Primary keys, IDs, references. The first attribute we add to our objects. They don't exist in the real world.

Problems

• Coupling

• Accidental Implementation

• Bijection Principle Violation.

Solutions

1. Reference object to objects.

2. Build a MAPPER.

3. Only use keys if you need to provide an external (accidental) reference. Databases, APIs, Serializations.

4. Use dark keys or GUIDs when possible.

5. If you are afraid of getting a big relation graph use proxies or lazy loading.

6. Don't use DTOs.

Code Smell 40 - DTOs

Maxi Contieri ・ Dec 2 '20

#oop #programming #tutorial #codenewbie

Sample Code

Wrong

Right

Detection

This is a design policy.

We can enforce business objects to warn us if we define an attribute or function including the sequence id.

Tags

• Accidental

Conclusion

Ids are not necessary for OOP. You reference objects (essential) and never ids (accidental).

In case you need to provide a reference out of your system's scope (APIs, interfaces, Serializations) use dark and meaningless IDs (GUIDs).

Relations

Code Smell 20 - Premature Optimization

Maxi Contieri ・ Nov 8 '20

#oop #developing #coding #codesmell

More info

What is (wrong with) software

Maxi Contieri ・ Oct 8 '20

#oop #solid #beginners #design

The One and Only Software Design Principle

Maxi Contieri ・ Oct 13 '20

#beginners #tutorial #design #oop

Credits

Photo by Maurice Williams on Unsplash

All problems in computer science can be solved by another level of indirection.

David Wheeler