime_with_precision?
  if mariadb?
    version >= '5.3.0'
  else
    version >= '5.6.4'
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 120
def supports_explain?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 128
def supports_foreign_keys?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 112
def supports_index_sort_order?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 124
def supports_indexes_in_create?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 92
def supports_migrations?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 96
def supports_primary_key?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 106
def supports_statement_cache?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 116
def supports_transaction_isolation?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 132
def supports_views?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 336
      def table_exists?(table_name)
        # Update lib/active_record/internal_metadata.rb when this gets removed
        ActiveSupport::Deprecation.warn("          #table_exists? currently checks both tables and views.
          This behavior is deprecated and will be changed with Rails 5.1 to only check tables.
          Use #data_source_exists? instead.
".squish)

        data_source_exists?(table_name)
      end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 332
def truncate(table_name, name = nil)
  execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 572
def type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil)
  sql = case type.to_s
  when 'integer'
    integer_to_sql(limit)
  when 'text'
    text_to_sql(limit)
  when 'blob'
    binary_to_sql(limit)
  when 'binary'
    if (0..0xfff) === limit
      "varbinary(#{limit})"
    else
      binary_to_sql(limit)
    end
  else
    super(type, limit, precision, scale)
  end

  sql << ' unsigned' if unsigned && type != :primary_key
  sql
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 648
def valid_type?(type)
  !native_database_types[type].nil?
end