Database Overview

Simply, A database is a collection of Data (Information), where database management system is called database management system (DBMS) and if this system maintain a relation, than it called Relational Database Management System(RDBMS).

Here some terms need to more clear which are as follows:

Data:

According to webopedia.com,

"Data refers to distinct pieces of information, usually formatted and stored in a way that is concordant with a specific purpose. Data can exist in various forms: as numbers or text recorded on paper, as bits or bytes stored in electronic memory, or as facts living in a person's mind. Since the advent of computer science in the mid-1900s, however, data most commonly refers to information that is transmitted or stored electronically."

In database, Data is made with character and it makes word, row and finally table.

Database:

For specific purpose, collection of one or more than one tables makes a database. According to Wikipedia,

a database is an organized collection of data, generally stored and accessed electronically from a computer system. 

DBMS:

A database management system is a collection of programs written to manage a database.

RDBMS:

Relational Data Model was developed by Dr. E.F. CODD. He developed the relational data model by taking the concept from Relational Algebra in June - 1970.

Relational Data Model has some 12 Rules which are named after Codd as Codd Rules. According to Codd a package can be called as RDBMS only if it satisfies the Codd Rules.