From e2ef25710682d884b2e6f5e99d47f18eb7083c68 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Fri, 6 Jun 2014 17:24:46 +0200
Subject: fk: `add_foreign_key` and `remove_foreign_key` for PostgreSQL
 adapter.

---
 .../connection_adapters/abstract_adapter.rb        |  5 ++++
 .../postgresql/schema_statements.rb                | 27 ++++++++++++++++++++++
 .../connection_adapters/postgresql_adapter.rb      |  4 ++++
 3 files changed, 36 insertions(+)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index cc494a7f40..294ed6d7bf 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -233,6 +233,11 @@ module ActiveRecord
         false
       end
 
+      # Does this adapter support creating foreign key constraints?
+      def supports_foreign_keys?
+        false
+      end
+
       # This is meant to be implemented by the adapters that support extensions
       def disable_extension(name)
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index b2aeb3a058..f09ce113d6 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -448,6 +448,33 @@ module ActiveRecord
           execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
         end
 
+        def add_foreign_key(from_table, to_table, options = {})
+          foreign_key_column = options.fetch(:column)
+          referenced_column = "id"
+          foreign_key_name = foreign_key_name(from_table, options)
+          execute <<-SQL
+ALTER TABLE #{quote_table_name(from_table)}
+ADD CONSTRAINT #{foreign_key_name}
+  FOREIGN KEY (#{quote_column_name(foreign_key_column)})
+  REFERENCES #{quote_table_name(to_table)} (#{quote_column_name(referenced_column)})
+          SQL
+        end
+
+        def remove_foreign_key(from_table, options = {})
+          foreign_key_name = foreign_key_name(from_table, options)
+          execute <<-SQL
+ALTER TABLE #{quote_table_name(from_table)}
+DROP CONSTRAINT #{foreign_key_name}
+          SQL
+        end
+
+        def foreign_key_name(table_name, options)
+          options.fetch(:name) do
+            column_name = options.fetch(:column)
+            "#{table_name}_#{column_name}_fk"
+          end
+        end
+
         def index_name_length
           63
         end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index be4ae47d09..34262cf91d 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -159,6 +159,10 @@ module ActiveRecord
         true
       end
 
+      def supports_foreign_keys?
+        true
+      end
+
       def index_algorithms
         { concurrently: 'CONCURRENTLY' }
       end
-- 
cgit v1.2.3


From 09b3a2847ca51d0e5dcebcb636d8770b19c397a7 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 10:59:18 +0200
Subject: fk: add `foreign_keys` for PostgreSQL adapter.

---
 .../postgresql/schema_definitions.rb               | 14 +++++++++++++
 .../postgresql/schema_statements.rb                | 24 ++++++++++++++++++++++
 2 files changed, 38 insertions(+)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
index 0867e5ef54..724e3fa1ee 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -89,6 +89,20 @@ module ActiveRecord
         attr_accessor :array
       end
 
+      class ForeignKeyDefinition < Struct.new(:from_table, :to_table, :options)
+        def name
+          options[:name]
+        end
+
+        def column
+          options[:column]
+        end
+
+        def primary_key
+          options[:primary_key]
+        end
+      end
+
       class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
         include ColumnMethods
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index f09ce113d6..b87fb85ae2 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -448,6 +448,30 @@ module ActiveRecord
           execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
         end
 
+        def foreign_keys(table_name)
+          fk_info = select_all <<-SQL
+SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confdeltype AS dependency
+FROM pg_constraint c
+JOIN pg_class t1 ON c.conrelid = t1.oid
+JOIN pg_class t2 ON c.confrelid = t2.oid
+JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
+JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
+JOIN pg_namespace t3 ON c.connamespace = t3.oid
+WHERE c.contype = 'f'
+  AND t1.relname = #{quote(table_name)}
+  AND t3.nspname = ANY (current_schemas(false))
+ORDER BY c.conname
+          SQL
+
+          fk_info.map do |row|
+            options = {
+              column: row['column'],
+              name: row['name'],
+              primary_key: row['primary_key'] }
+            ForeignKeyDefinition.new(table_name, row["to_table"], options)
+          end
+        end
+
         def add_foreign_key(from_table, to_table, options = {})
           foreign_key_column = options.fetch(:column)
           referenced_column = "id"
-- 
cgit v1.2.3


From 74b2fe4c0febe051cb48c7c25a565333ddf22bce Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 11:10:54 +0200
Subject: fk: `foreign_keys`, `add_foreign_key` and `remove_foreign_key` for
 MySQL

---
 .../abstract/schema_definitions.rb                 | 14 +++++++
 .../abstract/schema_statements.rb                  |  7 ++++
 .../connection_adapters/abstract_mysql_adapter.rb  | 44 ++++++++++++++++++++++
 .../postgresql/schema_definitions.rb               | 14 -------
 .../postgresql/schema_statements.rb                |  7 ----
 5 files changed, 65 insertions(+), 21 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index a9b3e9cfb9..b132543332 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -25,6 +25,20 @@ module ActiveRecord
     class ChangeColumnDefinition < Struct.new(:column, :type, :options) #:nodoc:
     end
 
+    class ForeignKeyDefinition < Struct.new(:from_table, :to_table, :options)
+      def name
+        options[:name]
+      end
+
+      def column
+        options[:column]
+      end
+
+      def primary_key
+        options[:primary_key]
+      end
+    end
+
     # Represents the schema of an SQL table in an abstract way. This class
     # provides methods for manipulating the schema representation.
     #
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 22823a8c58..55e3fb4477 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -625,6 +625,13 @@ module ActiveRecord
       end
       alias :add_belongs_to :add_reference
 
+      def foreign_key_name(table_name, options)
+        options.fetch(:name) do
+          column_name = options.fetch(:column)
+          "#{table_name}_#{column_name}_fk"
+        end
+      end
+
       # Removes the reference(s). Also removes a +type+ column if one exists.
       # <tt>remove_reference</tt>, <tt>remove_references</tt> and <tt>remove_belongs_to</tt> are acceptable.
       #
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index def04dbed2..431db591e6 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -192,6 +192,10 @@ module ActiveRecord
         true
       end
 
+      def supports_foreign_keys?
+        true
+      end
+
       def native_database_types
         NATIVE_DATABASE_TYPES
       end
@@ -501,6 +505,46 @@ module ActiveRecord
         execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options} #{index_algorithm}"
       end
 
+      def foreign_keys(table_name)
+        fk_info = select_all %{
+          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}'
+        }
+
+        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']}
+          ForeignKeyDefinition.new(table_name, row['to_table'], options)
+        end
+      end
+
+      def add_foreign_key(from_table, to_table, options = {})
+        foreign_key_column = options.fetch(:column)
+        referenced_column = "id"
+        foreign_key_name = foreign_key_name(from_table, options)
+        execute <<-SQL
+ALTER TABLE #{quote_table_name(from_table)}
+ADD CONSTRAINT #{foreign_key_name}
+FOREIGN KEY (#{quote_column_name(foreign_key_column)})
+REFERENCES #{quote_table_name(to_table)} (#{quote_column_name(referenced_column)})
+        SQL
+      end
+
+      def remove_foreign_key(from_table, options = {})
+        foreign_key_name = foreign_key_name(from_table, options)
+        execute <<-SQL
+ALTER TABLE #{quote_table_name(from_table)}
+DROP FOREIGN KEY #{foreign_key_name}
+        SQL
+      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
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
index 724e3fa1ee..0867e5ef54 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -89,20 +89,6 @@ module ActiveRecord
         attr_accessor :array
       end
 
-      class ForeignKeyDefinition < Struct.new(:from_table, :to_table, :options)
-        def name
-          options[:name]
-        end
-
-        def column
-          options[:column]
-        end
-
-        def primary_key
-          options[:primary_key]
-        end
-      end
-
       class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
         include ColumnMethods
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index b87fb85ae2..7a93d9cde7 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -492,13 +492,6 @@ DROP CONSTRAINT #{foreign_key_name}
           SQL
         end
 
-        def foreign_key_name(table_name, options)
-          options.fetch(:name) do
-            column_name = options.fetch(:column)
-            "#{table_name}_#{column_name}_fk"
-          end
-        end
-
         def index_name_length
           63
         end
-- 
cgit v1.2.3


From 1c170fdea2be04691c7daa8266084766fe963fff Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 11:50:37 +0200
Subject: fk: generalize using `AlterTable` and `SchemaCreation`.

---
 .../abstract/schema_creation.rb                    | 14 ++++++++
 .../abstract/schema_definitions.rb                 | 12 +++++++
 .../abstract/schema_statements.rb                  | 37 ++++++++++++++++++----
 .../connection_adapters/abstract_mysql_adapter.rb  | 24 +++-----------
 .../postgresql/schema_statements.rb                | 20 ------------
 5 files changed, 60 insertions(+), 47 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index 47fe501752..ad62eab4d2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -18,11 +18,25 @@ module ActiveRecord
           add_column_options!(sql, column_options(o))
         end
 
+        def visit_AddForeignKey(o)
+          <<-SQL
+ADD CONSTRAINT #{quote_column_name(o.name)}
+FOREIGN KEY (#{quote_column_name(o.column)})
+  REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
+          SQL
+        end
+
+        def visit_DropForeignKey(name)
+          "DROP CONSTRAINT #{name}"
+        end
+
         private
 
           def visit_AlterTable(o)
             sql = "ALTER TABLE #{quote_table_name(o.name)} "
             sql << o.adds.map { |col| visit_AddColumn col }.join(' ')
+            sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(' ')
+            sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(' ')
           end
 
           def visit_ColumnDefinition(o)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index b132543332..c18ebf1014 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -317,14 +317,26 @@ module ActiveRecord
 
     class AlterTable # :nodoc:
       attr_reader :adds
+      attr_reader :foreign_key_adds
+      attr_reader :foreign_key_drops
 
       def initialize(td)
         @td   = td
         @adds = []
+        @foreign_key_adds = []
+        @foreign_key_drops = []
       end
 
       def name; @td.name; end
 
+      def add_foreign_key(to_table, options)
+        @foreign_key_adds << ForeignKeyDefinition.new(name, to_table, options)
+      end
+
+      def drop_foreign_key(name)
+        @foreign_key_drops << name
+      end
+
       def add_column(name, type, options)
         name = name.to_s
         type = type.to_sym
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 55e3fb4477..da6b15dad0 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -625,13 +625,6 @@ module ActiveRecord
       end
       alias :add_belongs_to :add_reference
 
-      def foreign_key_name(table_name, options)
-        options.fetch(:name) do
-          column_name = options.fetch(:column)
-          "#{table_name}_#{column_name}_fk"
-        end
-      end
-
       # Removes the reference(s). Also removes a +type+ column if one exists.
       # <tt>remove_reference</tt>, <tt>remove_references</tt> and <tt>remove_belongs_to</tt> are acceptable.
       #
@@ -649,6 +642,36 @@ module ActiveRecord
       end
       alias :remove_belongs_to :remove_reference
 
+      def foreign_keys(table_name)
+        raise NotImplementedError, "foreign_keys is not implemented"
+      end
+
+      def add_foreign_key(from_table, to_table, options = {})
+        options = {
+          column: options.fetch(:column),
+          primary_key: "id",
+          name: foreign_key_name(from_table, options)
+        }
+        at = create_alter_table from_table
+        at.add_foreign_key to_table, options
+
+        execute schema_creation.accept at
+      end
+
+      def remove_foreign_key(from_table, options = {})
+        at = create_alter_table from_table
+        at.drop_foreign_key foreign_key_name(from_table, options)
+
+        execute schema_creation.accept at
+      end
+
+      def foreign_key_name(table_name, options) # :nodoc:
+        options.fetch(:name) do
+          column_name = options.fetch(:column)
+          "#{table_name}_#{column_name}_fk"
+        end
+      end
+
       def dump_schema_information #:nodoc:
         sm_table = ActiveRecord::Migrator.schema_migrations_table_name
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 431db591e6..6ba226765c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -10,6 +10,10 @@ module ActiveRecord
           add_column_position!(super, column_options(o))
         end
 
+        def visit_DropForeignKey(name)
+          "DROP FOREIGN KEY #{name}"
+        end
+
         private
 
         def visit_TableDefinition(o)
@@ -525,26 +529,6 @@ module ActiveRecord
         end
       end
 
-      def add_foreign_key(from_table, to_table, options = {})
-        foreign_key_column = options.fetch(:column)
-        referenced_column = "id"
-        foreign_key_name = foreign_key_name(from_table, options)
-        execute <<-SQL
-ALTER TABLE #{quote_table_name(from_table)}
-ADD CONSTRAINT #{foreign_key_name}
-FOREIGN KEY (#{quote_column_name(foreign_key_column)})
-REFERENCES #{quote_table_name(to_table)} (#{quote_column_name(referenced_column)})
-        SQL
-      end
-
-      def remove_foreign_key(from_table, options = {})
-        foreign_key_name = foreign_key_name(from_table, options)
-        execute <<-SQL
-ALTER TABLE #{quote_table_name(from_table)}
-DROP FOREIGN KEY #{foreign_key_name}
-        SQL
-      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
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 7a93d9cde7..c061337e71 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -472,26 +472,6 @@ ORDER BY c.conname
           end
         end
 
-        def add_foreign_key(from_table, to_table, options = {})
-          foreign_key_column = options.fetch(:column)
-          referenced_column = "id"
-          foreign_key_name = foreign_key_name(from_table, options)
-          execute <<-SQL
-ALTER TABLE #{quote_table_name(from_table)}
-ADD CONSTRAINT #{foreign_key_name}
-  FOREIGN KEY (#{quote_column_name(foreign_key_column)})
-  REFERENCES #{quote_table_name(to_table)} (#{quote_column_name(referenced_column)})
-          SQL
-        end
-
-        def remove_foreign_key(from_table, options = {})
-          foreign_key_name = foreign_key_name(from_table, options)
-          execute <<-SQL
-ALTER TABLE #{quote_table_name(from_table)}
-DROP CONSTRAINT #{foreign_key_name}
-          SQL
-        end
-
         def index_name_length
           63
         end
-- 
cgit v1.2.3


From a48b675d54101b048228d1011ffa426c2b7fe94d Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 12:09:58 +0200
Subject: fk: `:primary_key` option for non-standard pk's.

---
 .../active_record/connection_adapters/abstract/schema_statements.rb   | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index da6b15dad0..db04ebc802 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -647,9 +647,11 @@ module ActiveRecord
       end
 
       def add_foreign_key(from_table, to_table, options = {})
+        primary_key = options.fetch(:primary_key, "id")
+
         options = {
           column: options.fetch(:column),
-          primary_key: "id",
+          primary_key: primary_key,
           name: foreign_key_name(from_table, options)
         }
         at = create_alter_table from_table
-- 
cgit v1.2.3


From 402f303f1d938cf2c7781d7734c4ff8e6b874f35 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 14:26:50 +0200
Subject: fk: support dependent option (:delete, :nullify and :restrict).

---
 .../connection_adapters/abstract/schema_creation.rb        | 13 ++++++++++++-
 .../connection_adapters/abstract/schema_definitions.rb     |  4 ++++
 .../connection_adapters/abstract/schema_statements.rb      |  3 ++-
 .../connection_adapters/abstract_mysql_adapter.rb          | 14 +++++++++++++-
 .../connection_adapters/postgresql/schema_statements.rb    |  9 ++++++++-
 5 files changed, 39 insertions(+), 4 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index ad62eab4d2..57790d5667 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -19,11 +19,13 @@ module ActiveRecord
         end
 
         def visit_AddForeignKey(o)
-          <<-SQL
+          sql = <<-SQL
 ADD CONSTRAINT #{quote_column_name(o.name)}
 FOREIGN KEY (#{quote_column_name(o.column)})
   REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
           SQL
+          sql << " #{dependency_sql(o.dependent)}" if o.dependent
+          sql
         end
 
         def visit_DropForeignKey(name)
@@ -98,6 +100,15 @@ FOREIGN KEY (#{quote_column_name(o.column)})
           def options_include_default?(options)
             options.include?(:default) && !(options[:null] == false && options[:default].nil?)
           end
+
+          def dependency_sql(dependency)
+            case dependency
+              when :nullify then "ON DELETE SET NULL"
+              when :delete  then "ON DELETE CASCADE"
+              when :restrict then "ON DELETE RESTRICT"
+              else ""
+            end
+          end
       end
     end
   end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index c18ebf1014..66ebf82971 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -37,6 +37,10 @@ module ActiveRecord
       def primary_key
         options[:primary_key]
       end
+
+      def dependent
+        options[:dependent]
+      end
     end
 
     # Represents the schema of an SQL table in an abstract way. This class
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index db04ebc802..fe752126ad 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -652,7 +652,8 @@ module ActiveRecord
         options = {
           column: options.fetch(:column),
           primary_key: primary_key,
-          name: foreign_key_name(from_table, options)
+          name: foreign_key_name(from_table, options),
+          dependent: options.fetch(:dependent, nil)
         }
         at = create_alter_table from_table
         at.add_foreign_key to_table, options
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 6ba226765c..9610296043 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -524,7 +524,19 @@ module ActiveRecord
         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 = {
+            column: row['column'],
+            name: row['name'],
+            primary_key: row['primary_key']
+          }
+
+          if create_table_info =~ /CONSTRAINT #{quote_column_name(row['name'])} FOREIGN KEY .* REFERENCES .* ON DELETE (CASCADE|SET NULL|RESTRICT)/
+            options[:dependent] = case $1
+              when 'CASCADE'  then :delete
+              when 'SET NULL' then :nullify
+              end
+          end
+
           ForeignKeyDefinition.new(table_name, row['to_table'], options)
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index c061337e71..7b61ff81ba 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -467,7 +467,14 @@ ORDER BY c.conname
             options = {
               column: row['column'],
               name: row['name'],
-              primary_key: row['primary_key'] }
+              primary_key: row['primary_key']
+            }
+
+            options[:dependent] = case row['dependency']
+              when 'c'; :delete
+              when 'n'; :nullify
+              when 'r'; :restrict
+              end
             ForeignKeyDefinition.new(table_name, row["to_table"], options)
           end
         end
-- 
cgit v1.2.3


From d074b821489b6d58101d1474dd514990f4bdf0fa Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Tue, 10 Jun 2014 15:29:19 +0200
Subject: fk: infere column name from table names.

This allows to create and remove foreign keys without specifying a column.
---
 .../connection_adapters/abstract/schema_statements.rb  | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index fe752126ad..0f2af2c6d2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -647,10 +647,11 @@ module ActiveRecord
       end
 
       def add_foreign_key(from_table, to_table, options = {})
+        options[:column] ||= foreign_key_column_for(to_table)
         primary_key = options.fetch(:primary_key, "id")
 
         options = {
-          column: options.fetch(:column),
+          column: options[:column],
           primary_key: primary_key,
           name: foreign_key_name(from_table, options),
           dependent: options.fetch(:dependent, nil)
@@ -661,17 +662,26 @@ module ActiveRecord
         execute schema_creation.accept at
       end
 
-      def remove_foreign_key(from_table, options = {})
+      def remove_foreign_key(from_table, options_or_to_table = {})
+        if options_or_to_table.is_a?(Hash)
+          options = options_or_to_table
+        else
+          options = { column: foreign_key_column_for(options_or_to_table) }
+        end
+
         at = create_alter_table from_table
         at.drop_foreign_key foreign_key_name(from_table, options)
 
         execute schema_creation.accept at
       end
 
+      def foreign_key_column_for(table_name) # :nodoc:
+        "#{table_name.to_s.singularize}_id"
+      end
+
       def foreign_key_name(table_name, options) # :nodoc:
         options.fetch(:name) do
-          column_name = options.fetch(:column)
-          "#{table_name}_#{column_name}_fk"
+          "#{table_name}_#{options.fetch(:column)}_fk"
         end
       end
 
-- 
cgit v1.2.3


From 6955d864ceb0ba994ef4fb4c5e866463f247944b Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Wed, 11 Jun 2014 08:23:17 +0200
Subject: fk: rename `dependent` to `on_delete`

---
 .../connection_adapters/abstract/schema_creation.rb           | 11 +++++------
 .../connection_adapters/abstract/schema_definitions.rb        |  4 ++--
 .../connection_adapters/abstract/schema_statements.rb         |  2 +-
 .../connection_adapters/abstract_mysql_adapter.rb             |  4 ++--
 .../connection_adapters/postgresql/schema_statements.rb       |  4 ++--
 5 files changed, 12 insertions(+), 13 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index 57790d5667..aad4431910 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -24,7 +24,7 @@ ADD CONSTRAINT #{quote_column_name(o.name)}
 FOREIGN KEY (#{quote_column_name(o.column)})
   REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
           SQL
-          sql << " #{dependency_sql(o.dependent)}" if o.dependent
+          sql << " #{action_sql(o.on_delete)}" if o.on_delete
           sql
         end
 
@@ -101,12 +101,11 @@ FOREIGN KEY (#{quote_column_name(o.column)})
             options.include?(:default) && !(options[:null] == false && options[:default].nil?)
           end
 
-          def dependency_sql(dependency)
+          def action_sql(action = "DELETE", dependency)
             case dependency
-              when :nullify then "ON DELETE SET NULL"
-              when :delete  then "ON DELETE CASCADE"
-              when :restrict then "ON DELETE RESTRICT"
-              else ""
+              when :nullify then "ON #{action} SET NULL"
+              when :cascade  then "ON #{action} CASCADE"
+              when :restrict then "ON #{action} RESTRICT"
             end
           end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 66ebf82971..2d6cf2427c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -38,8 +38,8 @@ module ActiveRecord
         options[:primary_key]
       end
 
-      def dependent
-        options[:dependent]
+      def on_delete
+        options[:on_delete]
       end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 0f2af2c6d2..3f72e35bb5 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -654,7 +654,7 @@ module ActiveRecord
           column: options[:column],
           primary_key: primary_key,
           name: foreign_key_name(from_table, options),
-          dependent: options.fetch(:dependent, nil)
+          on_delete: options.fetch(:on_delete, nil)
         }
         at = create_alter_table from_table
         at.add_foreign_key to_table, options
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 9610296043..f3b7fe172e 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -531,8 +531,8 @@ module ActiveRecord
           }
 
           if create_table_info =~ /CONSTRAINT #{quote_column_name(row['name'])} FOREIGN KEY .* REFERENCES .* ON DELETE (CASCADE|SET NULL|RESTRICT)/
-            options[:dependent] = case $1
-              when 'CASCADE'  then :delete
+            options[:on_delete] = case $1
+              when 'CASCADE'  then :cascade
               when 'SET NULL' then :nullify
               end
           end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 7b61ff81ba..bf87395ef1 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -470,8 +470,8 @@ ORDER BY c.conname
               primary_key: row['primary_key']
             }
 
-            options[:dependent] = case row['dependency']
-              when 'c'; :delete
+            options[:on_delete] = case row['dependency']
+              when 'c'; :cascade
               when 'n'; :nullify
               when 'r'; :restrict
               end
-- 
cgit v1.2.3


From acd0287dc18a3fbba6fa4301cb31a7aecd22922b Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Wed, 11 Jun 2014 08:47:53 +0200
Subject: fk: support for on_update

---
 .../connection_adapters/abstract/schema_creation.rb   |  5 +++--
 .../abstract/schema_definitions.rb                    |  4 ++++
 .../connection_adapters/abstract/schema_statements.rb |  3 ++-
 .../connection_adapters/abstract_mysql_adapter.rb     | 17 +++++++++++------
 .../postgresql/schema_statements.rb                   | 19 ++++++++++++-------
 5 files changed, 32 insertions(+), 16 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index aad4431910..b896bd25e4 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -24,7 +24,8 @@ ADD CONSTRAINT #{quote_column_name(o.name)}
 FOREIGN KEY (#{quote_column_name(o.column)})
   REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
           SQL
-          sql << " #{action_sql(o.on_delete)}" if o.on_delete
+          sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
+          sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
           sql
         end
 
@@ -101,7 +102,7 @@ FOREIGN KEY (#{quote_column_name(o.column)})
             options.include?(:default) && !(options[:null] == false && options[:default].nil?)
           end
 
-          def action_sql(action = "DELETE", dependency)
+          def action_sql(action, dependency)
             case dependency
               when :nullify then "ON #{action} SET NULL"
               when :cascade  then "ON #{action} CASCADE"
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 2d6cf2427c..2e47e68754 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -41,6 +41,10 @@ module ActiveRecord
       def on_delete
         options[:on_delete]
       end
+
+      def on_update
+        options[:on_update]
+      end
     end
 
     # Represents the schema of an SQL table in an abstract way. This class
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 3f72e35bb5..18e73b0200 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -654,7 +654,8 @@ module ActiveRecord
           column: options[:column],
           primary_key: primary_key,
           name: foreign_key_name(from_table, options),
-          on_delete: options.fetch(:on_delete, nil)
+          on_delete: options[:on_delete],
+          on_update: options[:on_update]
         }
         at = create_alter_table from_table
         at.add_foreign_key to_table, options
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index f3b7fe172e..868181e677 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -530,17 +530,22 @@ module ActiveRecord
             primary_key: row['primary_key']
           }
 
-          if create_table_info =~ /CONSTRAINT #{quote_column_name(row['name'])} FOREIGN KEY .* REFERENCES .* ON DELETE (CASCADE|SET NULL|RESTRICT)/
-            options[:on_delete] = case $1
-              when 'CASCADE'  then :cascade
-              when 'SET NULL' then :nullify
-              end
-          end
+          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 extract_foreign_key_action(structure, name, action) # :nodoc:
+        if structure =~ /CONSTRAINT #{quote_column_name(name)} FOREIGN KEY .* REFERENCES .* ON #{action} (CASCADE|SET NULL|RESTRICT)/
+          case $1
+          when 'CASCADE'; :cascade
+          when 'SET NULL'; :nullify
+          end
+        end
+      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
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index bf87395ef1..7ffbe4434f 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -450,7 +450,7 @@ module ActiveRecord
 
         def foreign_keys(table_name)
           fk_info = select_all <<-SQL
-SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confdeltype AS dependency
+SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
 FROM pg_constraint c
 JOIN pg_class t1 ON c.conrelid = t1.oid
 JOIN pg_class t2 ON c.confrelid = t2.oid
@@ -470,12 +470,17 @@ ORDER BY c.conname
               primary_key: row['primary_key']
             }
 
-            options[:on_delete] = case row['dependency']
-              when 'c'; :cascade
-              when 'n'; :nullify
-              when 'r'; :restrict
-              end
-            ForeignKeyDefinition.new(table_name, row["to_table"], options)
+            options[:on_delete] = extract_foreign_key_action(row['on_delete'])
+            options[:on_update] = extract_foreign_key_action(row['on_update'])
+            ForeignKeyDefinition.new(table_name, row['to_table'], options)
+          end
+        end
+
+        def extract_foreign_key_action(specifier) # :nodoc:
+          case specifier
+          when 'c'; :cascade
+          when 'n'; :nullify
+          when 'r'; :restrict
           end
         end
 
-- 
cgit v1.2.3


From 9ae1a2c69f51a9065090a9c505f4d22ffbb84094 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Wed, 11 Jun 2014 11:16:31 +0200
Subject: fk: raise when identifiers are longer than
 `allowed_index_name_length`.

---
 .../active_record/connection_adapters/abstract/schema_statements.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 18e73b0200..5a863717e5 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -682,7 +682,11 @@ module ActiveRecord
 
       def foreign_key_name(table_name, options) # :nodoc:
         options.fetch(:name) do
-          "#{table_name}_#{options.fetch(:column)}_fk"
+          identifier = "#{table_name}_#{options.fetch(:column)}_fk"
+          if identifier.length > allowed_index_name_length
+            raise ArgumentError, "Foreign key name '#{identifier}' is too long; the limit is #{allowed_index_name_length} characters"
+          end
+          identifier
         end
       end
 
-- 
cgit v1.2.3


From 31e4c19331c9262574d354250675bba7dcf9dba2 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Wed, 11 Jun 2014 17:26:51 +0200
Subject: fk: `add/remove_foreign_key` are noop for adapters that don't support
 fk

---
 .../active_record/connection_adapters/abstract/schema_statements.rb   | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 5a863717e5..4da42717c1 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -647,6 +647,8 @@ module ActiveRecord
       end
 
       def add_foreign_key(from_table, to_table, options = {})
+        return unless supports_foreign_keys?
+
         options[:column] ||= foreign_key_column_for(to_table)
         primary_key = options.fetch(:primary_key, "id")
 
@@ -664,6 +666,8 @@ module ActiveRecord
       end
 
       def remove_foreign_key(from_table, options_or_to_table = {})
+        return unless supports_foreign_keys?
+
         if options_or_to_table.is_a?(Hash)
           options = options_or_to_table
         else
-- 
cgit v1.2.3


From 8550ba307d712ebede0d0695b5172bb3e9af16c9 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Fri, 20 Jun 2014 08:56:30 +0200
Subject: fk: raise for invalid :on_update / :on_delete values

---
 .../connection_adapters/abstract/schema_creation.rb           | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index b896bd25e4..e495304376 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -104,9 +104,14 @@ FOREIGN KEY (#{quote_column_name(o.column)})
 
           def action_sql(action, dependency)
             case dependency
-              when :nullify then "ON #{action} SET NULL"
-              when :cascade  then "ON #{action} CASCADE"
-              when :restrict then "ON #{action} RESTRICT"
+            when :nullify then "ON #{action} SET NULL"
+            when :cascade  then "ON #{action} CASCADE"
+            when :restrict then "ON #{action} RESTRICT"
+            else
+              raise ArgumentError, <<-MSG
+'#{dependency}' is not supported for :on_update or :on_delete.
+Supported values are: :nullify, :cascade, :restrict
+              MSG
             end
           end
       end
-- 
cgit v1.2.3


From 8768305f20d12c40241396092a63e0d56269fefe Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Fri, 20 Jun 2014 11:54:17 +0200
Subject: fk: use random digest names

The name of the foreign key is not relevant from a users perspective.
Using random names resolves the urge to rename the foreign key when the
respective table or column is renamed.
---
 .../connection_adapters/abstract/schema_creation.rb  |  2 +-
 .../abstract/schema_definitions.rb                   | 11 ++++++++++-
 .../abstract/schema_statements.rb                    | 20 ++++++++++++--------
 3 files changed, 23 insertions(+), 10 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index e495304376..5d13ee3633 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -30,7 +30,7 @@ FOREIGN KEY (#{quote_column_name(o.column)})
         end
 
         def visit_DropForeignKey(name)
-          "DROP CONSTRAINT #{name}"
+          "DROP CONSTRAINT #{quote_column_name(name)}"
         end
 
         private
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 2e47e68754..785cfd9dbc 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -35,7 +35,7 @@ module ActiveRecord
       end
 
       def primary_key
-        options[:primary_key]
+        options[:primary_key] || default_primary_key
       end
 
       def on_delete
@@ -45,6 +45,15 @@ module ActiveRecord
       def on_update
         options[:on_update]
       end
+
+      def custom_primary_key?
+        options[:primary_key] != default_primary_key
+      end
+
+      private
+      def default_primary_key
+        "id"
+      end
     end
 
     # Represents the schema of an SQL table in an abstract way. This class
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 4da42717c1..e203767992 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -650,11 +650,10 @@ module ActiveRecord
         return unless supports_foreign_keys?
 
         options[:column] ||= foreign_key_column_for(to_table)
-        primary_key = options.fetch(:primary_key, "id")
 
         options = {
           column: options[:column],
-          primary_key: primary_key,
+          primary_key: options[:primary_key],
           name: foreign_key_name(from_table, options),
           on_delete: options[:on_delete],
           on_update: options[:on_update]
@@ -674,8 +673,17 @@ module ActiveRecord
           options = { column: foreign_key_column_for(options_or_to_table) }
         end
 
+        fk_name_to_delete = options.fetch(:name) do
+          fk_to_delete = foreign_keys(from_table).detect {|fk| fk.column == options[:column] }
+          if fk_to_delete
+            fk_to_delete.name
+          else
+            raise ArgumentError, "Table '#{from_table}' has no foreign key on column '#{options[:column]}'"
+          end
+        end
+
         at = create_alter_table from_table
-        at.drop_foreign_key foreign_key_name(from_table, options)
+        at.drop_foreign_key fk_name_to_delete
 
         execute schema_creation.accept at
       end
@@ -686,11 +694,7 @@ module ActiveRecord
 
       def foreign_key_name(table_name, options) # :nodoc:
         options.fetch(:name) do
-          identifier = "#{table_name}_#{options.fetch(:column)}_fk"
-          if identifier.length > allowed_index_name_length
-            raise ArgumentError, "Foreign key name '#{identifier}' is too long; the limit is #{allowed_index_name_length} characters"
-          end
-          identifier
+          "fk_rails_#{SecureRandom.hex(5)}"
         end
       end
 
-- 
cgit v1.2.3


From 24e1aefb4b2d7b2b4babfd4bae1e9e613283b003 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Thu, 26 Jun 2014 13:09:45 +0200
Subject: fk: review corrections: indent, visibility, syntax, wording.

---
 .../abstract/schema_creation.rb                    | 36 +++++++++++-----------
 .../abstract/schema_statements.rb                  | 17 +++++-----
 .../connection_adapters/abstract_mysql_adapter.rb  | 22 ++++++-------
 .../postgresql/schema_statements.rb                | 24 +++++++--------
 4 files changed, 50 insertions(+), 49 deletions(-)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index 5d13ee3633..c1379f6bec 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -18,21 +18,6 @@ module ActiveRecord
           add_column_options!(sql, column_options(o))
         end
 
-        def visit_AddForeignKey(o)
-          sql = <<-SQL
-ADD CONSTRAINT #{quote_column_name(o.name)}
-FOREIGN KEY (#{quote_column_name(o.column)})
-  REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
-          SQL
-          sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
-          sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
-          sql
-        end
-
-        def visit_DropForeignKey(name)
-          "DROP CONSTRAINT #{quote_column_name(name)}"
-        end
-
         private
 
           def visit_AlterTable(o)
@@ -58,6 +43,21 @@ FOREIGN KEY (#{quote_column_name(o.column)})
             create_sql
           end
 
+          def visit_AddForeignKey(o)
+            sql = <<-SQL.strip_heredoc
+              ADD CONSTRAINT #{quote_column_name(o.name)}
+              FOREIGN KEY (#{quote_column_name(o.column)})
+                REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
+            SQL
+            sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
+            sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
+            sql
+          end
+
+          def visit_DropForeignKey(name)
+            "DROP CONSTRAINT #{quote_column_name(name)}"
+          end
+
           def column_options(o)
             column_options = {}
             column_options[:null] = o.null unless o.null.nil?
@@ -108,9 +108,9 @@ FOREIGN KEY (#{quote_column_name(o.column)})
             when :cascade  then "ON #{action} CASCADE"
             when :restrict then "ON #{action} RESTRICT"
             else
-              raise ArgumentError, <<-MSG
-'#{dependency}' is not supported for :on_update or :on_delete.
-Supported values are: :nullify, :cascade, :restrict
+              raise ArgumentError, <<-MSG.strip_heredoc
+                '#{dependency}' is not supported for :on_update or :on_delete.
+                Supported values are: :nullify, :cascade, :restrict
               MSG
             end
           end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index e203767992..1789cce123 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -661,7 +661,7 @@ module ActiveRecord
         at = create_alter_table from_table
         at.add_foreign_key to_table, options
 
-        execute schema_creation.accept at
+        execute schema_creation.accept(at)
       end
 
       def remove_foreign_key(from_table, options_or_to_table = {})
@@ -675,6 +675,7 @@ module ActiveRecord
 
         fk_name_to_delete = options.fetch(:name) do
           fk_to_delete = foreign_keys(from_table).detect {|fk| fk.column == options[:column] }
+
           if fk_to_delete
             fk_to_delete.name
           else
@@ -685,19 +686,13 @@ module ActiveRecord
         at = create_alter_table from_table
         at.drop_foreign_key fk_name_to_delete
 
-        execute schema_creation.accept at
+        execute schema_creation.accept(at)
       end
 
       def foreign_key_column_for(table_name) # :nodoc:
         "#{table_name.to_s.singularize}_id"
       end
 
-      def foreign_key_name(table_name, options) # :nodoc:
-        options.fetch(:name) do
-          "fk_rails_#{SecureRandom.hex(5)}"
-        end
-      end
-
       def dump_schema_information #:nodoc:
         sm_table = ActiveRecord::Migrator.schema_migrations_table_name
 
@@ -908,6 +903,12 @@ module ActiveRecord
       def create_alter_table(name)
         AlterTable.new create_table_definition(name, false, {})
       end
+
+      def foreign_key_name(table_name, options) # :nodoc:
+        options.fetch(:name) do
+          "fk_rails_#{SecureRandom.hex(5)}"
+        end
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 868181e677..4924f345fc 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -510,7 +510,7 @@ module ActiveRecord
       end
 
       def foreign_keys(table_name)
-        fk_info = select_all %{
+        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'
@@ -519,7 +519,7 @@ module ActiveRecord
           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"]
 
@@ -537,15 +537,6 @@ module ActiveRecord
         end
       end
 
-      def extract_foreign_key_action(structure, name, action) # :nodoc:
-        if structure =~ /CONSTRAINT #{quote_column_name(name)} FOREIGN KEY .* REFERENCES .* ON #{action} (CASCADE|SET NULL|RESTRICT)/
-          case $1
-          when 'CASCADE'; :cascade
-          when 'SET NULL'; :nullify
-          end
-        end
-      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
@@ -824,6 +815,15 @@ module ActiveRecord
         # ...and send them all in one query
         @connection.query  "SET #{encoding} #{variable_assignments}"
       end
+
+      def extract_foreign_key_action(structure, name, action) # :nodoc:
+        if structure =~ /CONSTRAINT #{quote_column_name(name)} FOREIGN KEY .* REFERENCES .* ON #{action} (CASCADE|SET NULL|RESTRICT)/
+          case $1
+          when 'CASCADE'; :cascade
+          when 'SET NULL'; :nullify
+          end
+        end
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 7ffbe4434f..30df98be1b 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -449,18 +449,18 @@ module ActiveRecord
         end
 
         def foreign_keys(table_name)
-          fk_info = select_all <<-SQL
-SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
-FROM pg_constraint c
-JOIN pg_class t1 ON c.conrelid = t1.oid
-JOIN pg_class t2 ON c.confrelid = t2.oid
-JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
-JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
-JOIN pg_namespace t3 ON c.connamespace = t3.oid
-WHERE c.contype = 'f'
-  AND t1.relname = #{quote(table_name)}
-  AND t3.nspname = ANY (current_schemas(false))
-ORDER BY c.conname
+          fk_info = select_all <<-SQL.strip_heredoc
+            SELECT t2.relname AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
+            FROM pg_constraint c
+            JOIN pg_class t1 ON c.conrelid = t1.oid
+            JOIN pg_class t2 ON c.confrelid = t2.oid
+            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
+            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
+            JOIN pg_namespace t3 ON c.connamespace = t3.oid
+            WHERE c.contype = 'f'
+              AND t1.relname = #{quote(table_name)}
+              AND t3.nspname = ANY (current_schemas(false))
+            ORDER BY c.conname
           SQL
 
           fk_info.map do |row|
-- 
cgit v1.2.3


From a5b3f372ab30e043d25b25b05e603e6ed33c0ee9 Mon Sep 17 00:00:00 2001
From: Yves Senn <yves.senn@gmail.com>
Date: Thu, 12 Jun 2014 08:42:00 +0200
Subject: fk: add docs

---
 .../abstract/schema_statements.rb                  | 58 ++++++++++++++++++++++
 1 file changed, 58 insertions(+)

(limited to 'activerecord/lib/active_record/connection_adapters')

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 1789cce123..5814c2b711 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -642,10 +642,54 @@ module ActiveRecord
       end
       alias :remove_belongs_to :remove_reference
 
+      # Returns an array of foreign keys for the given table.
+      # The foreign keys are represented as +ForeignKeyDefinition+ objects.
       def foreign_keys(table_name)
         raise NotImplementedError, "foreign_keys is not implemented"
       end
 
+      # Adds a new foreign key. +from_table+ is the table with the key column,
+      # +to_table+ contains the referenced primary key.
+      #
+      # The foreign key will be named after the following pattern: <tt>fk_rails_<identifier></tt>.
+      # +identifier+ is a 10 character long random string. A custom name can be specified with
+      # the <tt>:name</tt> option.
+      #
+      # ====== Creating a simple foreign key
+      #
+      #   add_foreign_key :articles, :authors
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT articles_author_id_fk FOREIGN KEY ("author_id") REFERENCES "authors" ("id")
+      #
+      # ====== Creating a foreign key on a specific column
+      #
+      #   add_foreign_key :articles, :users, column: :author_id, primary_key: "lng_id"
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT fk_rails_58ca3d3a82 FOREIGN KEY ("author_id") REFERENCES "users" ("lng_id")
+      #
+      # ====== Creating a cascading foreign key
+      #
+      #   add_foreign_key :articles, :authors, on_delete: :cascade
+      #
+      # generates:
+      #
+      #   ALTER TABLE "articles" ADD CONSTRAINT articles_author_id_fk FOREIGN KEY ("author_id") REFERENCES "authors" ("id") ON DELETE CASCADE
+      #
+      # The +options+ hash can include the following keys:
+      # [<tt>:column</tt>]
+      #   The foreign key column name on +from_table+. Defaults to <tt>to_table.singularize + "_id"</tt>
+      # [<tt>:primary_key</tt>]
+      #   The primary key column name on +to_table+. Defaults to +id+.
+      # [<tt>:name</tt>]
+      #   The constraint name. Defaults to <tt>fk_rails_<identifier></tt>.
+      # [<tt>:on_delete</tt>]
+      #   Action that happens <tt>ON DELETE</tt>. Valid values are +:nullify+, +:cascade:+ and +:restrict+
+      # [<tt>:on_update</tt>]
+      #   Action that happens <tt>ON UPDATE</tt>. Valid values are +:nullify+, +:cascade:+ and +:restrict+
       def add_foreign_key(from_table, to_table, options = {})
         return unless supports_foreign_keys?
 
@@ -664,6 +708,20 @@ module ActiveRecord
         execute schema_creation.accept(at)
       end
 
+      # Removes the given foreign key from the table.
+      #
+      # Removes the foreign key on +accounts.branch_id+.
+      #
+      #   remove_foreign_key :accounts, :branches
+      #
+      # Removes the foreign key on +accounts.owner_id+.
+      #
+      #   remove_foreign_key :accounts, column: :owner_id
+      #
+      # Removes the foreign key named +special_fk_name+ on the +accounts+ table.
+      #
+      #   remove_foreign_key :accounts, name: :special_fk_name
+      #
       def remove_foreign_key(from_table, options_or_to_table = {})
         return unless supports_foreign_keys?
 
-- 
cgit v1.2.3