The document discusses extending Magento entities, which are data items like customers and products, and the importance of proper implementation for stability and upgradability. It contrasts two approaches: using Entity-Attribute-Value (EAV) models and extension attributes, detailing their advantages, disadvantages, and appropriate use cases. The text warns against modifying core tables directly due to negative impacts on performance and maintainability.

1. 38. Magento-Meetup Wien
Ivan Cuk
Software Developer
From Core to Custom
A Deep Dive into Magento Entity Extension

2. What is a Magento Entity?
● Entity is data item (customer, product, order & more)
● Each item has its attributes and values for them
● Represented with one main entity database table (and few other tables)

3. Why this topic?
● Extending core entities is frequently needed for
customizations
● Important for the stability, modularity, upgradability
and overall quality of the Magento Store
● Different approaches (even within same teams)

4. Magento core entities
EAV Not EAV
customer order
customer_address invoice
catalog_category creditmemo
catalog_product shipment
EAV available with some entities, Extension Attributes with all entities

5. The Problem
When to use EAV and when to use Extension Attributes?
How to properly implement Extension Attributes and why
is that important?

6. Often seen approaches
Developers tend to some of the following things:
● Not use Extension Attributes at all: use a (hacky)
workaround
● Implement Extension Attributes almost always: EAV
capabilities are getting heavily overlooked

7. EAV Attributes
Basic EAV Attributes can be developed quickly.
No-brainer situation:
Attributes that have simple scalar values.
Example: a custom ERP-ID attribute for the customer
entity

8. EAV Attributes
Often overlooked: EAV Attributes can be also used for
more complex data-processing and functionalities.
EAV-Models:
attribute_model - overall behaviour
backend_model - before and after attribute save
frontend_model - data representation
source_model - retrieving set of choices

9. Extension Attributes
When?
● Entity without EAV
● The complexity of the new custom attributes requires
even more flexibility than what EAV offers

10. Extension Attributes
Advantages
● Unlimited flexibility
● Data saved in its own new tables

11. Extension Attributes
Disadvantage
● Implementation is can be complex and time consuming
● Some developers turn to hacking the core-tables as an
alternative

12. Modifying Core Tables?
● Not recommended - source:
https://experienceleague.adobe.com/docs/commerce-
operations/implementation-playbook/best-
practices/development/modifying-core-and-third-party-tables.html?lang=en
● Decreases upgradability & stability of the project
● Underlying logic contains raw SQL queries - can cause side effects difficult to
troubleshoot
● Changes can cause performance problems
● 3rd party modules expect standard core tables
● Standard ways are safer:
● With EAV-Attributes we are not changing DB-structure
● Extension Attributes have their own tables

13. Modifying Core Tables?
● We are using or relying on directly the implementation (model) classes
instead of Service Contracts
● Example: $model->getData('erp_id');

14. Service Contracts > Implementations

15. Extension Attributes
Not always used feature of extension attributes that can accelerate development:
● Join directives

16. Extension Attributes
Not always used feature of extension attributes that can accelerate development:
● Join directives

17. Conclusion
● Requirements & custom attributes
● The right implementation
● Full potential of the EAV attributes
● All features of the Extension Attributes
● Avoid hacky solutions when possible