Final answer:
In relational databases, relationships depicted in an E-R diagram are represented using foreign keys, junction tables, or associative entities, based on their cardinality and type.
Step-by-step explanation:
The question pertains to the representation of relationships in an Entity-Relationship (E-R) diagram within a relational database design. In a relational database, relationships between entities (tables) are vital to accurately model the complex associations of real-world data.
Relationships can have different cardinalities and types, such as one-to-one, one-to-many, or many-to-many. These are represented using foreign keys, junction tables, or associative entities, depending on the nature and complexity of the relationship.
For example, a one-to-one relationship might only require a foreign key in one of the tables linking directly to the primary key of the related table. In contrast, a many-to-many relationship typically involves an intermediate table called a junction table, which holds foreign keys that reference the primary keys of the involved tables, thus creating a set of linked pairs.