In Salesforce, data rarely lives in isolation. To model real-world business operations, objects must connect with one another. The most flexible and widely used relationship type in Salesforce is the Lookup Relationship . Understanding how lookups work under the hood is essential for designing high-performance data models and maintaining clean security controls. In plain words: A Lookup Relationship loosely connects two objects together. It creates a reference field on a child record pointing to a parent record without taking away the child record's independent ownership or security permissions.
Salesforce Platform & Administration