Difficulty: Easy
Correct Answer: Many-to-many relationship
Explanation:
Introduction / Context:
Data modeling requires precise identification of how entities relate. Some domains demand that each instance on one side can pair with multiple instances on the other side, and the reverse is also true. Recognizing this pattern drives how you design tables, keys, and constraints to avoid anomalies and to support efficient querying.
Given Data / Assumptions:
Concept / Approach:
A many-to-many relationship exists when multiple records on side A can be related to multiple records on side B, and vice versa. In relational design, this is implemented by introducing a junction (associative) table that holds foreign keys to both parent tables, often with its own primary key or a composite key to enforce uniqueness of each pairing.
Step-by-Step Solution:
Verification / Alternative check:
ER diagrams denote many-to-many with crow’s feet on both sides. Normalization guidelines recommend resolving many-to-many through a separate associative entity to maintain referential integrity and avoid repeating groups.
Why Other Options Are Wrong:
Common Pitfalls:
Forgetting to create a junction table; stuffing multiple IDs into a single field; omitting uniqueness constraints on the pairing, which causes duplicate links.
Final Answer:
Many-to-many relationship
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