I don't understand why you need to store the old value a second time. If you know that the value went from A -> B -> C, just store the new value, not the old. You can see that it changed from A->B->C without storing it twice.
On Tue, May 16, 2017 at 6:36 PM @Nandan@ <nandanpriyadarshi...@gmail.com> wrote: > The requirement is to create DB in which we have to keep data of Updated > values as well as which user update the particular book details and what > they update. > > We are like to create a schema which store book info, as well as the > history of the update, made based on book_title, author, publisher, price > changed. > Like we want to store what was old data and what new data updated.. and > also want to check which user updated the relevant change. Because suppose > if some changes not made correctly then they can check changes and revert > based on old values. > We are trying to make a USER based Schema. > > For example:- > id:- 1 > Name: - Harry Poter > Author : - JK Rolling > > New Update Done by user_id 2:- > id :- 1 > Name:- Harry Pottor > Author:- J.K. Rolls > > Update history also need to store as :- > User_id :- 2 > Old Author :- JK Rolling > New Author :- J.K. Rolls > > So I need to update the details of Book which is done by UPSERT. But also > I have to keep details like which user updated and what updated. > > > One thing that helps define the schema is knowing what queries will be > made to the database up front. > Few queries that the database needs to answer. > What are the current details of a book? > What is the most recent update to a particular book? > What are the updates that have been made to a particular book? > What are the details for a particular update? > > > Update frequently will be like Update will happen based on Title, name, > Author, price , publisher like. So not very high frequently. > > Best Regards, > Nandan >
