This presentation covers EAV type of data modeling. We would check various aspects of data modeling and compare them with different types of data modeling. Basically this relates to a type of data modeling in database.

1. EAV data model
Presenter: Sandeep Kumar Rout, Mindfire Solutions
Date: 20/03/2014

2. 1/2/12
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014
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3. 1/2/12
Agenda

Introduction

History

EAV hierarchy structure

Data Retrieve

EAV when to use?

Attribute Set

Pros

Cons Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

4. 1/2/12
EAV
Entity Attribute Value (EAV) is vertical data
modeling instead of horizontal data modeling
which we regularly use.
In mathematics, this model is known as a
sparse matrix.
EAV is also known as object–attribute–value
model, vertical database model and open
schema.
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

5. 1/2/12
EAV History
As a storage method EAV was used in early
object-oriented languages like SIMULA 67.
Functional languages such as LISP have also
use EAV data structure. They contain storage
structures that record object information in
attribute-value pairs – a principle
fundamental to EAV.
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

6. 1/2/12
EAV hierarchy structure
EAV hierarchy structure includes these
components:
- Entity : A component with a definitive
existence. Objects are entities. For e.g.
Products, User etc
- Attribute : The fields to which the entities
are related. This are similar to column names
in horizontal data models. Object properties
are attributes
i.e. :- Color, Name, Price etc
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

7. 1/2/12
- Value : The value to which entity and
attribute maps to. They are similar to row
value from horizontal database.
Example :- John, $22, blue etc
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

8. 1/2/12
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

9. 1/2/12
Data Retrieve
Case :-
To get phone no of employee whose id is 1
Basic model :
SELECT phone_no FROM employee WHERE
employee_id = 1;
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

10. 1/2/12
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014
Eav model :
SELECT value FROM employee_int as ei
JOIN employee as e
ON e.employee_id = ei.employee_id
JOIN employee_attribute as ea
ON ea.attribute_id = ei.attribute_id
WHERE e.employee_id = 1 AND
ea.attribute_name = 'phone_no'

11. 1/2/12
EAV when to use?
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014
Consider a case where there is need to add
new columns or remove new columns on a
regular basis. If using a simple single table it
needs frequent alteration of tables also causes
complexities
With EAV this can be done by simple addition
of a new row in attributes table.
So, generally eav is used in such cases.

12. 1/2/12
Attribute Set
Set of attributes combined to make the entity grouped with
their respective attributes only.
Example :- An online store having books and shirts.
Attributes used by book are different from attributes
used by shirt. So, they can be categorized into attributes
set.
Attribute set Shirt : size, color, price,material, manufacturer
etc
Attribute set Book : pages, author, type of binding,etc
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

13. 1/2/12
Pros

Flexible mechanism for attributes to work
with any sort of entities

Scalability – Can change the required data
without changing the structure of database
tables

Independent of hierarchy of data. Less time
to implement Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

14. 1/2/12
Cons

Performance

EAV don't store value as datatype specific.
Similar type of data are all grouped in one.
As int is generally used to store tinyint,int
etc.

No grouping of entities
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

15. 1/2/12
Indexing
This process is used to somehow compensate
the poor performance of EAV structure. It is
not similar to database indexing

This process is time consuming

In this process data from EAV structured
tables are retrieved and store in flat tables

Initially done after all entity types are
generated
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

16. 1/2/12

Need to perform this process regularly

Need to be performed on addition, updation
and deletion of data

Makes the data retrieval easier and faster

It completely eliminates old table and
generates new table when re-indexing is
performed.
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

17. Question and Answer
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

18. Thank you
Presenter: Sandeep Kumar Rout, Mindfire
Solutions
Date: 20/03/2014

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