Lesson 2 Flashcards
1
Q
Data modeling
A
The process of creating a specific data model for a determined problem domain
2
Q
Problem domain
A
A clearly defined area within the real-world environment, with a well-defined scope and boundaries that will be systematically addressed
3
Q
A Data model:
A
- A representation, usually graphic, of a complex “real-world” data structure.
- Data models are used in the database design phase of the Database Life Cycle
4
Q
Entity
A
A person, place, thing, concept, or event for which data can be stored
5
Q
Attribute
A
- A characteristic of an entity or object.
- An attribute has a name and a data type.
6
Q
One-to-many (1:M or 1…*) relationship
A
- Associations among two or more entities that are used by data models.
- In a 1:M relationship, one entity instance is associated with many instances of the related entity.
7
Q
Many-to-many (M:N or …) relationship
A
Association among two or more entities in which:
- one occurrence of an entity is associated with many occurrences of a related entity &
- one occurrence of the related entity is associated with many occurrences of the first entity.
8
Q
One-to-one (1:1 or 1…1) relationship
A
1:1 means only two entities are involved, and each instance in one entity is related to only one instance in the other
9
Q
Constraint
A
A restriction placed on data, usually expressed in the form of rules
10
Q
- Each record from first table is associated with many records in second table
- But each record in second table is associated with one record in first table.
What type of relationship is it?
A
One-to-many (1:M) relationship
11
Q
Single record in the first table is related to only one record in the second table and vice versa.
What type of relationship is it?
A
One-to-one (1:1) relationship
12
Q
Each record from first table is associated with many records in second table and one record in second table is associated with many records in first table
What type of relationship is it?
A
Many-to-many (M:M) relationship
13
Q
Business rule
For example, a pilot cannot be on duty for more than 10 hours during a 24-hour period
A
A description of a policy, procedure, or principle within an organization.
14
Q
Hierarchical model
A
An early database model whose basic concepts and characteristics formed the basis for subsequent database development
15
Q
Segment
A
In the hierarchical data model, the equivalent of a file system’s record type
16
Q
Network model
A
An early data model that represented data as a collection of record types in 1:M relationships.
17
Q
Schema
A
A logical grouping of database objects, such as tables, indexes, views, and queries that are related to each other.
18
Q
Subschema
A
The portion of the database that interacts with application programs.
19
Q
Data manipulation language (DML)
A
The set of commands that allows an end user to manipulate the data in the database, such as SELECT, INSERT, UPDATE, DELETE, COMMIT, and ROLLBACK.
20
Q
Data definition language (DDL)
A
The language that allows a database administrator to define the database structure, schema, and subschema
21
Q
Relational database
A
a collection of relations that contain the data describing a particular business environment.
22
Q
Relational model
A
- Each relation (table) is conceptually represented as a two-dimensional structure of intersecting rows and columns.
- The relations are related to each other through the sharing of common entity characteristics (values in columns).
23
Q
Relation
A
A logical construct perceived to be a two-dimensional structure that represents an entity set in the relational model composed of:
- intersecting rows (entities)
- columns (attributes)
24
Q
Tables are somtimes called ______
A
Relation
25
Tuple
a table **row**
## Footnote
In the relational model
26
Relational database **management system** (RDBMS)
1. A collection of programs that manages a relational database.
2. The RDBMS software _translates_ a user's logical requests (**queries**) into **commands** that physically locate and retrieve the requested data
27
Relational diagram
A graphical representation:
1. A relational database's entities
2. The attributes within those entities (fields)
3. & the relationships among the entities.
28
Entity relationship (ER) Model
- A data model that describes *relationships among entities at the **conceptual level**.* with the help of ER diagrams.
- The model was developed by Peter Chen.
## Footnote
(1:1, 1:M, and M:N)
29
Entity relationship diagram (ERD)
A diagram that depicts an entity relationship model's *entities, attributes, and relations*.
30
Entity instance (entity occurrence)
A row in a relational table
31
Entity set
A collection of like entities
32
Connectivity
The type of relationship between entities. Classifications include 1:1, 1:M, and M:N.
33
What are the 3 types of ER notations?
- Chen notation
- Crow's foot notation
- class diagram notation
34
Crow's Foot notation
A representation of the entity relationship diagram that uses a three-pronged symbol to represent the "**many**" sides of the relationship.
35
In relational database tables, a _____ describes a row and an ______ describes a column of that table.
Tuple; Attribute
36
OODM
- Object-oriented data model
| - A data model whose basic modeling structure is an object
37
Object
An abstract representation of a **realworld entity** that has a *unique identity, embedded properties*, and the ability to interact with other objects and itself
38
Object-oriented database management system
- OODBMS
| - Data management software used to manage data in an object-oriented database model.
39
Semantic data model
1. The first of a series of data models that more closely represented the *real world*.
2. Models both *data and their relationships in a single structure* known as an **object**.
40
Class
- A collection of *similar objects with shared* structure (**attributes**) and behavior (**methods**).
- A class encapsulates an object's data representation and a method's implementation.
## Footnote
Classes are organized in a class hierarchy.
41
Method
## Footnote
OODM
- In the object-oriented data model, a named *set of instructions* to perform an action.
- Methods represent **real-world actions**, and are invoked through messages
42
Class hierarchy
The organization of classes in a hierarchical tree.
1. Each parent class is a superclass
2. Each child class is a subclass.
43
Inheritance
In the object-oriented data model, the ability of an _object_ to inherit the data structure and methods of the *classes above it* in the class hierarchy.
44
UML
- Unified Model Language
- A language based on **object-oriented** concepts that provides tools such as diagrams and symbols to graphically model a system.
45
Class diagram
A diagram used to represent *data and their relationships* in [UML object notation](https://share.evernote.com/note/bd14e8af-c018-4343-912c-924e9f87786b).
46
_____ is a highly distributed, fault-tolerant file storage system designed to manage large amount of data at high speed.
HDFS (Hadoop Distributed File System)
47
ERDM
Extended Relational Data Model
1. A model that includes the object-oriented model's *best features*.
2. Inherently simpler relational database structural environment.
48
Object/Relational DBMS (O/R DBMS)
- A DBMS *based on the extended relational* model (ERDM). The ERDM, championed by many relational database researchers, constitutes the relational model's response to the OODM.
- This model includes many of the object-oriented model's **best features** within an inherently _simpler_ relational database **structure**.
49
Big Data
1. A movement to find *new and better ways to manage* large amounts of web-generated data and derive business _insight_ from it.
2. Simultaneously providing high performance and scalability at a *reasonable cost*.
50
What are the 3 V's in big data databases
- Volume
- Velocity
- Variety
51
Hadoop
* A Java based, open source, high speed, fault-tolerant, **distributed storage** with a computational framework.
* It uses low-cost hardware to *create clusters of thousands of computer nodes* to store and process data.
52
HDFS
- Hadoop Distributed File System
- A highly distributed, fault-tolerant file storage system designed to manage *large amounts of data at high speeds*.
53
What are the three types of nodes that HDFS uses?
- Name node
- Data node
- Client mode
54
Name node
Stores all the metadata about the file system
55
Data node
The data node **stores** fixed-size data _blocks_
56
Client node
Acts as the **interface** between the user application and the HDFS
57
MapReduce
- API that allows organizations to *process massive data stores*.
- An open-source (API) that provides fast data analytics services.
## Footnote
application programming interface
58
NoSQL
A new generation of database management systems that is *not based on the traditional* relational database model.
59
Key-value (Data model)
composed of two data elements:
1. A key and a value.
2. Every key has a corresponding value or set of values.
## Footnote
AKA associative or attribute-value data model.
60
Sparse data
A case in which:
1. The number of table attributes is very large.
2. However the number of actual data instances is low.
61
Eventual consistency
A model for database consistency in which *_updates_ to the database will propagate through the system* so that all data copies will be consistent eventually
62
In Chen notation, entities and relationships have to be oriented $ ?
1. In Chen notation, entities and relationships can be oriented either horizontally or vertically.
2. There is no strict rule requiring a specific orientation.
63
A(n) _______ is anything about which data are to be collected and stored.
entity
64
Even when a good database blueprint is available, how should it be implemented?
A good database blueprint acts as a common language for _everyone_ who interacts with the data, ensuring alignment and efficiency.
65
In the context of data models, an entity is _?
An entity is a person, place, thing, or event *about which data* will be collected and stored.
66
What is a disadvantage of the hierarchical data model?
It does not have standards.
67
In object oriented terms, a(n) _____ defines an object's **behavior**
Method
68
The object-oriented data model was developed in the _______ . (What is the year?)
1980s
69
A(n) _______ enables a database administrator to describe schema components.
Data definition langauge (DDL)
70
A data model is usually graphical (T/F)
True
71
Each row in a relation is called a ____
Tuple
72
Which of the following types of HDFS nodes stores all the metadata about a file system?
Name node
73
A _____ is a collection of similar objects with a shared structure and behavior.
Class
74
A _____ defines the environment in which data can be managed and is used to work with the data in the database.
data manipulation language,DML
75
The hierarchical data model was developed in the _______.
1960s-1970s
76
In a SQL-based relational database, why are tables not dependent on every other table?
1. Relational databases use relationships, not dependencies.
2. Tables are linked by shared columns (**keys**) to combine data, but they don't depend on each other to exist.
77
Business rules apply to not only businesses, but what else?
1. Businesses & government groups
2. Religious groups
3. Research laboratories.
78
From a database point of view, *the collection of data* becomes meaningful only when it reflects properly defined _______
Business rules
79
Today, most relational database products can be classified _?
As object/relational
80
_______ are important because they help to ensure data integrity.
Constraints
81
Students and classes have a _______ relationship.
Many-to-many relationship
82
In essence, database designers may be experts in data management and optimization, but still rely on _ ?
1. Collaboration (Key)
2. Efficiency and Performance (their focus)
3. Business Analysts
83
A _____ ____ is a brief, precise, and unambiguous description of a policy, procedure, or principle within a specific organization.
Business Rule
84
In _____ a three pronged symbol represents the "many" side of the relationship.
Crows foot notation
85
In the _______ model, each parent can have many children, but each child has only one parent.
Hierarchical
86
An implementation-ready data model should contain __ ?
Contain a description of the data structure that will *store the end-user data*.
87
Why must Business rules must be updated?
updates reflect any change in the organization's operational environment
88
Each column in a relation represents a _____
Attribute
89
A verb *associating two nouns* in a business rule translates to a(n) _______ in the data model.
Relationship
90
A(n) _______ is bidirectional.
Relationship
91
The _______ model was developed to allow designers to use a **graphical tool** to examine structures rather than describing them with text.
Entity Relationship
92
A(n) _______ is a restriction placed on the data.
Constraint
93
Each row in the relational table is known as __?
Is known as an entity instance or entity occurrence
94
A ______ is a relatively simple representation of more complex real-world data structures.
Data Model
95
A(n) _______ represents a particular type of object in the real world.
Entity
96
Oracle 12c is an example of the _______.
XML/Hybrid data model
97
The relational data model was developed in the _______.
1970s
98
Within the database environment, what does a Data model do?
Represents data _structures_ with the purpose of supporting a *specific problem domain*.
99
A _____ in a hierarchical model is the equivalent of a record in a file system
Segment
100
The relational model is hardware-dependent and software-independent. (T/F)
False
101
The relational model's foundation is a mathematical concept known as a _____
Relation
102
A ______ is the conceptual organization of an entire database as *viewed by a database administrator*.
Schema
103
The _______ data model is said to be a semantic data model.
Object-oriented
104
The network model has __ level dependence.
structural level dependence
105
Each row in the relational table is known as a(n) ______
Entity instance
106
In the ____ model, the user perceives the database as *a collection of records in 1:M relationships*, where each record can have more than one parent.
Network
107
A noun in a business rule translates to a(n) _______ in the data model.
Entity
108
Which of the following types of HDFS nodes acts as the interface between the user application and the HDFS?
Client node
109
The _______ data model uses the concept of inheritance.
Object-oriented
110
In an SQL-based relational database, how are rows related?
rows in different tables are related based on *common values in common attributes*
111
The hierarchical model is software-independent. (T/F)
False
112
What is true about NoSQL databases?
- not based on the relational model and SQL
- support [distributed database architectures](https://share.evernote.com/note/59aff3a8-4456-761f-39a2-5cb26b1caac5).
- provide high scalability, high availability, and fault tolerance.
- support very large amounts of sparse data.
- are *geared toward performance* rather than transaction consistency.
113
Why are *M:N relationships* not appropriate in a relational model?
M:N relationships aren't directly used in relational databases because they cause *data redundancy and integrity issues*, and make queries complex.
## Footnote
Instead, we use associative
114
In the _______ model, the basic logical structure is represented as an upside-down tree.
Hierarchical
115
Why should an *implementation-ready data model* find it necessary to contain enforceable rules? 3
1. An implementation-ready data model must contain enforceable rules to guarantee data integrity.
2. These rules ensure data accuracy, consistency, and completeness.
3. Without them, the data is vulnerable to errors and inconsistencies, making it unreliable.
116
The _______ model uses the term connectivity to label the relationship types.
entity relationship
117
A(n) _______ is the equivalent of a field in a file system
attribute
118
MySQL is an example of the _______.
Relational data model
119
A(n) ______'s main function is to help one understand the complexities of the *real world environment*.
Model
120
VMS/VSAM is an example of the _______.
File system data model
121
What is kind of tool are **business rules** considered?
They can serve as a **communication tool** between the users and designers.
122
A disadvantage of the relational database management system (RDBMS) is its inability to hide the complexities of the relational model from the user. (T/F)
False
123
NoSQL databases provide ______ tolerance
Fault
124
_______ are normally expressed in the form of rules.
Constraints
