In Salesforce, custom settings are application metadata that offers a reusable set of static data that different departments in your company can access.
Custom settings are classified into two types:
- Hierarchy Custom Settings
- List Custom Settings
The data in Hierarchy Custom Settings checks the organization, profile and user settings for the current user and makes the data visible for them accordingly. It uses a built-in hierarchical logic which lets you personalize settings for a specific user or a profile.
The data in List Custom Settings is directly visible to any user in the org. It provides a reusable set of static data which can be accessed across your organization.
Custom settings can be used to store a variety of data, such as configuration settings, feature switches, and business rules. They can be accessed using validation rules, workflows, Apex code, Lightning components, and the Salesforce API.
Advantages of Custom Settings
The main advantage of using Custom Settings is that the data is cached, which enables efficient access without the cost of repeated queries to the database. One doesn’t have to use SOQL queries which count against the governor limits.