CSE 511 Midterm Complete Questions And Answers
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Which of the following are the advantages of using a DBMS? ANS Data Independence, Data Security,
Concurrency, Data Administration... (Concurrent Access/Crash Recovery, Data Integration/Security, Reduced
App Development Time)
At which level of abstraction is the logical structure defined? ANS Conceptual Schema
What does the physical level of schema define? ANS files and indexes used
What do views do? ANS describe how user sees data (ex: course_info(cid:string, enrollmen:int))
Which of the following is true with regard to weak entities?
a. Owner entity set and weak entity set can participate in a many-to-many relationship.
b. Owner entity set and weak entity set must participate in a one-to-many relationship.
c. Weak entity must have total participation in the identifying relationship set.
d. Weak entities can exist without the owner entity ANS B: Owner set and weaker set must participate in a
one-to-many relationship set(one owner, and many weak entities)
C: Weak entities must have total participation in this identifying relationship set (When the owner entity is
deleted, all owned weak entities must also be deleted.)
Can be identified uniquely only by considering the primary key of another (owner) entity
SQL is a ______________ language ANS declarative (tells what data is to be retrieved but does not tell the
system how to retrieve it.
Which query can be used to list the student information for computer science majors [C] who are not double
majors in electrical engineering [E]? ANS C-E (difference)
Which of the following is true when using Heap Files?
a. Heap Files are efficient for loading bulk data.
, b. Heap Files are efficient for sorting.
c. Heap Files are not efficient for selective queries.
d. Heap Files are not efficient while working on relatively small relations ANS a. Heap Files are efficient
for loading bulk data.
c. Heap Files are not efficient for selective queries.
Heap files are not efficient for sorting and may be time-consuming.
Heap files are efficient while working on relatively small relations as indexing overheads are avoided.
What is the memory hierarchy? ANS Secondary Storage (Hard Disk) -> Computer Main Mem -> Caches -
> Registers
What storage is the fastest? ANS Registers
Which component loads pages from hard disk to memory? ANS Buffer Manager
stages pages from external storage to main memory buffer pool so DB can process info (read/write)
File and index layers make calls to the buffer manager
Less memory than disk space so you upload everything into main memory at once with buffer manager
Which of the following questions should be answered before creating an index?
a. What field(s) should be the search key?
b. Should you build several indexes?
c. Which relations should have indexes?
d. What records(s) should be the search key? ANS a. What field(s) should be the search key?
b. Should you build several indexes?
c. Which relations should have indexes?
The record(s) retrieved should not affect the decision of choosing an index.
Which of the following is NOT one of the levels of abstraction for databases?
Physical Schema
With Verified Study Solutions
Which of the following are the advantages of using a DBMS? ANS Data Independence, Data Security,
Concurrency, Data Administration... (Concurrent Access/Crash Recovery, Data Integration/Security, Reduced
App Development Time)
At which level of abstraction is the logical structure defined? ANS Conceptual Schema
What does the physical level of schema define? ANS files and indexes used
What do views do? ANS describe how user sees data (ex: course_info(cid:string, enrollmen:int))
Which of the following is true with regard to weak entities?
a. Owner entity set and weak entity set can participate in a many-to-many relationship.
b. Owner entity set and weak entity set must participate in a one-to-many relationship.
c. Weak entity must have total participation in the identifying relationship set.
d. Weak entities can exist without the owner entity ANS B: Owner set and weaker set must participate in a
one-to-many relationship set(one owner, and many weak entities)
C: Weak entities must have total participation in this identifying relationship set (When the owner entity is
deleted, all owned weak entities must also be deleted.)
Can be identified uniquely only by considering the primary key of another (owner) entity
SQL is a ______________ language ANS declarative (tells what data is to be retrieved but does not tell the
system how to retrieve it.
Which query can be used to list the student information for computer science majors [C] who are not double
majors in electrical engineering [E]? ANS C-E (difference)
Which of the following is true when using Heap Files?
a. Heap Files are efficient for loading bulk data.
, b. Heap Files are efficient for sorting.
c. Heap Files are not efficient for selective queries.
d. Heap Files are not efficient while working on relatively small relations ANS a. Heap Files are efficient
for loading bulk data.
c. Heap Files are not efficient for selective queries.
Heap files are not efficient for sorting and may be time-consuming.
Heap files are efficient while working on relatively small relations as indexing overheads are avoided.
What is the memory hierarchy? ANS Secondary Storage (Hard Disk) -> Computer Main Mem -> Caches -
> Registers
What storage is the fastest? ANS Registers
Which component loads pages from hard disk to memory? ANS Buffer Manager
stages pages from external storage to main memory buffer pool so DB can process info (read/write)
File and index layers make calls to the buffer manager
Less memory than disk space so you upload everything into main memory at once with buffer manager
Which of the following questions should be answered before creating an index?
a. What field(s) should be the search key?
b. Should you build several indexes?
c. Which relations should have indexes?
d. What records(s) should be the search key? ANS a. What field(s) should be the search key?
b. Should you build several indexes?
c. Which relations should have indexes?
The record(s) retrieved should not affect the decision of choosing an index.
Which of the following is NOT one of the levels of abstraction for databases?
Physical Schema
