![]() In an EAV model, no schema changes need to be made, rather a new attribute name is used.ĮAV models have many advantages over relational databases, but have many problems including complex query performance. When a new attribute needs to be created in a conventional database, either a new column needs to be added to a table, or a new table needs to be created. In an EAV database, each row represents one attribute-value pair. So a conventional table stores an entity in one row, each element in the row, and its column name represents the attribute-value pairs. ![]() In a conventional relational database, and entity would consist one a single table row, or a collection of rows from multiple related tables.Īn Attribute correlates to a conventional column name, and a Value would be a value in a row. The basic EAV model uses one table with three rows: Entity, Attribute, and Value.Īn Entity is a single piece of information. Because of the problems that arise basic EAV models are rarely used, instead more complex models are created around the basic EAV model to provide more structure and performance. The EAV model has many benefits when conventional relational-database approaches become overly complex, difficult to extend, and waste space when complex and sparse data is stored. EAV/CSG Database - Overview EAV/CSG - Entity-Attribute-Value with Classes, Sets and Graphs.Įntity-Attribute-Value (EAV) databases have been used for a long time, mostly in medical and bioinformatic databases, as a way to store complex heterogeneous data in a simple and extensible schema.
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