RELATIONAL DATABASE MANAGEMENT SYSTEM

RDBMS stands for Relational Database Management System.

RDBMS data is structured in database tables, fields and records.

Each RDBMS table consists of database table rows.

Each database table row consists of one or more database table fields.

RDBMS store the data into collection of tables, which might be related by common fields

It is called Relational Data Base Management System (RDBMS) because it is based on relational model introduced by E.F. Codd.

All modern database management systems like SQL, MS SQL Server, IBM DB2, ORACLE, My-SQL and Microsoft Access are based on RDBMS

How it works:

Data is represented in terms of tuples (rows) in RDBMS.

Relational database is most commonly used database. It contains number of tables and each table has its own primary key.

Due to a collection of organized set of tables, data can be accessed easily in RDBMS.

There are many operations that we can perform on a database. These are:-

History of RDBMS:

During 1970 to 1972, E.F. Codd published a paper to propose the use of relational database model.

RDBMS is originally based on that E.F. Codd’srelational model invention.


RDBMS Terminology:

§  Attribute: A kind of information that describes one aspect of a data object. For e.g. AGE is an attribute of a person, and SALARY is an attribute of an employee. Attribute is also called Column.

§  Relation: A data object defined by a set of attributes. For e.g. EMPLOYEE is a relation with various attributes that define the employee data object. RELATION is also called Table.

§  Tuple: An instance of data object with specific values for all attributes of the realtion. For e.g. one tuple of the Course relation is the operating system course with Operating System as the value of the Course Name attribute, and other values for other attributes.Tuple is also called Row or Record

§  Table: This is the structure defined to store data under it. It is also called as an ENTITY

§  Field: It is also known as attributes in database terminology. It defines the property of an entity. In other words, it is also called as column in a table. For e.g. if we have a company where employee details and department details are gathered. Employee details like empname, age, address, and so on each of which form attribute is stored under structure called as EMP Table.

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