The additional relation added to store a many-to-many relationship 1) may have intersection data 2) must have intersection data 3) must not have intersection data 4) can only have intersection data if it is part of the primary key c. can only have intersection data if it is part of a foreign key
The correct answer and explanation is:
The correct answer is 1) may have intersection data.
In database design, a many-to-many relationship occurs when multiple records in one table are associated with multiple records in another table. To represent this type of relationship, a third table (often called a junction table or bridge table) is introduced. This additional table holds foreign keys that reference the primary keys of the two tables involved in the many-to-many relationship.
The junction table may also contain additional columns, known as intersection data, which hold attributes or values specific to the combination of the records from both related tables. For instance, in a many-to-many relationship between students and courses, the junction table might store the date a student enrolled in a course or the grade the student received. These additional attributes are often necessary for providing more context or detailed information about the relationship between the two tables.
However, intersection data is not mandatory. In some cases, the junction table might only contain the foreign keys and serve solely to represent the many-to-many relationship, without storing any additional attributes. This means that intersection data may or may not be included, depending on the specific requirements of the system or application.
Therefore, the correct option is 1) may have intersection data, since it depends on the specific needs of the relationship and the additional information required. It is not a strict requirement to always have intersection data, though it is common in many applications.