DAA-C01 Question #69: Real Exam Question with Answer & Explanation

Question

What considerations are crucial when performing table joins between parent/child tables for maintaining data integrity? (Select all that apply)

Options

• AData redundancy prevention
• BEnsuring referential integrity
• CEstablishing foreign key constraints
• DMatching data types

Explanation

When joining parent/child tables, referential integrity (B) ensures that every child record's foreign key value corresponds to an existing parent record - preventing orphaned rows or broken relationships. Foreign key constraints (C) are the database mechanism that enforces referential integrity at the schema level, automatically rejecting inserts or deletes that would violate the parent/child relationship. Matching data types (D) is essential because a join on mismatched types (e.g., INT vs VARCHAR) will either fail outright or produce silent, incorrect results due to implicit casting.

Option A (data redundancy prevention) is a normalization concern - important in schema design, but not a consideration specific to performing joins or maintaining integrity between related tables.

Memory tip: Think "RFM - Referential integrity, Foreign keys, Matching types." These three work together as a chain: matching types make the join possible, foreign keys enforce the rule, and referential integrity is the goal that results from both.

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