Relationship In Database

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 To answer "What is a relationship in database?", it is an association between tables. 

A relational database collects different types of data sets that use tables, records, and columns. It is used to create a well-defined relationship between database tables so that relational databases can be easily stored. For example of relational databases such as Microsoft SQL Server, Oracle Database, MYSQL, etc


  1. One to One relationship
  2. One to many or many to one relationship
  3. Many to many relationships

One to One Relationship (1:1): It is used to create a relationship between two tables in which a single row of the first table can only be related to one and only one records of a second table. Similarly, the row of a second table can also be related to anyone row of the first table.



Following is the example to show a relational database, as shown below.


One to Many Relationship: It is used to create a relationship between two tables. Any single rows of the first table can be related to one or more rows of the second tables, but the rows of second tables can only relate to the only row in the first table. It is also known as a many to one relationship.

Representation of One to Many relational databases:


Many to Many Relationship: It is many to many relationships that create a relationship between two tables. Each record of the first table can relate to any records (or no records) in the second table. Similarly, each record of the second table can also relate to more than one record of the first table. It is also represented an N:N relationship.

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