[Solved] Given the view definition:CREATE VIEW dept_salary AS SELECT department_id, AVG(salary) AS avg_salary FROM employees GROUP BY department_id;Which of the following statements is true when trying to... | SQL

SQL - Views

Given the view definition:

CREATE VIEW dept_salary AS SELECT department_id, AVG(salary) AS avg_salary FROM employees GROUP BY department_id;

Which of the following statements is true when trying to update avg_salary through this view?

AYou can update <code>avg_salary</code> directly and it will change salaries in employees.

BYou cannot update <code>avg_salary</code> because the view uses aggregation.

CUpdating <code>avg_salary</code> will update all salaries in the department equally.

DThe view allows updates only if you use INSTEAD OF triggers.

Step-by-Step Solution

Solution:

Step 1: Analyze the view's use of aggregation
The view uses AVG() and GROUP BY, which creates a summary, not individual rows.
Step 2: Understand update limitations on aggregated views
Aggregated columns like avg_salary cannot be updated directly because they do not map to single rows.
Final Answer:
You cannot update avg_salary because the view uses aggregation. -> Option B
Quick Check:
Aggregated views are not updatable by default [OK]

Quick Trick: Aggregated views block direct updates [OK]

Common Mistakes:

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