what is difference between RDBMS and NoSql on basis of how information is store in them?

Question

I am searching web to understand the underlying concept of how actually information is stored in RDBMS and Nosql databases and found this:

In the world of database technology, there are two main types of databases: SQL and NoSQL—or, relational databases and non-relational databases. The difference speaks to how they’re built, the type of information they store, and how they store it. Relational databases are structured, like phone books that store phone numbers and addresses. Non-relational databases are document-oriented and distributed, like file folders that hold everything from a person’s address and phone number to their Facebook likes and online shopping preferences.

Here i can understand that in SQL based databases data is stored in form address and data and in NoSql everything is stored in one document.

Please correct me if I am wrong.

Can someone explain this with help of example.

Answer 1

RDBMS (Relational database management system) : is using SQL (Structured Query Language) to define and manipulate data. and it is used for large and complex query handling. in-order to work with RDBMS you need to define a structure (schema, table, constraints, ...etc). as an example (out of a town in-order for the people to live together they need to speak the same language, have a infrastructure, laws,..etc

NoSQL (Not only SQL "none relational database"): it is like a blog, you can store the data any way you like (some use a something like table called column oriented, document oriented, graph-base, KeyValue (one of the most common uses of keyValue to call data and store them in JSON file). as an example earth since there is no common structure to be used or a define language that all people speak, the way they build houses, and infrastructure is different but differences between one place and another doesn't effect other places.

I found this image as an example in https://www.upwork.com it explain a the differences between RDBMS and NoSQL in another way.

Useful URLs:
https://www.upwork.com/hiring/data/sql-vs-nosql-databases-whats-the-difference/
https://medium.com/xplenty-blog/the-sql-vs-nosql-difference-mysql-vs-mongodb-32c9980e67b2 (this can be used as an exmaple)
What are the differences between NoSQL and a traditional RDBMS?

Answer 2

SQL and NoSQL are misnomers - the names do not accurately reflect the things they label. It is better to think of them as the relational model of data and non-relational model. The model is the way in which the database system presents data to the external world i.e. client systems which read from and write to the database.

In this context "relation" is an academic word for things which in everyday use we would call tables. So a Relational database system is one which presents input and output in tables. Part of the definition of the relational model is that all entries in a table share a common definition.

In contrast document databases accept and supply data in the form of documents. In this context "document" typically means a valid JSON document. Documents within the database need not have the same content.

The important point is these terms refer to how the DBMS interacts with the outside world. They do not put any constraints on how the DBMS software is arranged internally. Of course it makes sense to structure the software to easily support the interface with minimal processing. So relational systems are likely to have on-disk and in-memory structures that are different to non-relational systems but they are not required to.

For example MongoDB (a document DB), MySql (relational) offer different storage engines with different on-disk formats, each of which is optimised for different conditions.