COE126 : Database Systems

Question 1

The overall logical structure of the database.

Answer 1

Logical Schema

Question 2

The overall physical structure of database.

Answer 2

Physical Schema

Question 3

The actual content of the database at a particular point in time.

Answer 3

Instances

Question 4

The ability to modify the modify schema without changing the logical schema.

Answer 4

Physical Data Independence

Question 5

Specification notation for defining the database schema

Answer 5

Data Definition Language (DDL)

Question 6

ID uniquely identifies instructors

Answer 6

Primary Key

Question 7

Language for accessing and updating the data organized by the appropriate data model. Also known as query model.

Answer 7

Data Manipulation Language (DML)

Question 8

Require a user to specify what data are needed and how to get those data.

Answer 8

Procedural DML

Question 9

Require a user to specify what data are needed without specifying how to get those data.

Answer 9

Declarative DML

Question 10

__________ is nonprocedural. A query takes as input several tables (possibly only one) and always returns a single table.

Answer 10

SQL Query Language

Question 11

Are programs that are used to interact with the database in this fashion.

Answer 11

Application Programs

Question 12

Deciding on the database schema. It requires what we find a “good” collection of relation schemas.

Answer 12

Logical Design

Question 13

Deciding on the physical layout of the database.

Answer 13

Physical Design

Question 14

A database system in partitioned into modules that deal with each of the responsibilities of the overall system.

Answer 14

Database Engine

Question 15

A program module that provides interface between the low-leveled data stored in the database and the application programs and queries submitted to the system.

Answer 15

Storage Manager

Question 16

Interprets DDL statements and records the definitions in the data dictionary.

Answer 16

DDL interpreter

Question 17

Translates DML statements in a query language into are evaluation plan consisting of low-level instructions that the query evaluation engine understands.

Answer 17

DML compiler

Question 18

Executes low-level instructions generated by the DML compiler.

Answer 18

Query Evaluation Engine

Question 19

A ___________ is a collection of operation that performs a single logical function in a database application.

Answer 19

transaction

Question 20

Ensures that the database remain in a consistent (correct) state despite the failures and transaction failures.

Answer 20

Transaction-management component

Question 21

Controls the interaction among the concurrent transaction, to ensure the consistency of the database

Answer 21

Concurrency-control manager

Question 22

The application resides at the client machine, where it invokes database system functionality at the server machine.

Answer 22

Two-tier architecture

Question 23

The client machine acts as a front end and does not contain any direct database calls.

Answer 23

Three-tier architecture

Question 24

A person who has central control over the system is called

Answer 24

Database Administrator (DBA)

Question 25

The set of allowed values of each attribute is called

Answer 25

Domain of the attribute

Question 26

Is the logical structure of the database.

Answer 26

Database schema

Question 27

is a snapshot of the data in the database at a given instant in time.

Answer 27

Database instance

Question 28

A procedural language consisting of a set of operation that take one or two relations as input and produce a new relation as their result.

Answer 28

Relational Algebra

Question 29

A unary operation that returns its argument relation, with certain attributes left out.

Answer 29

Project Operation

Question 30

A real-world entity having properties called attributes.

Answer 30

Entity

Question 31

Properties of entities that have values.

Answer 31

Attributes

Question 32

Logical association among entities.

Answer 32

Relationship

Question 33

Defines the number of association between two entities.

Answer 33

Cardinality

Question 34

Attributes that uniquely identity rows of a table.

Answer 34

Candidate Key

Question 35

The set of all the keys which help to identify rows in a table uniquely.

Answer 35

Super Key

Question 36

Used to establish relationships between two tables.

Answer 36

Foreign Key

Question 37

A set of two or more attributes that help identify each tuple in a table uniquely.

Answer 37

Composite Key

Question 38

A table can have multiple choices for a primary key; however it can choose only one.

Answer 38

Alternate Key

Question 39

A column or set of columns that uniquely identify each record in a table.

Answer 39

Unique Key

Question 40

One entity has only one event shared with another entity.

Answer 40

One-to-One Cardinality (1:1)

Question 41

One entity has an event that occurs one time, while the other entity can have more than one repetition of the event.

Answer 41

One-to-many Cardinality (1:n)

Question 42

Opposite of one-to-many, difference is due to perspective.

Answer 42

Many-to-one Cardinality (m:1)

Question 43

When both entities have the same event or relationship happen more than once.

Answer 43

Many-to-many Cardinality (m:n)

Question 44

A graphical representation of the entity relationship model.

Answer 44

ER diagram

Question 45

Is credited with introducing the widely adopted ER model in his paper "The Entity Relationship Model-Toward a Unified View of Data".

Answer 45

Peter Chen

Question 46

An entity that depends on the existence of another entity.

Answer 46

Weak Entity

Question 47

An attribute that can have more than one value.

Answer 47

Multivalued Attribute

Question 48

An attribute based on another attribute.

Answer 48

Derived Attribute

Question 49

Describes how entities interact.

Answer 49

Relationship

Question 50

If the same entity participates more than once in a relationship it is known as a

Answer 50

Recursive Relationship

Question 51

Each entity in the entity set is involved in at least one relationship in a relationship set.

Answer 51

Total Participation

Question 52

Each entity in the entity set may or may not occur in at least one relationship in a relationship set.

Answer 52

Partial Participation