OA Study

Question 1

What is a database application?

Answer 1

Software that helps business users interact with database systems

Question 2

What is the role of a database administrator?

Answer 2

Responsible for securing the database system against unauthorized users and enforcing procedures for user access and database system availability

Question 3

What does authorization in database systems entail?

Answer 3

Many database users should have limited access to specific tables, columns, or rows of a database

Question 4

What is metadata in the context of databases?

Answer 4

Data about the database, such as column names and the number of rows in each table

Question 5

How is a relational database structured?

Answer 5

Stores data in tables, columns, and rows, similar to a spreadsheet

Question 6

What is the SQL query language?

Answer 6

A standard language supported by all relational database systems

Question 7

What are the four main SQL statements?

Answer 7

• INSERT
• SELECT
• UPDATE
• DELETE

Question 8

What does the CREATE TABLE statement do?

Answer 8

Creates a new table by specifying the table and column names, with each column assigned a data type

Question 9

What are the common data types in a database?

Answer 9

• INT
• DECIMAL
• VARCHAR
• DATE

Question 10

What are the three phases of database design?

Answer 10

• Analysis
• Logical Design
• Physical Design

Question 11

What is an entity in database terms?

Answer 11

A person, place, activity, or thing

Question 12

What is a relationship in a database context?

Answer 12

A link between entities

Question 13

What is an attribute in a database?

Answer 13

A descriptive property of an entity

Question 14

What does logical design convert entities into?

Answer 14

Tables, keys, and columns

Question 15

What is the principle of data independence?

Answer 15

Physical design affects query processing speed but never affects the query result

Question 16

What is an API in the context of databases?

Answer 16

Application programming interface that simplifies the use of SQL with a general-purpose language

Question 17

What is a tuple in a database?

Answer 17

An ordered collection of elements enclosed in parentheses

Question 18

What does a column in a table represent?

Answer 18

A named set of values, with each value corresponding to a data type

Question 19

What are relational operations?

Answer 19

• Select
• Join
• Union
• Aggregate

Question 20

What does the SELECT statement do?

Answer 20

Retrieves data from a table

Question 21

What are the five sublanguages of SQL?

Answer 21

• Data Definition Language (DDL)
• Data Query Language (DQL)
• Data Manipulation Language (DML)
• Data Control Language (DCL)
• Data Transaction Language (DTL)

Question 22

What is a primary key?

Answer 22

A column, or group of columns, used to identify a row

Question 23

What is a foreign key?

Answer 23

A column, or group of columns, that refer to a primary key

Question 24

What does the UNIQUE constraint ensure?

Answer 24

Ensures that values in a column, or group of columns, are unique

Question 25

What is the BETWEEN operator used for?

Answer 25

Determines if a value is between two other values

Question 26

What does the LIKE operator do?

Answer 26

Matches text against a pattern using wildcard characters % and _

Question 27

What is the purpose of the ORDER BY clause?

Answer 27

Orders selected rows by one or more columns in ascending or descending order

Question 28

What does the COUNT() function do?

Answer 28

Counts the number of rows in the set

Question 29

What is an equijoin?

Answer 29

A join that compares columns of two tables with the = operator

Question 30

What is a subquery?

Answer 30

A query within another SQL query

Question 31

What is an entity-relationship model?

Answer 31

A high-level representation of data requirements, ignoring implementation details

Question 32

What are the steps in the analysis phase of database design?

Answer 32

* Discover entities, relationships, and attributes * Determine cardinality * Distinguish strong and weak entities * Create supertype and subtype entities

Question 33

What is a materialized view?

Answer 33

A view for which data is stored at all times and must be refreshed when base tables change

Question 34

What is the purpose of the model in database design?

Answer 34

Capturing data requirements while ignoring implementation details

Question 35

What does logical design convert in database design?

Answer 35

Entity-relationship model into tables, columns, and keys for a particular database system

Question 36

What does physical design specify in database design?

Answer 36

Indexes and how tables are organized on storage media

Question 37

What is the first step in the analysis process of database design?

Answer 37

Discover entities, relationships, and attributes

Question 38

Define cardinality in the context of database relationships

Answer 38

Maxima and minima of relationships and attributes

Question 39

What is the maximum in relationship cardinality?

Answer 39

The greatest number of instances of one entity that can relate to a single instance of another entity

Question 40

What is the minimum in relationship cardinality?

Answer 40

The least number of instances of one entity that can relate to a single instance of another entity

Question 41

What is a subtype entity?

Answer 41

A subset of another entity type, called the supertype entity

Question 42

What is the identifying relationship between a supertype and subtype called?

Answer 42

IsA relationship

Question 43

What is a partition of a supertype entity?

Answer 43

A group of mutually exclusive subtype entities

Question 44

What notation depicts cardinality in ER diagrams?

Answer 44

Crow's foot notation

Question 45

What is an intangible entity in a data model?

Answer 45

Documented in the data model but not tracked with data in the database

Question 46

What is an artificial key?

Answer 46

A single-column primary key created by the database designer when no suitable primary key exists

Question 47

What is functional dependence?

Answer 47

Dependence of one column on another

Question 48

What does normalization aim to eliminate?

Answer 48

Redundancy by decomposing a table into two or more tables

Question 49

Define Boyce-Codd normal form

Answer 49

An ideal normal form for tables with frequent inserts, updates, and deletes

Question 50

What is denormalization?

Answer 50

Intentionally introducing redundancy by merging tables

Question 51

List four alternative table structures supported by databases

Answer 51

* Heap table * Sorted table * Hash table * Table cluster

Question 52

What is a heap table?

Answer 52

A table where no order is imposed on rows

Question 53

What is the purpose of a hash table?

Answer 53

Assigns rows to buckets

Question 54

What is a table scan?

Answer 54

A database operation that reads table blocks directly, without accessing an index

Question 55

What is a dense index?

Answer 55

An index that contains an entry for every table row

Question 56

What is a multi-level index?

Answer 56

Stores column values and row pointers in a hierarchy

Question 57

What does a bitmap index consist of?

Answer 57

A grid of bits containing ones and zeros

Question 58

What is a tablespace in database terminology?

Answer 58

A database object that maps one or more tables to a single file

Question 59

What does physical design affect in database management?

Answer 59

Query performance but never affects query results

Question 60

What is the SQL syntax to create an index?

Answer 60

CREATE INDEX IndexName ON TableName (Column1, Column2, ..., ColumnN)