1 files changed, 46 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index ec44d020c2..ca6de37a6b 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -95,6 +95,8 @@ module ActiveRecord
 
         @active     = nil
         @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))
+
+        configure_connection
       end
 
       def supports_ddl_transactions?
@@ -128,6 +130,10 @@ module ActiveRecord
         true
       end
 
+      def supports_foreign_keys_in_create?
+        sqlite_version >= "3.6.19"
+      end
+
       def supports_views?
         true
       end
@@ -185,6 +191,19 @@ module ActiveRecord
         true
       end
 
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity # :nodoc:
+        old = select_value("PRAGMA foreign_keys")
+
+        begin
+          execute("PRAGMA foreign_keys = OFF")
+          yield
+        ensure
+          execute("PRAGMA foreign_keys = #{old}")
+        end
+      end
+
       #--
       # DATABASE STATEMENTS ======================================
       #++
@@ -424,6 +443,19 @@ module ActiveRecord
         rename_column_indexes(table_name, column.name, new_column_name)
       end
 
+      def foreign_keys(table_name)
+        fk_info = select_all("PRAGMA foreign_key_list(#{quote(table_name)})", "SCHEMA")
+        fk_info.map do |row|
+          options = {
+            column: row["from"],
+            primary_key: row["to"],
+            on_delete: extract_foreign_key_action(row["on_delete"]),
+            on_update: extract_foreign_key_action(row["on_update"])
+          }
+          ForeignKeyDefinition.new(table_name, row["table"], options)
+        end
+      end
+
       private
 
         def table_structure(table_name)
@@ -525,6 +557,8 @@ module ActiveRecord
             RecordNotUnique.new(message)
           when /.* may not be NULL/, /NOT NULL constraint failed: .*/
             NotNullViolation.new(message)
+          when /FOREIGN KEY constraint failed/i
+            InvalidForeignKey.new(message)
           else
             super
           end
@@ -574,6 +608,18 @@ module ActiveRecord
         def create_table_definition(*args)
           SQLite3::TableDefinition.new(*args)
         end
+
+        def extract_foreign_key_action(specifier)
+          case specifier
+          when "CASCADE"; :cascade
+          when "SET NULL"; :nullify
+          when "RESTRICT"; :restrict
+          end
+        end
+
+        def configure_connection
+          execute("PRAGMA foreign_keys = ON", "SCHEMA")
+        end
     end
   end
 end