Sixth Chapter Lesson-8 : Database Relation and it’s classification.

At the end of this lesson-

  • 1. You will be able to explain database relation.
  • 2. You will be able to describe the conditions of database relation.
  • 3. You will be able to explain classification of database relation.

 

Database Relation: Relation between records of a table with the records of another table of a database is called database relation.

Condition for making database relation:

  • There must have one common field between relational tables and data type, field size and format must be same for that common field.
  • There must have a primary key field on at least one of the relational tables.

 

Types of database relation: There are four types of database relation. They are –

  • One to One
  • One to Many
  • Many to One
  • Many to Many

 

One to One Relation: If a record of a relational table is related to only one record of another relational table, the relation between them is called one to one relation.

One to Many Relation: If a record of a relational table is related to multiple records of another relational table, the relation between them is called one to many relation.

Many to One Relation: If multiple records of a relational table are related to one record of another relational table, the relation between them is called many to one relation.

Many to Many: If multiple records of a relational table are related to multiple records of another relational table, the relation between them is called many to many relation.

Lesson Evaluation-

Knowledge Based Questions:

  • a.What is database relation?
  • a. What is database relationship?

Comprehension Based Questions:

  • b. Write down the conditions for making relation between two tables.
  • b. ‘There is condition for making relation between two tables’ – explain.

Creative Questions:

Read the stem and answer the following question:

d. Which type of relation exists between above two tables? Analyze with argument.

Multiple Choice Questions:

 


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