Multiple choice technology databases

In a query, Table_A is joined with Table_B based on the join criteria (Table_A.Column_1 = Table_B.Column_1). The SME in the team mentions that Table_B is the child of Table_A based on Column_1 (one-to-many relationship) and should always have value. Given these considerations, which of the following doesn't apply to this situation?

  1. There needs to be a Foreign Key relationship between the two tables.

  2. Table_B.Column_1 shouldn't have NULL values.

  3. There should be a clustered index on Table_A.Column_1 and a non-clustered index on Table_B.Column_1.

  4. Table_B.Column_1 should be unqiue.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a parent-child one-to-many relationship where the child column must always have a value, the child column (Table_B.Column_1) is a foreign key referencing the parent, must NOT allow NULLs, and is NOT unique (multiple child rows can reference same parent). Option D states 'Table_B.Column_1 should be unique' which is FALSE for a one-to-many relationship. Options A, B, and C all correctly describe the relationship: foreign key constraint, non-nullable child column, and proper indexing strategy.

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