Class: ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

Inherits:
AbstractAdapter show all
Includes:
Savepoints
Defined in:
activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

Direct Known Subclasses

Mysql2Adapter, MysqlAdapter

Defined Under Namespace

Classes: Column, MysqlDateTime, MysqlString, SchemaCreation

Constant Summary collapse

LOST_CONNECTION_ERROR_MESSAGES =
[
"Server shutdown in progress",
"Broken pipe",
"Lost connection to MySQL server during query",
"MySQL server has gone away" ]
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]

Constants inherited from AbstractAdapter

ActiveRecord::ConnectionAdapters::AbstractAdapter::ADAPTER_NAME, ActiveRecord::ConnectionAdapters::AbstractAdapter::SIMPLE_INT

Constants included from ActiveSupport::Callbacks

ActiveSupport::Callbacks::CALLBACK_FILTER_TYPES

Instance Attribute Summary

Attributes inherited from AbstractAdapter

#logger, #owner, #pool, #prepared_statements, #schema_cache, #visitor

Attributes included from QueryCache

#query_cache, #query_cache_enabled

Attributes included from DatabaseStatements

#transaction_manager

Instance Method Summary collapse

Methods included from Savepoints

#create_savepoint, #exec_rollback_to_savepoint, #release_savepoint, #supports_savepoints?

Methods inherited from AbstractAdapter

#active?, #adapter_name, #close, #collector, #column_name_for_operation, #create_savepoint, #current_savepoint_name, #disable_extension, #disconnect!, #enable_extension, #expire, #extensions, #lease, #lookup_cast_type, #prefetch_primary_key?, #raw_connection, #reconnect!, #release_savepoint, #requires_reloading?, #reset!, #substitute_at, #supports_ddl_transactions?, #supports_explain?, #supports_extensions?, #supports_partial_index?, #supports_savepoints?, type_cast_config_to_boolean, type_cast_config_to_integer, #type_map, #unprepared_statement, #verify!

Methods included from ColumnDumper

#column_spec, #migration_keys

Methods included from ActiveSupport::Callbacks

#run_callbacks

Methods included from ActiveSupport::Concern

#append_features, #class_methods, extended, #included

Methods included from QueryCache

#cache, #clear_query_cache, dirties_query_cache, #disable_query_cache!, #enable_query_cache!, included, #select_all, #uncached

Methods included from DatabaseLimits

#allowed_index_name_length, #column_name_length, #columns_per_multicolumn_index, #columns_per_table, #in_clause_length, #index_name_length, #indexes_per_table, #joins_per_query, #sql_query_length, #table_alias_length, #table_name_length

Methods included from Quoting

#quote, #quote_string, #quote_table_name_for_assignment, #type_cast

Methods included from DatabaseStatements

#add_transaction_record, #cacheable_query, #default_sequence_name, #delete, #exec_delete, #exec_insert, #exec_query, #exec_rollback_to_savepoint, #exec_update, #insert, #insert_fixture, #join_to_delete, #reset_sequence!, #reset_transaction, #rollback_db_transaction, #rollback_to_savepoint, #sanitize_limit, #select_all, #select_one, #select_rows, #select_value, #select_values, #supports_statement_cache?, #to_sql, #transaction, #transaction_isolation_levels, #transaction_open?, #transaction_state, #update

Methods included from SchemaStatements

#add_column, #add_foreign_key, #add_index_options, #add_reference, #add_timestamps, #assume_migrated_upto_version, #change_table, #column_exists?, #create_join_table, #drop_join_table, #dump_schema_information, #foreign_key_column_for, #index_exists?, #index_name, #index_name_exists?, #initialize_schema_migrations_table, #remove_column, #remove_columns, #remove_foreign_key, #remove_index, #remove_index!, #remove_reference, #remove_timestamps, #table_alias_for, #update_table_definition

Methods included from TimestampDefaultDeprecation

#emit_warning_if_null_unspecified

Constructor Details

#initialize(connection, logger, connection_options, config) ⇒ AbstractMysqlAdapter

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


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# 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 Method Details

#_quote(value) ⇒ Object

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


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 253

def _quote(value) # :nodoc:
  if value.is_a?(Type::Binary::Data)
    "x'#{value.hex}'"
  else
    super
  end
end

#add_index(table_name, column_name, options = {}) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 547

def add_index(table_name, column_name, options = {}) #:nodoc:
  index_name, index_type, index_columns, index_options, index_algorithm, index_using = add_index_options(table_name, column_name, options)
  execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options} #{index_algorithm}"
end

#begin_db_transactionObject


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# 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) ⇒ Object


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# 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

#bulk_change_table(table_name, operations) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 485

def bulk_change_table(table_name, operations) #:nodoc:
  sqls = operations.flat_map do |command, args|
    table, arguments = args.shift, args
    method = :"#{command}_sql"

    if respond_to?(method, true)
      send(method, table, *arguments)
    else
      raise "Unknown method called : #{method}(#{arguments.inspect})"
    end
  end.join(", ")

  execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
end

#case_insensitive_comparison(table, attribute, column, value) ⇒ Object


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# 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) ⇒ Object


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# 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) ⇒ Object


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# 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(table_name, column_name, type, options = {}) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 538

def change_column(table_name, column_name, type, options = {}) #:nodoc:
  execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
end

#change_column_default(table_name, column_name, default) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 523

def change_column_default(table_name, column_name, default) #:nodoc:
  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) ⇒ Object


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# 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

#charsetObject

Returns the database character set.


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 404

def charset
  show_variable 'character_set_database'
end

#clear_cache!Object

– DATABASE STATEMENTS ====================================== ++


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 310

def clear_cache!
  super
  reload_type_map
end

#collationObject

Returns the database collation strategy.


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 409

def collation
  show_variable 'collation_database'
end

#columns(table_name) ⇒ Object

Returns an array of Column objects for the table specified by table_name.


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 469

def columns(table_name)#:nodoc:
  sql = "SHOW FULL FIELDS FROM #{quote_table_name(table_name)}"
  execute_and_free(sql, 'SCHEMA') do |result|
    each_hash(result).map do |field|
      field_name = set_field_encoding(field[:Field])
      sql_type = field[:Type]
      cast_type = lookup_cast_type(sql_type)
      new_column(field_name, field[:Default], cast_type, sql_type, field[:Null] == "YES", field[:Collation], field[:Extra])
    end
  end
end

#columns_for_distinct(columns, orders) ⇒ Object

In MySQL 5.7.5 and up, ONLY_FULL_GROUP_BY affects handling of queries that use DISTINCT and ORDER BY. It requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column. See dev.mysql.com/doc/refman/5.7/en/group-by-handling.html


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 671

def columns_for_distinct(columns, orders) # :nodoc:
  order_columns = orders.reject(&:blank?).map { |s|
    # Convert Arel node to string
    s = s.to_sql unless s.is_a?(String)    # Remove any ASC/DESC modifiers

    s.gsub(/\s+(?:ASC|DESC)\b/i, '')
  }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }

  [super, *order_columns].join(', ')
end

#commit_db_transactionObject

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 341

def commit_db_transaction #:nodoc:
  execute "COMMIT"
end

#create_database(name, options = {}) ⇒ Object

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

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# 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

#create_table(table_name, options = {}) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 481

def create_table(table_name, options = {}) #:nodoc:
  super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
end

#current_databaseObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 399

def current_database
  select_value 'SELECT DATABASE() as db'
end

#disable_referential_integrityObject

REFERENTIAL INTEGRITY ====================================


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 295

def disable_referential_integrity #:nodoc:
  old = select_value("SELECT @@FOREIGN_KEY_CHECKS")

  begin
    update("SET FOREIGN_KEY_CHECKS = 0")
    yield
  ensure
    update("SET FOREIGN_KEY_CHECKS = #{old}")
  end
end

#drop_database(name) ⇒ Object

Drops a MySQL database.

Example:

drop_database('sebastian_development')

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 395

def drop_database(name) #:nodoc:
  execute "DROP DATABASE IF EXISTS `#{name}`"
end

#drop_table(table_name, options = {}) ⇒ Object


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# 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

#each_hash(result) ⇒ Object

The two drivers have slightly different ways of yielding hashes of results, so this method must be implemented to provide a uniform interface.

Raises:

  • (NotImplementedError)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 237

def each_hash(result) # :nodoc:
  raise NotImplementedError
end

#empty_insert_statement_valueObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 361

def empty_insert_statement_value
  "VALUES ()"
end

#emulate_booleansObject

:singleton-method: 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

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 139

class_attribute :emulate_booleans

#error_number(exception) ⇒ Object

Must return the MySQL error number from the exception, if the exception has an error number.

Raises:

  • (NotImplementedError)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 247

def error_number(exception) # :nodoc:
  raise NotImplementedError
end

#exec_rollback_db_transactionObject

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 345

def exec_rollback_db_transaction #:nodoc:
  execute "ROLLBACK"
end

#execute(sql, name = nil) ⇒ Object

Executes the SQL statement in the context of this connection.


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# 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

#execute_and_free(sql, name = nil) {|execute(sql, name)| ... } ⇒ Object

MysqlAdapter has to free a result after using it, so we use this method to write stuff in an abstract way without concerning ourselves about whether it needs to be explicitly freed or not.

Yields:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 323

def execute_and_free(sql, name = nil) #:nodoc:
  yield execute(sql, name)
end

#foreign_keys(table_name) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 552

def foreign_keys(table_name)
  fk_info = select_all <<-SQL.strip_heredoc
    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}'
  SQL

  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_algorithmsObject


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# 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

#indexes(table_name, name = nil) ⇒ Object

Returns an array of indexes for the given table.


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 445

def indexes(table_name, name = nil) #:nodoc:
  indexes = []
  current_index = nil
  execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
    each_hash(result) do |row|
      if current_index != row[:Key_name]
        next if row[:Key_name] == 'PRIMARY' # skip the primary key
        current_index = row[:Key_name]

        mysql_index_type = row[:Index_type].downcase.to_sym
        index_type  = INDEX_TYPES.include?(mysql_index_type)  ? mysql_index_type : nil
        index_using = INDEX_USINGS.include?(mysql_index_type) ? mysql_index_type : nil
        indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], [], nil, nil, index_type, index_using)
      end

      indexes.last.columns << row[:Column_name]
      indexes.last.lengths << row[:Sub_part]
    end
  end

  indexes
end

#join_to_update(update, select) ⇒ Object

In the simple case, MySQL allows us to place JOINs directly into the UPDATE query. However, this does not allow for LIMIT, OFFSET and ORDER. To support these, we must use a subquery.


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 352

def join_to_update(update, select) #:nodoc:
  if select.limit || select.offset || select.orders.any?
    super
  else
    update.table select.source
    update.wheres = select.constraints
  end
end

#native_database_typesObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 225

def native_database_types
  NATIVE_DATABASE_TYPES
end

#new_column(field, default, cast_type, sql_type = nil, null = true, collation = "", extra = "") ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 241

def new_column(field, default, cast_type, sql_type = nil, null = true, collation = "", extra = "") # :nodoc:
  Column.new(field, default, cast_type, sql_type, null, collation, strict_mode?, extra)
end

#pk_and_sequence_for(table) ⇒ Object

Returns a table's primary key and belonging sequence.


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# 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

#prepare_column_options(column, types) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 61

def prepare_column_options(column, types) # :nodoc:
  spec = super
  spec.delete(:limit) if :boolean === column.type
  spec
end

#primary_key(table) ⇒ Object

Returns just a table's primary key


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# 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

#quote_column_name(name) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 261

def quote_column_name(name) #:nodoc:
  @quoted_column_names[name] ||= "`#{name.to_s.gsub('`', '``')}`"
end

#quote_table_name(name) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 265

def quote_table_name(name) #:nodoc:
  @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
end

#quoted_date(value) ⇒ Object


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# 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_falseObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 277

def quoted_false
  QUOTED_FALSE
end

#quoted_trueObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 269

def quoted_true
  QUOTED_TRUE
end

#recreate_database(name, options = {}) ⇒ Object

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


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# 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_column(table_name, column_name, new_column_name) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 542

def rename_column(table_name, column_name, new_column_name) #:nodoc:
  execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
  rename_column_indexes(table_name, column_name, new_column_name)
end

#rename_index(table_name, old_name, new_name) ⇒ Object


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# 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) ⇒ Object

Renames a table.

Example:

rename_table('octopuses', 'octopi')

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# 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_creationObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 57

def schema_creation
  SchemaCreation.new self
end

#show_variable(name) ⇒ Object

SHOW VARIABLES LIKE 'name'


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# 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?Boolean

Returns:

  • (Boolean)

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# 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_bulk_alter?Boolean

:nodoc:

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 191

def supports_bulk_alter? #:nodoc:
  true
end

#supports_datetime_with_precision?Boolean

Returns:

  • (Boolean)

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# 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?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 213

def supports_foreign_keys?
  true
end

#supports_index_sort_order?Boolean

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

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 197

def supports_index_sort_order?
  true
end

#supports_indexes_in_create?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 209

def supports_indexes_in_create?
  true
end

#supports_migrations?Boolean

Returns true, since this connection adapter supports migrations.

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 183

def supports_migrations?
  true
end

#supports_primary_key?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 187

def supports_primary_key?
  true
end

#supports_transaction_isolation?Boolean

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

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 205

def supports_transaction_isolation?
  version >= '5.0.0'
end

#supports_views?Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 217

def supports_views?
  version >= '5.0.0'
end

#table_exists?(name) ⇒ Boolean Also known as: data_source_exists?

Returns:

  • (Boolean)

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# 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

#tables(name = nil, database = nil, like = nil) ⇒ Object Also known as: data_sources

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 413

def tables(name = nil, database = nil, like = nil) #:nodoc:
  sql = "SHOW TABLES "
  sql << "IN #{quote_table_name(database)} " if database
  sql << "LIKE #{quote(like)}" if like

  execute_and_free(sql, 'SCHEMA') do |result|
    result.collect { |field| field.first }
  end
end

#truncate(table_name, name = nil) ⇒ Object


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# 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) ⇒ Object

Maps logical Rails types to MySQL-specific data types.


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# 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_falseObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 281

def unquoted_false
  0
end

#unquoted_trueObject


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 273

def unquoted_true
  1
end

#update_sql(sql, name = nil) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 327

def update_sql(sql, name = nil) #:nodoc:
  super
  @connection.affected_rows
end

#valid_type?(type) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 686

def valid_type?(type)
  !native_database_types[type].nil?
end