Merge pull request #13313 from ccutrer/temp-tables

support creating temporary tables from queries

Conflicts:
	activerecord/CHANGELOG.md

activerecord/CHANGELOG.md

+*   Respect temporary option when dropping tables with MySQL.
+
+    Normal DROP TABLE also works, but commits the transaction.
+
+    *Cody Cutrer*
+
+*   Add option to create tables from a query.
+
+    *Cody Cutrer*
+
 *   `db:test:clone` and `db:test:prepare` must load Rails environment.
 
     `db:test:clone` and `db:test:prepare` use `ActiveRecord::Base`. configurations,

activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb

@@ -34,9 +34,10 @@ def visit_ColumnDefinition(o)
 
           def visit_TableDefinition(o)
             create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE "
-            create_sql << "#{quote_table_name(o.name)} ("
-            create_sql << o.columns.map { |c| accept c }.join(', ')
-            create_sql << ") #{o.options}"
+            create_sql << "#{quote_table_name(o.name)} "
+            create_sql << "(#{o.columns.map { |c| accept c }.join(', ')}) " unless o.as
+            create_sql << "#{o.options}"
+            create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
             create_sql
           end
 

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -49,14 +49,15 @@ class TableDefinition
       # An array of ColumnDefinition objects, representing the column changes
       # that have been defined.
       attr_accessor :indexes
-      attr_reader :name, :temporary, :options
+      attr_reader :name, :temporary, :options, :as
 
-      def initialize(types, name, temporary, options)
+      def initialize(types, name, temporary, options, as = nil)
         @columns_hash = {}
         @indexes = {}
         @native = types
         @temporary = temporary
         @options = options
+        @as = as
         @name = name
       end
 

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -131,6 +131,9 @@ def column_exists?(table_name, column_name, type = nil, options = {})
       # [<tt>:force</tt>]
       #   Set to true to drop the table before creating it.
       #   Defaults to false.
+      # [<tt>:as]
+      #   SQL to use to generate the table. When this option is used, the block is
+      #   ignored, as are the <tt>:id</tt> and <tt>:primary_key</tt> options.
       #
       # ====== Add a backend specific option to the generated SQL (MySQL)
       #
@@ -169,19 +172,31 @@ def column_exists?(table_name, column_name, type = nil, options = {})
       #     supplier_id int
       #   )
       #
+      # ====== Create a temporary table based on a query
+      #
+      #   create_table(:long_query, temporary: true,
+      #     as: "SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id")
+      #
+      # generates:
+      #
+      #   CREATE TEMPORARY TABLE long_query AS
+      #     SELECT * FROM orders INNER JOIN line_items ON order_id=orders.id
+      #
       # See also TableDefinition#column for details on how to create columns.
       def create_table(table_name, options = {})
-        td = create_table_definition table_name, options[:temporary], options[:options]
+        td = create_table_definition table_name, options[:temporary], options[:options], options[:as]
 
-        unless options[:id] == false
-          pk = options.fetch(:primary_key) {
-            Base.get_primary_key table_name.to_s.singularize
-          }
+        if !options[:as]
+          unless options[:id] == false
+            pk = options.fetch(:primary_key) {
+              Base.get_primary_key table_name.to_s.singularize
+            }
 
-          td.primary_key pk, options.fetch(:id, :primary_key), options
-        end
+            td.primary_key pk, options.fetch(:id, :primary_key), options
+          end
 
-        yield td if block_given?
+          yield td if block_given?
+        end
 
         if options[:force] && table_exists?(table_name)
           drop_table(table_name, options)
@@ -826,8 +841,8 @@ def rename_column_indexes(table_name, column_name, new_column_name)
         end
 
       private
-      def create_table_definition(name, temporary, options)
-        TableDefinition.new native_database_types, name, temporary, options
+      def create_table_definition(name, temporary, options, as = nil)
+        TableDefinition.new native_database_types, name, temporary, options, as
       end
 
       def create_alter_table(name)

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -492,6 +492,10 @@ def rename_table(table_name, new_name)
         rename_table_indexes(table_name, new_name)
       end
 
+      def drop_table(table_name, options = {})
+        execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}"
+      end
+
       def rename_index(table_name, old_name, new_name)
         if (version[0] == 5 && version[1] >= 7) || version[0] >= 6
           execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -973,8 +973,8 @@ def extract_table_ref_from_insert_sql(sql)
           $1.strip if $1
         end
 
-        def create_table_definition(name, temporary, options)
-          TableDefinition.new native_database_types, name, temporary, options
+        def create_table_definition(name, temporary, options, as = nil)
+          TableDefinition.new native_database_types, name, temporary, options, as
         end
 
         def update_table_definition(table_name, base)

activerecord/test/cases/adapters/mysql2/schema_test.rb

@@ -65,6 +65,15 @@ def test_dump_indexes
         assert_nil index_c.using
         assert_equal :fulltext, index_c.type
       end
+
+      def test_drop_temporary_table
+        @connection.transaction do
+          @connection.create_table(:temp_table, temporary: true)
+          # if it doesn't properly say DROP TEMPORARY TABLE, the transaction commit
+          # will complain that no transaction is active
+          @connection.drop_table(:temp_table, temporary: true)
+        end
+      end
     end
   end
 end

activerecord/test/cases/migration_test.rb

@@ -443,6 +443,32 @@ def test_create_table_with_binary_column
     Person.connection.drop_table :binary_testings rescue nil
   end
 
+  def test_create_table_with_query
+    Person.connection.drop_table :table_from_query_testings rescue nil
+    Person.connection.create_table(:person, force: true)
+
+    Person.connection.create_table :table_from_query_testings, as: "SELECT id FROM person"
+
+    columns = Person.connection.columns(:table_from_query_testings)
+    assert_equal 1, columns.length
+    assert_equal "id", columns.first.name
+
+    Person.connection.drop_table :table_from_query_testings rescue nil
+  end
+
+  def test_create_table_with_query_from_relation
+    Person.connection.drop_table :table_from_query_testings rescue nil
+    Person.connection.create_table(:person, force: true)
+
+    Person.connection.create_table :table_from_query_testings, as: Person.select(:id)
+
+    columns = Person.connection.columns(:table_from_query_testings)
+    assert_equal 1, columns.length
+    assert_equal "id", columns.first.name
+
+    Person.connection.drop_table :table_from_query_testings rescue nil
+  end
+
   if current_adapter? :OracleAdapter
     def test_create_table_with_custom_sequence_name
       # table name is 29 chars, the standard sequence name will