diff options
Diffstat (limited to 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb')
| -rw-r--r-- | activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb new file mode 100644 index 0000000000..72cf490d7e --- /dev/null +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -0,0 +1,552 @@ +require 'active_support/core_ext/object/blank' + +module ActiveRecord + module ConnectionAdapters + class AbstractMysqlAdapter < AbstractAdapter + class Column < ConnectionAdapters::Column + def extract_default(default) + if sql_type =~ /blob/i || type == :text + if default.blank? + return null ? nil : '' + else + raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}" + end + elsif missing_default_forged_as_empty_string?(default) + nil + else + super + end + end + + def has_default? + return false if sql_type =~ /blob/i || type == :text #mysql forbids defaults on blob and text columns + super + end + + private + + def extract_limit(sql_type) + case sql_type + when /blob|text/i + case sql_type + when /tiny/i + 255 + when /medium/i + 16777215 + when /long/i + 2147483647 # mysql only allows 2^31-1, not 2^32-1, somewhat inconsistently with the tiny/medium/normal cases + else + super # we could return 65535 here, but we leave it undecorated by default + end + when /^bigint/i; 8 + when /^int/i; 4 + when /^mediumint/i; 3 + when /^smallint/i; 2 + when /^tinyint/i; 1 + else + super + end + end + + # MySQL misreports NOT NULL column default when none is given. + # We can't detect this for columns which may have a legitimate '' + # default (string) but we can for others (integer, datetime, boolean, + # and the rest). + # + # Test whether the column has default '', is not null, and is not + # a type allowing default ''. + def missing_default_forged_as_empty_string?(default) + type != :string && !null && default == '' + end + end + + ## + # :singleton-method: + # By default, the MysqlAdapter will consider all columns of type <tt>tinyint(1)</tt> + # 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 + class_attribute :emulate_booleans + self.emulate_booleans = true + + LOST_CONNECTION_ERROR_MESSAGES = [ + "Server shutdown in progress", + "Broken pipe", + "Lost connection to MySQL server during query", + "MySQL server has gone away" ] + + QUOTED_TRUE, QUOTED_FALSE = '1', '0' + + NATIVE_DATABASE_TYPES = { + :primary_key => "int(11) DEFAULT NULL 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 } + } + + # FIXME: Make the first parameter more similar for the two adapters + def initialize(connection, logger, connection_options, config) + super(connection, logger) + @connection_options, @config = connection_options, config + @quoted_column_names, @quoted_table_names = {}, {} + end + + def self.visitor_for(pool) # :nodoc: + Arel::Visitors::MySQL.new(pool) + end + + def adapter_name #:nodoc: + self.class::ADAPTER_NAME + end + + # Returns true, since this connection adapter supports migrations. + def supports_migrations? + true + end + + def supports_primary_key? + true + end + + # Returns true, since this connection adapter supports savepoints. + def supports_savepoints? + true + end + + def native_database_types + NATIVE_DATABASE_TYPES + end + + # HELPER METHODS =========================================== + + # The two drivers have slightly different ways of yielding hashes of results, so + # this method must be implemented to provide a uniform interface. + def each_hash(result) # :nodoc: + raise NotImplementedError + end + + # Overridden by the adapters to instantiate their specific Column type. + def new_column(field, default, type, null) # :nodoc: + Column.new(field, default, type, null) + end + + # Must return the Mysql error number from the exception, if the exception has an + # error number. + def error_number(exception) # :nodoc: + raise NotImplementedError + end + + # QUOTING ================================================== + + def quote(value, column = nil) + if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary) + s = column.class.string_to_binary(value).unpack("H*")[0] + "x'#{s}'" + elsif value.kind_of?(BigDecimal) + value.to_s("F") + else + super + end + end + + def quote_column_name(name) #:nodoc: + @quoted_column_names[name] ||= "`#{name.to_s.gsub('`', '``')}`" + end + + def quote_table_name(name) #:nodoc: + @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`') + end + + def quoted_true + QUOTED_TRUE + end + + def quoted_false + QUOTED_FALSE + end + + # REFERENTIAL INTEGRITY ==================================== + + def disable_referential_integrity(&block) #: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 + + # DATABASE STATEMENTS ====================================== + + # Executes the SQL statement in the context of this connection. + def execute(sql, name = nil) + if name == :skip_logging + @connection.query(sql) + else + log(sql, name) { @connection.query(sql) } + end + rescue ActiveRecord::StatementInvalid => exception + if exception.message.split(":").first =~ /Packets out of order/ + raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information. If you're on Windows, use the Instant Rails installer to get the updated mysql bindings." + else + raise + end + end + + # MysqlAdapter has to free a result after using it, so we use this method to write + # stuff in a abstract way without concerning ourselves about whether it needs to be + # explicitly freed or not. + def execute_and_free(sql, name = nil) #:nodoc: + yield execute(sql, name) + end + + def update_sql(sql, name = nil) #:nodoc: + super + @connection.affected_rows + end + + def begin_db_transaction + execute "BEGIN" + rescue Exception + # Transactions aren't supported + end + + def commit_db_transaction #:nodoc: + execute "COMMIT" + rescue Exception + # Transactions aren't supported + end + + def rollback_db_transaction #:nodoc: + execute "ROLLBACK" + rescue Exception + # Transactions aren't supported + end + + def create_savepoint + execute("SAVEPOINT #{current_savepoint_name}") + end + + def rollback_to_savepoint + execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}") + end + + def release_savepoint + execute("RELEASE SAVEPOINT #{current_savepoint_name}") + end + + # 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. However, MySQL is too stupid to create a + # temporary table for this automatically, so we have to give it some prompting + # in the form of a subsubquery. Ugh! + def join_to_update(update, select) #:nodoc: + if select.limit || select.offset || select.orders.any? + subsubselect = select.clone + subsubselect.projections = [update.key] + + subselect = Arel::SelectManager.new(select.engine) + subselect.project Arel.sql(update.key.name) + subselect.from subsubselect.as('__active_record_temp') + + update.where update.key.in(subselect) + else + update.table select.source + update.wheres = select.constraints + end + end + + # SCHEMA STATEMENTS ======================================== + + def structure_dump #:nodoc: + if supports_views? + sql = "SHOW FULL TABLES WHERE Table_type = 'BASE TABLE'" + else + sql = "SHOW TABLES" + end + + select_all(sql).map do |table| + table.delete('Table_type') + sql = "SHOW CREATE TABLE #{quote_table_name(table.to_a.first.last)}" + exec_without_stmt(sql).first['Create Table'] + ";\n\n" + end.join("") + end + + # Drops the database specified on the +name+ attribute + # and creates it again using the provided +options+. + def recreate_database(name, options = {}) + drop_database(name) + create_database(name, options) + end + + # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>. + # Charset defaults to utf8. + # + # Example: + # create_database 'charset_test', :charset => 'latin1', :collation => 'latin1_bin' + # create_database 'matt_development' + # create_database 'matt_development', :charset => :big5 + 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 + + # Drops a MySQL database. + # + # Example: + # drop_database('sebastian_development') + def drop_database(name) #:nodoc: + execute "DROP DATABASE IF EXISTS `#{name}`" + end + + def current_database + select_value 'SELECT DATABASE() as db' + end + + # Returns the database character set. + def charset + show_variable 'character_set_database' + end + + # Returns the database collation strategy. + def collation + show_variable 'collation_database' + end + + def tables(name = nil, database = nil) #:nodoc: + sql = ["SHOW TABLES", database].compact.join(' IN ') + + execute_and_free(sql, 'SCHEMA') do |result| + result.collect { |field| field.first } + end + end + + def table_exists?(name) + return true if super + + 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).include? table + end + + # Returns an array of indexes for the given table. + 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] + indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], []) + end + + indexes.last.columns << row[:Column_name] + indexes.last.lengths << row[:Sub_part] + end + end + + indexes + end + + # Returns an array of +Column+ objects for the table specified by +table_name+. + def columns(table_name, name = nil)#:nodoc: + sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}" + execute_and_free(sql, 'SCHEMA') do |result| + each_hash(result).map do |field| + new_column(field[:Field], field[:Default], field[:Type], field[:Null] == "YES") + end + end + end + + def create_table(table_name, options = {}) #:nodoc: + super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB")) + end + + # Renames a table. + # + # Example: + # rename_table('octopuses', 'octopi') + def rename_table(table_name, new_name) + execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}" + end + + def add_column(table_name, column_name, type, options = {}) + execute("ALTER TABLE #{quote_table_name(table_name)} #{add_column_sql(table_name, column_name, type, options)}") + end + + 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 + + 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 + + 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 + + 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)}") + end + + # Maps logical Rails types to MySQL-specific data types. + def type_to_sql(type, limit = nil, precision = nil, scale = nil) + return super unless type.to_s == '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 + end + + def add_column_position!(sql, options) + if options[:first] + sql << " FIRST" + elsif options[:after] + sql << " AFTER #{quote_column_name(options[:after])}" + end + end + + # SHOW VARIABLES LIKE 'name' + def show_variable(name) + variables = select_all("SHOW VARIABLES LIKE '#{name}'") + variables.first['Value'] unless variables.empty? + end + + # Returns a table's primary key and belonging sequence. + def pk_and_sequence_for(table) + execute_and_free("DESCRIBE #{quote_table_name(table)}", 'SCHEMA') do |result| + keys = each_hash(result).select { |row| row[:Key] == 'PRI' }.map { |row| row[:Field] } + keys.length == 1 ? [keys.first, nil] : nil + end + end + + # Returns just a table's primary key + def primary_key(table) + pk_and_sequence = pk_and_sequence_for(table) + pk_and_sequence && pk_and_sequence.first + end + + def case_sensitive_modifier(node) + Arel::Nodes::Bin.new(node) + end + + def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key) + where_sql + end + + protected + + def quoted_columns_for_index(column_names, options = {}) + length = options[:length] if options.is_a?(Hash) + + case length + when Hash + column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) } + when Fixnum + column_names.map {|name| "#{quote_column_name(name)}(#{length})"} + else + column_names.map {|name| quote_column_name(name) } + end + end + + 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 + + def add_column_sql(table_name, column_name, type, options = {}) + add_column_sql = "ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" + add_column_options!(add_column_sql, options) + add_column_position!(add_column_sql, options) + add_column_sql + end + + 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 + + change_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" + add_column_options!(change_column_sql, options) + add_column_position!(change_column_sql, options) + change_column_sql + end + + def rename_column_sql(table_name, column_name, new_column_name) + options = {} + + if column = columns(table_name).find { |c| c.name == column_name.to_s } + options[:default] = column.default + options[:null] = column.null + 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}'")["Type"] + rename_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}" + add_column_options!(rename_column_sql, options) + rename_column_sql + end + + private + + def supports_views? + version[0] >= 5 + end + + def column_for(table_name, column_name) + unless column = columns(table_name).find { |c| c.name == column_name.to_s } + raise "No such column: #{table_name}.#{column_name}" + end + column + end + end + end +end |