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Why is it important that foreign key columns have the same data type as the referenced primary key columns in referential integrity enforcement?

hard📝 Conceptual Q10 of 15
SQL - Table Relationships
Why is it important that foreign key columns have the same data type as the referenced primary key columns in referential integrity enforcement?
ABecause primary keys can only be integers
BTo allow foreign keys to store different data types for flexibility
CBecause SQL automatically converts data types during foreign key checks
DTo ensure values match exactly and prevent type mismatch errors
Step-by-Step Solution
Solution:

  1. Step 1: Understand data type matching importance

    Foreign keys must match primary key data types to compare values correctly.

  2. Step 2: Identify consequences of mismatch

    Different types cause errors or failed integrity checks.

  3. Final Answer:

    To ensure values match exactly and prevent type mismatch errors -> Option D

  4. Quick Check:

    Matching data types prevent integrity errors [OK]
Quick Trick: Foreign key and primary key types must match exactly [OK]
Common Mistakes:
MISTAKES
  • Thinking SQL auto-converts types during checks
  • Assuming foreign keys can have different types
  • Believing primary keys are always integers

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