Given the basic E R diagram and relational model, which of the the following is incorrect? 

This question was previously asked in
UGC NET Computer Science (Paper 2) 17 June 2023 Official Paper
View all UGC NET Papers >
  1. An attribute of an entity can have more than one value
  2. An attribute of an entity can be composite
  3. In a row of relational table, an attribute can have more than one value
  4. In a row of a relational table, an attribute can have exactly one value or a NULL value

Answer (Detailed Solution Below)

Option 3 : In a row of relational table, an attribute can have more than one value
Free
UGC NET Paper 1: Held on 21st August 2024 Shift 1
10.8 K Users
50 Questions 100 Marks 60 Mins

Detailed Solution

Download Solution PDF

The correct answer is In a row of relational table, an attribute can have more than one value

Key Points

  • In a relational database model, each attribute of a tuple (or row) must have only one value.
  • This is a reflection of the atomicity property of the relational model.
  • If more than one value is required, it should be represented as another row, or possibly in another table depending on the relationship.
  • This is to maintain the integrity and simplicity of the design.
  • However, it's worth mentioning that some modern DBMS do support multi-valued attributes, although this is outside the scope of the classical relational model.

Additional Information

  •  An attribute in an ER diagram refers to a property or characteristic of an entity or relationship. In a relational model, it's equivalent is a table column.
  • In ER modeling, an attribute can be single-valued or multi-valued. However, in a strict relational database model, each attribute of a row must have a single value (atomicity). If multiple values are needed, they can be normalized and placed in separate rows or tables.
  • A composite attribute can be divided into smaller sub-attributes, which come together to represent a fuller concept. For example, an entity "Person" might have a composite attribute "Full Name", subdivided into "First Name" and "Last Name".
  • In relational model, an attribute in a row can hold a single value or be marked as NULL, representing the absence of a value or unknown information.
Latest UGC NET Updates

Last updated on Jun 12, 2025

-> The UGC NET June 2025 exam will be conducted from 25th to 29th June 2025.

-> The UGC-NET exam takes place for 85 subjects, to determine the eligibility for 'Junior Research Fellowship’ and ‘Assistant Professor’ posts, as well as for PhD. admissions.

-> The exam is conducted bi-annually - in June and December cycles.

-> The exam comprises two papers - Paper I and Paper II. Paper I consists of 50 questions and Paper II consists of 100 questions. 

-> The candidates who are preparing for the exam can check the UGC NET Previous Year Papers and UGC NET Test Series to boost their preparations.

More ER Model Questions

Get Free Access Now
Hot Links: teen patti - 3patti cards game online teen patti teen patti master downloadable content teen patti refer earn teen patti all