CODEWITHSUNDEEP
database
biswpo
biswpo

Reputation: 809

Why database is considered different from a file system

Well every database book starts with the story that how earlier people used to store data as files and it was very inconvenient. After database came, things became really easy and seamless, because we can now query data etc. My question is how are the tables really stored in the disk and retrieved ? Aren't they stored as files only or they are just copied to the address space bit by bit, and access via address only ? Or there is a underneath file system and the database server handles accessing the file system and presents the abstraction of a table in front of us.

Might be a very trivial question but, I have not found answer in any book

Upvotes: 0

Views: 375

Answers (1)

Siddharth
Siddharth

Reputation: 321

The question is not trivial, but the distinction between the two is quite apparent.

File systems provide a way to logically view the streams in a hierarchical manner. A virtual representation of what lies on the disk; which would otherwise just be a binary stream, unreadable.

When we talk about storing data, we can extend a method of writing data to files and later define our own protocols for CRUD'ing on it; thus mimicking a fractional part of what databases do.

There are numerous limitations to storing data in files. If you store them in file and define your own protocol, it will be very specific to you. Plus, there are various other concerns like security, disaster recovery etc etc.

Even though everything is stored in some or the other way on disk, the main advantage databases bring to the table versus files are the mechanisms that they offer.

To minimize the io, we have db caches and numerous other features.

As you imagine a File system to be something that helps visualize and access the data on the disk in streams, we can imagine a database to be such a tool for data - Data systems, which organizes your data. Files can only fractionally do that; again, unless you extend your program to mimic a database.

How the tables are really stored on the disk and retrieved, that's a vast topic. Advise reading your favourite database internals. A book by Korth might also be a good read.

Upvotes: 1

Related Questions