Redundancy

Characteristic Name:	Redundancy
Definition:	The data is recorded in exactly one place
Dimension:	Consistency
Granularity:	Record
Characteristic Type:	Declarative
Implementation Form:	Rule-based approach

Verification Metric:

The volume of redundant data as a percentage to total data

Validation Metric:

To what extent required rules have been identified and implemented to maintain the declarative characteristic in concern.

BackgroundGuidelines

The original definitions given below formed the basis of the consolidated definition of the characteristic.

Definition:	Source:
A measure of unwanted duplication existing within or across systems for a particular field, record, or data set.	D. McGilvray, “Executing Data Quality Projects: Ten Steps to Quality Data and Trusted Information”, Morgan Kaufmann Publishers, 2008. More from this source
There is only one record in a given data store that represents a Single Real-World Object or Event.	ENGLISH, L. P. 2009. Information quality applied: Best practices for improving business information, processes and systems, Wiley Publishing. More from this source
Determines the extent to which the columns are not repeated.	G. GATLING, C. B., R. CHAMPLIN, H. STEFANI, G. WEIGEL 2007. Enterprise Information Management with SAP, Boston, Galileo Press Inc. More from this source

The implementation guidelines are guidelines to follow in regard to the characteristic. The scenarios are examples of the implementation

Guidelines:	Scenario:
Maintain the database schema eliminating the causes for redundancies of entities and attributes	(1) All customers are in customer table
Ensure that there are no redundant records across distributed databases	(1) Organisation has different customer bases maintained in different databases. But one customer is available only in one database
Ensure that same entity is not originally captured more than once in the systems	(1) Medical Insurance system refers employee bank details from the payroll.
Ensure that there are no temporary table backups are available in the database	(1) Created a backup for employees as employee_temp for a specific purpose and it is still in the database