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From Jonathan Haddad <...@jonhaddad.com>
Subject Re: Reg:- Data Modelling Concepts
Date Wed, 17 May 2017 01:44:44 GMT
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@ <nandanpriyadarshi298@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
>

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