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Suppose a stored procedure is executed the first time, taking 200ms. On the second execution, it takes 40ms. Why?
Suppose a DBA runs:
DROP VIEW IF EXISTS big_sale_orders;
What is the effect?
Consider the procedure:
CREATE PROCEDURE GetOrders
@StartDate DATE = '2025-01-01',
@EndDate DATE = NULL
AS
SELECT * FROM Orders
WHERE OrderDate >= @StartDate
AND (@EndDate IS NULL OR OrderDate <= @EndDate);
If we run:
EXEC GetOrders;
What happens?
Let R(ABCDEFGH) satisfy the following functional dependencies:
A -> B, CH -> A, B -> E, BD -> C, EG -> H, DE -> F.
Which of the following FD's is also guaranteed to be satisfied by R?
Which of the following is true for a clustered index?
Which of the following statements is NOT true about subqueries
Consider the relation Courses(C, T, H, R, S, G), whose attributes may be thought of information as course, teacher, hour, room, student, and grade. Let the set of FD’s for Courses be C->T, HR -> C, HT -> R, HS -> R, and CS -> G. Intuitively, the first says that a course has a unique teacher, and the second says that only one course can meet in a given room at a given hour. The third says that a teacher can be only one room at a given hour, and the fourth says that the same about students. The last says that students get only one grade in a course.
Let’s choose the key of Courses?
Indexing performs poorly when:
A table has 1,000,000 rows. A B-Tree index with height 3 is created on the primary key column. How many node lookups are required on average to find a row?