What is a database? It is a collection of records on a computer (made with data entry) with the purpose of being consulted to answer queries by a program. When the query is taken up by a program it uses the database to answer the query/question, and then we have information. And the program used to get the information and manage the database is called as the DBMS (Data Base Management System).
Databases have “schema” that is nothing but the description about the type of facts in a database. There are many ways of organizing a schema and thus we have different models of databases. The most common model of database used today is the relational database. In a relational model database data is arranged in rows and columns. The basic models of databases are:
- Network model
- Flat model
- Hierarchical model
- Relational model
- Object database model
- Dimensional model
- Post-relational database model
RDBMS refers to Relational Database Management System. In a relational data base model there are relations, attributes, and domains. While a relation is a table with columns and rows, named columns of the relation are called attributes. Attributes are allowed to take a set of values that are referred to as the domain.