Database technologies are continuously evolving and now there are a few of them! In last 50 years, we have seen the revolution of database evolution. It’s not like no one is using the databases that were introduced 50 years ago and it’s not like everyone is just on the same page when it comes to the new database technology.
Let’s not dive deep into the usages of databases but just learn about the types of databases.
Here are the few different types of databases that used widely. Large organizations may or may not use the same databases for their internal purposes.
1. Relational Databases
Relational model of data was proposed by E. F. Codd in 1970 and relational databases are based on that model. So, they have been around for a while!
Why does it called a “Relational” database?
As the name suggests there is a relation between the data stored in the database. The data is stored in multiple tables and they are connected using some kind of relations between those tables. The table consists of rows and columns in a table.
What do you use for CRUD operations?
The relational database management system also known as RDBMS is the program that allows you to perform CRUD operations. CRUD operations involve steps like create, read, update, and delete data.
What language do you use for CRUD operations?
SQL which is a Structured Query Language that is used for CRUD operations. That means you can use SQL to create, update, read and delete the data from the tables.
If your organization has more structured data, you should consider using Relational databases since they both go well together.
Examples of Relational Databases
MySQL, PostgreSQL, Microsoft SQL Server, Oracle Database
2. NoSQL/Non-relational Databases
Any database that is not using SQL, is considered a NoSQL database. Basically they don’t have relations between the data stored and that’s why they are also called non-relational databases.
Data can be stored in a JSON (JavaScript Object Notation) kind of file in a key-value format.
As opposite to the relational database, this type of databases go really well with unstructured data. Some organizations use it with semi-structured data as well.
Advantage of using NoSQL databases?
You can make changes anytime without worrying about it affecting to other tables since they won’t have relationships involved.
Examples of NoSQL databases
MongoDB, Apache Cassandra, CouchDB, Redis, Riak KV, Neo4j (graph db)
3. Hierarchical Databases
These databases are the oldest ones. They were developed around 60s. They look like a organizational hierarchy or a tree. One parent and multiple childs where child can only have one parent.
Why to use Hierarchical Databases?
They actually provide high performance despite sounded like an old and complex database system. They are also very quick to find something from the database.
Examples of Hierarchical Databases
IBM Information Management System (IMS), Windows Registry
database examples hierarchical microsoft NoSQL relational
