Namespace
Methods
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Constants
LOST_CONNECTION_ERROR_MESSAGES = [ "Server shutdown in progress", "Broken pipe", "Lost connection to MySQL server during query", "MySQL server has gone away" ]
 
QUOTED_FALSE = '1', '0'
 
NATIVE_DATABASE_TYPES = { :primary_key => "int(11) auto_increment PRIMARY KEY", :string => { :name => "varchar", :limit => 255 }, :text => { :name => "text" }, :integer => { :name => "int", :limit => 4 }, :float => { :name => "float" }, :decimal => { :name => "decimal" }, :datetime => { :name => "datetime" }, :time => { :name => "time" }, :date => { :name => "date" }, :binary => { :name => "blob" }, :boolean => { :name => "tinyint", :limit => 1 } }
 
INDEX_TYPES = [:fulltext, :spatial]
 
INDEX_USINGS = [:btree, :hash]
 
Class Public methods
emulate_booleans

By default, the MysqlAdapter will consider all columns of type tinyint(1) as boolean. If you wish to disable this emulation (which was the default behavior in versions 0.13.1 and earlier) you can add the following line to your application.rb file:

ActiveRecord::ConnectionAdapters::Mysql[2]Adapter.emulate_booleans = false
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 139
class_attribute :emulate_booleans
new(connection, logger, connection_options, config)

FIXME: Make the first parameter more similar for the two adapters

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 168
def initialize(connection, logger, connection_options, config)
  super(connection, logger)
  @connection_options, @config = connection_options, config
  @quoted_column_names, @quoted_table_names = {}, {}

  @visitor = Arel::Visitors::MySQL.new self

  if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
    @prepared_statements = true
  else
    @prepared_statements = false
  end
end
Instance Public methods
begin_db_transaction()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 332
def begin_db_transaction
  execute "BEGIN"
end
begin_isolated_db_transaction(isolation)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 336
def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end
case_insensitive_comparison(table, attribute, column, value)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 659
def case_insensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    super
  else
    table[attribute].eq(value)
  end
end
case_sensitive_comparison(table, attribute, column, value)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 651
def case_sensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    table[attribute].eq(value)
  else
    super
  end
end
case_sensitive_modifier(node, table_attribute)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 646
def case_sensitive_modifier(node, table_attribute)
  node = Arel::Nodes.build_quoted node, table_attribute
  Arel::Nodes::Bin.new(node)
end
change_column_null(table_name, column_name, null, default = nil)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 528
def change_column_null(table_name, column_name, null, default = nil)
  column = column_for(table_name, column_name)

  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end

  change_column table_name, column_name, column.sql_type, :null => null
end
charset()

Returns the database character set.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 404
def charset
  show_variable 'character_set_database'
end
clear_cache!()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 310
def clear_cache!
  super
  reload_type_map
end
collation()

Returns the database collation strategy.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 409
def collation
  show_variable 'collation_database'
end
create_database(name, options = {})

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 activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 383
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
  else
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
  end
end
current_database()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 399
def current_database
  select_value 'SELECT DATABASE() as db'
end
data_source_exists?(name)
Alias for: table_exists?
drop_table(table_name, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 509
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end
empty_insert_statement_value()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 361
def empty_insert_statement_value
  "VALUES ()"
end
execute(sql, name = nil)

Executes the SQL statement in the context of this connection.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 316
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end
foreign_keys(table_name)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 552
      def foreign_keys(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'
          FROM information_schema.key_column_usage fk
          WHERE fk.referenced_column_name is not null
            AND fk.table_schema = '#{@config[:database]}'
            AND fk.table_name = '#{table_name}'
".strip_heredoc

        create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]

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

          options[:on_update] = extract_foreign_key_action(create_table_info, row['name'], "UPDATE")
          options[:on_delete] = extract_foreign_key_action(create_table_info, row['name'], "DELETE")

          ForeignKeyDefinition.new(table_name, row['to_table'], options)
        end
      end
index_algorithms()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 229
def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end
native_database_types()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 225
def native_database_types
  NATIVE_DATABASE_TYPES
end
pk_and_sequence_for(table)

Returns a table's primary key and belonging sequence.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 628
def pk_and_sequence_for(table)
  execute_and_free("SHOW CREATE TABLE #{quote_table_name(table)}", 'SCHEMA') do |result|
    create_table = each_hash(result).first[:"Create Table"]
    if create_table.to_s =~ /PRIMARY KEY\s+(?:USING\s+\w+\s+)?\((.+)\)/
      keys = $1.split(",").map { |key| key.delete('`"') }
      keys.length == 1 ? [keys.first, nil] : nil
    else
      nil
    end
  end
end
primary_key(table)

Returns just a table's primary key

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 641
def primary_key(table)
  pk_and_sequence = pk_and_sequence_for(table)
  pk_and_sequence && pk_and_sequence.first
end
quoted_date(value)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 285
def quoted_date(value)
  if supports_datetime_with_precision? && value.acts_like?(:time) && value.respond_to?(:usec)
    "#{super}.#{sprintf("%06d", value.usec)}"
  else
    super
  end
end
quoted_false()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 277
def quoted_false
  QUOTED_FALSE
end
quoted_true()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 269
def quoted_true
  QUOTED_TRUE
end
recreate_database(name, options = {})

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 369
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end
rename_index(table_name, old_name, new_name)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 513
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)

Renames a table.

Example:

rename_table('octopuses', 'octopi')
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 504
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
schema_creation()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 57
def schema_creation
  SchemaCreation.new self
end
show_variable(name)

SHOW VARIABLES LIKE 'name'

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 620
def show_variable(name)
  variables = select_all("select @@#{name} as 'Value'", 'SCHEMA')
  variables.first['Value'] unless variables.empty?
rescue ActiveRecord::StatementInvalid
  nil
end
strict_mode?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 682
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end
supports_datetime_with_precision?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 221
def supports_datetime_with_precision?
  version >= '5.6.4'
end
supports_foreign_keys?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 213
def supports_foreign_keys?
  true
end
supports_index_sort_order?()

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 197
def supports_index_sort_order?
  true
end
supports_indexes_in_create?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 209
def supports_indexes_in_create?
  true
end
supports_migrations?()

Returns true, since this connection adapter supports migrations.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 183
def supports_migrations?
  true
end
supports_primary_key?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 187
def supports_primary_key?
  true
end
supports_transaction_isolation?()

MySQL 4 technically support transaction isolation, but it is affected by a bug where the transaction level gets persisted for the whole session:

bugs.mysql.com/bug.php?id=39170

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 205
def supports_transaction_isolation?
  version >= '5.0.0'
end
supports_views?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 217
def supports_views?
  version >= '5.0.0'
end
table_exists?(name)
Also aliased as: data_source_exists?
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 428
def table_exists?(name)
  return false unless name.present?
  return true if tables(nil, nil, name).any?

  name          = name.to_s
  schema, table = name.split('.', 2)

  unless table # A table was provided without a schema
    table  = schema
    schema = nil
  end

  tables(nil, schema, table).any?
end
truncate(table_name, name = nil)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 424
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)

Maps logical Rails types to MySQL-specific data types.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 581
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    case limit
    when 0..0xfff;           "varbinary(#{limit})"
    when nil;                "blob"
    when 0x1000..0xffffffff; "blob(#{limit})"
    else raise(ActiveRecordError, "No binary type has character length #{limit}")
    end
  when 'integer'
    case limit
    when 1; 'tinyint'
    when 2; 'smallint'
    when 3; 'mediumint'
    when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
    when 5..8; 'bigint'
    else raise(ActiveRecordError, "No integer type has byte size #{limit}")
    end
  when 'text'
    case limit
    when 0..0xff;               'tinytext'
    when nil, 0x100..0xffff;    'text'
    when 0x10000..0xffffff;     'mediumtext'
    when 0x1000000..0xffffffff; 'longtext'
    else raise(ActiveRecordError, "No text type has character length #{limit}")
    end
  when 'datetime'
    return super unless precision

    case precision
      when 0..6; "datetime(#{precision})"
      else raise(ActiveRecordError, "No datetime type has precision of #{precision}. The allowed range of precision is from 0 to 6.")
    end
  else
    super
  end
end
unquoted_false()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 281
def unquoted_false
  0
end
unquoted_true()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 273
def unquoted_true
  1
end
valid_type?(type)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 686
def valid_type?(type)
  !native_database_types[type].nil?
end
Instance Protected methods
add_column_sql(table_name, column_name, type, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 792
def add_column_sql(table_name, column_name, type, options = {})
  td = create_table_definition table_name, options[:temporary], options[:options]
  cd = td.new_column_definition(column_name, type, options)
  schema_creation.visit_AddColumn cd
end
add_index_length(option_strings, column_names, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 756
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) && length[name].present?}
    when Integer
      column_names.each {|name| option_strings[name] += "(#{length})"}
    end
  end

  return option_strings
end
add_index_sql(table_name, column_name, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 834
def add_index_sql(table_name, column_name, options = {})
  index_name, index_type, index_columns = add_index_options(table_name, column_name, options)
  "ADD #{index_type} INDEX #{index_name} (#{index_columns})"
end
add_timestamps_sql(table_name, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 844
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 = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 798
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

  options[:name] = column.name
  schema_creation.accept ChangeColumnDefinition.new column, type, options
end
quoted_columns_for_index(column_names, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 769
def quoted_columns_for_index(column_names, options = {})
  option_strings = Hash[column_names.map {|name| [name, '']}]

  # 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
remove_column_sql(table_name, column_name, type = nil, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 826
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)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 830
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 = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 839
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 = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 848
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)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 813
def rename_column_sql(table_name, column_name, new_column_name)
  column  = column_for(table_name, column_name)
  options = {
    name: new_column_name,
    default: column.default,
    null: column.null,
    auto_increment: column.extra == "auto_increment"
  }

  current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
  schema_creation.accept ChangeColumnDefinition.new column, current_type, options
end
subquery_for(key, select)

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 activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 743
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
translate_exception(exception, message)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 781
def translate_exception(exception, message)
  case error_number(exception)
  when 1062
    RecordNotUnique.new(message, exception)
  when 1452
    InvalidForeignKey.new(message, exception)
  else
    super
  end
end