Chapter 4: Relational Databases

Question 1

Entity

Answer 1

Something about which data is stored: resources, activities (events), people (agents). Entity = students

Question 2

Attributes/ Fields

Answer 2

Characteristics of the entity. The data for each attribute stored in fields.

Question 3

Records

Answer 3

Individual Items, people or activities. ex: entity = students, record = one specific students information.

Question 4

Primary Key

Answer 4

Attribute that uniquely ids each record. Usually a single attribute and can be combined with another primary key attribute. (concatenated key for many to many relationships)

Question 5

database

Answer 5

a set of inter-related, centrally coordinated files

Question 6

Database management system (DBMS)

Answer 6

the interface between the database and the various application programs.

Question 7

Database System

Answer 7

the database, the DBMS, and the application programs that access the database through the DBMS .It separates the storage and use of data elements.

Question 8

Master Files

Answer 8

stores data about Resources and people (agents), spans accounting periods, changes infrequently, similar to ledgers (AR subsidiary ledger customer information)

Question 9

Transaction Files

Answer 9

Stores data about activities (events), each transaction is a record, or multiple records. Similar to Journals (Sales Journal Captures all Sales transactions)

Question 10

Database Administrator (DBA)

Answer 10

responsible for the database

Question 11

Data warehouse

Answer 11

separate databases that contain both detailed and summarized data for a number of years and is used for analysis rather than transaction processing. They are updated periodically not in real time like transaction processing databases.

Question 12

Business Intelligence

Answer 12

the use of data warehouses for strategic decision making.

Question 13

two main techniques used in business intelligence:

Answer 13

OLAP and Data Mining

Question 14

Online Analytical Processing (OLAP)

Answer 14

using queries to guide the investigation of hypothesized relationships in data

Question 15

Advantages of database systems

Answer 15

1. Data Integration
2. data sharing
3. Minimal Data redundancy and data inconsistencies
4. Data independence
5. Cross-functional analysis

Question 16

Data Integration

Answer 16

Master files are combined into large “pools” of data that many application programs access.

Question 17

Data Sharing

Answer 17

Integrating data are more easily shared with authorized uses. Databases are easily browsed to a problem or obtain detailed information underlying a report.

Question 18

Data Independence

Answer 18

because data and the programs that use them are independent of each other, each can be changed without changing the other, This facilitates programming and simplifies data management.

Question 19

Cross-functional Analysis

Answer 19

in a database system, relationships, such as the association between selling costs and promotional campaigns, can be explicitly defined and used in the preparation of management reports.

Question 20

Logical View

Answer 20

how people conceptually organize and understand the data.

Question 21

Physical view

Answer 21

refers to how and where data are physically arranged and stored in the computer system.

Question 22

Schema

Answer 22

describes the logical structure of a database.

Question 23

3 levels of schema

Answer 23

Conceptual
External
Internal

Question 24

Conceptual level of schema

Answer 24

organization-wide view of the entire database. Includes all data elements and relationships.

Question 25

External level of schema

Answer 25

user view of portions of the database.Consists of individual user views of portions of the data base, each of which is referred to as a subschema

Question 26

Internal level of schema

Answer 26

a low-level view of the database, describes how the data are stored and accessed, including record layouts, definition, addresses, and indexes.

Question 27

Data dictionary

Answer 27

contains information about the structure of teh database. It is maintained by the DBMS

Question 28

Reports of data dictionary

Answer 28

1. programs or reports using a data item 2. synonyms for the data elements in a file 3. data elements used by a user.

Question 29

Data Query Languages (DQL)

Answer 29

interrogate and manipulate the data. Contains powerful, easy-to-use commands that enables users to retrieve, sort, order, and display data.

Question 30

Report Writer

Answer 30

simplifies queries and report by giving users limited choices.

Question 31

Data definition language (DDL) - not on pp

Answer 31

builds the data dictionary, creates the database, describes logical views for each user, and specifies records or field security constraints.

Question 32

Data Manipulation Language (DML) - not on pp

Answer 32

changes database content, including data element updates, insertions, and deletions.

Question 33

Relational Data model

Answer 33

represents conceptual and external level schemas as if data are stored in tables. Their actually not stored in tables but in the manner described in the internal level schema.

Question 34

Requirements of Relational Database

Answer 34

1. every column in a row must be single valued 2. Primary keys cannot be null 3. foreign keys, if not null must have values that correspond to the value of the primary key in another table 4. All non-key attributes in a table must describe a characteristic of the object identified by the primary key.

Question 35

Entity integrity rule

Answer 35

every row in a table represents something and that it can be identified. the primary key have a non-null value. This ensures that a specific object exists in the world and can be identified.

Question 36

referential integrity key

Answer 36

any non-null value of a foreign key must correspond to a primary key in the referenced table

Question 37

Normalization

Answer 37

assumes everything is in one large file/table. Separates attributes into multiple files/table - eliminate anomalies: delete, update, insert

Question 38

Semantic Data Modeling

Answer 38

Use business processes to create diagrams representing the database structure. Proper modeling eliminates anomalies. Preferred method because it captures the end user requirements

Question 39

update anomaly

Answer 39

data values updates are not correctly recorded

Question 40

delete anomaly

Answer 40

occurs when deleting a row has unintended consequences.no way to store information about prospective customers until they ma

Question 41

data modeling

Answer 41

the process of creating a logical representation of the structure of the database based on a company's business processes.