On UPDATE CASCADE ensures which of the following
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Normalization
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Data Integrity
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Materialized Views
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All of the above
ON UPDATE CASCADE is a referential integrity constraint that automatically updates child records when the parent key changes. This ensures data remains consistent across related tables. Normalization reduces redundancy, materialized views pre-compute results, and the cascade specifically serves integrity.
To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) Normalization - UPDATE CASCADE does not directly ensure normalization. Normalization is a process of organizing data in a database to eliminate redundancy and dependency. It helps in improving data integrity and reducing data anomalies, but UPDATE CASCADE itself does not enforce normalization rules.
Option B) Data Integrity - This option is correct because UPDATE CASCADE helps to maintain data integrity. When a foreign key relationship is defined with the UPDATE CASCADE option, it means that if a referenced row in the parent table is updated, the corresponding rows in the child tables will also be automatically updated. This ensures that the foreign key references remain valid and the data integrity is preserved.
Option C) Materialized Views - UPDATE CASCADE is not directly related to materialized views. Materialized views are precomputed views that store the results of complex queries and can be refreshed periodically. They are used to improve query performance. UPDATE CASCADE does not have any impact on materialized views.
Option D) All of the above - This option is incorrect because only option B (Data Integrity) is ensured by UPDATE CASCADE. Options A (Normalization) and C (Materialized Views) are not directly related to UPDATE CASCADE.
The correct answer is B. UPDATE CASCADE ensures data integrity by automatically updating the corresponding rows in child tables when a referenced row in the parent table is updated.