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abstract_mysql_adapter.rb
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abstract_mysql_adapter.rb
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require 'active_support/core_ext/string/strip'
module ActiveRecord
module ConnectionAdapters
class AbstractMysqlAdapter < AbstractAdapter
include Savepoints
module ColumnMethods
def primary_key(name, type = :primary_key, **options)
options[:auto_increment] = true if type == :bigint
super
end
def json(*args, **options)
args.each { |name| column(name, :json, options) }
end
end
class ColumnDefinition < ActiveRecord::ConnectionAdapters::ColumnDefinition
attr_accessor :charset
end
class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
include ColumnMethods
def new_column_definition(name, type, options) # :nodoc:
column = super
case column.type
when :primary_key
column.type = :integer
column.auto_increment = true
end
column.charset = options[:charset]
column
end
private
def create_column_definition(name, type)
ColumnDefinition.new(name, type)
end
end
class Table < ActiveRecord::ConnectionAdapters::Table
include ColumnMethods
end
class SchemaCreation < AbstractAdapter::SchemaCreation
private
def visit_DropForeignKey(name)
"DROP FOREIGN KEY #{name}"
end
def visit_TableDefinition(o)
name = o.name
create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE #{quote_table_name(name)} "
statements = o.columns.map { |c| accept c }
statements.concat(o.indexes.map { |column_name, options| index_in_create(name, column_name, options) })
create_sql << "(#{statements.join(', ')}) " if statements.present?
create_sql << "#{o.options}"
create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
create_sql
end
def visit_AddColumnDefinition(o)
add_column_position!(super, column_options(o.column))
end
def visit_ChangeColumnDefinition(o)
change_column_sql = "CHANGE #{quote_column_name(o.name)} #{accept(o.column)}"
add_column_position!(change_column_sql, column_options(o.column))
end
def column_options(o)
column_options = super
column_options[:charset] = o.charset
column_options
end
def add_column_options!(sql, options)
if options[:charset]
sql << " CHARACTER SET #{options[:charset]}"
end
if options[:collation]
sql << " COLLATE #{options[:collation]}"
end
super
end
def add_column_position!(sql, options)
if options[:first]
sql << " FIRST"
elsif options[:after]
sql << " AFTER #{quote_column_name(options[:after])}"
end
sql
end
def index_in_create(table_name, column_name, options)
index_name, index_type, index_columns, _, _, index_using = @conn.add_index_options(table_name, column_name, options)
"#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns}) "
end
end
def update_table_definition(table_name, base) # :nodoc:
Table.new(table_name, base)
end
def schema_creation
SchemaCreation.new self
end
def column_spec_for_primary_key(column)
spec = {}
if column.auto_increment?
spec[:id] = ':bigint' if column.bigint?
return if spec.empty?
else
spec[:id] = column.type.inspect
spec.merge!(prepare_column_options(column).delete_if { |key, _| [:name, :type, :null].include?(key) })
end
spec
end
private
def schema_limit(column)
super unless column.type == :boolean
end
def schema_precision(column)
super unless /time/ === column.sql_type && column.precision == 0
end
def schema_collation(column)
if column.collation && table_name = column.instance_variable_get(:@table_name)
@collation_cache ||= {}
@collation_cache[table_name] ||= select_one("SHOW TABLE STATUS LIKE '#{table_name}'")["Collation"]
column.collation.inspect if column.collation != @collation_cache[table_name]
end
end
public
class Column < ConnectionAdapters::Column # :nodoc:
delegate :strict, :extra, to: :sql_type_metadata, allow_nil: true
def initialize(*)
super
assert_valid_default(default)
extract_default
end
def extract_default
if blob_or_text_column?
@default = null || strict ? nil : ''
elsif missing_default_forged_as_empty_string?(default)
@default = nil
end
end
def has_default?
return false if blob_or_text_column? # MySQL forbids defaults on blob and text columns
super
end
def blob_or_text_column?
sql_type =~ /blob/i || type == :text
end
def case_sensitive?
collation && !collation.match(/_ci$/)
end
def auto_increment?
extra == 'auto_increment'
end
private
# 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
def assert_valid_default(default)
if blob_or_text_column? && default.present?
raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
end
end
end
class MysqlTypeMetadata < DelegateClass(SqlTypeMetadata) # :nodoc:
attr_reader :extra, :strict
def initialize(type_metadata, extra: "", strict: false)
super(type_metadata)
@type_metadata = type_metadata
@extra = extra
@strict = strict
end
def ==(other)
other.is_a?(MysqlTypeMetadata) &&
attributes_for_hash == other.attributes_for_hash
end
alias eql? ==
def hash
attributes_for_hash.hash
end
protected
def attributes_for_hash
[self.class, @type_metadata, extra, strict]
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) 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 },
bigint: { name: "bigint" },
json: { name: "json" },
}
INDEX_TYPES = [:fulltext, :spatial]
INDEX_USINGS = [:btree, :hash]
# 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 = {}, {}
@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
MAX_INDEX_LENGTH_FOR_CHARSETS_OF_4BYTES_MAXLEN = 191
CHARSETS_OF_4BYTES_MAXLEN = ['utf8mb4', 'utf16', 'utf16le', 'utf32']
def initialize_schema_migrations_table
if CHARSETS_OF_4BYTES_MAXLEN.include?(charset)
ActiveRecord::SchemaMigration.create_table(MAX_INDEX_LENGTH_FOR_CHARSETS_OF_4BYTES_MAXLEN)
else
ActiveRecord::SchemaMigration.create_table
end
end
# Returns true, since this connection adapter supports migrations.
def supports_migrations?
true
end
def supports_primary_key?
true
end
def supports_bulk_alter? #:nodoc:
true
end
# Technically MySQL allows to create indexes with the sort order syntax
# but at the moment (5.5) it doesn't yet implement them
def supports_index_sort_order?
true
end
# MySQL 4 technically support transaction isolation, but it is affected by a bug
# where the transaction level gets persisted for the whole session:
#
# http://bugs.mysql.com/bug.php?id=39170
def supports_transaction_isolation?
version >= '5.0.0'
end
def supports_indexes_in_create?
true
end
def supports_foreign_keys?
true
end
def supports_views?
version >= '5.0.0'
end
def supports_datetime_with_precision?
version >= '5.6.4'
end
def native_database_types
NATIVE_DATABASE_TYPES
end
def index_algorithms
{ default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
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
def new_column(field, default, sql_type_metadata = nil, null = true, default_function = nil, collation = nil) # :nodoc:
Column.new(field, default, sql_type_metadata, null, default_function, collation)
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) # :nodoc:
if value.is_a?(Type::Binary::Data)
"x'#{value.hex}'"
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 unquoted_true
1
end
def quoted_false
QUOTED_FALSE
end
def unquoted_false
0
end
def quoted_date(value)
if supports_datetime_with_precision?
super
else
super.sub(/\.\d{6}\z/, '')
end
end
# REFERENTIAL INTEGRITY ====================================
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
#--
# DATABASE STATEMENTS ======================================
#++
def clear_cache!
super
reload_type_map
end
# Executes the SQL statement in the context of this connection.
def execute(sql, name = nil)
log(sql, name) { @connection.query(sql) }
end
# 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.
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"
end
def begin_isolated_db_transaction(isolation)
execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
begin_db_transaction
end
def commit_db_transaction #:nodoc:
execute "COMMIT"
end
def exec_rollback_db_transaction #:nodoc:
execute "ROLLBACK"
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.
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
def empty_insert_statement_value
"VALUES ()"
end
# SCHEMA STATEMENTS ========================================
# Drops the database specified on the +name+ attribute
# and creates it again using the provided +options+.
def recreate_database(name, options = {})
drop_database(name)
sql = create_database(name, options)
reconnect!
sql
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, 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(&:first)
end
end
def truncate(table_name, name = nil)
execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
end
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
# 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]
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
# Returns an array of +Column+ objects for the table specified by +table_name+.
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]
type_metadata = fetch_type_metadata(sql_type, field[:Extra])
new_column(field_name, field[:Default], type_metadata, field[:Null] == "YES", nil, field[:Collation])
end
end
end
def create_table(table_name, options = {}) #:nodoc:
super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
end
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
# 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)}"
rename_table_indexes(table_name, new_name)
end
# Drops a table from the database.
#
# [<tt>:force</tt>]
# Set to +:cascade+ to drop dependent objects as well.
# Defaults to false.
# [<tt>:if_exists</tt>]
# Set to +true+ to only drop the table if it exists.
# Defaults to false.
# [<tt>:temporary</tt>]
# Set to +true+ to drop temporary table.
# Defaults to false.
#
# Although this command ignores most +options+ and the block if one is given,
# it can be helpful to provide these in a migration's +change+ method so it can be reverted.
# In that case, +options+ and the block will be used by create_table.
def drop_table(table_name, options = {})
execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end
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
def change_column_default(table_name, column_name, default_or_changes) #:nodoc:
default = extract_new_default_value(default_or_changes)
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) #:nodoc:
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)}")
rename_column_indexes(table_name, column_name, new_column_name)
end
def add_index(table_name, column_name, options = {}) #:nodoc:
index_name, index_type, index_columns, _, 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_algorithm}"
end
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
def table_options(table_name)
create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]
# strip create_definitions and partition_options
raw_table_options = create_table_info.sub(/\A.*\n\) /m, '').sub(/\n\/\*!.*\*\/\n\z/m, '').strip
# strip AUTO_INCREMENT
raw_table_options.sub(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')
end
# Maps logical Rails types to MySQL-specific data types.
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
case type.to_s
when 'binary'
binary_to_sql(limit)
when 'integer'
integer_to_sql(limit)
when 'text'
text_to_sql(limit)
else
super
end
end
# SHOW VARIABLES LIKE 'name'
def show_variable(name)
variables = select_all("select @@#{name} as 'Value'", 'SCHEMA')
variables.first['Value'] unless variables.empty?
rescue ActiveRecord::StatementInvalid
nil
end
# Returns a table's primary key and belonging sequence.
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
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, table_attribute)
node = Arel::Nodes.build_quoted node, table_attribute
Arel::Nodes::Bin.new(node)
end
def case_sensitive_comparison(table, attribute, column, value)
if column.case_sensitive?
table[attribute].eq(value)
else
super
end
end
def case_insensitive_comparison(table, attribute, column, value)
if column.case_sensitive?
super
else
table[attribute].eq(value)
end
end
def strict_mode?
self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end
def valid_type?(type)
!native_database_types[type].nil?
end
protected
def initialize_type_map(m) # :nodoc:
super
register_class_with_limit m, %r(char)i, MysqlString
m.register_type %r(tinytext)i, Type::Text.new(limit: 2**8 - 1)
m.register_type %r(tinyblob)i, Type::Binary.new(limit: 2**8 - 1)
m.register_type %r(text)i, Type::Text.new(limit: 2**16 - 1)
m.register_type %r(blob)i, Type::Binary.new(limit: 2**16 - 1)
m.register_type %r(mediumtext)i, Type::Text.new(limit: 2**24 - 1)
m.register_type %r(mediumblob)i, Type::Binary.new(limit: 2**24 - 1)
m.register_type %r(longtext)i, Type::Text.new(limit: 2**32 - 1)
m.register_type %r(longblob)i, Type::Binary.new(limit: 2**32 - 1)
m.register_type %r(^float)i, Type::Float.new(limit: 24)
m.register_type %r(^double)i, Type::Float.new(limit: 53)
m.register_type %r(^json)i, MysqlJson.new
register_integer_type m, %r(^bigint)i, limit: 8
register_integer_type m, %r(^int)i, limit: 4
register_integer_type m, %r(^mediumint)i, limit: 3
register_integer_type m, %r(^smallint)i, limit: 2
register_integer_type m, %r(^tinyint)i, limit: 1
m.alias_type %r(tinyint\(1\))i, 'boolean' if emulate_booleans
m.alias_type %r(set)i, 'varchar'
m.alias_type %r(year)i, 'integer'
m.alias_type %r(bit)i, 'binary'
m.register_type(%r(enum)i) do |sql_type|
limit = sql_type[/^enum\((.+)\)/i, 1]
.split(',').map{|enum| enum.strip.length - 2}.max
MysqlString.new(limit: limit)
end
end
def register_integer_type(mapping, key, options) # :nodoc:
mapping.register_type(key) do |sql_type|
if /unsigned/i =~ sql_type
Type::UnsignedInteger.new(options)
else
Type::Integer.new(options)
end
end
end
def extract_precision(sql_type)
if /time/ === sql_type
super || 0
else
super
end
end
def fetch_type_metadata(sql_type, extra = "")
MysqlTypeMetadata.new(super(sql_type), extra: extra, strict: strict_mode?)
end
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
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
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 = {})
td = create_table_definition(table_name)
cd = td.new_column_definition(column_name, type, options)
schema_creation.accept(AddColumnDefinition.new(cd))
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
td = create_table_definition(table_name)
cd = td.new_column_definition(column.name, type, options)
schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
end
def rename_column_sql(table_name, column_name, new_column_name)
column = column_for(table_name, column_name)
options = {
default: column.default,
null: column.null,
auto_increment: column.auto_increment?
}
current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
td = create_table_definition(table_name)
cd = td.new_column_definition(new_column_name, current_type, options)
schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
end
def remove_column_sql(table_name, column_name, type = nil, options = {})
"DROP #{quote_column_name(column_name)}"
end
def remove_columns_sql(table_name, *column_names)
column_names.map {|column_name| remove_column_sql(table_name, column_name) }
end
def add_index_sql(table_name, column_name, options = {})
index_name, index_type, index_columns, _, index_algorithm, index_using = add_index_options(table_name, column_name, options)
index_algorithm[0, 0] = ", " if index_algorithm.present?
"ADD #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})#{index_algorithm}"
end
def remove_index_sql(table_name, options = {})
index_name = index_name_for_remove(table_name, options)
"DROP INDEX #{index_name}"
end
def add_timestamps_sql(table_name, options = {})
[add_column_sql(table_name, :created_at, :datetime, options), add_column_sql(table_name, :updated_at, :datetime, options)]
end
def remove_timestamps_sql(table_name, options = {})
[remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
end
private
# 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!
def subquery_for(key, select)
subsubselect = select.clone
subsubselect.projections = [key]
subselect = Arel::SelectManager.new(select.engine)
subselect.project Arel.sql(key.name)
# Materialized subquery by adding distinct
# to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on'
subselect.from subsubselect.distinct.as('__active_record_temp')
end
def version
@version ||= Version.new(full_version.match(/^\d+\.\d+\.\d+/)[0])
end
def mariadb?
full_version =~ /mariadb/i
end
def supports_rename_index?
mariadb? ? false : version >= '5.7.6'
end
def configure_connection
variables = @config.fetch(:variables, {}).stringify_keys
# By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
variables['sql_auto_is_null'] = 0
# Increase timeout so the server doesn't disconnect us.
wait_timeout = @config[:wait_timeout]
wait_timeout = 2147483 unless wait_timeout.is_a?(Fixnum)
variables['wait_timeout'] = self.class.type_cast_config_to_integer(wait_timeout)
defaults = [':default', :default].to_set
# Make MySQL reject illegal values rather than truncating or blanking them, see
# http://dev.mysql.com/doc/refman/5.6/en/sql-mode.html#sqlmode_strict_all_tables
# If the user has provided another value for sql_mode, don't replace it.
unless variables.has_key?('sql_mode') || defaults.include?(@config[:strict])
variables['sql_mode'] = strict_mode? ? 'STRICT_ALL_TABLES' : ''
end
# NAMES does not have an equals sign, see
# http://dev.mysql.com/doc/refman/5.6/en/set-statement.html#id944430
# (trailing comma because variable_assignments will always have content)
if @config[:encoding]
encoding = "NAMES #{@config[:encoding]}"
encoding << " COLLATE #{@config[:collation]}" if @config[:collation]
encoding << ", "
end
# Gather up all of the SET variables...
variable_assignments = variables.map do |k, v|
if defaults.include?(v)