Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CS 6400 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Naming rules

A

Singular names are used for entities

Nouns are entity types, verbs are relationship types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Complex attributes

A

More than one residence with multiple parts of the address

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are important aspects of a model?

A

Only emphasizes selected aspects of the real world

Is described in some language

can be erroneous

may have features that do not exist in reality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Relationship

A

Defines a relationship set
Example: “WORKS_FOR” relationship
Degree of relationship is the number of participants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What may be a reason NOT to use a Database Management System?

  1. Need to support multiple users
  2. Need for persistent storage of data
  3. The overhead of providing security, concurrency control, recovery and integrity control
  4. Need for data independence
A
  1. The overhead of providing security, concurrency control, recovery and integrity control
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Differences between databases and file processing

A

Each user maintains separate files and programs to manipulate those files

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the difference between schema and data

A

A schema describes the intention of the data. The data describes the extension. Data is information about reality.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is atomicity? (in terms of DBMS transactions)

A

either everything in a transaction is executed or nothing is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a schema

A

A structure described in a formal language supported by the database management system (DBMS). The term “schema” refers to the organization of data as a blueprint of how the database is constructed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a naive end user?

A

querying and updating (posting withdrawals at a bank)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the workers behind the scenes?

A

They are not interested in the content of the database.

DBMS system designers and implementer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Transaction

A

executing program that includes database access (reading or writing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How to draw an attribute?

A

oval attached by straight line to entity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ternary degree

A

Supplier, part, project

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Program-operation independence

A

the user can operate on the data by using functions regardless of how the operations are implemented

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is controlling redundancy

A

Make sure data is not in more than one place.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

DBMS interfaces

A

Menu based interface

Apps for mobile devices

Forms based interface

GUI

Natural language interfaces

Keyword-based database search

Speech input and output

Interfaces for parametric use

More advanced interfaces for the DBA (privileged commands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What definition languages do SQL represent?

A

SQL represents DDL, VDL, and DML. SDL used to be part of it but was removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Entity set / entity collection

A

All EMPLOYEE entities in the company

Entity type describes schema (intention) for a set of entities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Completeness (total) constraint (optional)

A

Every entity in a superclass must be a member of at least one subclass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Union Types

A

OWNER can be a COMPANY, a BANK, or a PERSON
It can be one of multiple entity types, but not more than one at once.
Only inherits one of the types, not all of them
Some models don’t have union sets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Total specialization

A

if every entity must be a member of a subclass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a casual end user of a database

A

occasionally use data but need help

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

NULL values

A

Doesn’t apply, for example: maiden name for a man or apartment number for a single family home
Both known and unknown nulls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Generalization

A 
Generalizing several classes into a common super class
Superclass is an IS-A relationship
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How to draw key attribute

A

they have their names underlined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Program-data independence

A

In file processing, changes to the file require changes to the application programs. Databases have program-data independence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Database system utilities

A

Loading: loading data files. Conversion tools to transfer from one DBMS to another
Backup: backup and restore
Database storage reorganization: for optimizing performance
Performance monitoring: database usage and gives stats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Recursive relationships

A

An employee can supervise another employee

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

In simplest terms, what is a database?

A

A model of reality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Key attributes

A

Key uniqueness constraint
“Name” can be unique key of COMPANY since no two companies can have the same name
PERSON can have a social security number
Some entities have more than one key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Association

A

Objects from several independent classes

IS-ASSOCIATED-WITH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Knowledge representation

A

accurately modeling a domain of knowledge by creating an ontology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Give examples of constraints:

A

emails must be unique

emails are not allowed to be null

birthdate must be after 1900

hometown must be a city in the US

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

View

A

a perspective of data or virtual data of the database

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How to draw a partial key?

A

underlined with dotted line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is a collection of related data?

A

A database

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Total or partial category

A

Total category
Union of all entities in its superclass

Partial category
Subset of the union

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Design choices for ER conceptual design

A

Relationships can start as entities, and then be elevated as the design evolves
The inverse is true too

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How to draw weak attribute?

A

Double rectangle with entity in double diamonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Binary degree

A

One employee to one department

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Stored vs derived

attributes

A

Stored is storing the actual name

Derived is like calculating the age from the birth date

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Two Types of DML?

A 
High level DML (non-procedural)
Like SQL
Set at a time
Called the query language
End users typically use this

Low level (procedural)
Also called record-at-a-time dml
More like a programming language

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Data Model

A

an abstract model that organizes elements of data and standardizes how they relate to one another and to properties of the real world entities.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Defining a database

A

specifying the data types, structures, constraints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Conceptual representation

A

no details about how data is stored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Name 3 data models we will use in this class

A

Entity-Relationship model

Relational Model

Hierarchical Model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is physical data independence?

A

A measure of how much the internal schema can change without affecting the application programs.

The ability to change the schema at lower level (in ANSI/SPARC three level architecture) without affecting the schema at the next higher level is called data independence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is an entity?

A

A real world object or concept (employee or project)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Conceptual Schema?

A

Conceptual level describes the structure of the whole database for a group of users.
Conceptual schema is a representation of the entire content of the database.
These schema contains all the information to build relevant external records.
It hides the internal details of physical storage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Logical data independence

A

Change conceptual schema without having to change external schema
View of data report isn’t changed by how the grade_report file is structured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the software process

A

Analysis, Specification, Design, Implementation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Data Abstraction

A

Hides lower level data structures to only see essential views.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

3 Types of Schema?

A

External Schema: Use of data. As viewed by a user.

Conceptual Schema: Meaning of data

Internal Schema: Storage of data

External schema for user views.
Conceptual schema integrates external schemata.
Internal schema that defines physical storage structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Single vs multi-valued attributes

A

Single valued is age

Multi valued is like list of cities visited, names of siblings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Data model can be described using a class diagram using UML

A 
Class:  entity
Operation (what an object can do)
Domain:  data type
Association:  relationship
Link attribute:  relationship attribute
Class:  entity
Operation (what an object can do)
Domain:  data type
Association:  relationship
Link attribute:  relationship attribute
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Database Protection

A

protecting against malfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Client Module

A

a program that runs on a pc or mobile device. Has a user friendly UI to access information stored in the database

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Basic client/server architectures

A

Define specialized servers with specific functionality

For example, file server, print server, web, email servers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How does a system analyst use a database?

A

requirements of end users to develop specs for software

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Data definition language (DDL):

A

Define both internal and conceptual schemas

Passed into a DDL compiler

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Server Module

A

Handles data storage, search, etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What does a database administrator do?

A

Responsible for authorizing database access, monitoring its use, and dealing with software and hardware

Deals with performance, security breaches, etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Subtype

A 
Employee can be general type, but they can be specialized into secretary, technician, manager, etc
These are subclasses or subtypes of the employee
Subclasses have specialized attributes that their parent class doesn’t have
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Concurrency control

A

allows for multiple users to connect and update at the same time

For example, multiple airline agents booking seats at the same time. Called online transaction processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Entity Relationship Diagram

A

Shows entities, attributes and attributes

Attributes are simple vs composite, single vs multi values, stored vs derived

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the stages of database design?

A

Requirements specification and analysis: what is needed

Conceptual design

Logical design

Physical design

68
Q

Role names and recursive relationships

A

Role name: what the relationship means

Employee = employee/worker
Department = department/employer
69
Q

What are advantages of a DBMS system?

A 
good for data intensive apps
has persistent storage of data
has centralized control of data
has control of redundancy
has control of consistency and integrity
has multiple user support
has sharing of data
data documentation
data independence
control of access and security
backup and control
70
Q

Manipulating a database

A

querying and changing data

71
Q

Impedance mismatch problem?

A

data structures provided by the DBMS were incompatible with the programming languauge’s data structures

72
Q

Constructing a database

A

storing data into a database

73
Q

What is a key?

A

keys are uniqueness constraints

74
Q

4 possible constraints:

A

Disjoint total
Disjoint partial
Overlapping total
Overlapping partial

75
Q

Physical / Low Level data model

A

Details on how data is stored on the system.

76
Q

How to draw a component attribute

A

they are connected together

77
Q

Conceptual / High Level Data Models

A

Concepts close to the way many users perceive data.

Uses entities, attributes, and relationships.

78
Q

What is the Database Design Process?

A

Requirements collection and analysis
(Know data requirements and functional requirements)

Create conceptual schema for the database (conceptual design)

Logical design, data model mapping (create a database in the DBMS system)

Physical design
(Internal storage is specified)

79
Q

Identification

A

Some classes are uniquelty indentificable by an identifier
Identification distinguishes between classes and objects, and relates them to their real world counterparts
Based on system of unique names

80
Q

How were early databases designed differently?

A

Early databases mixed conceptual relationships with physical storage
Grades were stored next to student record
Difficult to reorganize and to add new types of queries
Only provided programming language interfaces

81
Q

Maintaining a database?

A

allowing the system to evolve as requirements change over time

82
Q

How to draw strong entity

A

rectangular box

83
Q

Specialization

A

Classifying a class into specialized subclasses

84
Q

View definition language (VDL):

A

Specifies user views and their mappings to conceptual schemas

85
Q

What does a Database Designer do?

A

Identifies data, designs structures to represent and store the data

Develops views of data

86
Q

Participation constraint

A

Minimum number of relationships

Employee must work for one company

87
Q

Metadata

A

data about the data

88
Q

Entity and Attributes differences?

A

Entity is a thing or object in the real world

Attribute: property that describes the entity

89
Q

DBMS component modules

A

Database and DBMS catalog are stored on disk controlled by the OS
Have own buffer management and stored data manager
Casual users will run interactive query interface
Query compiler changes them to an internal form
Query optimizer optimizes a query
Precompiler extracts DML commands
Runtime database processor: executes privileged commands, query plans, canned transactions
Concurrency control, backup and recovery systems as separate modules
Client program is on a separate computer. DBMS is on database server

90
Q

Centralized DBMS architectures

A

On older systems, all parts of the DBMS system were on one machine

91
Q

What is a surrogate?

A

A surrogate is a system generated artificial identifier for an entity. It represents an entity of the real world inside the database. It is immutable by the application programs. It is a unique identifier.

92
Q

How to draw entity relationship diagram

A

Regular strong entities are drawn in rectangular boxes
Relationships are diamond shaped boxes attached to participating entities with straight lines
Attributes are shown in ovals, attached by straight line to entity
Component attributes are connected together
Key attributes have their names underlined
Weak attributes are double rectangles with entities in double diamonds
Partial key underlined with dotted line

93
Q

DBMS data manipulation language (DML)

A

retrieval, insert, deletion, modification

94
Q

Bottom-up conceptual synthesis

A

We have staff, faculty, alumnus, student. And we create a generalized person from this list of existing entity types

95
Q

Referential integrity

A

A feature provided by relational database management systems (RDBMS’s) that prevents users or applications from entering inconsistent data. Most RDBMS’s have various referential integrity rules that you can apply when you create a relationship between two tables.

96
Q

Which of the statements does NOT describe differences between a database schema and a database state?

  1. A database schema is relatively stable over time while the database state changes over time
  2. A database state is relatively stable over time while the database schema changes over time
  3. A database schema described the structure of the data that constitutes the database state
  4. The database state can only be changed under the structures and rules described in the database schema
A
  1. A database state is relatively stable over time while the database schema changes over time
97
Q

Dynamic Aspect

A

A set of valid user defined operations allowed on database objects. For instance, compute GPA which can be applied to a student object.

98
Q

Disjointness constraints (optional)

A

Subclasses of the specialization must be disjoint sets

This means an entity can be a member of at most one subclass

99
Q

What is a Database Management System?

  1. A model of structures of reality
  2. A model of processes of reality
  3. A software system allowing you to define and use models of structures of reality
  4. An application system that accesses a database
A
  1. A software system allowing you to define and use models of structures of reality
100
Q

Three Schema Architecture

A

Internal level has internal schema to describe physical storage
Conceptual level has conceptual schema
Structure of database for community of users. Hides physical storage data
External schema (view level) hides database, only shows high level data

101
Q

Representational Data Model

A

An in between point between high and low level data models. Concepts that can be understood by end users but are not far away to the way data is stored.

102
Q

What is a standalone user?

A

maintain personal databases

103
Q

Top down conceptual refinement

A

Specialize a superclass into subclasses (employee into assistant, manager, etc)

104
Q

What is a sophisticated end user?

A

engineers, scientists, analysts, etc

105
Q

Issues when coming up with a database design

A 
Many specializations and subclasses can cause a model to become cluttered, so only choose the most important ones
If a subclass has few specific attributes, it can probably be merged into the superclass or added as a type
Unions should be avoided unless necessary
Overlapping and partial is the default constraint
106
Q

Properties of a database?

A

Represents the real world
Coherent with inherent meaning
Built for a specific purpose

107
Q

Carnality ratio

A

Maximum number of relationship instances an entity can participate in
Only can work for one department
1-1, 1-many, many-many

108
Q

Information Flow Diagram

A

Information flow showing boundaries of the system. NOT Control flow. Documents connect to tasks. Never connect two documents, and never connect two tasks.`

109
Q

Describe process modeling

A

The use of a model to represent processes of reality

processes may be embedded in program code or executed ad-hoc

110
Q

External Schema?

A

External level is related to the data which is viewed by individual end users.
This level includes a no. of user views or external schemas.
This level is closest to the user.
External view describes the segment of the database that is required for a particular user group and hides the rest of the database from that user group.

111
Q

When would we not want to use a DBMS?

A

When the initial investment in hardware, software, and training is too high

the generality of a database is not needed (overhead for security, concurrency, recovery, etc)

data and applications are simple and stable

real-time requirements cannot be met by it

multiple user access is not needed

112
Q

Database Normalization?

A

Storing data in only one place in the database

113
Q

Facts that can be recorded and have implicit meaning

A

data

114
Q

Three-Tier and n-Tier architectures

A

Adds an intermediate layer between client and database server
Middle tier is called application server or web server
Accepts requests and translates them to database requests
Can add multiple layers for additional abstraction

115
Q

Additional implications of using databases

A 
Potential to enforce standards 
Reduced application development time
Flexibility
Available up to date information
Economies of scale
116
Q

Internal Schema?

A

Physical level describes the physical storage structure of data in database.
It is also known as Internal Level.
This level is very close to physical storage of data.
At lowest level, it is stored in the form of bits with the physical addresses on the secondary storage device.
At highest level, it can be viewed in the form of files.
The internal schema defines the various stored data types. It uses a physical data model.

117
Q

How does an application programmer use a database?

A

Implement specs as programs, test, debug, document, maintain, etc the frontend for using databases

118
Q

User-defined specialization

A

if it’s up to the user not the attribute (defined manually for each entity)

119
Q

Classification

A 
Assigning similar objects to object classes
Instantiation:  is a member of, or is an instance of
Exception objects:  objects that differ from other objects in a class
Class properties:  properties that apply to a class as a whole and not to individual objects
EER cannot represent instances (only superclass, subclass)
120
Q

What is an access path?

A

Search structure that makes the search more efficient (directory structure).

121
Q

What does physical data independence allow you to do?

  1. Change the Conceptual Schema without changing the Internal Schema
  2. Change the Internal Schema without changing the Conceptual Schema
  3. Change the External Schema without changing the Conceptual Schema
  4. Change the Application Programs without changing the Internal Schema
A
  1. Change the Internal Schema without changing the Conceptual Schema
122
Q

What is data consistency?

A

Does the database have any internal conflicts? If not, then we have good consistency.

123
Q

Classification of Database Management Systems

A

By Data model

By Number of users

By Number of sites (centralized or distributed database)

By Homogeneous vs Heterogeneous

By Cost

By Types of access path

124
Q

What is data abstraction?

A

Data abstraction is the reduction of a particular body of data to a simplified representation of the whole. Allows for program-data independence and program-operation independence.

125
Q

Composite / molecular object

A

A combination of other types of classes

126
Q

What is data modeling?

A

fixing a perception of structures of reality and representing this perception

127
Q

shared subclass

A

Subclass with more than one superclass

128
Q

Basic Operations

A

A standard set of behaviors for retrieval and updates.

129
Q

What do database operations do

A

Operations support change and retrieval of data

insert a new user

select emails and birthdate

130
Q

What are the actors on the scene?

A

Database Administrators
Database Designers
End Users
Software Developers

They are interested in the specific content of the database

131
Q

How to draw a relationship?

A

a diamond

132
Q

What is an attribute?

A

A property about an entity (name of person, gender, address, etc).

133
Q

Tools, application environments, and communication facilities

A

Data dictionary system
Stores design decisions, usage standards, program descriptions (such as confluence)
Application development environment
Powerbuilder, jbuilder
Communication software
Allows people to log into databases to do work

134
Q

How to classify DB by data model?

A 
Relational data model (main)
Database is a collection of tables
Usually in SQL
Object data model (not widespread used)
Data is a collection of objects and their properties
Have methods (kind of like C++ classes)
Key-value storage (NOSQL)
Document based, graph-based, column-based, key-based
Gives unique key to each value
Document data model
Data is documents
Graph data model
Data is a series of nodes and edges
Column data model
Columns of rows scattered on disk
network data models (legacy)
Represents data as record types
Hierarchical (legacy)
Data is represented as a tree
No standard language
Object-relational DBMS
Tree structured (XML)
Standard on the web.  Elements with tags
135
Q

Attribute-defined specialization

A

If all subclasses in a specialization have their membership on the same attribute of the superclass (job type for example)

136
Q

Partial specialization

A

entity doesn’t have to be part of any subclass

137
Q

What are advantages of the DBMS approach?

A

Controlling redundancy
Access Control

Persistent storage for program objects

Storage Structures for efficient query processing

Provides for backup and recovery

Allows for multiple user interfaces

Represents complex relationships among data

Enforcing data integrity

Permitting inferencing and actions using rules and triggers

138
Q

Specialization hierarchies

A

There may be more than one level of specialization

Employee can subclass into programmer which can subclass into front-end developer

Every subclass must only have one class/subclass relationship (single inheritance)

139
Q

Storage definition language (SDL):

A

Specify internal schema

Mapping between the two is specified in any of them

140
Q

Database Application Development Methodology Assumptions:

A

Business Processes are Known

Documents are Known

Tasks are Known

System Boundary is known

One database schema unifying all views can be designed (difficult)

141
Q

What is a relationship?

A

An association between entities. For example, an employee entity works on a project entity.

142
Q

What is isolation? (in terms of DBMS transactions)

A

Isolation: each transaction is separate

143
Q

Having some redundant data to improve query performance?

A

Controlled redundancy

144
Q

Sharing a database

A

allowing multiple users to access

145
Q

Ontologies

A

An ontology is a specification or conceptualization
Conceptualization, a set of concepts and relationships that are part of reality
Specification: language used to specify the conceptualization

146
Q

Aggregation

A

Building composite obhejts from their componenent parts
IS-A-PART-OF, or IS-A-COMPONENT-OF
Car is a combination of seats, a steering wheel, and wheels

147
Q

What is a constraint?

A

Constraints express rules that cannot be expressed by the data structures alone.

148
Q

Attributes of relationship types

A

Works_on can have number of hours an employee worked on a project

149
Q

Generalization

A

If we have objects like a car and truck, we can generalize certain common features into a generalized super class

150
Q

What do anteaters eat?

A

ants

151
Q

Self Describing Data Model

A

Where the data storage combines the description of the data with the data itself (metadata + data)
XML, key-value stores, and NOSQL

152
Q

What do end users of a database do? How do they use a database?

A

Their job requires access to the database for querying, updating, generating reports, etc

153
Q

Value set (domain)

A

The range of values that may be used

154
Q

DBMS?

A

Database management system

A computerized system that allows users to create and maintain a database
Software system for defining, constructing, manipulating, and sharing databases

155
Q

Schemas

A

Need to distinguish between description of the database and the database itself
Database diagram: description of database
Eah object in the schema is a schema construct
The database in each moment in time is called a database state or snapshot. Current set of occurrences or instances
When we define a new database, we only define its schema (we have an empty state, no data)
Every time a database is updated, we get a new database state
Schema is not supposed to change frequently
Schema evolution: when adding new field of data (such as birthday field to a student object)

156
Q

Specialization lattice

A

Every subclass can have more than one parent (multiple inheritance)

157
Q

What is logical data independence?

A

Logical data independence is a measure of how much the conceptual schema can change without affecting the application programs.

The ability to change the conceptual schema, i.e, the overall database view without affecting the next higher level external schema, i.e. end users’ view of the database is logical data independence.

158
Q

Data independence

A

Capacity to change schema at one level without having to change schema at another

159
Q

Composite vs Simple attributes

A

Simple attributes are basic strings, values, etc

Composite attributes have multiple parts like different parts of an address (can be subdivided)

160
Q

Abstraction concepts

A

Classification, identification, specialization, aggregation

161
Q

Software Development Process when it comes to Datbases

A

Information Flow Diagram

Tasks

ER Diagram

Abstract code with SQL

Relational Schema

PHP code with SQL

MySQL Relational Platform

162
Q

What is data integrity?

A

Integrity means does data reflect reality well?

163
Q

Physical data independence

A

Ability to change internal schema without having to change conceptual schema
For example, improve performance of updating

164
Q

Data model is a data abstraction that supports what

A

data abstraction that supports the conceptual representation. Hides storage and implementation details

165
Q

Two-tier client

A

User interface and application programs were first moved to the user side
On server side, the query server (SQL server)
Client program communicates with server using ODBC (open database connectivity) via an API
For Java, JDBC is used

166
Q

Predicate defined subclass (condition defined)

A

If a job type is “secretary”, they could be part of the SECRETARY subclass

167
Q

Weak Entity Types

A

Entities that do not have key attributes of their own
Depends on a strong entity to exist
Partial key: can uniquely identify weak entities that are related to the same owner

CS 6400 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions