Database Concepts - Exam 2

Which of the following are true regarding file structures for DBMS? Select all that apply. -A disk drive is formatted into a single block that can store records -A file is a sequence of records stored in binary format -Relative data and information is stored collectively in file formats -File records are mapped onto a disk drive is formatted into several blocks -A file is a sequence of records stored in character format

-A file is a sequence of records stored in binary format -Relative data and information is stored collectively in file formats -File records are mapped onto a disk drive is formatted into several blocks

Regarding the mapping process of hierarchical entities, which of the following are included? Select all that apply. -Add primary keys of higher-level entities in the table of lower-level entities -Declare primary key of higher-level table and the primary key for lower-level table -Add primary keys of lower-level entities in the table of higher-level entities -Do not need to declare foreign key constraints, it happens automatically -Create tables for all higher-level entities

-Add primary keys of higher-level entities in the table of lower-level entities -Declare primary key of higher-level table and the primary key for lower-level table -Create tables for all higher-level entities

Which of the following attributes defines Second Normal Form? Select all that apply. -No non-prime attribute is transitively dependent on prime key attribute -Cannot have transitive dependency -Cannot have partial dependency -Every non-prime attribute should be fully functionally dependent on prime key attribute

-Cannot have partial dependency -Every non-prime attribute should be fully functionally dependent on prime key attribute

Which of the following attributes define Third Normal Form? -Cannot have partial dependency -The values in an atomic domain are indivisible units. -Must have a prime attribute -Cannot have transitive dependency -Each attribute must contain only a single value from its pre-defined domain

-Cannot have partial dependency -The values in an atomic domain are indivisible units. -Must have a prime attribute -Cannot have transitive dependency -Each attribute must contain only a single value from its pre-defined domain

Which of the following are part of the Mapping Relationship process? Select all that apply. -Declare primary key -Declare a primary key composing all the primary keys of participating entities -Add the primary keys of all participating Entities as fields of table with their respective data types -Entity's attributes should become fields of tables with their respective data types

-Declare a primary key composing all the primary keys of participating entities -Add the primary keys of all participating Entities as fields of table with their respective data types

Which of the following are part of the Mapping Entity process? Select all that apply. -Declare primary key -Declare all foreign key constraints -Create table for a relationship -Create table for each entity

-Declare primary key -Create table for each entity

What do ER diagrams mainly comprise of? Select all that apply. -DBMS -Entities -Entity Attributes -Relationships -Databases -Association among entities

-Entities -Entity Attributes -Association among entities -Relationships

Which of the following attributes defines First Normal Form? Select all that apply. -has a prime attribute -all the attributes in a relation must have atomic domains -Each attribute must contain only a single value from its pre-defined domain -No non-prime attribute is transitively dependent on prime key attribute -The values in an atomic domain are indivisible units

-all the attributes in a relation must have atomic domains -Each attribute must contain only a single value from its pre-defined domain -The values in an atomic domain are indivisible units

When using inheritance, which of the following is true? -the entities have nothing in common -higher-level entities to inherit the attributes of lower-level entities -lower-level entities to inherit the attributes of higher-level entities -the entities have the same attributes

-lower-level entities to inherit the attributes of higher-level entities

Dr Edgar F. Codd, after his extensive research on the Relational Model of database systems, came up with rules a database must obey in order to be regarded as a true relational database. How many are there?

12

What is a join regarding DBMS?

A Cartesian product followed by a selection process

How is a relation instance defined?

A finite set of tuples in the relational database system

How is a relation schema defined?

A relation schema describes the relation name (table name), attributes, and their names

In a relational data model what is a tuple?

A single row

Regarding inheritance, when the details of entities are generally hidden from the user, what is this known as?

Abstraction

The structure description of the entire database must be stored as a data dictionary.

Active Online Catalog

if a -> b holds and y is attribute set, then ay -> by also holds.

Augmentational Rule

More than one such minimal subset of attributes.

Candidate Keys

Removes all the locks; saves the data; releases all the buffers and file handlers.

Close

Related records from the one or more relations are kept in the same disk block.

Clustered File Organization

If an FD X->Y holds, where x intersect Y = o

Completely Non-Trivial

A database can only be accessed using a language having linear syntax that supports data definition, data manipulation, and transaction management operations.

Comprehensive Data Sub-Language Rule

How are derived attributes depicted?

Dashed Ellipse

Relationships are represented by a __________.

Diamond shaped box

The end-user must not be able to see that the data is distributed over various locations.

Distribution Independence

Every attribute is bound to have a specific range of values.

Domain Constraints

When representing total participation, what indicates this in an ER Diagram?

Double Lines

How are multivalued attributes depicted?

Double ellipse

Attributes are represented by means of __________.

Ellipses

When Theta join uses only equality comparison operator.

Equijoin

T/F A binary relationship is where more than two entities are participating.

False

All the tuples from both participating relations are included in the resulting relation.

Full Outer Join

At UCF, everyone associated with the university is a Person. Each Person has a specific role they fulfill, Student, Faculty, Staff, and Maintenance. Based on the fact that the ER Model has the power of expressing database entities in a conceptual hierarchical manner, referencing Person, what would the entity be considered as?

Generalization

The ER Model has the power of expressing database entities in a conceptual hierarchical manner. Going up in this structure is called what?

Generalization

Every single data element is guaranteed to be accessible logically with a combination of table-name, primary-key, and attribute-name.

Guaranteed Access Rule

The hash function determines the location of disk block where the records are to be placed.

Hash File Organization

The Operating System allocates memory area to that file without any further accounting details.

Heap File Organization

A database must support insertion, updation, and deletion by row, union, intersection, and minus operations.

High-Level Insert, Update, and Delete Rule

Everything in database must be stored in a table format.

Information Rule

Includes only those tuples with matching attributes and the rest are discarded in the resulting relation.

Inner Joins

A database must be independent of the application that uses it.

Integrity Independence

One minimal subset of attributes in the relation, which can identify a tuple uniquely.

Key

All the tuples from the Left relation are included in the resulting relation.

Left Outer Join

Every file has a file pointer, which tells the current position where the data is to be read or written.

Locate

The logical data in a database must be independent of its user's view.

Logical Data Independence

If there is at least one common attribute that exists between two relations and the attributes must have the same name and domain.

Natural Join

If a system has an interface that provides access to low-level records, then the interface must not be able to subvert the system and bypass security and integrity constraints.

Non-Subversion Rule

If an FD X->Y holds, where Y is not a subset of X.

Non-Trivial

A file can be opened in one of the two modes: read mode write mode.

Open

To include all the tuples from the participating relations in the resulting relation.

Outer Joins

The data stored in a database must be independent of the applications that access the database.

Physical Data Independence

The memory storage that is directly as accessible to the CPU comes under this category.

Primary Memory

The very next data to the file pointer is read.

Read

Entities are represented by means of __________.

Rectangle

If a relation refers to a key attribute of a different or same relation, then that key element must exist.

Referential Integrity Constraints

If alpha is a set of attribute and beta is_subset_of alpha, then alpha holds beta.

Reflexive rule

All the tuples from the Right relation are included in the resulting relation.

Right Outer Join

Includes memory devices that are not a part of the CPU chipset or motherboard.

Secondary memory

Records are placed in the file in some sequential order based on the unique key field or search key.

Sequential File Organization

When representing partial participation, what indicates this in an ER Diagram?

Single Lines

At UCF, everyone associated with the university is a Person. Each Person has a specific role they fulfill, Student, Faculty, Staff, and Maintenance. Based on the fact that the ER Model has the power of expressing database entities in a conceptual hierarchical manner, referencing Student, what would the entity be considered as?

Specialization

The ER Model has the power of expressing database entities in a conceptual hierarchical manner. Entities divided into sub-groups based on their characteristics is called what?

Specialization

NULL values in a database must be given a systematic and uniform treatment.

Systematic Treatment of NULL Values

Used to store huge volumes of data external to the computer system.

Tertiary memory

Combines tuples from different relations provided they satisfy the theta condition.

Theta Join

Same as transitive rule in algebra, if a-> b and b->c holds, then a->c also holds.

Transitivity Rule

If a functional dependency (FD) X->Y holds, Y is a subset of X.

Trivial

T/F Armstrong's Axioms are a set of rules, that when applied repeatedly, generates a closure of functional dependencies

True

T/F Composite attributes are represented by ellipses that are connected with an ellipse

True

T/F ER Model, when conceptualized into diagrams, gives a good overview of entity-relationship.

True

T/F It is possible to create relational schema using ER diagram

True

T/F We cannot import all the ER constraints into relational model, but an approximate schema can be generated.

True

Functional dependency (FD) is a set of constraints between how many attributes in a relation?

Two

All the views of a database, which can theoretically be updated, must also be updatable by the system.

View Updating Rule

Enables data to be edited: deletion, insertion, or modification.

Write

Functional dependency is represented by an arrow sign (→) that is, X→Y, where X functionally determines Y. As a result, which attributes determine the values in the relationship?

left-hand side attributes determine the values of attributes on the right-hand side

What is a relation key?

one or more attributes which can identify the tuple in the relation uniquely

What is the definition of a weak entity set?

one which does not have any primary key associated with it

What is the attribute domain?

some pre-defined value scope

What is the format are relations saved in a relational data model?

tables