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C175 Data Management Foundations > Lesson 5 > Flashcards

Lesson 5 Flashcards

1
Q

atomic attribute

A

An attribute that cannot be further subdivided to produce meaningful components. For example, a person’s last name attribute cannot be meaningfully subdivided.

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2
Q

atomicity

A

The transaction property that requires all parts of a transaction to be treated as a single, indivisible, logical unit of work. All parts of a transaction must be completed or the entire transaction is aborted.

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3
Q

Boyce-Codd normal form (BCNF)

A

A special type of third normal form (3NF) in which every determinant is a candidate key. A table in BCNF must be in 3NF.

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4
Q

determinant

A

Any attribute in a specific row whose value directly determines other values in that row.

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5
Q

denormalization

A

A process by which a table is changed from a higher-level normal form to a lower-level normal form, usually to increase processing speed. Denormalization potentially yields data anomalies.

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6
Q

dependency diagram

A

A representation of all data dependencies (primary key, partial, or transitive) within a table.

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7
Q

first normal form (1NF)

A

The first stage in the normalization process. It describes a relation depicted in tabular format, with no repeating groups and a primary key identified. All nonkey attributes in the relation are dependent on the primary key.

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8
Q

fourth normal form (4NF)

A

A table is in 4NF if it is in 3NF and contains no multiple independent sets of multivalued dependencies.

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9
Q

granularity

A

The level of detail represented by the values stored in a table’s row. Data stored at its lowest level of granularity is said to be atomic data.

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10
Q

nonprime attribute

A

An attribute that is not part of a key.

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11
Q

normalization

A

A process that assigns attributes to entities so that data redundancies are reduced or eliminated.

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12
Q

partial dependency

A

A condition in which an attribute is dependent on only a portion (subset) of the primary key.

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13
Q

repeating group

A

In a relation, a characteristic describing a group of multiple entries of the same type for a single key attribute occurrence. For example, a car can have multiple colors for its top, interior, bottom, trim, and so on

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14
Q

second normal form (2NF)

A

The second stage in the normalization process, in which a relation is in 1NF and there are no partial dependencies (dependencies in only part of the primary key).

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15
Q

third normal form (3NF)

A

A table is in 3NF when it is in 2NF and no nonkey attribute is functionally dependent on another nonkey attribute; that is, it cannot include transitive dependencies.

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16
Q

transitive dependency

A

A condition in which an attribute is dependent on another attribute that is not part of the primary key.

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17
Q

Some very specialized applications may require normalization beyond the _____.

A

4NF

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18
Q

What must be eliminated for each row to define a single entity?

A

Repeating groups must be eliminated to ensure that each row represents a single entity.

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19
Q

What is the purpose of normalization in database design?

A

Normalization is used to organize data so that attributes are correctly assigned to entities, thereby reducing or eliminating data redundancies.

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20
Q

A table that has all key attributes defined, has no repeating groups, and all its attributes are dependent on the primary key is said to be in _____.

A

1NF

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21
Q

If a table in 1NF has a single-attribute primary key, what can be said about its compliance with 2NF?

A

A table with a single-attribute primary key in 1NF is automatically in 2NF because there cannot be any partial dependencies.

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22
Q

A relational table must not contain a(n) _____.

A

repeating group

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23
Q

When designing a database, you should _____.

A

make sure that the table entities are normalized before table structures are created

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24
Q

A dependency based on only a part of a composite primary key is called a _______

A

partial dependency

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25
Q

What condition must a table satisfy to be classified as in Boyce-Codd Normal Form (BCNF)?

A

A table is in BCNF if every determinant in the table is a candidate key.

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26
Q

What can reporting anomalies in a table lead to for managers?

A

‘Reporting anomalies can cause a multitude of problems for managers, and they generally require database design fixes rather than application programming to resolve.

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27
Q

What is true about a table in 2NF regarding transitive dependencies?

A

A table in 2NF may exhibit transitive dependency, where the primary key can rely on one or more nonprime attributes to functionally determine other nonprime attributes.

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28
Q

An atomic attribute _____ .

A

cannot be further subdivided

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29
Q

Granularity refers to _____.

A

the level of detail represented by the values in a table’s row

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30
Q

Attribute A _____ attribute B if all of the rows in the table that agree in value for attribute A also agree in value for attribute B.

A

determines

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31
Q

All relational tables satisfy the ______ requirements.

A

1NF

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32
Q

From a system functionality point of view, _____ attribute values can be calculated when they are needed to write reports or invoices.

A

derived

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33
Q

What is the objective of normalization in database design?

A

The objective of normalization is to ensure that each table conforms to the concept of well-formed relations, reducing redundancies and improving data integrity

34
Q

1NF, 2NF, and 3NF are _____.

A

normalization stages

35
Q

A table that is in 1NF and includes no partial dependencies is said to be in _____.

A

2NF

36
Q

In the ______, no row may contain two or more multivalued facts about an entity.

A

4NF

37
Q

Is normalization always a desirable aspect of database design?’

A

Normalization is important, but higher levels may not always be necessary for every database, depending on specific business requirements

38
Q

________ is a process that is used for changing attributes to entities.

A

Normalization

39
Q

What is the distinction between a partial dependency and a transitive dependency in database design?

A
  1. A partial dependency occurs when a nonprime attribute is dependent on only a part of a composite primary key.
  2. A transitive dependency arises when a nonprime attribute is dependent on another nonprime attribute, indirectly relating to the primary key
40
Q

What is incorrect about categorizing dependencies based on a part of a composite primary key?

A

‘Dependencies based on only a part of a composite primary key are called partial dependencies, not transitive dependencies.

41
Q

Data redundancy produces _____ .

A

data anomalies

42
Q

Dependencies can be identified with the help of a dependency ______.

A

diagram

43
Q

Before converting a table into 3NF, it is imperative that the table already be in _____.

A

2NF

44
Q

From a structural point of view, 2NF is better than _____.

A

1NF

45
Q

_______ is a process of organizing the data in the database to avoid insertion anomaly, data redundancy, update and deletion anomaly.

A

Normalization

46
Q

If a table has multiple candidate keys and one of those candidate keys is a composite key, the table can have _____ based on this composite candidate key even when the primary key chosen is a single attribute.

A

partial dependencies

47
Q

Of the following normal forms, _____ is mostly of theoretical interest.

A

DKNF

48
Q

For most business transactional databases, we should normalize relations into _____.

A

3NF

49
Q

Do all relational tables satisfy the requirements of First Normal Form (1NF)?

A

Yes, all relational tables meet the requirements of First Normal Form (1NF), which prohibits repeating groups and mandates a primary key

50
Q

Normalization works through a series of stages called normal forms. For most purposes in business database design, _____ stages are as high as you need to go in the normalization process.

A

Three

51
Q

What do the arrows in a dependency diagram signify?

A

The arrows in a dependency diagram indicate desirable functional dependencies among the attributes of a table.

52
Q

A(n) _____ exists when there are functional dependencies such that Y is functionally dependent on X, Z is functionally dependent on Y, and X is the primary key.

A

transitive dependency

53
Q

Because a partial dependency can exist only when a table’s primary key is composed of several attributes, a table whose ______ key consists of only a single attribute is automatically in 2NF once it is in 1NF.

A

primary

54
Q

The problem with transitive dependencies is that they still yield data _______, inconsistencies, and irregularities.

A

anomalies

55
Q

A table that displays data redundancies yields _____.

A

anomalies

56
Q

What leads to data redundancies in the context of partial dependencies

A

Data redundancies occur because every row entry requires duplication of data, particularly with partial dependencies present in multi-attribute primary keys.

57
Q

What is the process that works through a series of stages called normal forms in database design

A

Normalization is the process that works through a series of stages known as normal forms to reduce redundancy and improve data integrity.

58
Q

When a table contains only one candidate key, _____ are considered to be equivalent.

A

the 3NF and the BCNF

59
Q

How do dependency diagrams assist in understanding a table’s structure

A

Dependency diagrams provide a visual overview of all the relationships and dependencies among a table’s attributes, aiding in database design and normalization

60
Q

Most designers consider the BCNF as a special case of the _____.

A

3NF

61
Q

What describes a dependency based on only a part of a composite primary key?

A

A dependency based on only a part of a composite primary key is known as a partial dependency.

62
Q

What defines a determinant in a relational database context?

A

A determinant is any attribute in a table whose value directly determines other attribute values in the same row, not merely within a column.

63
Q

A _____ derives its name from the fact that a collection of multiple entries of the same type can exist for any single key attribute occurrence.

A

repeating group

64
Q

An attribute that cannot be further subdivided is said to be ______.

A

atomic

65
Q

BCNF can be violated only if the table contains more than one _____ key.

A

candidate

66
Q

What is the result of data redundancy in a database?

A

Data redundancy produces data anomalies, which can lead to inconsistencies and errors in the database

67
Q

__________ specifies that a non-prime attribute is functionally dependent on part of a candidate key.

A

partial dependency

68
Q

When designing a new database structure based on the business requirements of the end users, the database designer will construct a data model using a technique such as _____ ______ _______ ______.

A

Crow’s Foot notation ERDs

69
Q

________ refers to the level of detail represented by the values stored in a table’s row.

A

Granularity

70
Q

How does improving atomicity affect queries in a database

A

Improving atomicity leads to more flexible queries because it ensures that data is stored at its most detailed level, allowing for more precise information retrieval.

71
Q

A table that is in 2NF and contains no transitive dependencies is said to be in _____.

A

3NF

72
Q

An attribute that is part of a key is known as a(n) _____ attribute.

A

prime

73
Q

Any attribute whose value determines other values within a row is known as a _______

A

determinant

74
Q

What is a key requirement of relational models regarding data representation?

A

Relational models require that key values must be identified as part of a table or collection of tables in order to maintain relational integrity

75
Q

Any attribute that is at least part of a key is known as a

A

key attribute

76
Q

________ is a process to help reduce the likelihood of data anomalies.

A

normalization

77
Q

What characterizes a transitive dependency in a database?

A

A transitive dependency is characterized by an attribute being functionally dependent on another non-key attribute, rather than directly on the primary key.

78
Q

What type of dependencies are classified as based on part of a composite primary key?

A

Dependencies based on only a part of a composite primary key are known as partial dependencies.

79
Q

Does normalization aim to produce a lower normal form in databases?

A

No, normalization works to progress through higher normal forms to eliminate redundancy and anomalies, not to produce lower normal forms.

80
Q

From a structural point of view, 3NF is better than _____.

A

2NF

C175 Data Management Foundations (19 decks)

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