Persistent Systems Interview Question

// Technical Interview // -firstly introduction 1- polymorphism 2- types of polymorphism 3- code for linked list reversal 4- sorting techniques and their complexities 5- osi model 6- primary and foreign key 7-difference between linked list and array 8- had to write basic sql queries (4-5) 9- puzzle // HR round // 1- Introduction 2- Why persistent? 3- Any offers in hand? 4- Weakness and strength