MCQ King
Oracle – Keys Constraints
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1. What is the primary purpose of a primary key in a database table?
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2. Which constraint enforces referential integrity between tables?
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3. What is the maximum number of columns that can be included in a primary key constraint in Oracle?
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4. Which type of key uniquely identifies a row within a table?
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5. What does a foreign key constraint ensure in a database table?
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6. Which constraint is used to enforce data uniqueness within a column or set of columns?
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7. In Oracle, which constraint is used to limit the values that can be inserted into a column?
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8. Which constraint ensures that a column cannot have NULL values?
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9. What is the purpose of a composite key constraint?
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10. Which type of key is automatically generated by the database management system?
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11. What is the primary purpose of a check constraint in a database table?
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12. In Oracle, what is the default action of the CASCADE option in a foreign key constraint?
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13. Which constraint is used to create a rule for acceptable values in a column?
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14. In Oracle, what is the purpose of the ON DELETE SET NULL action in a foreign key constraint?
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15. What is the primary benefit of using a surrogate key in a database table?
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16. Which constraint is used to define a candidate key as the primary key for a table?
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17. What happens when a primary key constraint is violated during an INSERT operation?
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18. In Oracle, what is the purpose of the ON DELETE CASCADE action in a foreign key constraint?
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19. Which type of key constraint can have multiple instances within a table?
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20. What is the primary purpose of a candidate key in a database table?
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21. Which constraint is used to specify a condition that must be met for data to be inserted or updated?
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22. In Oracle, what is the purpose of the ON DELETE SET DEFAULT action in a foreign key constraint?
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23. What is the primary difference between a primary key and a unique key constraint?
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24. Which type of key is derived from the data itself and is unique within a table?
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25. In Oracle, what is the primary purpose of the ON DELETE NO ACTION action in a foreign key constraint?
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