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Virtual/generated column support for MySQL 5.7.5+ and MariaDB 5.2.0+

MySQL generated columns: https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html
MariaDB virtual columns: https://mariadb.com/kb/en/mariadb/virtual-computed-columns/

Declare virtual columns with `t.virtual name, type: …, as: "expression"`.
Pass `stored: true` to persist the generated value (false by default).

Example:

    create_table :generated_columns do |t|
      t.string  :name
      t.virtual :upper_name, type: :string,  as: "UPPER(name)"
      t.virtual :name_length, type: :integer, as: "LENGTH(name)", stored: true
      t.index :name_length  # May be indexed, too!
    end

Closes #22589
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kamipo authored and jeremy committed Dec 14, 2015
1 parent c98e08d commit 65bf1c60053e727835e06392d27a2fb49665484c
@@ -1,3 +1,22 @@
* Virtual/generated column support for MySQL 5.7.5+ and MariaDB 5.2.0+.

MySQL generated columns: https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html
MariaDB virtual columns: https://mariadb.com/kb/en/mariadb/virtual-computed-columns/

Declare virtual columns with `t.virtual name, type: …, as: "expression"`.
Pass `stored: true` to persist the generated value (false by default).

Example:

create_table :generated_columns do |t|
t.string :name
t.virtual :upper_name, type: :string, as: "UPPER(name)"
t.virtual :name_length, type: :integer, as: "LENGTH(name)", stored: true
t.index :name_length # May be indexed, too!
end

*Ryuta Kamizono*

* Deprecate `initialize_schema_migrations_table` and `initialize_internal_metadata_table`.

*Ryuta Kamizono*
@@ -106,6 +106,7 @@ def column_options(o)
column_options[:primary_key] = o.primary_key
column_options[:collation] = o.collation
column_options[:comment] = o.comment
column_options[:as] = o.as
column_options
end

@@ -9,7 +9,7 @@ module ConnectionAdapters #:nodoc:
# are typically created by methods in TableDefinition, and added to the
# +columns+ attribute of said TableDefinition object, in order to be used
# for generating a number of table creation or table changing SQL statements.
ColumnDefinition = Struct.new(:name, :type, :limit, :precision, :scale, :default, :null, :first, :after, :auto_increment, :primary_key, :collation, :sql_type, :comment) do #:nodoc:
ColumnDefinition = Struct.new(:name, :type, :limit, :precision, :scale, :default, :null, :first, :after, :auto_increment, :primary_key, :collation, :sql_type, :comment, :as) do # :nodoc:
def primary_key?
primary_key || type.to_sym == :primary_key
end
@@ -173,6 +173,7 @@ def primary_key(name, type = :primary_key, **options)
:text,
:time,
:timestamp,
:virtual,
].each do |column_type|
module_eval <<-CODE, __FILE__, __LINE__ + 1
def #{column_type}(*args, **options)
@@ -374,6 +375,7 @@ def new_column_definition(name, type, options) # :nodoc:
column.primary_key = type == :primary_key || options[:primary_key]
column.collation = options[:collation]
column.comment = options[:comment]
column.as = options[:as]
column
end

@@ -7,7 +7,7 @@ module ConnectionAdapters # :nodoc:
# Adapter level by over-writing this code inside the database specific adapters
module ColumnDumper
def column_spec(column)
[schema_type(column), prepare_column_options(column)]
[schema_type_with_virtual(column), prepare_column_options(column)]
end

def column_spec_for_primary_key(column)
@@ -59,6 +59,14 @@ def default_primary_key?(column)
schema_type(column) == :bigint
end

def schema_type_with_virtual(column)
if supports_virtual_columns? && column.virtual?
:virtual
else
schema_type(column)
end
end

def schema_type(column)
if column.bigint?
:bigint
@@ -346,6 +346,11 @@ def supports_multi_insert?
true
end

# Does this adapter support virtual columns?
def supports_virtual_columns?
false
end

# This is meant to be implemented by the adapters that support extensions
def disable_extension(name)
end
@@ -141,6 +141,14 @@ def supports_datetime_with_precision?
end
end

def supports_virtual_columns?
if mariadb?
version >= "5.2.0"
else
version >= "5.7.5"
end
end

def supports_advisory_locks?
true
end
@@ -15,6 +15,10 @@ def case_sensitive?
def auto_increment?
extra == "auto_increment"
end

def virtual?
/\b(?:VIRTUAL|STORED|PERSISTENT)\b/.match?(extra)
end
end
end
end
@@ -2,8 +2,8 @@ module ActiveRecord
module ConnectionAdapters
module MySQL
class SchemaCreation < AbstractAdapter::SchemaCreation
delegate :add_sql_comment!, to: :@conn
private :add_sql_comment!
delegate :add_sql_comment!, :mariadb?, to: :@conn
private :add_sql_comment!, :mariadb?

private

@@ -32,6 +32,7 @@ def add_table_options!(create_sql, options)
def column_options(o)
column_options = super
column_options[:charset] = o.charset
column_options[:stored] = o.stored
column_options
end

@@ -44,6 +45,13 @@ def add_column_options!(sql, options)
sql << " COLLATE #{collation}"
end

if as = options[:as]
sql << " AS (#{as})"
if options[:stored]
sql << (mariadb? ? " PERSISTENT" : " STORED")
end
end

add_sql_comment!(super, options[:comment])
end

@@ -3,8 +3,7 @@ module ConnectionAdapters
module MySQL
module ColumnMethods
def primary_key(name, type = :primary_key, **options)
options[:auto_increment] = true if [:primary_key, :integer, :bigint].include?(type) && !options.key?(:default)
options[:limit] = 8 if [:primary_key].include?(type)
options[:auto_increment] = true if [:integer, :bigint].include?(type) && !options.key?(:default)
super
end

@@ -58,24 +57,29 @@ def unsigned_decimal(*args, **options)
end

class ColumnDefinition < ActiveRecord::ConnectionAdapters::ColumnDefinition
attr_accessor :charset, :unsigned
attr_accessor :charset, :unsigned, :stored
end

class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
include ColumnMethods

def new_column_definition(name, type, options) # :nodoc:
column = super
case column.type
case type
when :virtual
type = options[:type]
when :primary_key
column.type = :integer
column.auto_increment = true
type = :integer
options[:limit] ||= 8
options[:auto_increment] = true
options[:primary_key] = true
when /\Aunsigned_(?<type>.+)\z/
column.type = $~[:type].to_sym
column.unsigned = true
type = $~[:type].to_sym
options[:unsigned] = true
end
column.unsigned ||= options[:unsigned]
column = super
column.unsigned = options[:unsigned]
column.charset = options[:charset]
column.stored = options[:stored]
column
end

@@ -14,6 +14,13 @@ def column_spec_for_primary_key(column)
def prepare_column_options(column)
spec = super
spec[:unsigned] = "true" if column.unsigned?

if supports_virtual_columns? && column.virtual?
spec[:as] = extract_expression_for_virtual_column(column)
spec[:stored] = "true" if /\b(?:STORED|PERSISTENT)\b/.match?(column.extra)
spec = { type: schema_type(column).inspect }.merge!(spec)
end

spec
end

@@ -46,6 +53,21 @@ def schema_collation(column)
column.collation.inspect if column.collation != @table_collation_cache[table_name]
end
end

def extract_expression_for_virtual_column(column)
if mariadb?
create_table_info = create_table_info(column.table_name)
if %r/#{quote_column_name(column.name)} #{Regexp.quote(column.sql_type)} AS \((?<expression>.+?)\) #{column.extra}/m =~ create_table_info
$~[:expression].inspect
end
else
sql = "SELECT generation_expression FROM information_schema.columns" \
" WHERE table_schema = #{quote(@config[:database])}" \
" AND table_name = #{quote(column.table_name)}" \
" AND column_name = #{quote(column.name)}"
select_value(sql, "SCHEMA").inspect
end
end
end
end
end
@@ -6,23 +6,27 @@ class Mysql2DatetimePrecisionQuotingTest < ActiveRecord::Mysql2TestCase
end

test "microsecond precision for MySQL gte 5.6.4" do
stub_version "5.6.4"
assert_microsecond_precision
stub_version "5.6.4" do
assert_microsecond_precision
end
end

test "no microsecond precision for MySQL lt 5.6.4" do
stub_version "5.6.3"
assert_no_microsecond_precision
stub_version "5.6.3" do
assert_no_microsecond_precision
end
end

test "microsecond precision for MariaDB gte 5.3.0" do
stub_version "5.5.5-10.1.8-MariaDB-log"
assert_microsecond_precision
stub_version "5.5.5-10.1.8-MariaDB-log" do
assert_microsecond_precision
end
end

test "no microsecond precision for MariaDB lt 5.3.0" do
stub_version "5.2.9-MariaDB"
assert_no_microsecond_precision
stub_version "5.2.9-MariaDB" do
assert_no_microsecond_precision
end
end

private
@@ -41,5 +45,8 @@ def assert_match_quoted_microsecond_datetime(match)
def stub_version(full_version_string)
@connection.stubs(:full_version).returns(full_version_string)
@connection.remove_instance_variable(:@version) if @connection.instance_variable_defined?(:@version)
yield
ensure
@connection.remove_instance_variable(:@version) if @connection.instance_variable_defined?(:@version)
end
end
@@ -0,0 +1,59 @@
require "cases/helper"
require "support/schema_dumping_helper"

if ActiveRecord::Base.connection.supports_virtual_columns?
class Mysql2VirtualColumnTest < ActiveRecord::Mysql2TestCase
include SchemaDumpingHelper

self.use_transactional_tests = false

class VirtualColumn < ActiveRecord::Base
end

def setup
@connection = ActiveRecord::Base.connection
@connection.create_table :virtual_columns, force: true do |t|
t.string :name
t.virtual :upper_name, type: :string, as: "UPPER(`name`)"
t.virtual :name_length, type: :integer, as: "LENGTH(`name`)", stored: true
end
VirtualColumn.create(name: "Rails")
end

def teardown
@connection.drop_table :virtual_columns, if_exists: true
VirtualColumn.reset_column_information
end

def test_virtual_column
column = VirtualColumn.columns_hash["upper_name"]
assert_predicate column, :virtual?
assert_match %r{\bVIRTUAL\b}, column.extra
assert_equal "RAILS", VirtualColumn.take.upper_name
end

def test_stored_column
column = VirtualColumn.columns_hash["name_length"]
assert_predicate column, :virtual?
assert_match %r{\b(?:STORED|PERSISTENT)\b}, column.extra
assert_equal 5, VirtualColumn.take.name_length
end

def test_change_table
@connection.change_table :virtual_columns do |t|
t.virtual :lower_name, type: :string, as: "LOWER(name)"
end
VirtualColumn.reset_column_information
column = VirtualColumn.columns_hash["lower_name"]
assert_predicate column, :virtual?
assert_match %r{\bVIRTUAL\b}, column.extra
assert_equal "rails", VirtualColumn.take.lower_name
end

def test_schema_dumping
output = dump_table_schema("virtual_columns")
assert_match(/t\.virtual\s+"upper_name",\s+type: :string,\s+as: "UPPER\(`name`\)"$/i, output)
assert_match(/t\.virtual\s+"name_length",\s+type: :integer,\s+as: "LENGTH\(`name`\)",\s+stored: true$/i, output)
end
end
end
@@ -101,12 +101,7 @@ def test_remove_timestamps_creates_updated_at_and_created_at

def test_primary_key_creates_primary_key_column
with_change_table do |t|
if current_adapter?(:Mysql2Adapter)
@connection.expect :add_column, nil, [:delete_me, :id, :primary_key, { first: true, auto_increment: true, limit: 8, primary_key: true }]
else
@connection.expect :add_column, nil, [:delete_me, :id, :primary_key, primary_key: true, first: true]
end

@connection.expect :add_column, nil, [:delete_me, :id, :primary_key, primary_key: true, first: true]
t.primary_key :id, first: true
end
end

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