A database is a collection of inter-related data organized in the form of tables, schemas, and views. It helps to retrieve, update, insert and delete data efficiently.
Database Management System is a software that organizes the database and provides a platform to perform various operations like creating a table, updating, sorting, deleting data, and so on.
Relational Database Management System (RDBMS) is Database Management System introduced by E.F.Codd based on the relational model. MS SQL Server, Oracle, and MySQL are RDBMS.
Popular Relational Database Management System:
MySQL: MySQL is an open source SQL database used for Web application development. The main advantages are it is easy to use, it is most reliable and inexpensive. The main disadvantage is poor performance.
PostgreSQL: PostgreSQL is an Powerful, open-source object-relational Database Management System.The main advantages are it is easy to use, it is most reliable and inexpensive. The main disadvantages are slow in performance and less popular.
Oracle DB: Oracle DB is owned by Oracle. It is not open sourced and is mainly used in the banking industry. It is a Powerful Combination of technology and built specifically for banks. The main disadvantage is it is not free to use.
SQLite: SQLite is an open-source SQL database. It stores the whole database into one file. It is used as a database in cellphones, PDAs, MP3, and other electronic gadgets.