Outlined steps for creating a database? (NoSQL)

I have a school project in which I am creating a Non Relational Document (or Key Value if suggested to) DBMS. Pretty much I am only looking for the outline of what I will need to implement. While I have an idea in mind, I would like to know approaches other people would take to d开发者_开发问答o the same project.

The DBMS is going to be used with a basic web application that stores user login info (password, name, email, zipcode) and a short message (similar to twitter). The web application will retrieve data based on different factors and write to the DB. I wanted to make it possible to be used on 2 different machines (similar to a horizontal scale), but that might be thrown out due to time.

I plan to program in Java, but I am open to using another language if necessary.

Thank you.

A key/value is easy; it can also be used as the basis for building a non-key-value store. The important thing is to work out a workable API. You could store nodes that have a name, and access two kinds of properties (child nodes and attributes), for example.

The question's rather broad; what design criteria do you have?