module ActiveRecord::ConnectionAdapters

Constants

CHARSETS_OF_4BYTES_MAXLEN

Public Class Methods

new(connection, logger, connection_options, config) click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 65
def initialize(connection, logger, connection_options, config)
  super(connection, logger, config)

  @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))

  if version < '5.0.0'
    raise "Your version of MySQL (#{full_version.match(/^\d+\.\d+\.\d+/)[0]}) is too old. Active Record supports MySQL >= 5.0."
  end
end

Public Instance Methods

begin_db_transaction() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 228
def begin_db_transaction
  execute "BEGIN"
end
begin_isolated_db_transaction(isolation) click to toggle source
# File 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
case_sensitive_comparison(table, attribute, column, value) click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 615
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
charset() click to toggle source

Returns the database character set.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 300
def charset
  show_variable 'character_set_database'
end
clear_cache!() click to toggle source

Clears the prepared statements cache.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 198
def clear_cache!
  reload_type_map
  @statements.clear
end
collation() click to toggle source

Returns the database collation strategy.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 305
def collation
  show_variable 'collation_database'
end
create_database(name, options = {}) click to toggle source

Create a new MySQL database with optional :charset and :collation. Charset defaults to utf8.

Example:

create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
create_database 'matt_development'
create_database 'matt_development', charset: :big5
# File 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
current_database() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 295
def current_database
  select_value 'SELECT DATABASE() as db'
end
data_source_exists?(table_name) click to toggle source
# File 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 = #{quote(schema)} AND table_name = #{quote(name)}"

  select_values(sql, 'SCHEMA').any?
end
data_sources() click to toggle source
# File 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 = #{quote(@config[:database])}"

  select_values(sql, 'SCHEMA')
end
drop_table(table_name, options = {}) click to toggle source

Drops a table from the database.

:force

Set to :cascade to drop dependent objects as well. Defaults to false.

:if_exists

Set to true to only drop the table if it exists. Defaults to false.

:temporary

Set to true to drop temporary table. Defaults to false.

Although this command ignores most options and the block if one is given, it can be helpful to provide these in a migration's change method so it can be reverted. In that case, options and the block will be used by create_table.

# File 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
empty_insert_statement_value() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 257
def empty_insert_statement_value
  "VALUES ()"
end
execute(sql, name = nil) click to toggle source

Executes the SQL statement in the context of this connection.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 217
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end
explain(arel, binds = []) click to toggle source
# File 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
foreign_keys(table_name) click to toggle source
# File 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 = #{quote(schema)}
            AND fk.table_name = #{quote(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
index_algorithms() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 160
def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end
native_database_types() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 156
def native_database_types
  NATIVE_DATABASE_TYPES
end
recreate_database(name, options = {}) click to toggle source

Drops the database specified on the name attribute and creates it again using the provided options.

# File 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
rename_index(table_name, old_name, new_name) click to toggle source
Calls superclass method
# File 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
rename_table(table_name, new_name) click to toggle source

Renames a table.

Example:

rename_table('octopuses', 'octopi')
# File 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
show_variable(name) click to toggle source

SHOW VARIABLES LIKE 'name'

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 594
def show_variable(name)
  select_value("SELECT @@#{name}", 'SCHEMA')
rescue ActiveRecord::StatementInvalid
  nil
end
strict_mode?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 643
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end
supports_advisory_locks?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 144
def supports_advisory_locks?
  true
end
supports_datetime_with_precision?() click to toggle source
# File 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
supports_explain?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 120
def supports_explain?
  true
end
supports_foreign_keys?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 128
def supports_foreign_keys?
  true
end
supports_index_sort_order?() click to toggle source

Technically MySQL allows to create indexes with the sort order syntax but at the moment (5.5) it doesn't yet implement them

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 112
def supports_index_sort_order?
  true
end
supports_indexes_in_create?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 124
def supports_indexes_in_create?
  true
end
supports_migrations?() click to toggle source

Returns true, since this connection adapter supports migrations.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 92
def supports_migrations?
  true
end
supports_primary_key?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 96
def supports_primary_key?
  true
end
supports_statement_cache?() click to toggle source

Returns true, since this connection adapter supports prepared statement caching.

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 106
def supports_statement_cache?
  true
end
supports_transaction_isolation?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 116
def supports_transaction_isolation?
  true
end
supports_views?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 132
def supports_views?
  true
end
table_exists?(table_name) click to toggle source
# File 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
truncate(table_name, name = nil) click to toggle source
# File 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
type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil) click to toggle source

Maps logical Rails types to MySQL-specific data types.

Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 571
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
valid_type?(type) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 647
def valid_type?(type)
  !native_database_types[type].nil?
end

Protected Instance Methods

add_column_sql(table_name, column_name, type, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 747
def add_column_sql(table_name, column_name, type, options = {})
  td = create_table_definition(table_name)
  cd = td.new_column_definition(column_name, type, options)
  schema_creation.accept(AddColumnDefinition.new(cd))
end
add_index_length(quoted_columns, **options) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 715
def add_index_length(quoted_columns, **options)
  if length = options[:length]
    case length
    when Hash
      length = length.symbolize_keys
      quoted_columns.each { |name, column| column << "(#{length[name]})" if length[name].present? }
    when Integer
      quoted_columns.each { |name, column| column << "(#{length})" }
    end
  end

  quoted_columns
end
add_index_sql(table_name, column_name, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 791
def add_index_sql(table_name, column_name, options = {})
  index_name, index_type, index_columns, _, index_algorithm, index_using = add_index_options(table_name, column_name, options)
  index_algorithm[0, 0] = ", " if index_algorithm.present?
  "ADD #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})#{index_algorithm}"
end
add_options_for_index_columns(quoted_columns, **options) click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 729
def add_options_for_index_columns(quoted_columns, **options)
  quoted_columns = add_index_length(quoted_columns, options)
  super
end
add_timestamps_sql(table_name, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 802
def add_timestamps_sql(table_name, options = {})
  [add_column_sql(table_name, :created_at, :datetime, options), add_column_sql(table_name, :updated_at, :datetime, options)]
end
change_column_sql(table_name, column_name, type, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 753
def change_column_sql(table_name, column_name, type, options = {})
  column = column_for(table_name, column_name)

  unless options_include_default?(options)
    options[:default] = column.default
  end

  unless options.has_key?(:null)
    options[:null] = column.null
  end

  td = create_table_definition(table_name)
  cd = td.new_column_definition(column.name, type, options)
  schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
end
extract_precision(sql_type) click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 703
def extract_precision(sql_type)
  if /time/ === sql_type
    super || 0
  else
    super
  end
end
fetch_type_metadata(sql_type, extra = "") click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 711
def fetch_type_metadata(sql_type, extra = "")
  MySQL::TypeMetadata.new(super(sql_type), extra: extra, strict: strict_mode?)
end
remove_column_sql(table_name, column_name, type = nil, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 783
def remove_column_sql(table_name, column_name, type = nil, options = {})
  "DROP #{quote_column_name(column_name)}"
end
remove_columns_sql(table_name, *column_names) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 787
def remove_columns_sql(table_name, *column_names)
  column_names.map {|column_name| remove_column_sql(table_name, column_name) }
end
remove_index_sql(table_name, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 797
def remove_index_sql(table_name, options = {})
  index_name = index_name_for_remove(table_name, options)
  "DROP INDEX #{index_name}"
end
remove_timestamps_sql(table_name, options = {}) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 806
def remove_timestamps_sql(table_name, options = {})
  [remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
end
rename_column_sql(table_name, column_name, new_column_name) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 769
def rename_column_sql(table_name, column_name, new_column_name)
  column  = column_for(table_name, column_name)
  options = {
    default: column.default,
    null: column.null,
    auto_increment: column.auto_increment?
  }

  current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
  td = create_table_definition(table_name)
  cd = td.new_column_definition(new_column_name, current_type, options)
  schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
end
translate_exception(exception, message) click to toggle source
Calls superclass method
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 734
def translate_exception(exception, message)
  case error_number(exception)
  when 1062
    RecordNotUnique.new(message)
  when 1452
    InvalidForeignKey.new(message)
  when 1406
    ValueTooLong.new(message)
  else
    super
  end
end

Private Instance Methods

can_perform_case_insensitive_comparison_for?(column) click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 623
def can_perform_case_insensitive_comparison_for?(column)
  column.case_sensitive?
end
configure_connection() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 831
def configure_connection
  variables = @config.fetch(:variables, {}).stringify_keys

  # By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
  variables['sql_auto_is_null'] = 0

  # Increase timeout so the server doesn't disconnect us.
  wait_timeout = @config[:wait_timeout]
  wait_timeout = 2147483 unless wait_timeout.is_a?(Integer)
  variables['wait_timeout'] = self.class.type_cast_config_to_integer(wait_timeout)

  defaults = [':default', :default].to_set

  # Make MySQL reject illegal values rather than truncating or blanking them, see
  # http://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sqlmode_strict_all_tables
  # If the user has provided another value for sql_mode, don't replace it.
  if sql_mode = variables.delete('sql_mode')
    sql_mode = quote(sql_mode)
  elsif !defaults.include?(strict_mode?)
    if strict_mode?
      sql_mode = "CONCAT(@@sql_mode, ',STRICT_ALL_TABLES')"
    else
      sql_mode = "REPLACE(@@sql_mode, 'STRICT_TRANS_TABLES', '')"
      sql_mode = "REPLACE(#{sql_mode}, 'STRICT_ALL_TABLES', '')"
      sql_mode = "REPLACE(#{sql_mode}, 'TRADITIONAL', '')"
    end
    sql_mode = "CONCAT(#{sql_mode}, ',NO_AUTO_VALUE_ON_ZERO')"
  end
  sql_mode_assignment = "@@SESSION.sql_mode = #{sql_mode}, " if sql_mode

  # NAMES does not have an equals sign, see
  # http://dev.mysql.com/doc/refman/5.7/en/set-statement.html#id944430
  # (trailing comma because variable_assignments will always have content)
  if @config[:encoding]
    encoding = "NAMES #{@config[:encoding]}"
    encoding << " COLLATE #{@config[:collation]}" if @config[:collation]
    encoding << ", "
  end

  # Gather up all of the SET variables...
  variable_assignments = variables.map do |k, v|
    if defaults.include?(v)
      "@@SESSION.#{k} = DEFAULT" # Sets the value to the global or compile default
    elsif !v.nil?
      "@@SESSION.#{k} = #{quote(v)}"
    end
    # or else nil; compact to clear nils out
  end.compact.join(', ')

  # ...and send them all in one query
  @connection.query  "SET #{encoding} #{sql_mode_assignment} #{variable_assignments}"
end
subquery_for(key, select) click to toggle source

MySQL is too stupid to create a temporary table for use subquery, so we have to give it some prompting in the form of a subsubquery. Ugh!

# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 814
def subquery_for(key, select)
  subsubselect = select.clone
  subsubselect.projections = [key]

  # Materialize subquery by adding distinct
  # to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on'
  subsubselect.distinct unless select.limit || select.offset || select.orders.any?

  subselect = Arel::SelectManager.new(select.engine)
  subselect.project Arel.sql(key.name)
  subselect.from subsubselect.as('__active_record_temp')
end
supports_rename_index?() click to toggle source
# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 827
def supports_rename_index?
  mariadb? ? false : version >= '5.7.6'
end