CHP 9 Flashcards Preview

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Flashcards in CHP 9 Deck (29)
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1
Q

Normalization

A

process of converting complex data structures into simple, stable data structures

2
Q

View integration

A

combine normalized data requirements from all user interfaces into one consolidated logical database model

3
Q

Primary Key

A

an attribute (or combination of attributes) whose value is unique across all occurrences of a relation

4
Q

Relational database model

A

data represented as a set of relatable tables or relations

5
Q

Relation

A

named 2 dimension table of data. consist of a set of named columns and an arbitrary number of unnamed rows

6
Q

Well-structured relations (table)

A

relation that contains a min amount of redundancy and allows users to insert, modify, and delete rows w/o error/instances

7
Q

Functional Dependency

A

constraint b/w 2 attributes in which the value of one attribute is determined by the value of another attribute

8
Q

Second Normal Form (2nf)

A

if every non-primary key attribute is functionally dependent on the whole primary key

9
Q

Third Normal Form

A

relation that is in 2NF and has no functional dependencies between 2 or more non-primary key attributes

10
Q

Foreign Key

A

attribute that appears as a non primary key attribute in one relation and as a primary key attribute in another relation

11
Q

Referential Integrity

A

rule that states that either each foreign key value must match a primary key value in another relation or be null

12
Q

recursive foreign key

A

foreign key in a relation that references the primary key values of that same relation

13
Q

Synonym

A

2 different names that are used for the same attribute (emp_id and Emp_No)

14
Q

Homonym

A

single attribute that is used for 2 or more different attributes (ex account>loan, bank, savings)

15
Q

Field

A

smallest unit of named application data recognized by system software

16
Q

Data type

A

coding scheme recognized by system software for representing organizational data

17
Q

Calculated field

A

field that can be derived from other database fields.

18
Q

Default Value

A

value a field will assume unless an explicit value is entered for that field

19
Q

Null Value

A

a special value, distinct from 0, blank, or any other value, that indicates that the value for the field is missing/unknown

20
Q

physical table

A

a named set of rows and columns that specifies the fields in each row of the table

21
Q

Denormalization

A

process of splitting/combining normalized relations into physical table based on affinity of use of rows and fields

22
Q

Physical file

A

named set of table rows stored in a contiguous section of secondary memory

23
Q

File organization

A

technique for physically arranging the records of a file

24
Q

Pointer

A

field of data that can be used to locate a related field or row of data

25
Q

Sequential File organization

A

rows in a file are stored sequence according to a primary key value

26
Q

Indexed file organization

A

A file organization in which rows are stored either sequentially or nonsequentially, and an index is created that allows software to locate individual rows.

27
Q

Index

A

A table used to determine the location of rows in a file that satisfy some condition.

28
Q

Secondary key

A

One or a combination of fields for which more than one row may have the same combination of values.

29
Q

Hashed file organization

A

file organization in which the address of each row is determined using an algorithm