2. The Database Environment Flashcards

1
Q

What are the components of the database environment?

A
  1. Users
  2. Database management system (DBMS)
  3. Physical database (including hardware and data)
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2
Q

What does the database management system diagram look like?

A

From multiple users -> multiple application softwares -> single database management software -> single physical database

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3
Q

What is the mnemonic for advantages of a database?

A

Red cost Intel secure independence, Stanley accessed.

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4
Q

What are the advantages of a database ?

A
  1. Reduced data redundancy
  2. Lower capturing costs, data entered once
  3. Integrity of data maintained, updates occur same place
  4. Increased security, centrally controlled
  5. Data is independent from application software
  6. Standardization of data structures
  7. Access to data is easy
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5
Q

What is the mnemonic for disadvantages of a database?

A

Costa complexly times failures

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6
Q

What are the disadvantages of databases?

A
  1. Costs to start up
  2. Complex to design and use
  3. Time-consuming to design
  4. Failure of the database would mean failure of application software and may result in shut down of organization
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7
Q

Who are the various database users?

A
  1. End user
  2. Application programmer
  3. Database administrator
  4. Data administrator
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8
Q

How do end users use the database?

A

They capture data and extract informatiom

Low skill level, they use application software

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9
Q

What are application programmers responsible for?

A

Creating, maintaining, updating and managing application and DBMS software

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10
Q

What is the responsibility of the database administrator?

A

Managing and controlling the database

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11
Q

What is another name for a data administrator?

A

Database analyst

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12
Q

What are data administrators responsible for?

A

Controlling and managing data

Manage integrity of data by setting standards

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13
Q

What is DBMS?

A

Integrated set of software that provides a user friendly interface to users

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14
Q

What is an example of DBMS?

A

Microsoft access

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15
Q

What are the levels of the three-level database architecture?

A
  1. External level
  2. Conceptual level
  3. Internal level
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16
Q

What is another name for the external level of architecture?

A

User view

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17
Q

What is the external level?

A

End users view of data and database

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18
Q

How many view can the external view have?

A

An infinite amount

E.g. Cash clerk will have a different input screen than a credit sales clerk etc.

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19
Q

What is the conceptual level?

A

A complete view of the entire database and all the data

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20
Q

Who normally uses the conceptual view?

A

The database administrator

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21
Q

How many variations are there of the conceptual view?

A

Only one

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22
Q

What is another name for the internal level?

A

Physical view

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23
Q

What is the internal view?

A

It is the low level view of how the data is stored physically. E.g. Harddrive etc.

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24
Q

How many physical views are there?

A

Only one

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25
Q

How is binary code concerned with the physical view?

A

Binary code is only one facet of the physical view

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26
Q

Who updates and manages all levels of database architecture?

A

The database administrator

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27
Q

What are the key components of the DBMS?

A
  1. Data dictionary

2. Data language

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28
Q

What is a data field?

A

A single data value, it is the smallest unit of data

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29
Q

What is a data dictionary?

A

Contains records for each data field and provides detailed description of each data field

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30
Q

What are database languages used for?

A

The users to interact with the database

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31
Q

What are the database languages included?

A
  1. Data definition language
  2. Data control language
  3. Data manipulation language
  4. Data query language
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32
Q

What is SQL?

A

Structured query language and combines all previously mentioned languages

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33
Q

What is the data definition language used for?

A

Define a database and includes commands to:

  1. Create, modify and delete database and it’s objects
  2. Define and describe data structure
  3. Create data dictionary
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34
Q

What are data objects?

A
  1. Tables
  2. Views
  3. Rules
  4. Indexes
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35
Q

Who usually uses DDL?

A

The administrator

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36
Q

What is the purpose of the data control language?

A

Used to control security and access to database objects and data

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37
Q

Who uses the DCL?

A

Only the database administrator

38
Q

What is DML used for?

A

Used to insert, maintain, delete and modify data store in database

39
Q

Who uses the DML?

A

All users of the database. Usually used through application software

40
Q

What is the difference between the DDL and DML?

A

The DML is for the data stored where DDL is for the objects on the databas

41
Q

What is DQL used for and who uses it?

A

Used to extract information and used by all users

42
Q

What is the definition of a database?

A

Organized collection of related data that is stored and managed electronically and can provide data to different application software

43
Q

What is a database model?

A

Theoretical data structure

44
Q

What are the different database models?

A
  1. Hierarchical
  2. Network
  3. Object-orientated
  4. Relational
  5. Multidimensional
45
Q

What relationship does a hierarchical database model have?

A

One-to-many relationship

46
Q

What is wrong with the hierarchical model?

A

It is very inflexible

47
Q

What is an example of a hierarchical model?

A

Microsoft windows explorer

48
Q

What kind of relationship does a network model have?

A

A many-to-many relationship. Data can be accessed through different paths

49
Q

Is the network model used often?

A

No it’s mostly obsolete now

50
Q

What is a relational model?

A

Data is stored on two dimensional rows and columns like a table

51
Q

What is a disadvantage of relational model?

A

It processes data slower and slower to retrieve data

52
Q

What are the benefits of relational model?

A
  1. Data can be modified without changing the data structure
  2. Structure can be easily customized
  3. Data doesn’t need to be duplicate
  4. Most users can easily understand it
  5. It is easy to find data
53
Q

What is object-orientated model?

A

Where data and it’s operations are stored in the database

54
Q

What is a benefit of object-orientated model?

A

Is can process more type of data like images, audio, video etc.

55
Q

Where would object-orientated models be used?

A

For more specialized databases such as multimedia web based applications and molecular biology databases and defense industries.

56
Q

What is a disadvantage of object-orientated model?

A

Expensive to implement and most businesses wouldn’t need to process all types of data besides text

57
Q

What is a multidimensional databases?

A

It’s like a relational model but with more dimensions.

58
Q

What does the multidimensional model look like?

A

It has a cube-like structure

59
Q

What is an advantage of multidimensional database?

A

Easy to maintain

60
Q

What is multidimensional model used for?

A

Mainly for data warehouses

61
Q

What does multidimensional models give rise to?

A
  1. Business intelligence software

2. Online analytical processing

62
Q

What are the classifications of physical location of storage?

A
  1. Centralized

2. Distributed

63
Q

What is centralized database?

A

All data is stored in one location e.g. A server

64
Q

How do users interact with a centralized database?

A

Through networks

65
Q

What is an advantage of centralized database?

A

All data is immediately up to date

66
Q

What kind of input and processing is used for centralized database?

A
  1. Online input

2. Real-time processing

67
Q

What are distributed databases?

A

Several interlinked databases tried on different computer in different locations

68
Q

What are the two different distributed databases?

A
  1. Partitioned

2. Replicated

69
Q

What is a partitioned database?

A

A database split into smaller parts and the parts applicable to certain users will be made available to them at the nearest location

70
Q

When would a partitioned database generally be used?

A

When there is a minimal necessity for users to share data

71
Q

Example of places using partitioned database?

A

Branches don’t need to share customers info with each other

72
Q

What is a replicated database?

A

Where the original database is replicated to all locations

73
Q

Example of business using replicated database?

A

Pharmacy nationwide, where customers have scripts

74
Q

What are the methods to update different replicated databases?

A
  1. Duplication

2. Synchronization

75
Q

What is duplication?

A

Where master database is duplicate to all other databases at a specific frequency
Rewrites all databases

76
Q

What is synchronization?

A

This involves a two way update between master database and distributed databases

77
Q

What is the most common database model used?

A

Relational database

78
Q

What is a data value?

A

Characters that populate a data field

79
Q

What is a data field?

A

Contains data value

Similar to a cell

80
Q

What is an attribute?

A

Similar to a column in spreadsheet

81
Q

What is a field name?

A

The name of all attributes

82
Q

What is a data record?

A

A row

83
Q

What is a primary data field?

A

Primary key

Unique data field that identify data records

84
Q

What is a foreign key?

A

A data field entered into another data record to create a relation between the two

85
Q

What are the purpose of foreign keys?

A

To prevent duplication of data

86
Q

What is a database file?

A

Also known as database table

Collection of data records

87
Q

What are the types of database files?

A
  1. Master
  2. Transaction
  3. Reference
  4. Histroy
88
Q

What is a master file?

A

Data records that contain info of a semi-permanent nature. They don’t change regularly.

89
Q

What info is contained in master files?

A

Info about organizations sources and subjects.

E.g. Customers, suppliers, inventory, employees

90
Q

What are transaction files?

A

Files containing records relating to daily activities. They change regularly