From 859fba7c4bf7d33b4f9655914ed4bdc85380552e Mon Sep 17 00:00:00 2001
From: Ryuta Kamizono <kamipo@gmail.com>
Date: Sun, 30 Sep 2018 18:30:47 +0900
Subject: Handle DELETE with LIMIT in Arel
MySQL supports DELETE with LIMIT and ORDER BY.
https://dev.mysql.com/doc/refman/8.0/en/delete.html
Before:
```
Post Destroy (1.0ms) DELETE FROM `posts` WHERE `posts`.`id` IN (SELECT `id` FROM (SELECT `posts`.`id` FROM `posts` WHERE `posts`.`author_id` = ? ORDER BY `posts`.`id` ASC LIMIT ?) __active_record_temp) [["author_id", 1], ["LIMIT", 1]]
```
After:
```
Post Destroy (0.4ms) DELETE FROM `posts` WHERE `posts`.`author_id` = ? ORDER BY `posts`.`id` ASC LIMIT ? [["author_id", 1], ["LIMIT", 1]]
```
---
activerecord/lib/active_record/relation.rb | 5 +++-
activerecord/lib/arel/delete_manager.rb | 11 ++------
activerecord/lib/arel/nodes/delete_statement.rb | 13 +++++++---
activerecord/lib/arel/nodes/update_statement.rb | 3 +--
activerecord/lib/arel/tree_manager.rb | 29 +++++++++++++++++++++
activerecord/lib/arel/update_manager.rb | 29 ++-------------------
activerecord/lib/arel/visitors/mysql.rb | 22 +++++++++-------
activerecord/lib/arel/visitors/to_sql.rb | 34 ++++++++++++-------------
8 files changed, 77 insertions(+), 69 deletions(-)
(limited to 'activerecord/lib')
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index db06bd9e26..5bad5bfcc2 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -484,9 +484,12 @@ module ActiveRecord
stmt = Arel::DeleteManager.new
stmt.from(table)
- if has_join_values? || has_limit_or_offset?
+ if has_join_values? || offset_value
@klass.connection.join_to_delete(stmt, arel, arel_attribute(primary_key))
else
+ stmt.key = arel_attribute(primary_key)
+ stmt.take(arel.limit)
+ stmt.order(*arel.orders)
stmt.wheres = arel.constraints
end
diff --git a/activerecord/lib/arel/delete_manager.rb b/activerecord/lib/arel/delete_manager.rb
index 2def581009..fdba937d64 100644
--- a/activerecord/lib/arel/delete_manager.rb
+++ b/activerecord/lib/arel/delete_manager.rb
@@ -2,6 +2,8 @@
module Arel # :nodoc: all
class DeleteManager < Arel::TreeManager
+ include TreeManager::StatementMethods
+
def initialize
super
@ast = Nodes::DeleteStatement.new
@@ -12,14 +14,5 @@ module Arel # :nodoc: all
@ast.relation = relation
self
end
-
- def take(limit)
- @ast.limit = Nodes::Limit.new(Nodes.build_quoted(limit)) if limit
- self
- end
-
- def wheres=(list)
- @ast.wheres = list
- end
end
end
diff --git a/activerecord/lib/arel/nodes/delete_statement.rb b/activerecord/lib/arel/nodes/delete_statement.rb
index eaac05e2f6..5be42a084a 100644
--- a/activerecord/lib/arel/nodes/delete_statement.rb
+++ b/activerecord/lib/arel/nodes/delete_statement.rb
@@ -3,8 +3,7 @@
module Arel # :nodoc: all
module Nodes
class DeleteStatement < Arel::Nodes::Node
- attr_accessor :left, :right
- attr_accessor :limit
+ attr_accessor :left, :right, :orders, :limit, :key
alias :relation :left
alias :relation= :left=
@@ -15,6 +14,9 @@ module Arel # :nodoc: all
super()
@left = relation
@right = wheres
+ @orders = []
+ @limit = nil
+ @key = nil
end
def initialize_copy(other)
@@ -24,13 +26,16 @@ module Arel # :nodoc: all
end
def hash
- [self.class, @left, @right].hash
+ [self.class, @left, @right, @orders, @limit, @key].hash
end
def eql?(other)
self.class == other.class &&
self.left == other.left &&
- self.right == other.right
+ self.right == other.right &&
+ self.orders == other.orders &&
+ self.limit == other.limit &&
+ self.key == other.key
end
alias :== :eql?
end
diff --git a/activerecord/lib/arel/nodes/update_statement.rb b/activerecord/lib/arel/nodes/update_statement.rb
index 5184b1180f..017a553c4c 100644
--- a/activerecord/lib/arel/nodes/update_statement.rb
+++ b/activerecord/lib/arel/nodes/update_statement.rb
@@ -3,8 +3,7 @@
module Arel # :nodoc: all
module Nodes
class UpdateStatement < Arel::Nodes::Node
- attr_accessor :relation, :wheres, :values, :orders, :limit
- attr_accessor :key
+ attr_accessor :relation, :wheres, :values, :orders, :limit, :key
def initialize
@relation = nil
diff --git a/activerecord/lib/arel/tree_manager.rb b/activerecord/lib/arel/tree_manager.rb
index ed47b09a37..149c69ce7a 100644
--- a/activerecord/lib/arel/tree_manager.rb
+++ b/activerecord/lib/arel/tree_manager.rb
@@ -4,6 +4,35 @@ module Arel # :nodoc: all
class TreeManager
include Arel::FactoryMethods
+ module StatementMethods
+ def take(limit)
+ @ast.limit = Nodes::Limit.new(Nodes.build_quoted(limit)) if limit
+ self
+ end
+
+ def order(*expr)
+ @ast.orders = expr
+ self
+ end
+
+ def key=(key)
+ @ast.key = Nodes.build_quoted(key)
+ end
+
+ def key
+ @ast.key
+ end
+
+ def wheres=(exprs)
+ @ast.wheres = exprs
+ end
+
+ def where(expr)
+ @ast.wheres << expr
+ self
+ end
+ end
+
attr_reader :ast
def initialize
diff --git a/activerecord/lib/arel/update_manager.rb b/activerecord/lib/arel/update_manager.rb
index fe444343ba..a809dbb307 100644
--- a/activerecord/lib/arel/update_manager.rb
+++ b/activerecord/lib/arel/update_manager.rb
@@ -2,30 +2,14 @@
module Arel # :nodoc: all
class UpdateManager < Arel::TreeManager
+ include TreeManager::StatementMethods
+
def initialize
super
@ast = Nodes::UpdateStatement.new
@ctx = @ast
end
- def take(limit)
- @ast.limit = Nodes::Limit.new(Nodes.build_quoted(limit)) if limit
- self
- end
-
- def key=(key)
- @ast.key = Nodes.build_quoted(key)
- end
-
- def key
- @ast.key
- end
-
- def order(*expr)
- @ast.orders = expr
- self
- end
-
###
# UPDATE +table+
def table(table)
@@ -33,15 +17,6 @@ module Arel # :nodoc: all
self
end
- def wheres=(exprs)
- @ast.wheres = exprs
- end
-
- def where(expr)
- @ast.wheres << expr
- self
- end
-
def set(values)
if String === values
@ast.values = [values]
diff --git a/activerecord/lib/arel/visitors/mysql.rb b/activerecord/lib/arel/visitors/mysql.rb
index ee75b6bb25..0f7d5aa803 100644
--- a/activerecord/lib/arel/visitors/mysql.rb
+++ b/activerecord/lib/arel/visitors/mysql.rb
@@ -65,6 +65,19 @@ module Arel # :nodoc: all
collector = inject_join o.values, collector, ", "
end
+ collect_where_for(o, collector)
+ end
+
+ def visit_Arel_Nodes_Concat(o, collector)
+ collector << " CONCAT("
+ visit o.left, collector
+ collector << ", "
+ visit o.right, collector
+ collector << ") "
+ collector
+ end
+
+ def collect_where_for(o, collector)
unless o.wheres.empty?
collector << " WHERE "
collector = inject_join o.wheres, collector, " AND "
@@ -77,15 +90,6 @@ module Arel # :nodoc: all
maybe_visit o.limit, collector
end
-
- def visit_Arel_Nodes_Concat(o, collector)
- collector << " CONCAT("
- visit o.left, collector
- collector << ", "
- visit o.right, collector
- collector << ") "
- collector
- end
end
end
end
diff --git a/activerecord/lib/arel/visitors/to_sql.rb b/activerecord/lib/arel/visitors/to_sql.rb
index 87f8c36f9b..575bfd6e36 100644
--- a/activerecord/lib/arel/visitors/to_sql.rb
+++ b/activerecord/lib/arel/visitors/to_sql.rb
@@ -76,12 +76,8 @@ module Arel # :nodoc: all
def visit_Arel_Nodes_DeleteStatement(o, collector)
collector << "DELETE FROM "
collector = visit o.relation, collector
- if o.wheres.any?
- collector << WHERE
- collector = inject_join o.wheres, collector, AND
- end
- maybe_visit o.limit, collector
+ collect_where_for(o, collector)
end
# FIXME: we should probably have a 2-pass visitor for this
@@ -97,12 +93,6 @@ module Arel # :nodoc: all
end
def visit_Arel_Nodes_UpdateStatement(o, collector)
- if o.orders.empty? && o.limit.nil?
- wheres = o.wheres
- else
- wheres = [Nodes::In.new(o.key, [build_subselect(o.key, o)])]
- end
-
collector << "UPDATE "
collector = visit o.relation, collector
unless o.values.empty?
@@ -110,12 +100,7 @@ module Arel # :nodoc: all
collector = inject_join o.values, collector, ", "
end
- unless wheres.empty?
- collector << " WHERE "
- collector = inject_join wheres, collector, " AND "
- end
-
- collector
+ collect_where_for(o, collector)
end
def visit_Arel_Nodes_InsertStatement(o, collector)
@@ -814,6 +799,21 @@ module Arel # :nodoc: all
}
end
+ def collect_where_for(o, collector)
+ if o.orders.empty? && o.limit.nil?
+ wheres = o.wheres
+ else
+ wheres = [Nodes::In.new(o.key, [build_subselect(o.key, o)])]
+ end
+
+ unless wheres.empty?
+ collector << " WHERE "
+ collector = inject_join wheres, collector, " AND "
+ end
+
+ collector
+ end
+
def infix_value(o, collector, value)
collector = visit o.left, collector
collector << value
--
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