> ## Content Index
> Fetch the complete content index at: https://www.namastesalesforce.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# 02 · Relationship types, decided with three questions
- URL: https://www.namastesalesforce.com/training/data-model/relationship-types-three-questions/
- Published: 2025-04-17T09:00:00.000Z
- Updated: 2025-04-17T09:00:00.000Z
- Description: Lookup, master-detail or junction — answered by ownership, cascade delete, and roll-ups.
- Author: Swarnil Singhai
- Tags: Data Model Basics, #training, #duration-15m, #Import 2026-09-03 19:13

Lookup, master-detail or junction — answered by ownership, cascade delete, and roll-ups.

## The three questions

Does the child make sense without the parent? Should deleting the parent delete the child? Do you need roll-up summaries? Master-detail answers no, yes, yes; lookup answers the reverse.

## Converting later is possible, painful

You can switch lookup to master-detail only while every child has a parent, and the switch rewrites sharing. Decide up front; this is a one-way door that pretends not to be.

## Practice in your org

- Open your Developer Edition org and follow along step by step
- Change one thing at a time and note what happens
- When something breaks, read the error before searching for it