Module 1: Introduction to Databases and Transactions Flashcards

1
Q

Is shared collection of logically related data (and a description of this data), designed to
meet the information needs of an organization

A

Database

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2
Q

Database is composed of:

A

Entities and Relations

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3
Q

Is a collection of application programs that perform services for the end users
such as the production of reports

A

File-based System

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4
Q

5 Limitations of the File-based Approach

A
  1. Separation and Isolation of Data
  2. Duplication of Data
  3. Data Dependence
  4. Incompatible File Formats
  5. Fixed Queries/Proliferation of Application Programs
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5
Q

The Limitations of the File-based Approach can be attributed to two factors:

A
  1. Definition of data embedded in the application programs, rather than being stored separately
    and independently
  2. There is no control over the access and manipulation of data beyond that imposed by the
    application programs
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6
Q
  • Is software designed to assist in maintaining and
    utilizing large collections of data
  • A general-purpose software system that facilitates the processes of defining,
    constructing, & manipulating databases for various applications
A

Database Management System or DBMS

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7
Q

A database involves specifying the data types, structures, and constraints for the
data to be stored in the database

A

Defining

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8
Q

The database is the process of storing data itself on some storage medium that
is controlled by the DBMS

A

Constructing

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9
Q

A database includes such functions as querying the database to retrieve specific
data, updating the database to reflect changes in the miniworld, & generating reports from
the data

A

Manipulating

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10
Q

Is a software that enables user to define, create and maintain that database and which
provides controlled access to the database

A

DBMS

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11
Q

DBMS provides the following facilities:

A
  • Allows users to define the database through DDL (Data Definition Language)
  • Allows user to insert, update, delete and retrieve data through DML (Data Manipulation
    Language)
  • Provides controlled access to the database.
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12
Q

Provides controlled access to the database

A

DBMS

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13
Q

DBMS may provide:

A
  • A security system, which prevents unauthorized users from accessing the database
  • An integrity system, which maintains the consistency of stored data
  • A concurrency control system, which allows shared access of the database
  • A recovery control system, which restores the database to a previous consistent state following a hardware or software failure
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14
Q

What are we going to cover?

  • How do we represent the world with a database?
A

Database Design and Application Development

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15
Q

What are we going to cover?

  • How can we answer questions about enterprising this data?
A

Data Analysis

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16
Q

What are we going to cover?

  • How does a DBMS allow many users to access data concurrently, and
    how does it protect against failures?
A

Concurrency and Robustness

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17
Q

What are we going to cover?

  • How does the database cope with large amounts of data?
A

Efficiency and Scalability

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18
Q

Who created the first general purpose DBMS Integrated Data Store, where and when?

A

Charles Bachman; at GE; early 1960s

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19
Q

It creates the basis for the network model (standardized by CODASYL)

A

DBMS Integrated Data Store

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20
Q

Develops the Information Management System (IMS)

A

IBM

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21
Q

_____ uses and alternate model, called the _____.

A

Information Management System (IMS); Hierarchical Data Model

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22
Q

Is created around IMS

A

SABRE

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23
Q

Who from IBM creates the relational data model and when?

A

Edgar Codd; 1970

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24
Q

In _____, Codd receives the _____

for his contributions to database theory.

A

1981; Turing Award

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25
Q

In _____, _____ developed by IBM, becomes the standard query language for databases

A

1980s; SQL

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26
Q

SQL is

standardized by

A

ISO

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27
Q

In _____ and _____, IBM, Oracle, Informix and others develop powerful _____.

A

1980s and 1990s; DBMS

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28
Q

In the _____, DBMS are showing how useful they can be.

A

Internet Age

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29
Q

4 Forms of Data

A
  1. Text
  2. Image
  3. Audio
  4. Video
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30
Q

4 Data Sources

A
  1. PC
  2. Web
  3. Phone
  4. Bar Code
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31
Q
  • Are data that describe the properties of data (but do not include that data)
  • Allow database designers & users to understand what data exist, what the data mean
    and what the fine distinctions are between seemingly similar data items
A

Metadata

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32
Q

12 Advantages of Why we use DBMS

A
  1. Control of data redundancy
  2. Data consistency
  3. Sharing of data
  4. Data integrity and security
  5. Enforcement of Standards
  6. Economy of scale
  7. Balanced conflicting requirements
  8. Data independence
  9. Efficient data access
  10. Data administration
  11. Concurrent access and crash recovery
  12. Reduced application development time
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33
Q

7 Disadvantages of Why we use DBMS

A
  1. Complexity
  2. Size
  3. Cost of DBMS
  4. Additional hardware costs
  5. Cost of conversion
  6. Performance
  7. Higher impact of a failure
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34
Q
  • Is responsible for the management of the data resource including database planning, development
    and maintenance of the standards, policies and procedures and logical database design
  • Consults with and advises senior managers, ensuring that the direction of database development will
    ultimately support corporate objectives
A

Data Administrators

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35
Q

Is responsible for the physical realization of the database system, including physical database design
and implementation, security and integrity control, maintenance of the operational system and
ensuring satisfactory performance for the applications and users.

A

Database Administrators

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36
Q

Two Types of Designers

A
  1. Logical Database Designer

2. Physical Database Designer

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37
Q
  • Is concerned with identifying the data, the relationships between data and the constraints on
    the data that is to be stored in the database.
  • Must have a thorough and complete understanding of the organization’s data andof the
    business rules.
A

Logical Database Designer

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38
Q

Takes the logical data model and decides how it is to be physically realized

A

Physical Database Designer

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39
Q

Physical database designer involves:

A
  • Mapping the logical data model into a set of tables and integrity constraints;
  • Selecting specific storage structures and access methods for the data to achieve
    good performance for the database activities;
  • Designing any security measure required on the data.
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40
Q
  • Responsible in the implementation of the application programs that provide the required
    functionality for the end users.
  • Work from the specification produced by systems analyst.
A

Application Programmers

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41
Q
  • Are the clients for the database – the database has been designed and implemented, and is being maintained to server their information needs.
A

End Users

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42
Q

End users can be classified according to the way they use the system:

A
  1. Naive Users

2. Sophisticated Users

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43
Q
  • Are typically unaware of the DBMS.
  • They invoke database operations by entering simple commands or choosing options
    form a menu.
A

Naive Users

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44
Q
  • Familiar with the structure of the database and the facilities offered by the DBMS.
  • May use a high-level query language such as SQL to perform the required operations.
A

Sophisticated Users

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45
Q

Is a collection of high level description constructs that hide many low-level
storage details

A

Data Model

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46
Q

Most current DBMS use the _____.

A

Relational Data Model

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47
Q

The central data description in this model is the _____ (_____ - same as in set theory mathematics).

A

Relation; A Set of Tuples

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48
Q

For convenience, we refer to each tuple as a _____.

A

Row

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49
Q

Is a description of the data in terms of the data model

A

Schema

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50
Q

In the relational model the

schema looks like:

A

RelationName(field1 : type1, …, fieldn : typen)

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51
Q
  • Is the abstract graphical representation of an enterprise

- Usually the beginning of database development

A

Enterprise Data Model

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52
Q

Is language-independent. It can be drawn using a pen and a paper.

A

Data Modeling

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53
Q

Purpose of Enterprise Data Model

A

It creates an overall picture or explanation of organizational data NOT the design of the database

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54
Q

4 Data Modeling Tools

A
  1. Entity Relationship Diagram
  2. Unified Modeling Language
  3. Data Flow Diagram
  4. Data Dictionary
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55
Q

6 Components of Information System Architecture (ISA)

A
  1. Data
  2. Processes
  3. Network
  4. People
  5. Events and Point in Time
  6. Reasons
56
Q

Component of Information System Architecture that may be represented as ERD

A

Data

57
Q

Component of Information System Architecture that manipulate data; represented by DFD, object-models with methods or other notations

A

Processes

58
Q

Component of Information System Architecture that transports data around & between organizations and business partners

A

Network

59
Q

Component of Information System Architecture that the source & receiver of data / information and performs processes

A

People

60
Q

Component of Information System Architecture that shows when processes are performed (e.g State-Transition
Diagrams)

A

Events and Point in Time

61
Q

Component of Information System Architecture that shows events & rules governing the processing of data. Some diagramming
tools exist for rules (e.g decision tables)

A

Reasons

62
Q

It is a formal methodology in creating and maintaining information system

A

Information Engineering

63
Q

2 Classifications of Information Engineering

A
  1. Bottom-up Planning

2. Top-down Planning

64
Q

Projects are requested by IS users who need certain info to do their job

A

Bottom-up

65
Q

Generic IS planning methodology that attempts to gain a broad understanding of the IS needs of
the entire org

A

Top-down

66
Q

4 Steps of Top-down

A
  1. Planning
  2. Analysis
  3. Design
  4. Implementation
67
Q

Results in an IS architecture, including an enterprise model (INFO. SYSTEM PLANNING)

A

Planning

68
Q

Is the road map setting the direction of systems development

A

Information System Planning (ISP)

69
Q

The Goal of Information Systems Planning

A

To align IT with the business strategies of the organization

70
Q

Goal: Business Alignment Steps:

A
  1. Identify strategic planning factors
  2. Identify corporate planning objects
  3. Developing an enterprise model
71
Q

Goal: Business Alignment Steps:

  • Goals
  • Critical Success Factors
  • Problem Areas
A

Identify Strategic Planning Factors

72
Q

Goal: Business Alignment Steps:

  • Identifying corporate planning objects is also called as enterprise analysis.
  • It requires the analysis of organization-wide information requirements in terms of organizational units, functions and processes and information requirements
A

Identify Corporate Planning Objects

73
Q

Are various departments, branches or program areas in the

organization

A

Organizational Units

74
Q

Geographic locations of business units where business

operations occur

A

Organizational Locations

75
Q

Related groups of business processes that support the mission of the organization

A

Business Functions

76
Q

Major categories of data about people, places, events & things managed by the organization. Key attributes are also discussed in this section

A

Entity Types

77
Q

Application software & supporting procedures for handling sets of
data

A

Information System

78
Q

Goal: Business Alignment Steps:

Contains:

  • Functional decomposition
  • Entity Relationship Diagram
  • Planning matrix
A

Developing an Enterprise Model

79
Q

Process of breaking down the functions of an organization into progressively greater level of details

A

Functional Decomposition

80
Q

Used to describe Enterprise model by depicting the entity types, relationships between entities & how business operates. (BUSINESS RULES - govern the validity of data)

A

Entity Relationship Diagram

81
Q

Shows Inter-relationships between planning objects

A

Planning Matrix

82
Q

8 Alternative Systems Building Approaches

A
  1. Traditional Systems Development Lifecycle
  2. Rapid Application Development (RAD)
  3. Prototyping
  4. Computer-Aided Software Engineering Tools
  5. Integrated-CASE (I-CASE) Tools
  6. Application Software Packages
  7. Outsourcing
  8. End User Development
83
Q

– Also known as the SDLC
– Methodological, Highly Structured
– Includes many checks & balance

A

Traditional Systems Development Lifecycle

84
Q

– Iterative process of rapidly repeating analysis, design & implementation steps until desired system is acquired

A

Rapid Application Development (RAD)

85
Q

RAD works best when:

A
  • Most of the database needed already exists

- Systems that primary retrieve data

86
Q

– Process of building experimental system quickly and inexpensively for demonstration &
evaluation
– Iterative
– May be used as an alternative to the systems development life cycle

A

Prototyping

87
Q

Software that provides automated support for some portion of the systems development process

A

Computer-Aided Software Engineering Tools

88
Q

3 Features of Computer-Aided Software Engineering Tools

A
  1. Ability to draw data models using entity relationships & other notations (ensures consistency
    across diagrams)
  2. Ability to generate codes (database definition commands to be given to DBMS)
  3. Information Repository
89
Q
  • Provides support across whole life-cycle but such tools are rarely used since they tend to be strong in supporting certain phases but weak in supporting other phases of the system
  • Created as case tool that has the ability to share the metadata that are developed during each stage of the process
A

Integrated-CASE (I-CASE) Tools

90
Q

Set of prewritten, precoded application software programs commercially available for sale or lease.

A

Application Software Packages

91
Q

Application Software Packages requires _____.

A

customization

92
Q

Contracting computer center operations, telecommunications networks, or applications development to external vendors

A

Outsourcing

93
Q
  • Development of information systems by end users with little or no formal assistance from technical specialists
  • Allows users to specify their own business needs
A

End User Development

94
Q

Describes the data stored in the database

A

Conceptual Schema

95
Q

Creating a good conceptual schema is not a simple task, and it is called _____.

A

Conceptual Database Design

96
Q

Conceptual Database Design involves:

A
  • Determining the different relations needed
  • The number of fields per relation
  • The type of each field
97
Q

Specifies how the relations are actually stored in secondary storage devices

A

Physical Schema

98
Q

Physical Schema also specifies _____ used to speed up the access to the relations

A

Auxiliary Data Structures (Indexes)

99
Q

Decisions about the physical schema depend upon:

A
  • Understanding how the data is going to be accessed

- The facilities provided by the DBMS

100
Q

2 Examples of Physical Schema

A
  1. Store all relations in unsorted files of records

2. Create indexes in the first column of every relation, and in the sal column of faculty

101
Q

Is a refinement of the conceptual schema

A

External Schema

102
Q

Every database has _____ conceptual and _____ physical schema, but it can have _____ external schemas

A

one; one; many

103
Q

Each external schema:

A

Users

104
Q

External Schema is tailored to a particular group of users consists of _____ of the conceptual schema

A

one or more views and relations

105
Q

Is conceptually a relation, but its records are not stored in the database; instead, they are computed from other relations.

A

View

106
Q

Means that programs are isolated from changes in the way the data is structured and stored.

A

Data Independence

107
Q

Users are shielded from the logical structure of the data (e.g. a relation is split into 2 or more)

A

Logical Data Independence

108
Q

As long as the conceptual schema remains the same, we can change the storage details of the application without affecting the user

A

Physical Data Independence

109
Q

Example of External Schema

A

CourseInfo(cid: string, fname: string, enrollment: integer)

110
Q

Data for an IS may reside in _____ to balance various organizational and technical factors

A

multiple locations or tiers of computers

111
Q

Three-tier Database Architecture:

  • Desktop or laptop computer which concentrates on managing the user-system interface and localized data
A

Client-tier

112
Q

Three-tier Database Architecture:

  • Performs calculations and provides access to data shared within the workgroup
A

Department (Workgroup) Minicomputer Server Tier

113
Q

Three-tier Database Architecture:

  • Performs sophisticated calculations and manages the merging of data from multiple sources across the organization
A

Enterprise Server (Minicomputer or Mainframe) Tier

114
Q

_____ in which database SW on a server (called _____) performs database commands sent to it from client workstations and application programs on each client concentrate on user interface functions

A

LAN-based Environment; Database Server or Database Engine

115
Q

5 Advantages of LAN-based Environment

A
  1. Allows for simultaneous processing on multiple processors for the same application.
  2. Possible to take advantage of the best data processing features of each computer platform.
  3. Can mix client tech (kiosks, networked PCs) while sharing common data.
  4. Processing can be performed close to source of processed data thus improving response times & reducing network traffic.
  5. Allows open-system standard.
116
Q

Why do we need a DBMS?

A

To answer queries

117
Q

A _____ provides a specialized language, called _____ to ask questions to the DBMS

A

DBMS; Query Language

118
Q

When several users access (and possibly modify) a database concurrently, the DBMS must order their request carefully to avoid _____

A

conflicts

119
Q

DBMS should also protect users from _____.

A

system failures

120
Q

DBMS should deal with crashes in the _____ of a _____.

A

middle; transaction

121
Q

Is a conceptually indivisible group of operations that a user wants to perform (for example, getting transferring money from one account to another)

A

Transaction

122
Q

An important task of a DBMS

A

Is to schedule concurrent accesses in a way that every user can ignore the fact that others are accessing the data at the same time

123
Q

A DBMS allows user to think that their programs are executed in _____

A

isolation

124
Q

Has to be implemented to allow transactions to be interleaved

A

Locking

125
Q

Allow several transactions to hold (and access) an object at the same time

A

Shared Locks

126
Q

Only one transaction can hold the object

A

Exclusive Locks

127
Q

The DBMS maintains a _____ of everything it writes

A

log

128
Q

The log is created _____ the operation is done: _____

A

before; write-ahead log

129
Q

Example of a Conceptual Schema

A

Students(sid:string, name: string, login: string, age: integer, gpa: integer,gpa: real)

Faculty(fid: string, fname:string, sal: real)

Courses(cid: string, cname: string, credits: integer) Teaches(fid: string, cid: string)

Enrolled(sid: string, cid: string, grade: string)

130
Q

Relational Data Model Example (A Relation of Students)

A

Students(sid : string, name : string, age : integer, gpa : real)

131
Q

File-based Sample for Sales Files

A

Property_for_Rent (Property Number, Street, Area, City, Post Code, Property Type, Number of Rooms, Monthly Rent, Owner Number)

Owner (Owner Number, FirstName, LastName, Address, Telephone Number)

Renter (Renter Number, FirstName, LastName, Address, Telephone Number, Preferred Type, Maximum Rent)

132
Q

File-based Sample for Contracts Files

A

Lease (Lease Number, Property Number, Renter Number, Monthly Rent, Payment Method, Deposit, Paid, Rent StartDate, Rent Finish Date, Duration)

Property_for_Rent (Property Number, Street, Area, City, Post Code, Property Type, Number of Rooms, Monthly Rent, Owner Number)

Renter (Renter Number, FirstName, LastName, Address, Telephone Number, Preferred Type,
Maximum Rent)

133
Q

File-based Sample for The Personnel Department also Stores Staff Details, namely:

A

Staff(Staff Number, FirstName, LastName, Address, Telephone Number, Position, Sex, Date of Birth, Salary, National Insurance Number, Branch Number)

134
Q

Can present a consistent, unchanging picture of the structure of the database, even if the underlying database is changed (for example, fields added or removed, relationships changed,
files split, restructured or renamed).

A

View

135
Q

If fields are added or removed from a file, and these fields

are not required by the view, the view is _____.

A

not affected by this change

136
Q

A view helps provide

the _____.

A

Program-data Independence