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What Is an Entity-Attribute-Value Model?

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  • Written By: Eugene P.
  • Edited By: A. Joseph
  • Last Modified Date: 30 July 2014
  • Copyright Protected:
    2003-2014
    Conjecture Corporation
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An entity-attribute-value model is a method of representing a collection of data within a computer.‭ ‬The model is designed to allow an entity to be described by a narrow set of attributes that are selected from a larger list of possible attributes.‭ ‬By indexing the larger list of attributes,‭ ‬it is possible to attach only relevant information to the entity‭’‬s data structure.‭ ‬This approach allows a program or database to keep a dynamic list of all possible attributes that can grow as needed while maintaining the integrity of the data that already has been recorded.

One way for a person to visualize the entity-attribute-value model is to imagine a personal address book as it relates to a complete phone book.‭ ‬The phone book lists every person in an area.‭ ‬A personal address book lists only those people from the phone book‭ ‬who are relevant to the owner.‭ ‬It would be inefficient to carry a personal address book that listed thousands of people who are unknown,‭ ‬so the personal address book contains only the people who are relevant to the owner.‭ ‬In this example,‭ ‬the names of the people in the phone book are the attributes, and their phone numbers are the values of those attributes.

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This approach to creating databases or other types of information management software has many benefits.‭ All possible attributes‭ ‬are stored‭ ‬in a single list,‭ ‬so each record does not have to have‭ ‬a‭ ‬large amount of unused variables or fields.‭ ‬This reduces the size of records being stored.‭ ‬It also keeps the information attached to an entity pertinent and terse so that hundreds of empty attribute fields do not have to be traversed to see the fields with a value.‭ ‬New attributes can be readily added without the need for a complete database conversion,‭ ‬or even any modifications to existing records.

Another advantage of using the entity-attribute-value model is that the attributes in the list do not have to be all of the same data type.‭ ‬Each attribute can not only be a different type of data,‭ ‬but in‭ ‬object-oriented‭ ‬programming, they can be entirely different program classes.‭ ‬This provides a great amount of flexibility in the design of a database that relies on this form of data modeling.

The entity-attribute-value model is not an exclusive data model.‭ ‬In most databases,‭ ‬traditional relational structures can also be used to represent data where it is more practical to do so.‭ ‬The surrounding data record can be handled relationally while the interior fields are managed with the entity-attribute-value model.

A database or program that uses the entity-attribute-value model of data modeling will most likely need to make use of‭ ‬metadata.‭ ‬Metadata is a collection of rules and guidelines that bridges the divide between the user and the data.‭ ‬It can define what values are valid for a certain attribute,‭ ‬how the value should be displayed and possibly even how the attributes could be arranged when generating reports.‭ ‬Without the implementation of metadata,‭ ‬the entity-attribute-value model can become an inflexible and cumbersome database structure.

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