SCHOOL OF MATHEMATICAL AND COMPUTER SCIENCES


Department of Computer Science




F20BD


BIG DATA MANAGEMENT

Semester 2 2018/19





Duration: Two Hours









ANSWER THREE QUESTIONS




F20BD
Page 2 of 7


Q1
(a)
(i) In terms of a NoSQL database system, what does it mean for the
system to be CP?

(2 marks)

(ii) Can a distributed data management system be both CP and AP,
explain your answer?

(2 marks)

(iii) Give an example of an AP system and explain why a company
might choose to be AP rather than CP?

(2 marks)

(iv) Some NoSQL database systems use MVCC – what does it mean
and why is it used?

(3 marks)


(b) Big Data is sometimes described using the 5 Vs where the 5th V
is VALUE – what are the other 4 Vs and what do they mean?

(4 marks)

(c)
(i) Explain Consistent Hashing and why it is used with regard to
NoSQL database systems.

(3 marks)


(ii) What is a Bloom filter, how and why does the Cassandra NoSQL
database system use them?


(4 marks)


F20BD
Page 3 of 7


Q2
(a) What is BSON and how is it related to NoSQL database systems?
(2 marks)

(b) What is referential integrity and is it supported by MongoDB?
(2 marks)

(c) Look at the following MongoDB command:
db.d1.find({"person.lastname":"Smith"}).count()


(i) What type of object is d1?
(1 mark)

(ii) What data type would be returned from running this statement,
assuming matching records were found?

(1 mark)

(iii) What does the dot notation syntax tell you about the document
schema?

(2 marks)

(iv) You have a database which includes names and addresses, but
have noticed a spelling error and all entries with the lastname of
“Jnes” should be “Jones”. Write the MongoDB command to make
this change.


(3 marks)

QUESTION CONTINUES ON NEXT PAGE
F20BD
Page 4 of 7


(d) Denormalise these RDBMS entities for storage in MongoDB, with
Employee as an embedded document of Project, showing your
answer as a suitable JSON schema.

CREATE TABLE Employee
(
empID int(5) Not Null Primary Key,
firstName varchar(30),
lastName varchar(30),
email varchar(30)
);

CREATE TABLE Project
(
pID int(8) Not Null Primary Key,
pName varchar(50),
startDate date,
endDate date,
managedBy int(5),
FOREIGN KEY (managedBy) REFERENCES Employee(empID)
);


(6 marks)

(e) MongoDB is considered as a schema-less database system.
Explain what this means, yet why JSON schemas may be
included.

(3 marks)

F20BD
Page 5 of 7


Q3
(a) Define the term “Data Integration” and explain the 3 components
required to implement a data integration system.

(4 marks)

(b)
(i) Describe the RDF data model and what are the permissible
values for each part.

(4 marks)

(ii) Explain how RDF supports data integration.
(2 marks)

(c) Consider the following RDF:

PREFIX rdfs:
PREFIX foaf:
PREFIX xsd:
PREFIX ex:

ex:Country a rdfs:Class .
ex:City a rdfs:Class .
ex:CapitalCity rdfs:subClassOf ex:City .
ex:cityIn a rdfs:Property ;
rdfs:Domain ex:City ;
rdfs:Range ex:Country .
ex:capitalOf a rdfs:Property ;
rdfs:Domain ex:CapitalCity ;
rdfs:Range ex:Country .
ex:population a rdfs:Property ;
rdfs:Range xsd:integer .

ex:London rdfs:label "London" ;
ex:capitalOf ex:UK ;
ex:cityIn ex:UK ;
ex:population 14040163 .
ex:UK rdfs:label "UK" ;
ex:population 65648100 .


(i) What triple(s) can we infer about ex:London and ex:UK?
(3 marks)

(ii) Assume the above is part of a larger dataset.

Write a SPARQL query to find the labels of all capital cities.

(3 marks)

(iii) Write a SPARQL query to calculate the average city population by
country.

(4 marks)

F20BD
Page 6 of 7


Q4
(a) Explain the difference between an OWL ontology and a Shape
Expression (ShEx) Schema.

(4 marks)

(b) Provide an RDF graph that conforms to the following Shape
Expression.
(The minimally satisfying graph is sufficient. You can provide the
graph as abstract syntax or Turtle.)

PREFIX foaf:
PREFIX rdf:
PREFIX rdfs:
PREFIX xsd:
PREFIX hwu:

hwu:StudentShape {
rdf:type [hwu:Student] ;
foaf:name xsd:string ;
foaf:mbox IRI? ;
hwu:studies @hwu:CourseShape {1,8}
}

hwu:CourseShape {
rdf:type [hwu:Course] ;
rdfs:label xsd:string
}


(6 marks)

QUESTION CONTINUES ON NEXT PAGE
F20BD
Page 7 of 7


(c) Assume that the following entities are defined in an OWL ontology
about HWU staff and courses:
Classes: Academic, Course, Campus, Dubai, Malaysia, Orkney
Object Properties: teaches, locatedAt

Dubai, Malaysia and Orkney are disjoint subclasses of Campus.
teaches has the domain Academic and the range Course.
locatedAt has the domain Academic and the range Campus.


(i) Use Manchester Syntax to define classes for UniversityStaff and
AdministrativeStaff such that academics and administrative staff
are types of university staff, and no member of staff can be both
an academic and an administrator.

(4 marks)

(ii) Use Manchester Syntax to define the class OrkneyAcademic.
Such an academic is based in Orkney and teaches at least one
course.

(4 marks)

(d) Describe two of the services performed by a standard Description
Logic reasoner.

(2 marks)



END OF PAPER