The _____ category includes storage media that can be operated on directly by the computers central processing unit.
Answer: A
Correct answer: Primary storage
Primary storage - main memory and cache - is the storage the CPU can address directly. Secondary storage such as disk must be read into primary storage before the processor can work on it.
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Between DRAM and magnetic disk storage another form of memory, called ______ memory is becoming common because it is non volatile.
Answer: B
Correct answer: Flash
Flash memory keeps its contents without power, unlike DRAM, and is far faster than a magnetic disk, so it fills the gap between the two in the storage hierarchy.
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The transactions like adding an employee, enrolling a student in a course are examples of _______
Answer: A
Correct answer: Logical
Adding an employee or enrolling a student is one logical operation as the user sees it, though the DBMS may carry it out as several physical writes to different tables and index pages. Keeping the two levels apart is what lets a transaction be treated as indivisible.
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Given the following relation S(SNO,SNAME,CITY) write a query to update the value of CITY to KANPUR for the supplier S1
Answer: C
Correct answer: UPDATE S SET CITY = KANPUR WHERE SNO=S1
The UPDATE statement has a fixed shape: UPDATE table SET column = value WHERE condition. SET is required before the assignment and WHERE before the condition; FOR and RENAME have no place in it.
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Change Staff table by removing default of Assistant for position column
Answer: A
Correct answer: ALTER TABLE Staff ALTER position DROP DEFAULT;
Removing a default is a change to the column, so the statement is ALTER TABLE, then ALTER on the named column, then DROP DEFAULT. Omitting the column name leaves the clause with nothing to act on, and MODIFY is not the keyword that begins the statement.
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Create a table with the following attributes: Employee(EMPNO integer, EMPNAME of 10 characters)
Answer: A
Correct answer: Create table Employee(EMPNO int, EMPNAME char(10));
A ten-character column is declared char(10); String is not an SQL type and a bare string has no length. The table must also be named as the question specifies, which rules out the options calling it Emplo or Emp.
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By ______ an area on disk in certain ways, one can make it represent a bit value of either zero (0) or one (1).
Answer: C
Correct answer: Magnetizing
A disk surface is coated with a magnetic material, and writing a bit means magnetizing a small region in one of two directions, which the head later reads back as 0 or 1.
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The size of a data item is called its _______, which can be a field of some record or may be a larger unit such as a record.
Answer: B
Correct answer: Granularity
Granularity is the size of the item a lock or an operation applies to - a field, a record, a page, a whole table. Fine granularity allows more concurrency but costs more in locking overhead, which is the trade-off the term exists to describe.
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A weak entity has an ______ dependency on its owner entity, which can be used for both ON UPDATE and ON DELETE.
Answer: C
Correct answer: Existence
A weak entity cannot exist without its owner: a dependant without an employee, an order line without an order. That existence dependency is why deleting the owner must delete the weak entity too, which is what the ON DELETE action expresses.
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In an ER diagram the ___shape specifies the Attibute and a ____ shape specifies the primary key attribute.
Answer: A
Correct answer: Oval; An oval with an underlined attribute
In an E-R diagram an attribute is drawn as an oval, and the attribute that serves as the primary key is shown by underlining its name. Rectangles are entities and diamonds relationships.
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