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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] |
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
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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 520 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
Returns the database character set.
Returns the database collation strategy.
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 375 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
Executes the SQL statement in the context of this connection.
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 544 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
Returns a table's primary key and belonging sequence.
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 620 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
Returns just a table's primary key
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 505 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
Renames a table.
Example:
rename_table('octopuses', 'octopi')
SHOW VARIABLES LIKE 'name'
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 612 def show_variable(name) variables = select_all("select @@#{name} as 'Value'", 'SCHEMA') variables.first['Value'] unless variables.empty? rescue ActiveRecord::StatementInvalid nil end
Technically MySQL allows to create indexes with the sort order syntax but at the moment (5.5) it doesn't yet implement them
Returns true, since this connection adapter supports migrations.
MySQL 4 technically support transaction isolation, but it is affected by a bug where the transaction level gets persisted for the whole session:
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 420 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
Maps logical Rails types to MySQL-specific data types.
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 573 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 784 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 748 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 826 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 790 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 761 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 805 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
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 735 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
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 773 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