What term describes a situation where data may not be entered into a relation due to the absence of a complete primary key?

The situation where data cannot be entered into a relation because a complete primary key is absent is referred to as an insertion anomaly. In relational database design, a primary key is essential as it uniquely identifies each record in a table. If the primary key is not fully defined, it becomes impossible to add a new record accurately without causing duplication or ambiguity.

This problem often arises in poorly designed databases where the data structure does not enforce the necessary relationships or completeness of data entries. By understanding insertion anomalies, database designers can create more robust schemas that ensure all necessary data can be entered seamlessly and without error. This concept is critical for maintaining data integrity and ensuring a well-functioning database system.

In contrast, the other terms in the options describe different concepts. Locking relates to the control of database access during transactions to prevent conflicts. Normal form refers to the rules governing how tables are structured to reduce redundancy and dependency. An intermediate entity is not a widely used term in this context and typically refers to a linking table in a many-to-many relationship. Understanding these distinctions helps clarify why insertion anomaly specifically addresses the challenge of completing data entries due to primary key issues.