CS5200 Database Management Systems Northeastern

In a RAID 5 configuration of four 1TB solid state disks, the total available storage is ___ TB. Enter the number in TB only, e.g., 7.

3

In the relationship, "helicopter is a particular type of aircraft", helicopter is a(n) ____________.

subclass

The join operation in the relational model can be defined as _________.

the cartesian product of two relations followed by a selection

In a relational database, null values are not appropriate for which one of the following?

to allow to duplicate rows by making the primary key values null

Let A1, A2, and A3 be attributes in a relation R. If both of these functional dependencies hold: A1 → A2 and A2 → A3, then A1 → A3 holds, because of the _________ rule.

transitivity property, transitive dependency, transitivity, transitivity rule, transitive

A key attribute:

uniquely identifies a row

The DBMS ensures that after every update that the database is in a _______ state.

valid

If attributes A and B together uniquely determine attribute C, then it is follows that:

(A,B) is a composite key

For the entity-relationship model expressed in the IE diagram below, what is the minimum number of tables required to implement it in BCNF. Enter the number below. https://imgur.com/W4xN1FA

0 (with margin: 0) OR 3 (with margin: 0) OR 3 (with margin: 0) OR 0 (with margin: 0) OR 3 (with margin: 0) OR

A relation is at least in ______ form if it has no multivalued attributes.

1 NF

Consider the relation Project(pid,name,budget) with relation instances {(100,'GOTAM',30000), (140,'Ravix',40000), (250,'NUflex',25000), (106,'AlphaLaunch',8000)}. What is the degree of the relation? Enter the value below as a number, e.g., 876.

3

Let M and N be two entities in an E-R diagram containing only single-valued attributes. R1 and R2 are two relationship between M and N. Assume that R1 has a one-to-many and R2 has a many-to-many multiplicity. What is the minimum number of tables required to represent M, N, R1 and R2?

3

RAID 5 requires a minimum of ___ disks.

3

Consider the relation R(A, B, C, D) with the following set of functional dependencies {A → BC, B→ A, A→ C, A→ D, D→ A}. How many candidate keys are there in R?

3 (Simple candidate key means single attributed key. As (A)+ = {A, B, C, D}, (B)+ = {B,A, C, D}, (C)+ = {C} and (D)+ = {D, A, B, C}. So, A, B and D are candidate keys which are simple as well. So, correct option is 3.)

Consider the relation Project(pid,name,budget) with relation instances {(100,'GOTAM',30000), (140,'Ravix',40000), (250,'NUflex',25000), (106,'AlphaLaunch',8000)}. What is the cardinality of the relation? Enter the value below as a number, e.g., 876.

4

A relation is in ______ form if it is in BCNF and has no multivalued dependencies.

4 NF

Which multiplicity expressions are valid in a UML Class Diagram showing relationships between domain entities?

5..5, 2..10, 0..*, 1, 1..C.N

Which of the following statements about RAID is correct?

A RAID 1 configuration of four 1TB disks has a storage capacity of 2TB

independence

A database management systems supports and simplifies application and data ___________.

Consider the UML Class Diagram regarding a petting zoo below and answer these questions. Which of the following statements is true? https://imgur.com/I5Iib7J

A petter may adopt no more than one animal.

An aggregation association is drawn using which one of the symbols below?

A small open diamond at the end of a line connecting two tables

For every value of attribute A, there is a unique value of attribute B, but not the same value of attribute C. Which of the following functional dependencies holds?

A → B

If attribute A determines both attributes B and C, then it follows that ________ is also true.

A → B

Which of these benefits does a RAID 0 storage system provide? Check all that apply.

Better read performance compared to a single disk, Increased write performance compared to a single disk

Consider the relational schema with two relations R(a, b, c) and S(d, e, f). Assume that d is a foreign key in S that refers to the primary key of R. Consider the following four operations on the relations R and S. I. Insert a new tuple into R II. Insert a new tuple into S III. Remove a tuple from R IV. Remove a tuple from S Which of the following can cause referential integrity constraint violations in the above relational schema?

Both II and III

The person responsible in an organization for, among other things, maintenance, security, and recovery of databases is the _________.

DBA

For the ER Diagram below, which of the following statements are NOT correct? Check all that apply.https://imgur.com/undefined

Every track must have a genre., An album can be co-created by multiple artists., Some artists have published several albums.

True or False? In a RAID 10 configuration, data is encrypted to ensure data privacy and to guard against data theft.

False

https://imgur.com/AT1olwd What relationship exists between domain entities (business objects) Highlighter and WritingInstrument?

Generalization

Edger F. Codd

IBM research scientist is credited with the invention of the relational model for storing data and non-procedural methods for retrieving data

Which of the following statements about RAID 1 are correct? Check all that apply.

Increased fault tolerance compared to a single disk or RAID 0

An aggregation relationship (in which the part is not permanently fused to its container) is represented in UML notation by a _______.

Line with hollow diamond at one end

A composition relationship (in which the part is permanently fused to its container) is represented in UML notation by a _______.

Line with solid diamond at one end

Inheritance relationships are represented in the UML notation by which of these?

Lines with hollow triangular arrow at one end

Which of the following is not a relational database management system?

MongoDB

Which of these below is a valid example of a taxonomy?

Powerboats, sailboats, and pontoon boats are all types of vessels.

Given the table definition below, write a query that finds the name of the visitor with the second highest number of visits. CREATE TABLE Visitor ( VID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, FIRST_NAME CHAR(25), LAST_NAME CHAR(25), NUMVISITS INTEGER, JOIN_DATE DATETIME);

SELECT FIRST_NAME FROM Visitor WHERE NUMVISITS < (SELECT MAX(NUMVISITS) FROM Visitor) ORDER BY NUMVISITS DESC LIMIT 1;

________ is the main language used to define queries in relational database system and is based on relational algebra.

SQL

Given the following UML Class Diagram, which statement is correct: https://imgur.com/x6uxOeg

Some instances of A may not be connected to any instance of B

Given the following information, which of the statements below are *not* correct for the UML Class Diagram below. Check all that apply. At TTCG, courses are organized into modules. Each module is dedicated to a topic and is divided into units that last no more than 20 minutes, so that three units are an hour of material. Modules can be shared between courses. To support teaching a unit requires a presentation deck, at least one example, and an exercise. It also needs instructor notes to support delivery by other instructors. Each presentation deck is one or more slides plus pre-recorded videos and demonstrations. These elements are commonly called presentation materials. https://imgur.com/yQ4aNqh

The aggregation relationship between Course and Module is appropriate as presented, The composition relationship between Unit and Example is on the correct end of the relationship.

Which of the following is not a restriction or constraint for a table to be a relation?

The columns must be ordered

In the query below, what is the difference between INTEGER ad INTEGER(15)? Why is it used? CREATE TABLE Worker ( WORKER_ID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, FIRST_NAME TEXT, LAST_NAME TEXT, SALARY INTEGER(15), JOINING_DATE DATETIME, DEPARTMENT CHAR(25) );

The size parameter specifies the maximum display width (which is 255). Used to limit the digits of salary to 15 digits.

For the table definition below, write a SQL UPDATE statement that changes all annual salaries to monthly salaries. CREATE TABLE Worker ( WORKER_ID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, FIRST_NAME TEXT, LAST_NAME TEXT, SALARY DOUBLE, JOINING_DATE DATETIME, DEPARTMENT CHAR(25) );

UPDATE Worker SET SALARY = SALARY / 12;

_______ and XPath is the main query mechanism for XML databases.

Xquery

In the UML Class Diagram below, the connection (relationship) between Zoo and Animal is a(n) _________ . https://imgur.com/I5Iib7J

association

A functional dependency is a relationship between or among _________.

attributes

In a RAID 0 configuration, data is _______ across disks.

block-level striped

What is the most common method of specifying a primary key in a relational schema description?

by underlining the attributes that comprise the primary key

All potential primary keys for an entity, class, or table are called its __________ keys.

candidate

The primary key is selected from the list of ___________.

candidate keys

What is are some of the differences between the char, varchar, text, memo, and blob databases in CREATE TABLE? Are they supported by all databases?

char: max 255 characters varchar: max 65,535 characters text: stores long string, max 2GB text data blob (binary large object): stores very large amount of data (even video, audio) and does not have a fixed size memo: stores large amount of text, max 65,536 character

In a centralized database system, the database, application code, and user interface are all on the same computer or virtual machine while in a __________ architecture, the database resides on a remote computer and is accessed over the network by application programs.

client/server

Each class can be considered a _______ for storing data about a set of similar things.

collections of like objects, set of objects, template, collection of objects, blueprint, structure

The ________ level in database architecture describes what data is stored, the relationships among the various kinds of data without concern how the data is actually stored in storage devices.

conceptual

Only after requirements collection and analysis are substantially complete should the ______________ phase of the database implementation process start.

conceptual design

Which three of the following are the levels that are part of the three-schema architecture?

conceptual schema, external schema, internal schema

SQL is both a data ______ and ______ language.

definition, manipulation

In which of the following types of databases is the data stored on multiple computers and storage devices connected either through a SAN or a LAN?

distributed database

RAID 10 is _______.

fault tolerant and fast, combining the benefits of RAID 0 and RAID 1

Consider a relation R (A, B, C, D, E, F, G, H), where each attribute is single-valued. Given the functional dependencies below, the relation is in ______ normal form. `CH → G A → BC B → CFH E → A F → EG`

first but not second

In a relational schema, relationships between relations (or tables) are created using _______.

foreign keys

CREATE TABLE Worker ( WORKER_ID INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, FIRST_NAME TEXT, LAST_NAME TEXT, SALARY INTEGER(15), JOINING_DATE DATETIME, DEPARTMENT CHAR(25) );

generate a unique number for every new record added into a table. This is generally used for the primary key column as it becomes easy for the developers to automatically generate a unique number for every new record.

One of the oldest data models is the ________ data model which organizes data in a tree structure in which child nodes are related to parent nodes.

hierarchical

The way that data is stored on disk devices and spread across devices, such as in RAID systems, is known as the ___________ level.

internal

common drawbacks (disadvantages) of a file-based approach to storing data

lack of insulation between application and data, frequent data inconsistency, no enforcement of data integrity constraints, increased data redundancy

https://imgur.com/Z974lQL

lessons are collections of tutorials and examples, some learning assets may not be allocated to a lesson, there are some examples which are not included in any lesson, some lessons may not have any examples

https://imgur.com/a/sFAqwEz Which of the following statements about the UML Class Diagram below are correct?

no video has more than two narrators, every video is narrated, a video must have at least one narrator

To prevent modification anomalies, which of the following are created for a relation?

normal forms

In a RAID 5 configuration, ____ information is spread across the disks to allow restoration of data in case of failure.

parity

Which one is correct in a relational database? (The symbol ⊆ means subset-of)

primary key ⊆ candidate key ⊆ super key

Any set of attributes that allows us to identify unique rows (tuples) in a given relation are known as super keys. Out of these super keys we can always choose a proper subset among these which can be used as a __________ key. Such keys are known as __________ keys. If there is a combination of two or more attributes which is being used as the primary key then we call it as a __________ key.

primary, candidate, compound/composite

Determining how the physical disk devices are accessed to retrieve the data efficiently is the responsibility of the __________.

query engine in the database

In a relational database, the term row is synonymous with the term:

record

The fact that the value of a foreign key attribute must exist in another set of one or more key attributes in another table, is called a(n) __________.

referential integrity constraint

A database can be defined as a set or collection of ________ data from which users can efficiently retrieve the desired information.

related

SQLite is a _________ database.

relational

Which of the following below are among the main objectives of a modern DBMS? Check all that apply.

security from unauthorized access, methods for manipulating data, methods for defining data, recovery of data during failures, methods for retrieving data

Explain the bolded clause in the query below. What does it do? What does it mean? Why is it important? CREATE TABLE Bonus ( WORKER_REF_ID INTEGER, BONUS_AMOUNT INTEGER(10), BONUS_DATE DATETIME, FOREIGN KEY (WORKER_REF_ID) REFERENCES Worker(WORKER_ID) ON **DELETE CASCADE**);

specify whether you want rows deleted in a child table when corresponding rows are deleted in the parent table

In RAID 5, parity information is ________.

spread across all disks