Class: ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

Inherits:
AbstractAdapter
  • Object
show all
Includes:
Savepoints
Defined in:
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

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, #prepare_column_options

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, #quoted_date, #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?, #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?, #columns_for_distinct, #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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 162

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 243

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 527

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_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 314

def begin_db_transaction
  execute "BEGIN"
end

#begin_isolated_db_transaction(isolation) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 318

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 465

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 637

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 629

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 624

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 518

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 503

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 508

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 ⇒ Object

Returns the database character set.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 386

def charset
  show_variable 'character_set_database'
end

#clear_cache! ⇒ Object

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



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 292

def clear_cache!
  super
  reload_type_map
end

#collation ⇒ Object

Returns the database collation strategy.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 391

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 449

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

#commit_db_transaction ⇒ Object

:nodoc:



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

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 365

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 461

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

#current_database ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 381

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

#disable_referential_integrity ⇒ Object

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



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

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 377

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

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



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 489

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 227

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

#empty_insert_statement_value ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 343

def empty_insert_statement_value
  "VALUES ()"
end

#emulate_booleans ⇒ Object

: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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 133

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 237

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

#exec_rollback_db_transaction ⇒ Object

:nodoc:



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

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 298

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 305

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

#foreign_keys(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 532

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_algorithms ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 219

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 425

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 334

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_types ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 215

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 231

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 606

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) ⇒ Object

Returns just a table’s primary key



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 619

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 251

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 255

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

#quoted_false ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 267

def quoted_false
  QUOTED_FALSE
end

#quoted_true ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 259

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 351

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 522

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 493

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 484

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 ⇒ Object 



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# File '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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 600

def show_variable(name)
  variables = select_all("SHOW VARIABLES LIKE '#{name}'", 'SCHEMA')
  variables.first['Value'] unless variables.empty?
end

#strict_mode? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 645

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 185

def supports_bulk_alter? #:nodoc:
  true
end

#supports_foreign_keys? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 207

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 191

def supports_index_sort_order?
  true
end

#supports_indexes_in_create? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 203

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 177

def supports_migrations?
  true
end

#supports_primary_key? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 181

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 199

def supports_transaction_isolation?
  version[0] >= 5
end

#supports_views? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 211

def supports_views?
  version[0] >= 5
end

#table_exists?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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

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

:nodoc:



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

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 405

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 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 561

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 ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 271

def unquoted_false
  0
end

#unquoted_true ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 263

def unquoted_true
  1
end

#update_sql(sql, name = nil) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 309

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

#valid_type?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 649

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