Slide 2

Question 1

Database Fundamentals

Answer 1

 Database Fundamentals & Advantages
 Relational Databases
 Database Management Systems (DBMS)
 Practice designing databases

Question 2

Understanding Data as the Backbone of Information

Answer 2

 Data Quality
 Granularity, redundancy
 Data integrity constraints
 Access controls

Question 3

The data hierarchy

Answer 3

Database - file- record-field-byte-bit

Question 4

Database

Answer 4

Collection of data organized to serve many applications by centralizing data and controlling redundant data

Question 5

Database management system (DBMS) - software through which users and application programs interact with a database (e.g. Microsoft Access)

Answer 5

 Software that manages one or more databases  Interfaces between application programs and physical data files  Separates logical and physical views of data ( How a data looks to the user (logical)  How data is actually stored (physical) )
 Enables organization to centralize data management and security

Question 6

Files are maintained separately by different departments (or apps) - if every app manages its own data

Answer 6

 Data redundancy: Presence of duplicate data in multiple files
 Data inconsistency: Same attribute has different values in different applications
 Lack of flexibility
 Poor security
 Lack of data sharing and availability

Question 7

Database examples:

Answer 7

 Web applications like Wordpress use a database (typically MySQL)
 Search engines use a (massive) database to store pages and indexes
 iPhone Apps can use the SQLite database to store and manage their data
 Enterprise Applications used by accounting, marketing, and operations use databases to centralize and share information

Question 8

Database fundamentals

Answer 8

 Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

 Relational database (dominant model) – stores information in the form of logically related twodimensional tables

Question 9

Table
Record(row)
Field(columns)

Answer 9

 Table – a collection of similar records

 Record (row) – a person, place, thing, transaction, or event about which information is stored

 Fields (columns) – characteristics or properties of an record  The columns in each table contain the fields

Question 10

Database Structure

Answer 10

• Represent data as two-dimensional tables called relations or files
• Each table contains data on entity and attributes

Question 11

Primary key

Answer 11

Field in table used for key fields

Question 12

Foreign key

Answer 12

Primary key used in second table as look-up field to identify records from original table
• (When a field is used in one table to create a relationship, but it is NOT a primary key, it is then called a foreign key)

Question 13

Row (tuples)

Answer 13

records for different entities

Question 14

fields (columns)

Answer 14

Represents attribute for entity

Question 15

The big three in database

Answer 15

table, queries, reports

Question 16

Parts of table

Answer 16

 Column  aka Field, Attribute, or Property  Row  aka Record or Tuple
 Primary Key  Foreign Keys

Question 17

Relationships

Answer 17

 Use Foreign Key to link

One-to-One, One-to-Many  (Many-to-Many)

Question 18

Database advantages from a business perspective includ

Answer 18

 Increased flexibility
 Increased scalability (Reduce and Increase)and performance
 Reduced information redundancy (Repeating information)
 Increased information integrity (quality)
 Increased information security

Question 19

Information granularity尺度

Answer 19

refers to the extent of detail within the information

Question 20

Factors affecting granularity

Answer 20

 Level of abstraction
(fine or detailed, coarse or summarized)
 Frequency of gathering data items

Question 21

Characteristics of high quality Information:

Answer 21

 Accuracy 
 Completeness 
 Consistency 
 Uniqueness 
 Timeliness

Question 22

The four primary sources of low quality information include

Answer 22

1. Online customers intentionally enter inaccurate information to protect their privacy 2. Information from different systems have different entry standards and formats 3. Call center operators enter abbreviated or erroneous information by accident or to save time 4. Third party and external information contains inconsistencies, inaccuracies, and errors

Question 23

Potential business effects resulting from low quality information include:

Answer 23

 Inability to accurately track customers
 Difficulty identifying valuable customers
 Inability to identify selling opportunities
 Marketing to nonexistent customers
 Difficulty tracking revenue due to inaccurate invoices
 Inability to build strong customer relationships

Question 24

A well-designed database should: (increased flexibility)

Answer 24

 Handle changes quickly and easily
 Provide users with different views
 Have only one physical view (Physical view – deals with the physical storage of information on a storage device)
 Have multiple logical views (Logical view – focuses on how users logically access information)

Question 25

Databases reduce information redundancy

Answer 25

Inconsistency is one of the primary problems with redundant information

Question 26

Databases offer several security features including

Answer 26

 Password – provides authentication of the user  Access level – determines who has access to the different types of information  Access control – determines types of user access, such as read-only acces

Question 27

Data quality audit:

Answer 27

 Structured survey of the accuracy and level of completeness of the data in an information system

Question 28

Data cleansing :

Answer 28

 Software to detect and correct data that are incorrect, incomplete, improperly formatted, or redundant  Enforces consistency among different sets of data from separate information system

Question 29

Ensuring data quality:

Answer 29

 More than 25% of critical data in Fortune 1000 company databases are inaccurate or incomplete  Most data quality problems stem from faulty input  Before new database in place, need to:  Identify and correct faulty data  Establish better routines for editing data once database in operation

Question 30

How do organizations use data? Data management is always a work-in-progress!

Answer 30

 As senses and alerts to identify threats and opportunities - Relevant and timely  As evidence and input for decisions and analysis - Standardized and legitimate  As common language for collaboration and communication - Consistent across different users and departments  As organization of work and responsibilities - Clear roles and authorizations for access and manipulation

Question 31

Integrity constrain

Answer 31

rules embedded in the database management system that help ensure the quality of information  Relational integrity constraint – rule that enforces basic and fundamental information-based constraints  Business - critical integrity constraint – rule that enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraints

Question 32

Increased scalability and performance

Answer 32

A database must scale to meet increased demand, while maintaining acceptable performance levels  Scalability – refers to how well a system can adapt to increased demands  Performance – measures how quickly a system performs a certain process or transaction

Question 33

Data standardization/centralization allows for consistency, but it is not a trivial task

Answer 33

 Different systems may use different data standards (e.g. SCM partners)  Data from third parties may not be standardized or aligned with an organization’s data standards (e.g. sources on the Internet)  Online customers may feed the system with incorrect data due to privacy concerns  Employees may seek shortcuts in data entry, such as abbreviations  Different parties may wish to defend their own standard

Question 34

Most DBMS enforce (or at least give the option to enforce) rules to achieve consistency

Answer 34

 Validation rules for data entry |  Business rules for entity relationships

Question 35

Validation rules

Answer 35

work to standardize data structure (formatting, character limitations, mandatory data input, etc.) eg. “Phone number of a customer must include area code”

Question 36

Business rules

Answer 36

enforce logical relationships across entities. | eg.“Each part can be provided by only one supplier”