Core OOP Principles | Dataford Interview Questions

What are the four main principles of object-oriented programming?

Use the supplied relational data to return the four principles and their examples. The result should include one row per core principle and preserve the standard instructional order.

Output

Columns: principle_name, definition, and examples
Include only the four core principles, with examples combined into one field
Order by the instructional order stored in the data

Output details

Filter principles using the data's is_core = TRUE flag.
Sort rows by display_order ascending.
Deduplicate examples, sort them alphabetically, and separate them with '; '.
Return NULL in examples when a principle has no examples.

Schema

oop_principles

Column	Type	Description
principle_idPK	INT	Unique principle identifier
principle_name	VARCHAR(100)	Name of the object-oriented programming concept
definition	TEXT	Concise definition of the concept
is_core	BOOLEAN	Whether the concept is one of the four requested principles
display_order	INT	Conventional instructional order

principle_examples

Column	Type	Description
example_idPK	INT	Unique example identifier
principle_id	INT	Referenced object-oriented principle
example_text	VARCHAR(255)	Illustrative example of the principle

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Problem