A relational database is a type of database that stores data in tables with rows and columns. 

  • Each table represents a relation , which is a set of facts about a certain entity or concept. 
  • Each row in a table represents a tuple , which is an instance or occurrence of the relation. 
  • Each column in a table represents an attribute , which is a property or characteristic of the relation.
  • Each attribute has a domain , which is the set of possible values that it can take.

Commonly used terminologies in relational data model:

  • Attribute -  Characteristic or parameters for which data are to be stored in a relation. Simply stated, the columns of a relation are the attributes which are also referred to as fields.
  • Tuple - Each row of data in a relation (table) is called a tuple. In a table with n columns, a tuple is a relationship between the n related values. 
  • Domain - It is a set of values from which an attribute can take a value in each row. Usually, a data type is used to specify a domain for an attribute. 
  • Degree -  The number of attributes in a relation is called the Degree of the relation
  • Cardinality - The number of tuples in a relation is called the Cardinality of the relation.
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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.