Record relationships
A relationship is formed by a Lookup field being created from one object to another, often referred to as a parent and child relationship. There are two types of relationships in Salesforce: Master-Detail and Lookup.
Custom Metadata Type objects only support lookup relationships to other Custom Metadata Type objects or other Custom Object or Custom Field metadata. Some features described in this section only apply to Custom Objects, such as lookup filters and referential integrity. Custom Setting objects do not support any form of record relationships.
In some aspects, these types of relationships share similarities in how they are referenced when using SOQL and Apex and how they are input through the user interface (such as Lookup filters described in the previous chapter). However, there are different limits depending on the referential integrity features that you use. You should keep these in mind when defining your own object model within...