Fixed persistency layer.

Now we have ODBC .. that accepts various connection string (including SQLite, MySQL,...)
  And EiffelStore+MySQL.
Updated sql scripts to work with MySQL, and SQLite.
Added a sql_statement (s: STRING): STRING that converts ROC sql statement to fit the underlying database engine.
 mostly to adapt incompatibilities such as AUTO_INCREMENT for MySQL and AUTOINCREMENT for SQLite
 by default SQL script should be written following MySQL SQL syntax.
Warning: to use ODBC persistence driver, it has to be installed on the target machine.

library/persistence/store_mysql/tests/transactions/transaction_test_set.e

@@ -0,0 +1,87 @@
+note
+	description: "[
+		Eiffel tests that can be executed by testing tool.
+	]"
+	author: "EiffelStudio test wizard"
+	date: "$Date: 2015-01-27 19:15:02 +0100 (mar., 27 janv. 2015) $"
+	revision: "$Revision: 96542 $"
+	testing: "type/manual"
+
+class
+	TRANSACTION_TEST_SET
+
+inherit
+
+	EQA_TEST_SET
+		redefine
+			on_prepare,
+			on_clean
+		select
+			default_create
+		end
+	ABSTRACT_DB_TEST
+		rename
+			default_create as default_db_test
+		end
+
+
+feature {NONE} -- Events
+
+	on_prepare
+			-- <Precursor>
+		do
+			(create {CLEAN_DB}).clean_db (connection)
+		end
+
+	on_clean
+			-- <Precursor>
+		do
+		end
+
+feature -- Test routines
+
+	test_user_rollback
+		note
+			testing:  "execution/isolated"
+		local
+			u: detachable CMS_USER
+		do
+			u := storage.user_by_name ("test")
+			if u = Void then
+				u := custom_user ("test", "test","test@admin.com")
+				storage.new_user (u)
+			end
+			assert ("Has user:", storage.has_user)
+			u.set_email ("test@example.com")
+			storage.sql_begin_transaction
+			storage.update_user (u)
+			assert ("Has user:", storage.user_by_email ("test@example.com") /= Void)
+			storage.sql_rollback_transaction
+			assert ("Not has user:", storage.user_by_email ("test@example.com") = Void)
+		end
+
+	test_user_node_rollback
+		note
+			testing:  "execution/isolated"
+		local
+			u: detachable CMS_USER
+		do
+			u := storage.user_by_name ("test")
+			if u = Void then
+				u := custom_user ("test", "test","test@admin.com")
+				storage.new_user (u)
+			end
+
+			connection.begin_transaction
+			u.set_email ("test@example.com")
+			assert ("Has user:", storage.user_by_email ("test@example.com") /= Void)
+--			storage.new_node (default_node)
+--			assert ("Has one node:", storage.nodes_count = 1)
+			connection.rollback
+			assert ("Not has user:", storage.user_by_email ("test@example.com") = Void)
+--			assert ("Has no node:", storage.nodes_count = 0)
+		end
+
+end
+
+