Create select-for-update.sql

Author: Deepak-Vohra

sql-queries-11/select-for-update.sql

@@ -0,0 +1,31 @@
+//First Session
+START TRANSACTION;
+SELECT * FROM DEPARTMENT WHERE id=5 FOR UPDATE;
+
+//Second Session
+START TRANSACTION;
+SELECT * FROM DEPARTMENT WHERE id=5;
+
+//First Session
+UPDATE DEPARTMENT SET code='MATH' WHERE id=5;
+
+//Second Session
+SELECT * FROM DEPARTMENT WHERE id=5 FOR SHARE;
+
+//First Session
+COMMIT;
+
+//Second Session
+SELECT * FROM DEPARTMENT WHERE id=5 FOR SHARE;
+
+//Second Session
+START TRANSACTION;
+UPDATE DEPARTMENT SET code='TEMP' WHERE id<5 OR id>5;
+
+//First Session
+COMMIT
+//Second Session
+COMMIT;
+
+SELECT * FROM DEPARTMENT;
+