- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Domain-Key Normal Form
A relation is in DKNF when insertion or delete anomalies are not present in the database. Domain-Key Normal Form is the highest form of Normalization. The reason is that the insertion and updation anomalies are removed. The constraints are verified by the domain and key constraints.
A table is in Domain-Key normal form only if it is in 4NF, 3NF and other normal forms. It is based on constraints −
Domain Constraint
Values of an attribute had some set of values, for example, EmployeeID should be four digits long −
EmpID | EmpName | EmpAge |
0921 | Tom | 33 |
0922 | Jack | 31 |
Key Constraint
An attribute or its combination is a candidate key
General Constraint
Predicate on the set of all relations.
Every constraint should be a logical sequence of the domain constraints and key constraints applied to the relation. The practical utility of DKNF is less.
Advertisements