Quote from: harshalone on September 10, 2018, 01:32:47 PM

But instead of saving users information in a usual database what I want to do is; I want to store them in blockchain.

Can you explain why you want to store them in a blockchain? Because I would expect you first wite down your requirements and then try to find a technical solution which best fits those requirements. It looks like you did it the other way around: Starting with a technical solution (blockchain) which then should accomplish whatever requirement you came up with.

Quote from: harshalone on September 10, 2018, 01:32:47 PM

I register on a website and then I create a book and start writing the first page.
once the first page is finished click on save button.
Now, this information should create a block and could be only opened by its author.

The very idea of a blockchain is that all information stored in there is publicly available. So once again: why do you think blockchain is the best option for your idea?

Quote from: harshalone on September 10, 2018, 01:32:47 PM

So everytime i add another page it should create a block and add to the blockchain.

What will happen if I decide to change some text on my first page already saved? How is a page (which is a single block in your solution) linked to another page in your solution? So will it be linked to a random page from another user or only to my own pages?

Quote from: harshalone on September 10, 2018, 01:32:47 PM

my query is where will this blockchain saved? in database? or its a raw file which user could download on their own computer?

Well the entire idea of a (public) blockchain is that all the information will be stored on every node (every computer which is part of the network). What would be the incentive in your solution for people to keep a copy of all these pages they can't even read themselves?

I personally would expect for your idea to just have a regular server-based solution with a database to store the pages. Users can then lookup previous saved pages of themselves and if needed alter them. All of this based on authentication (user credentials given in the webpage).

To make a long story short: Blockchain is a great solution for some problems, but relational databases are way better solutions for others!