Database Class Vocab Flashcards
1
Q
Integrated Database
A
A collection of related data that can be used simultaneously by many departments and users in an enterprise.
2
Q
Enterprise
A
Typical database is a large one belonging to a business or organization
3
Q
Metadata
A
Data about data
4
Q
Concurrent use
A
A database system allows several users to access the database concurrently. Answering different questions from different users with the same (base) data is a central aspect of an information system
5
Q
Query
A
A database query is a piece of code (a query) that is sent to a database in order to get information back from the database. It is used as the way of retrieving the information from database A database
6
Q
End User
A
People who use the data to perform their jobs
7
Q
Data redundancy
A
The redundancy or multiple copies of data
8
Q
Data Consistency
A
Consistency states that only valid data will be written to the database.
9
Q
Integrity constraint
A
Ensures accuracy and consistency of data is kept in a relational database
10
Q
Data Encryption
A
(computer science) the encryption of data for security purposes.
11
Q
Economy of Scale
A
The saving in cost of production that is due to mass production
12
Q
Backup
A
The activity of copying files or databases so that they will be preserved in case of equipment failure or other catastrophe.
13
Q
Recovery log
A
A database recovery log keeps a record of all changes made to a database, including the addition of new tables or updates to existing ones. This log is made up of a number of log extents, each contained in a separate file called a log file.
14
Q
User view
A
A way of portraying information in a database
15
Q
Semantic model
A
Attempts to capture the meaning of the data it represents.
16
Q
SQL
A
Structured Query Language
17
Q
XML
A
Extensible Markup Language. The need to exchange data between these internet-based resources led to the adaption of Extensible Markup Language.
18
Q
Data mining
A
A process of analyzing the data statistically to enable the organization to unearth the trends that may be present in its own records.
19
Q
Record
A
One row of data.
20
Q
Field
A
A specific column of data.
21
Q
Back End data
A
Information structure or application, e.g. database.
22
Q
Front End data
A
The interface that allows a user to access the information or application.
23
Q
operational data
A
Since thedatabase contains data about the organization’s operations (called operational
data) that is used by many departments, and since it is professionally managed
by a DBA, there is an increased appreciation of the value of the data itself,
independent of the applications that use it.
24
Q
resource
A
any asset that is of value to an organization and that incurs costs
25
data
refers to the bare facts recorded in the database.
26
Information
processed data that is in a form that is useful for making decisions
27
enterprise
the organization for which the database is designed
28
miniworld or a universe of discourse
The part of the real world that will be represented in the database
29
conceptual model
forms the second level of data discussion
30
entities
persons, places, events, objects, or concepts about which we collect data
31
entity sets
group similar entities
32
attributes
characteristics or properties to describe the entity and thatthe organization considers important
33
relationships
associations with other entities
34
logical model
The structure of the database, called the logical model of the database, is the
third level of discussion
35
intension
The logical model is also called the intension of the database, and it is relatively permanent
36
database schema
written description of the logical model
37
schema evolution
The schema may change occasionally if new data needs arise
38
metadata
data about data
39
record type
equivalent representation, such as a class
40
data item types
represents an attribute of an entity
41
data item
smallest named unit of stored data
42
data aggregates
Data items are sometimes grouped together to form data aggregates, which are named groups of data items within a record
43
record
a named collection of related data items and/or data
aggregates
44
data dictionary
Information about the logical structure of the database is stored in a DBMS also called a data directory or system catalog
45
data instances
The fourth level of discussion concerns actual data in the database itself. It
consists of data instances or occurrences
46
file
(sometimes called a data set) is a named collection of record occurrences
47
database
may be thought of as a named collectionof related files
48
extension
The data stored in the database at a given moment is called anextension of the database, or a database instance or database state
49
valid state
which means it should satisfy all the constraints specified in the schema
50
data sublanguage
The language that is used to describe a database to a DBMS
51
A data sublanguage consists of two parts:
A data sublanguage consists of two parts: a data definition language (DDL) and a data manipulation language (DML
52
host program
general purpose language program in, for example, C, C++, C#, Java, COBOL, Fortran, or Ada.
53
prototype
implementing a test environment or program
54
CASE
(Computer-Aided Software Engineering)packages include various tools for system analysis, project management, and
design that can be very useful in the database design process
55
Project management software
another type of tool that can be applied effectively to database development
56
integrated data dictionary or system catalog
If the data dictionary is part of the DBMS, itis referred to as an integrated data dictionary or system catalog
57
freestanding
If the data dictionary is available without a particular DBMS
58
synonyms
different names for the same item
59
homonyms
identical names for different data items
60
There are usually several types of graphs and charts available, such as
Gantt charts and PERT charts, which are similar
61
external level
The way users think about data is called the external level
62
internal level
Theinternal level is the way the data is actually stored using standard data
structures and file organizations.
63
The external level consists of many different
The external level consists of many different external views or external
models of the database
64
virtual
Some views might include virtual or calculated data, data not actually stored as
such, but created when needed.
65
external record
record as seen by a particular user, a part ofhis or her external view
66
The external views are described in
The external views are described in external schemas (also calledsubschemas) that are written in the data definition language (DDL)
67
The logical schema is a
The logical schema is a complete description of the information content of the
database
68
The DBMS uses the logical schema to create the
logical record interface
69
The process of abstraction, which means
The process of abstraction, which means identifyingcommon properties of a set of objects rather than focusing on details, is used to
categorize data
70
The internal level covers
The internal level covers the physical implementation of the database. It
includes the data structures and file organizations used to store data on physical
storage devices.
71
internal schema
The internal schema, written in DDL, is a complete description of the internal model
72
internal record
An internal record is a single storedrecord. It is the unit that is passed up to the internal level
73
stored record interface
stored record interface is the boundary between the physical level, for which the operating
system may be responsible, and the internal level, for which the DBMS is
responsible
74
physical record interface
physical record interface, which is a lower boundary where storage details,
such as exactly what portion of what track contains what data, are hidden
75
external/logical mapping
tells the DBMS which objects on the logical level correspond to which objects in a particular user’s external view
76
logical/internal mapping
logical/internal mapping gives thecorrespondence between logical objects and internal ones, in that it tells how the
logical objects are physically represented
77
data independence
means that upper levels are unaffected by changes to lower levels
78
There are two kinds of data independence:
logical and physical
79
A data model is a
A data model is a collection of tools often including a type of diagram and
specialized vocabulary for describing the structure of the database
80
semantic model
The Entity-Relationship model is an example of a semantic model. Semantic
models are used to describe the conceptual and external levels of data, and are
independent of the internal and physical aspects
81
Now we also define a relationship set as
a set of relationships of the same type, and we add the fact that relationships
themselves might have descriptive attributes.
82
The relational model is an example of a
The relational model is an example of a record-based model, one that
essentially pictures what the logical records will look like. Record-based models
are used to describe the external, logical, and to some extent the
internal levels of the database
83
Two older record-based models are the
Two older record-based models are the network and thehierarchical models mentioned ¡n Section 1.6. They are primarily of historic
interest, since they are no longer widely used for developing new databases.
84
object
It is based on the notion of anobject, which, like an entity, is a representation of some person, place, event, or
concept in the real world that we wish to represent in the database.
85
While entities have only attributes, objects have both a
state and a behavior
86
class
A class is similar to an entity set and consists of the set of objects having the
same structure and behavior
87
The object-oriented model uses
The object-oriented model uses encapsulation,incorporating both data and functions in a unit where they are protected from
modification from outside
88
Every object in a database must have a unique
Every object in a database must have a unique object identifier that functions as a permanent primary key
89
Entity-relationship
The entity-relationship model uses E-R diagranis to represent an enterprise
schema, a conceptual level description that is independent of any DBMS
90
E-R diagrams
The entity-relationship model uses E-R diagranis to represent an enterprise
schema, a conceptual level description that is independent of any DBMS
91
Entity types
Entities are categorized into entity types, and a collection of entitiesof the same type forms an entity set
92
Entity set
Entities are categorized into entity types, and a collection of entitiesof the same type forms an entity set
93
Entity instances
The individual entities that belong to the set at a given moment are entity instances
94
Rectangle
On an E-R diagram, a rectangle represents an entity set
95
Attributes
Attributes are representations of properties of the real-world entities. They are represented as ovals on an E-R diagram
96
Ovals
Attributes are representations of properties of thereal-world entities. They are represented as ovals on an E-R diagram
97
Null
Null values occurwhen an entity instance is missing a value for a particular attribute
98
Multivalued
Attributescan also be multivalued, composite, and/or derived
99
Composite
Attributescan also be multivalued, composite, and/or derived
100
Derived
Attributescan also be multivalued, composite, and/or derived
101
Superkey
A superkey is an attribute set that uniquely identifies entity instances.
102
Candidate key
A minimal superkey, one with no proper subset
| that is also a superkey, is called a candidate key
103
Primary key
The primary key of anentity is the candidate key that the designer chooses for unique identification
104
Alternate keys
The other candidate keys can become alternate keys
105
Secondary key
A secondary key, whichprovides another way to access records, might or might not have unique values
106
Composite key
A composite key is one that has more than one attribute. No attribute of a
primary key can have null values
107
Relationship
A relationship is an association or interaction between entities
108
Relationship set
A relationshipset consists of all relations of a given relationship type
109
Degree
Relationships have adegree, which is the number of entity instances in each occurrence of the
relationship
110
Binary
Relationships may be binary, linking two entities, ternary, linkingthree entities, or n-ary, linking n entities.
111
Ternary
Relationships may be binary, linking two entities, ternary, linking three entities, or n-ary, linking n entities.
112
n-ary
Binary relationship instances can berepresented as ordered pairs, ternary instances as ordered triples, and n-ary
instances as ordered n-tuples of entity instances
113
Diamond
A diamond is used torepresent a relationship set on an E-R diagram
114
Cardinality constraints
Relationships have cardinalityconstraints, which specify how many entity instances may be related in the
entire relationship set
115
Participation constraints
Relationships also have participationconstraints, which can be total, indicating that all members of the entity
set must participate in the relationship, or partial, if not all members have to
participate.
116
Total
Relationships also have participationconstraints, which can be total, indicating that all members of the entity
set must participate in the relationship, or partial, if not all members have to
participate.
117
Partial
Relationships also have participationconstraints, which can be total, indicating that all members of the entity
set must participate in the relationship, or partial, if not all members have to
participate.
118
Recursive
If a relationship is recursive, i.e., defined on a single entity set, or if two
entity sets are related in more than one way, the role or function an entity
plays in a relationship can be identified
119
Role
If a relationship is recursive, i.e., defined on a single entity set, or if two
entity sets are related in more than one way, the role or function an entity
plays in a relationship can be identified
120
Existence dependent
An entity is existence dependent on another if it cannot exist in the database
without a corresponding instance of the other entity
121
Weak
A weak entityis shown on an E-R diagram within a double rectangle with its identifying
relationship shown as a double diamond.
122
Strong
If such an entity has nokey of its own, but must use the primary key attribute of the entity it depends
on, it is called weak. The entity it depends on is called strong.
