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" }, :timestamp => { :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 141
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 175
def initialize(connection, logger, connection_options, config)
  super(connection, logger)
  @connection_options, @config = connection_options, config
  @quoted_column_names, @quoted_table_names = {}, {}

  if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
    @prepared_statements = true
    @visitor = Arel::Visitors::MySQL.new self
  else
    @visitor = unprepared_visitor
  end
end
Instance Public methods
add_column_position!(sql, options)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 560
def add_column_position!(sql, options)
  if options[:first]
    sql << " FIRST"
  elsif options[:after]
    sql << " AFTER #{quote_column_name(options[:after])}"
  end
end
begin_db_transaction()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 318
def begin_db_transaction
  execute "BEGIN"
end
begin_isolated_db_transaction(isolation)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 322
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 597
def case_insensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    super
  else
    table[attribute].eq(value)
  end
end
case_sensitive_modifier(node)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 593
def case_sensitive_modifier(node)
  Arel::Nodes::Bin.new(node)
end
change_column_default(table_name, column_name, default)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 499
def change_column_default(table_name, column_name, default)
  column = column_for(table_name, column_name)
  change_column table_name, column_name, column.sql_type, :default => default
end
change_column_null(table_name, column_name, null, default = nil)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 504
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 390
def charset
  show_variable 'character_set_database'
end
collation()

Returns the database collation strategy.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 395
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 369
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 385
def current_database
  select_value 'SELECT DATABASE() as db'
end
drop_table(table_name, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 487
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}"
end
empty_insert_statement_value()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 347
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 302
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end
index_algorithms()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 234
def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end
limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 605
def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
  where_sql
end
native_database_types()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 230
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 575
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 588
def primary_key(table)
  pk_and_sequence = pk_and_sequence_for(table)
  pk_and_sequence && pk_and_sequence.first
end
quote(value, column = nil)

QUOTING ==================================================

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 259
def quote(value, column = nil)
  if value.kind_of?(String) && column && column.type == :binary
    s = value.unpack("H*")[0]
    "x'#{s}'"
  elsif value.kind_of?(BigDecimal)
    value.to_s("F")
  else
    super
  end
end
quoted_false()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 282
def quoted_false
  QUOTED_FALSE
end
quoted_true()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 278
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 355
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 491
def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    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 482
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 34
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 569
def show_variable(name)
  variables = select_all("SHOW VARIABLES LIKE '#{name}'", 'SCHEMA')
  variables.first['Value'] unless variables.empty?
end
strict_mode?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 609
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, 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 207
def supports_index_sort_order?
  true
end
supports_migrations?()

Returns true, since this connection adapter supports migrations.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 193
def supports_migrations?
  true
end
supports_primary_key?()
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 197
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 226
def supports_transaction_isolation?
  version[0] >= 5
end
table_exists?(name)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 409
def table_exists?(name)
  return false unless name
  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
type_cast(value, column)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 211
def type_cast(value, column)
  case value
  when TrueClass
    1
  when FalseClass
    0
  else
    super
  end
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 529
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
  else
    super
  end
end
valid_type?(type)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 613
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 666
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 630
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 Fixnum
      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 710
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)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 720
def add_timestamps_sql(table_name)
  [add_column_sql(table_name, :created_at, :datetime), add_column_sql(table_name, :updated_at, :datetime)]
end
change_column_sql(table_name, column_name, type, options = {})
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 672
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 643
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 702
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 706
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 715
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)
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 724
def remove_timestamps_sql(table_name)
  [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 687
def rename_column_sql(table_name, column_name, new_column_name)
  options = { name: new_column_name }

  if column = columns(table_name).find { |c| c.name == column_name.to_s }
    options[:default] = column.default
    options[:null] = column.null
    options[:auto_increment] = (column.extra == "auto_increment")
  else
    raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
  end

  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 621
def subquery_for(key, select)
  subsubselect = select.clone
  subsubselect.projections = [key]

  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 655
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