• Skip to main content
  • Skip to primary sidebar
  • Skip to secondary sidebar
  • Skip to footer

Computer Notes

Library
    • Computer Fundamental
    • Computer Memory
    • DBMS Tutorial
    • Operating System
    • Computer Networking
    • C Programming
    • C++ Programming
    • Java Programming
    • C# Programming
    • SQL Tutorial
    • Management Tutorial
    • Computer Graphics
    • Compiler Design
    • Style Sheet
    • JavaScript Tutorial
    • Html Tutorial
    • Wordpress Tutorial
    • Python Tutorial
    • PHP Tutorial
    • JSP Tutorial
    • AngularJS Tutorial
    • Data Structures
    • E Commerce Tutorial
    • Visual Basic
    • Structs2 Tutorial
    • Digital Electronics
    • Internet Terms
    • Servlet Tutorial
    • Software Engineering
    • Interviews Questions
    • Basic Terms
    • Troubleshooting
Menu

Header Right

Home » Database » Rdbms » What are the CODD’S Rules in RDBMS ?
Next →
← Prev

What are the CODD’S Rules in RDBMS ?

By Dinesh Thakur

Dr. E.F. Codd, the founder of the relational database systems, framed twelve rules to assist a database product to qualify as relational. An RDBMS product has to satisfy at least six of the 12 rules of Codd to be accepted as a full-fledged RDBMS. There is no RDBMS package commercially available that satisfies all the 12 rules. These rules are:

 1. Information Rule: All information in a relational database including table names, column names is represented in the form of tables. This simple view of data speeds up design and learning process. User productivity is improved since knowledge of only one language is necessary to access all data such as description of the table and attribute definitions, integrity constraints. Action can be taken when the constraints are violated. Access to data can be restricted. All these information are also stored in tables.

2. Guaranteed Access Rule: Every piece of data in a relational database, can be accessed by using a primary key value that identifies the row and a column name. User productivity is improved since there is no need to resort to using physical pointers or addresses. It also provides data independence and makes it possible to retrieve each individual piece of data stored in a relational database by specifying the name of the table in which it is stored, the column and the primary key, which identifies the cell in which it is stored.

3. Comprehensive Data Sub-language Rule : The RDBMS may support several languages. But at least one of them should allow the user to do all the following: define tables and views, query and update data, set integrity constraints, set authorizations and define transactions. User productivity is improved since there is just one approach that can be used for all database operations. In a multi-user environment the user does not have to worry about the data integrity and such things will be taken care of by the system. Also only users with proper authorization will be able to access data.

4. View Updating Rule: Any view that can be updated theoretically can be updated using the ·RDBMS. Data consistency is ensured since the changes made in the view are transmitted to the base table and vice-versa.

5. High Level Insert, Update and Delete: The RDBMS supports insertion, updating and deletion at a table level. The performance is improved since the commands act on a set of records rather than one record at a time.

6. Physical Data Independence: The execution of ad hoc requests and application programs is not affected by changes in the physical data access and storage methods. Database administrators can make changes to the physical access and storage method, which improve performance and do not require changes in the application programs or requests. Here the user specifies” what he wants and need not worry about how the data is obtained.

7. Logical Data Independence: Logical changes in tables and views such as adding deleting columns or changing field “lengths need not necessitate modifications in the programs or in the format of ad hoc requests. For example, adding an attribute or column to the base table should not disrupt the programs or the interactive commands that have no use for the new attribute.

8. Integrity Independence: Like table and view definitions, integrity constraints are stored in the on line catalog or data dictionary” and can therefore .be changed without necessitating changes in the application programs. Integrity constraints specific to a particular Relational Database must be definable in the relational data sub-language and storable in the catalog or data dictionary. At least the entity integrity and referential integrity must be supported.

9. Non subversion Rule: If the RDBMS has a language that accesses the information of a record at a time, this language should not be used to bypass the integrity constraints. This is necessary for data integrity.

10. Systematic Treatment of Null Values: In relational database management system null values should be supported for the representation of missing and inapplicable information. The database management system must have a consistent method for representing null values. For example, null values for numeric data must be distinct from zero or any other numeric value and for character data, it must be different from a string of blanks.

11. Database Description Rule: The description of a database is stored and maintained in the form of tables. This allows the users with appropriate authority to query information using similar ways and using the same languages. This implies that a data dictionary should be present within the RDBMS that is constructed of tables and l or views that can be examined using the Structured Query Language (SQL).

12. Distribution Independence: The RDBMS package must have distribution independence. Thus, RDBMS package must makes it possible for the database to be distributed across multiple computers even though they are having heterogeneous platforms both for hardware and operating system. This is one of the most attractive aspects of the RDBMS. Database systems built on the relational framework are well suited for today’s Client/Server database design.

You’ll also like:

  1. Boyce-Codd Normal Form (BCNF)
  2. What are the RDBMS Components?
  3. Difference between DBMS and RDBMS
Next →
← Prev
Like/Subscribe us for latest updates     

About Dinesh Thakur
Dinesh ThakurDinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular Computer Notes blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps.

Dinesh Thakur is a Freelance Writer who helps different clients from all over the globe. Dinesh has written over 500+ blogs, 30+ eBooks, and 10000+ Posts for all types of clients.


For any type of query or something that you think is missing, please feel free to Contact us.


Primary Sidebar

DBMS

Database Management System

    • DBMS - Home
    • DBMS - Definition
    • DBMS - What is
    • DBMS - Entity Sets
    • DBMS - Components
    • DBMS - Languages
    • DBMS - Normalization
    • DBMS - Data Models
    • DBMS - Processing System
    • DBMS - Advantages
    • DBMS - ER-Model
    • DBMS - Functional Dependence
    • DBMS - Relational Model
    • DBMS - Architecture
    • DBMS - Network Model
    • DBMS - Approach
    • DBMS - Data Independence
    • DBMS - Relational Schema
    • DBMS - Instance
    • DBMS - Functions and Service
    • DBMS - Server
    • DBMS - DBA
    • DBMS - Instance & Schemas
    • DBMS - System Type
    • DBMS - DDL, DML and DCL
    • DBMS - Users
    • DBMS - Model
    • DBMS - System Structure
    • DBMS - Role of DBA
    • DBMS - Metadata
    • DBMS - ER-Diagram
    • DBMS - E-R Model Problems
    • DBMS - DBMS Vs.RDBMS
    • DBMS - Basic Construction of E-R
    • DBMS - E-R Notation
    • DBMS - Database View
    • DBMS - Concurrency Control
    • DBMS - Schema
    • DBMS - Procedure for Access
    • DBMS - Object
    • DBMS - dBase
    • DBMS - Relational Algebra
    • DBMS - Deadlock
    • DBMS - Relational Database
    • DBMS - Query
    • DBMS - Schema

DBMS Normal Forms

    • Database - CODD’S Rules
    • Database - 1NF
    • Database - 2NF
    • Database - 3NF
    • Database - 4NF
    • Database - 5NF
    • Database - BCNF

Advance Database

    • Database - File Organization
    • Database - Type Lock
    • Database - Transaction
    • Database - Key Type
    • Database - Relational Algebra
    • Database - Components
    • Database - Deadlock Detect
    • Database - Design Methodology
    • Database - Relational Operators
    • Database - Relational Calculus
    • Database - Lock Granularity
    • Database - Deadlocks Handling
    • Database - Concurrent Control
    • Database - Denormalization
    • Database - Starvation
    • Database - OODB
    • Database - Data Warehouse
    • Database - Fragmentation
    • Database - Data Replication
    • Database - Distributed
    • Database - Transparences
    • Database - ORDBMSS
    • Database - Data Mining
    • Database - Security
    • Database - DBTG
    • Database - OLAP
    • Database - Integrity
    • Database - Data Encryption
    • Database - Recover
    • Database - Data Protection

Some Other Advance Articls

  • Adv of Distributed DBMS
  • Homogeneous and Heterogeneous
  • Causes for Database Failure
  • DBMS Architecture
  • Features for Any DBMS
  • OLTP Systems Vs Data Warehousing
  • Data Warehousing Architecture

Other Links

  • DBMS - PDF Version

Footer

Basic Course

  • Computer Fundamental
  • Computer Networking
  • Operating System
  • Database System
  • Computer Graphics
  • Management System
  • Software Engineering
  • Digital Electronics
  • Electronic Commerce
  • Compiler Design
  • Troubleshooting

Programming

  • Java Programming
  • Structured Query (SQL)
  • C Programming
  • C++ Programming
  • Visual Basic
  • Data Structures
  • Struts 2
  • Java Servlet
  • C# Programming
  • Basic Terms
  • Interviews

World Wide Web

  • Internet
  • Java Script
  • HTML Language
  • Cascading Style Sheet
  • Java Server Pages
  • Wordpress
  • PHP
  • Python Tutorial
  • AngularJS
  • Troubleshooting

 About Us |  Contact Us |  FAQ

Dinesh Thakur is a Technology Columinist and founder of Computer Notes.

Copyright © 2025. All Rights Reserved.

APPLY FOR ONLINE JOB IN BIGGEST CRYPTO COMPANIES
APPLY NOW