What is required to create a many-to-many relationship between two Entities?

To establish a many-to-many relationship between two Entities in a relational database or in OutSystems, a third Entity, often referred to as a junction or associative Entity, is essential. This intermediary Entity is designed to hold references that link the two primary Entities together.

In this case, the third Entity would contain two attributes: one representing the identifier of the first Entity (Order ID) and another for the second Entity (Product ID). This setup effectively allows each record in the first Entity to be associated with multiple records in the second Entity and vice versa, thereby fulfilling the criteria for a many-to-many relationship.

By using this third Entity, you create a normalized database structure that avoids redundancy and maintains data integrity, making the relationships manageable and scalable. This design is a foundational concept in relational database management that supports complex associations between data objects.