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Absolute
– SQL keyword. Used in a ‘fetch’ statement to move
to a particular row of the query. [ p141]
Abstract
Conceptual Class – a conceptual class is called abstract if
every one of its instances must also be an instance of one of its
subclasses. See also Concptual Class Partition. [ p406]
Access
– see Microsoft Access.
Access
Manager – part of the DBMS that takes a plan produced by
the query optimiser and translates it into accesses to pages of
memory containing data. [ p321]
Access
Method – a software module providing data access and
manipulation primitives for each access structure. [ p321]
Accessor
– a method used to retrieve data from an object. [ p405]
Add
– SQL keyword: command to add items to a composite object. [
p98]
Additive
Rule – an inference rule for functional dependencies. Also
called the Union Rule. If X 
Y and X Z then X
YZ. Contrast with the projective rule. [ p479]
Aggregate
Query – an SQL query that returns some function of a
collection of rows, rather than the rows themselves. See
count,avg,min,max,sum. [ p113]
Aggregation
– a kind of association used to model whole-part relationships.
See also composite, composition, composite aggregation. [ p414]
All
– SQL keyword. Used in an aggregate query to summarise all
non-null values of an attribute, with repetition. Used after union,
intersect or except to include/exclude all rows, irrespective of
repetition. Used with nested queries to compare an
attribute/attributes with the rows returned by the nested query,
returning true if all rows satisfy the comparison. [ p114,120,123]
All
Key relation – a relation whose key consists of all its
attributes. [ p518]
Alter
– SQL keyword: command to change an object specification.
[ p97]
Analysis
Object Model – see Domain Model.
Analysis
Patterns – a tool for identifying classes in a conceptual
model. [ p133]
And
– SQL keyword: Used as a Boolean operator to construct the
where clause of a query. [ p104]
Anomaly
– an inconsistency in a database. See Update Anomaly, Insertion
Anomaly, Deletion Anomaly, Modification Anomaly. [ p471-472]
Any
– SQL keyword. Used with nested queries to compare an
attribute/attributes with the rows returned by the nested query,
returning true if at least one row satisfies the comparison. [
p123]
Application
Designers – define and create programs for the database.
[ p9]
Are
system generated – SQL-3 keyword. Used with ‘values
for’ to denote that the DBMS should generate OIDs in the given
attribute. [ p425]
Armstrong’s
Inference Rules – The additive, augmentation and transitive
rules taken together. These three are logically complete, in that any
other valid inference rule may be derived from them. [ p481]
Array-sequenced
organisation – a way data may be arranged in memory
(primary or secondary). The sequence of tuples is dictated by an
index. [ p323]
As
– SQL keyword. An optional keyword used to specify aliases for
attributes or tables in a query. [ p101] SQL keyword: Part of the
syntax of ‘create view’ [ p133] SQL-3 keyword: Part
of the syntax of ‘external’ [ p426]
Asc
– SQL keyword. Used with order by to denote how the rows
returned by a query are to be sorted (ascending). [ p113]
Assertion
– SQL keyword. Used to specify a condition (not dependent on
any particular table) that must always be true of the data in the
database. [ p132,133]
Association
– a relationship between (instances of) types that indicates
some meaningful and interesting connection. [ p153]
Association
Class – a class encapsulating (capturing) information about
an association between other classes. [ p411-413, p285]
Atomic
data types – the most simple forms of data, Boolean,
string, integer, and so forth. [ p399]
Attribute
– the name of a column of a table, indicating the meaning of
the data in that column. [ p18] A logical data value of an object.
See simple attribute. [ p167]
Attribute
Preservation Property – the property of a decomposition D =
{R1, R2, …, Rk} of R that the union of the Ri is in fact R.
[ p503]
Augmentation
Rule – an inference rule for functional dependencies. If X
Y then XZ
YZ. Sometimes stated as: If X
Y then XZ Y. [ p479]
for MVD’s: If X 
Y and Z is a subset of W, then WX
YZ. [ p516]
Authorization
– SQL keyword used to specify the owner of a schema. [
p90-91]
Avg
– SQL keyword. Used to perform an aggregate query that returns
the average value of an attribute. [ p115]
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CallableStatement
– a class in java.sql used to execute SQL stored procedures.
[ p182]
Candidate
Key – a synonym for key, in a relation schema with more
that one key. [ p477,485]
Cardinality
– the number of elements of the relation (that is, rows in the
table) [ p17]
Cartesian
Product – set of all ordered pairs (or triples etc) of
elements from two (or three etc) sets. [ p16] A natural join of
two relations with no common attributes, whose tuples are all
possible combinations of the tuples of the original relations. [
p54]
Cascade
– SQL keyword. Indicates behaviour of the RDBMS when an object
is modified (deleted or changed) when there are other objects
dependent on it. See cascade, set null, set default, no action, on
update, on delete. [ p96] Used in the drop command similarly. See
also restrict. [ p98] Used similarly in the revoke command to
ensure that if a user has passed on privileges to others, their
privileges are also revoked when the user’s is. See also
restrict. [ p138]
Cascaded
– SQL keyword. Used to indicate that a ‘check option’
added to a view should also apply to the views used to define it (if
any). [ p134]
Casual
User – a user of the DB who interact with the DB in
various, unpredetermined ways. Often familiar with the DDL and DML.
[ p9]
Char
– SQL keyword. Synonym for character. [ p88]
Character
– SQL keyword: domain of textual data. See char, varchar
Check
– SQL keyword. Used in the creation of tables to specify
complex conditions the data must satisfy. [ p131]
Check
Option – SQL keyword. Used to ensure that modifications
made to a view result in rows that still belong to the view. [
p134]
Class
– a container for objects. A class has an interface and an
implementation. [ p402] In some OODBMSs, a class is just an
interface and an implementation, and the object containers are called
extensions or extents. [ p403]
Class
Diagram – a UML notation for a class or concept. [ p128]
Class.forName
– forName is a method of the Class class in java. It returns an
object of type Class representing the named class. A side effect of
this is that the class is loaded into the JVM. If the class happens
to be a Driver, this in turn will create a Driver object and register
the object with the DriverManager. [ p184]
Class
Hierarchy – aka Generalization-Specialization Class
Hierarchy. The way in which subclasses and superclasses are
organised, with subclasses placed under their superclasses. See
Software Class Hierarchy. [ p396]
Client-Server
Architecture – a way to organise software using a DBMS and
the DBMS itself so that they communicate over a computer network with
the DBMS waiting for requests from the software. [ p176]
Close
– SQL keyword, used to tell the DBMS that the named cursor is
no longer needed. Syntax: close Cursorname. [ p141]
Closure
– the closure of a set of functional dependencies F is the set
F+ of all functional dependencies that may be inferred
from F. [ p481] The closure of a set of attributes X under a set F
of functional dependencies is X+, the set of all
attributes Y such that X Y
is in F+. [ p481] The closure of a set F of FDs and
MVDs is the set of all such that may be inferred from F. [ p517]
Coalescence
Rule – an inference rule for FDs and MVDs. If X
Y and there exists W such that W
Y
is empty, WZ and Z is a
subset of Y, then X Z.
[ p517]
Column
– SQL keyword: used in add, alter or drop to denote a column
(attribute) of a table. [ p98]
Combination
– an unwise strategy for representing a one-to-one association
in an RDMBS, by merging the tables of the associated classes. [
p284]
Common
Associations List – a tool used to identify associations
for a domain model – a list of common types of associations.
[ p155]
Complementation
Rule – for MVD’s. {X
Y} ╞
{X
(R – (X
Y))}. [
p516]
Compilation
– the process of optimising a query and converting it into a
sequence of page accesses. [ p333]
Compiled
Query – a query that has been compiled and stored. (see
compilation) [ p333]
Complete
Join – a natural join r1
r2
in which every tuple of r1 and r2 contributes to the join. [ p51]
Complex
Data Type – A data type with some detailed structure, for
example a record, list, bag or set. [ p399]
Composite
– the ‘whole’ in a whole-part relationship
(aggregation). [ p414]
Composite
Aggregation – see Composition. [ p415]
Composition
– a form of aggregation where the ‘part’ is part of
only one ‘whole’, and its existence and location and
other features are tied to the whole. Contrast with Shared
Aggregation. [ p415]
Conceptual
Class – a category of things in the real world, depicted in
a domain model. [ p145]
Conceptual
Class Category List – a tool to help identify conceptual
classes – a list of common categories of conceptual classes.
[ p134]
Conceptual
Class Partition – a division of a conceptual class into
disjoint subclasses. [ p400]
Conceptual
Data Models – any data model in which data is described
independently of the logical model used to organise the data, instead
relating the data to real-world concepts. An example is the E-R
model. Usually used to help design the database. [ p6]
Conceptual
Model – see Domain Model.
Concurrency
– the capacity of a system to handle many users simultaneously.
[ p417]
connect
– a static method of DriverManager used to connect to a
database at a specified URL. [ p184]
Connection
– a class in java.sql that represents a connection between the
client software and the database server. [ p182]
Constraint
– SQL keyword. Used in add, alter or drop to denote a
constraint on a table. [ p98]
Constraints
– SQL keyword. See ‘set constraints’.
Constructor
– a method used to help create a new object and initialise its
data. [ p405]
Contradiction
– a statement that cannot be true. [ p479]
Contravariance
– replacing a type by a supertype. See Covariance. [ p415]
Control
source – Microsoft Access keyword. The property of a form
element that indicates the attribute it should display. [ p179]
Cost
Model – a formula or algorithm for estimating the ‘cost’
of a particular form of a query. Usually taking into account expected
memory usage and time. [ p333]
Count
– SQL keyword. Used in an aggregate query to count the rows
returned. [ p114]
Counter
– Access SQL keyword. If the data type of an attribute is
‘counter’, then new tuples take on successive integer
values. Foreign keys should be of type long. See Identifier domain.
[ p278]
Covariance
– replacing a type by a subtype. See contravariance. [ p414]
Cover
– a set of functional dependencies F covers another such set E,
if E is a subset of the closure of F. [ p482]
Create
– SQL keyword. Used to create an object in SQL. [ p90,91]
createStatement
- method of the class Connection used to create a Statement object.
[ p186]
Current
Of – SQL keyword. Used in the where clause of an update or
delete statement to indicate that the update or delete should be
applied to the current row of the named cursor. [ p141]
Cursor
– a mechanism in SQL for allowing a set of tuples to be
manipulated one by one. [ p140]
Cursor
for – SQL keyword used to declare a cursor. Syntax: declare
cursorname [scroll] cursor for SelectStatement for
<read only | update [of AttributeList]> [ p140]
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Dangling
tuple – in an incomplete natural join r1r2,
the tuples of r1 and r2 which do not contribute to tuples of the join
[ p51, Elm p511]
DAO
– Data Access Object. One of two ways for Microsoft Access to
read data from other databases. See also ‘Link Tables’.
[ p179]
Data
– bits and bytes and strings that have no meaning in and of
themselves. [ p2]
Data
Access Object – see DAO
Database
– a collection of data, used to represent information of
interest to an information system. [ p2] a set of relation
(instances) satisfying a given schema [ p22]
Database
Administrator – Responsible for the design, control and
administration of a DB. [ p9]
Database
Client – a program that connects to a database server in
order to use the database controlled by the server. [ p176]
Database
Instance – a database, in the second sense [ p22]
Database
Management System – see DBMS
DatabaseMetaData
– a class in java.sql that contains information about the
database server. [ p182]
Database
Server – a program that awaits connections from a database
client, processes commands from the client, and returns results from
the database. [ p176]
Data
Definition Language – used to define the logical, external
and physical schemas and access rights. [ p8]
Data
dictionary – a collection of information stored in the DBMS
about what objects exist. [ p99]
Data
Independence – the property of a DBMS that allows users and
programs to refer to data at a level of abstraction that ignores the
actual implementation of the DB. Cf Physical and Logical
independence. [ p7]
Data
Manipulation Language – used to query and update data to
the database. [ p8]
Data
Model – a combination of constructs used to organise data.
[ p5]
Data
type – see simple attribute.
Date
– SQL keyword. Domain of date values. See also timestamp. [
p89]
Day
– SQL keyword. Used to specify Interval attributes. [ p90]
DB
– see Database.
DBA
– see Database Administrator.
DBMS –
a software system able to manage large, shared, persistent
collections of data while ensuring reliability and privacy. [ p3]
DDL
– see Data Definition Language.
Deallocate
prepare – SQL keyword. Used to indicate that a previously
prepared SQL command is no longer needed. Syntax: deallocate prepare
CommandName [ p144]
Decimal
– SQL keyword. Synonym for Numeric. [ p88]
Decision
tree – a tree structure representing the various decisions
that need to be made by the query optimiser. See ‘execution
plan’ [ p340]
Declarativeness
– the existence in a system of a high-level query language.
[ p417]
Declare
– SQL keyword. Used to declare cursors. [ p140]
Decomposition
– a collection D = {R1, R2, …, Rk} of relation schemas
that together contain all the attributes of a larger relation schema
R. [ p502]
Decomposition
Algorithm – An algorithm for decomposing a relation into
smaller relations that satisfy some normal form. An example is
Elmasari Algorithm 15.3. Contrast with ‘Relational Synthesis
Algorithm’ [ p509]
Decomposition
Rule – See Projective Rule.
Deep
Equality – the two objects must have identical values when
OIDs in their structure are recursively substituted with the
structure of the objects they reference. See superficial equality,
identical. [ p402]
Deferred
– SQL keyword. Used with ‘set constraints’ to
specify that a constraint should only be checked after a full
transaction is completed. [ p133]
Delete
– SQL keyword. Denotes the privilege of being able to delete
rows from a table or view. [ p137]
Delete
From – SQL keyword. Used o remove rows from a table. [
p129]
Default
– SQL keyword. Used to specify the default value of an
attribute or domain. [ p92] Used with update…set to change
the value of an attribute to the default value. [ p130]
Degree
(of a relation) – the number of terms in the cartesian product.
[ p17]
Deletion Anomaly
– an inconsistency introduced into a badly designed database
when data is deleted without taking into account the bad design. [
p472]
Denormalization
– the process of transforming a database schema into one
satisfying only a lower normal form, usually by storing joins of
tables directly instead of as views, for performance reasons. [
p484]
Dependency
– a dependency between two package exists if one package
references elements of the other. [ p424] See also ‘functional
dependency’.
Dependecy Preservation Property
– a desirable property of a database schema that all functional
dependencies are represented within some individual relations within
the schema. [ p484] More technically, a decomposition D = {R1, R2,
…, Rk} of R has the dependency preservation property with
respect to F if the closure of the union of all the pRi(F)
equals the closure of F. [ p504]
Dependent
class – a class whose objects cannot exist without some
other objects also existing. See ‘Flow of Identity’ [
p277]
Dereferencing
– accessing data in an object referenced by an attribute. [
p427]
Derived
Attribute – an attribute of a class which may be derived
from other attributes or from the nature of associations between
objects of the class and other objects. [ p175]
Derived
Element – an element (attribute or association) that may be
derived from other elements in the domain model. [ p421]
Derived
Relation – a relation which is calculated from other
relations in the database. See also base relation, materialized view,
virtual relation, view. [ p65]
Desc
– SQL keyword. Used with ‘order by’ to denote how
the rows returned by a query are to be sorted (descending). [
p113]
Design
Creep – the (poor) practice of making design and
implementation decisions during the analysis phase. [ p172]
Destructor
– a method used to cancel (destroy) an object, and possibly
other linked objects. [ p405]
Dictionary
– see Data Dictionary.
Distinct
– SQL keyword. Used in an aggregate query to summarise distinct
non-null values of an attribute. [ p114]
Difference
(between two relations) – the difference r1 – r2 is the
set of all tuples belonging to r1 but not to r2. [ p43]
Distinct
– SQL keyword: ‘select distinct attr’ causes
the query to discard duplicate rows in the returned view. [ p108]
Distinct
Table – a phrase used in Blaha to indicate that an
association should be represented by a table in the RDBMS distinct
from the tables for the classes. [ p282,283,etc]
DML
– see Data Manipulation Language.
Domain
(of a relation) – one of the sets used to form the Cartesian
product of which the relation is a subset. That is, the type of data
that appears in a column of a table. [ p16]
Domain
– SQL keyword specifying that an operation acts on a domain
object. [ p91]
Domain
Constraint – (also Value constraint). A form of tuple
constraint which specifies allowable values of particular attribute
(eg Mark must be between 0 to 100). [ p29]
Domain
Model – a visual representation of conceptual classes of
real-world objects in a domain of interest. [ p128]
Domain
Object Model – see Domain Model.
Double-dot
notation – Notation in SQL-3 (..) used to access
subcomponents of the object stored in an attribute. [ p427]
Double
precision – SQL keyword for double precision values. See
also float, real. [ p89]
Driver
– a software component allowing a software system to use
databases stored on DBMSs by a particular vendor. [ p179] An
abstract class (interface??) in the java.sql package that is
subclassed by database vendors to provide Drivers for their
databases. [ p182]
Driver
Manager – software that is aware of the available drivers
on a system, and is able to load the correct drivers to handle
requests as the requests arrive. [ p179]
DriverManager
– A class in java.sql that provides a Driver Manager. [
p182]
Driver
Package – a software component that may be incorporated
into database client software, allowing it to use a particular
driver. [ p179]
Drop
– SQL keyword. Command to delete an object. [ p98]
Durability
– The capacity of a system to support persistent data. [
p417]
Dynamic
Lookup – see late binding.
Dynamic
properties – that part of a class or type definition that
describes the behaviour of the objects (that is, the methods). [
p399]
Dynamic
SQL – SQL statements that are generated and used by a
program at runtime rather than compile time. [ p142]
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Elementary
Domain – the basic domains (datatypes) available in SQL.
[ p88]
Elimination
– a strategy for representing single inheritance in an RDBMS by
simply ignoring subclasses with no extra attributes. [ p288]
Embedded
SQL – SQL statements inserted into a program written in a
general-purpose programming language. The program must be processed
by a pre-processor before being compiled. [ p181]
Encapsulation
– the ability, in a system, to hide data inside objects and
only allow access to the data via public methods. [ p416]
Inbuilding SQL commands into a program written in a general purpose
computer language. [ p139]
End
User – uses the database in fixed, routine, predefined
ways. [ p9]
Entity-Relationship
Model – An example of a conceptual data model. [ p6]
Entry-sequenced
organisation – a way data may be arranged in memory
(primary or secondary). The sequence of tuples is dictated by the
order of entry. [ p323]
Entry
SQL – basic level SQL implemented in all commercial RDBMSs
[ p86]
Enumeration
Domain – a data type allowing a few fixed values. Eg,
(“Mon”, “Tue”, … , “Sun”).
[ p278]
Enumeration
Encoding – a correspondence of enumeration values to
numbers. [ p280]
Enumeration
String – A string corresponding to a value of an
enumeration domain. [ p279]
Enumeration
Table – a table in an RDBMS containing the allowed values
of an enumeration. [ p280]
Equality
– see superficial equality and deep equality. [ p402]
Equi-join
– a theta join where the tuples of the Cartesian product are
selected according to a number of equalities between attributes. [
p54]
Equivalent
– two sets E and F of functional dependencies are equivalent if
their closures are equal. [ p482]
E-R
model – see Entity-Relationship model.
Except
– SQL keyword. Used to find the ‘difference’ of the
output of two SQL ‘select’ statements (queries). [
p120]
EXEC
SQL – Typical keyword used to embed SQL statements in a
general purpose programming language. [ p181]
Execute
– SQL keyword. Used to execute a previously prepared SQL
command. Contrast with ‘execute immediate’. Syntax:
execute CommandName [into TargetList] [using
ParameterList] [ p144]
execute
– a method of the class statement that may be used to send any
SQL command to a database server. [ p186]
Execute
immediate – SQL keyword. Causes the immediate execution of
an SQL command contained in a given string. Syntax: execute immediate
SQLString. Used to make dynamic SQL possible. [ p143]
executeQuery
– a method of the class Statement used to send a SELECT
statement to a database server. [ p186]
executeUpdate
– a method of the class Statement used to send any statement
except a SELECT statement to a database server. [ p186]
Execution
plan – a set of choices that might be made by a query
optimiser. Represented by a leaf node of a decision tree, that is, by
a path through the decision tree. [ p340]
Existence-Based
Identity – Objects are distinguished via an object
identifier, that is, in the RDBMS, an extra field is added to each
table to contain the ID of the object. [ p276]
Exists
– SQL keyword. Used with nested queries. Exists (Query)
returns true if Query returns at least one row. [ p126]
Extensibility
– the ability to define new types or classes based on existing
ones. [ p416]
Extension
– The set of examples of a conceptual class [ p131] See
‘class’ [ p403] A particular instance of a relation
schema [ p477]
Extensional
Component (of a database) – the state or instance. [ p6]
Extent
– see ‘class’ [ p403]
External
– SQL-3 keyword. Used as part of a ‘returns’
statement to indicate thyat a function is defined outside the DBMS in
a general purpose language. Syntax: ‘returns type as
external name filename language language’ [
p426]
External
Schema – a particular view of the database as presented to
a particular user. [ p7]
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Fat
Relation – a relation with many attributes. [ p473]
Fetch
– SQL keyword. Used to retrieve data from a query via a cursor.
Syntax: fetch [Position from] Cursorname into
FetchList. [ p140]
Fifth
Normal Form – The information content of the database
cannot be reconstructed from smaller record types, that is, record
types with smaller numbers of attributes than the original. [
p123]
First
– SQL keyword. Used in ‘fetch’ to retrieve the
first row of the query. [ p140]
First
Normal Form – all occurrences of a record must contain the
same number of fields. [ p120] Data types of attributes must be
atomic, and relations may not be nested. [ p485]
Float
– SQL keyword. Domain of floating point values. See also double
precision, real. [ p89]
Flow
of Identity – notation added to the UML diagram of the
domain model indicating which objects or classes derive identity
(existence etc) from which others. Identity flow is indicated with an
arrow from a dependent class to an independent class. See independent
class, dependent class. [ p277]
From
– SQL keyword. Used to construct queries. Specifies what tables
the attributes are selected from. [ p101] SQL keyword, used to
specify the user in a ‘revoke’ statement. [ p138] SQL
keyword used if a position is specified when ‘fetch’ing
data from a cursor. [ p140]
For
– SQL keyword. Part of the syntax for ‘cursor’
declaration. [ p140]
Foreign
key – SQL keyword. Used to define a referential constraint
in SQL. See also ‘references’. [ p96]
Foreign
Key Constraint – see Referential constraint.
Foreign
Key Attribute – a (poor choice) attribute which is a piece
of text or similar basic data type which actually refers to a complex
object. Should be removed and replaced with an association. [
p172]
Form
– a page of a Graphical User Interface used to display the
results of a query. [ p178]
Fourth
Generation Language – a highly sophisticated development
tool allowing easy creation of database management applications. [
p139]
Fourth
Normal Form – a record type should satisfy 3NF, and should
not contain more than one independent `mutivalued fact’ about a
key. [ p122] a relation R in the fourth normal form with respect
to a set of MVDs F, if for every nontrivial X
Y in F+, X is a superkey of R. [ p517]
Full
functional dependency – a functional dependency X
Y where X’ Y does
not hold for any proper subset X’ of X. See also
‘partial dependency’, ‘second normal form’
[ p488]
Full
outer join – an outer join r1 FULL
r2 where dangling tuples from both r1 and r2 are padded with blanks
and inserted into the join. [ p53]
Full
[Outer] Join – SQL keyword: used to join two tables before
selecting from them. See join. [ p109]
Full
SQL – implementing even the most advanced and newest
features of the SQL standard. [ p86]
Function
– SQL-3 keyword used to manipulate (create etc) functions.
Functional
Dependency – a field (or set of fields) A is functionally
dependent on a set of fields X if it is invalid to have two records
with the same values for X but different values for A. [ p121]
More formally, Y is functionally dependent on X if for any two tuples
t1, t2 in the universal relation schema, we have t1[X] = t2[X]
implies t1[Y] = t2[Y]. Denoted X
Y.
Functions
– terminology used in SQL-3 for methods. [ p426]
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Generalization
– identifying commonality among concepts and defining a more
general concept encompassing them. See superclass, specialization.
[ p396] A form of migration where an object moves from a subclass
to a superclass. [ p410]
Generalization-Specialization
Class Hierarchy – see class hierarchy. [ p396]
Generalization
Table – a table in an RDBMS used to indicate which classes
are subclasses of which superclasses. [ p291]
getColumnCount
– a method of ResultSetMetaData that returns the number of
columns of the ResultSet. [ p190]
getColmunName
– a method of ResultSetMetaData that returns the name of a
given column. [ p190]
getColumnType
– a method of ResultSetMetaData that returns a code
representing the type of data stored in a given column. [ p190]
getColumnTypeName
– a method of ResultSetMetaData returning a String representing
the type of data stored in a given column. [ p190]
getMetaData
– a method applied to a ResultSet object that returns the
ResultSetMetaData associated with the ResultSet. [ p187]
getResultSet
– a method of Statement to retrieve the most recently generated
ResultSet. Usually used after an execute statement was performed with
a SELECT query as the argument. [ p195]
getString
– a method of ResultSet that returns the data in the current
row of the given column. See also next. Methods getFloat, getInt,
getBigDecimal etc also exist (see box on Ric p191). [ p190]
getTimeDateFunctions
– a method applied to a DatabaseMetaData object to discover the
time and date functions available on the database server. [ p186]
getUpdateCount
– a method of Statement used to determine the number of rows
affected by the most recent update or delete query. Usually used
after the execute method is used to send on non-select SQL command to
the database. [ p195]
getUserName
– a method applied to a DatabaseMetaData object to discover the
username. [ p186]
Grant
– SQL keyword. Used to give a privilege on a resource to a
user. Syntax: grant priv on res to user [with
grant option]. [ p137]
Group
by – SQL keyword. Used to modify an aggregate query to
partition the rows according to the values of given attributes before
doing the calculations required by the aggregate query. See [
p116]
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Identical
– objects in an OODBMS such as O2 are identical if they share
the same OID. See also superficial equality, deep equality. [
p402]
Identifier
Domain – an RDBMS specific domain allowing easy allocation
of new object identifiers. See Counter, Sequence. [ p278]
Identity
– the manner in which individual objects are distinguished in
an RDBMS. See Value-Based Identity, Existence-Based Identity. [
p276]
Immediate
– SQL keyword. Used with ‘set constraints’ to
indicate that a given constraint should be immediately checked after
every step of a transaction, not merely when the whole transaction is
completed. [ p133]
Impedance
Mismatch – The fact that an SQL query returns whole blocks
of data, but high-level general-purpose languages generally can only
handle single items of data one at a time – and the problem of
using the two approaches together. [ p407, p139]
Implementation
(of a class) – the implementation of the methods of a class.
Sometimes also descriptions of the data structures to be used for
storing its data. [ p403]
Implementation
(of a method) – See ‘method implementation’.
In
– SQL keyword. Used with nested queries. Attr in (Query)
is equivalent to Attr = any (Query). [ p125]
Incomplete
join – a natural join r1r2
where not every tuple of r1 and r2 contributes to a tuple of
the join. See: dangling tuple. [ p51]
Independent
class – a class whose objects exist “independently”,
that is, they do not depend on other classes for their existence or
identity. See ‘Flow of Identity’ [ p277]
Independent
multivalued fact – two multivalued facts are independent if
the actual values for one fact do not affect the possible or actual
values of another. See ‘fourth normal form’ [ p122]
Index
– a structure (usually a tree structure) allowing quick access
to data stored in the database via a key. [ p337]
index
– SQL keyword. Used to create or drop an index for a database.
Syntax: ‘create [unique] index IndexName on
TableName(AttributeList)’ or ‘drop index
IndexName’. [ p343]
Indexed
access – access to data via an index. [ p337]
Indivisible
Data Type – a synonym for atomic data type. [ p485]
Infer
– deduce logically. Used in Elmasari to refer specifically to
functional dependencies. A functional dependency X
Y can be inferred from a set F of functional dependency if X
Y can be deduced logically from F via the application of various
inference rules. [ p479]
Inference Rules
– a rule that may be used to infer functional dependencies from
others. See Reflexive Rule, Augmentation Rule, Transitive Rule,
Projective Rule, Additive Rule, Pseudotransitive rule. [ p479]
Information
– data within a context that provides it with meaning. [ p2]
Information
system – the procedures whereby information within an
organization is managed. [ p1]
Inheritance
– a software mechanism allowing superclass ‘things’
(associations, attributes and methods) to apply to subclasses. [
p409]
Inner
Join – SQL keyword: used to join two tables before
selecting from them. See join. [ p109]
Input
parameter – data that is received by a method at the time
it is called. [ p405]
Insert
– SQL keyword. Denotes the privilege of being able to add data
to a table or view. [ p137]
Insert
into – SQL keyword. Used to add data to a table. [ p128]
Insertion Anomaly
– an inconsistency introduced into a badly designed database
when new data is inserted without taking into account the bad design.
[ p471]
Instance
(of a database) – the values stored within the database at a
particular time. [ p6] (of a class) an object that can belong to
the class, but cannot belong to any of its subclasses without
modification. Contrasted with ‘member’ship of objects.
[ p410] Synonym for Extension [ p477]
Integer
– SQL keyword. Domain of integers. See also numeric, decimal,
smallint. [ p88]
Integrity
Constraint – a property that must be satisfied by all
correct database instances. See Predicate, intra-relational
constraint, inter-relational constraint. [ p29]
Intension
– the definition of a conceptual class [ p131]
Intensional
Component (of a database) – the schema. [ p6]
Interface
– the ‘type’ of a class. A description of its
data and method signatures. [ p402]
Intermediate
SQL – features of SQL that are commonly used in commercial
products. [ p86]
Internal
Schema – the implementation of the logical schema by means
of physical storage structures (files, etc). [ p7]
Inter-record
redundancy – a redundancy in the database schema that does
not arise within a single relation taken alone. [ p125]
Inter-relational
constraint – an integrity constraint that involves more
than one relation of the database (eg StudentNumber in EXAMS must
match a value of StudentNumber in STUDENTS). Contrast with
Intra-relational constraint. [ p29]
Intersect
– SQL keyword. Used to find the intersection of the output o
two select statements (queries). [ p120]
Intersection
– the intersection of two relations r1 and r2 is the set of
tuples belonging to both r1 and r2 (contrast with union or
difference). [ p43]
Interval
– SQL keyword, domain of time intervals. [ p89]
Into
– SQL keyword. Part of the syntax of ‘fetch’. [
p140] SQL keyword. Part of the syntax of ‘execute’. [
p144]
Intra-Relational
Constraint – a form of integrity constraint that is defined
with reference to a single relation or table in the database.
Examples are tuple constraints and domain or value constraints.
Contrast with Inter-relational constraint. [ p29]
Invocation
– see ‘method invocation’.
Is
– SQL keyword: used in the where clause of a query: “is
null” or “is not null”. [ p106] SQL-3 keyword:
used as part of the ‘scope for’ syntax. [ p425]
Is-a
rule – a rule to help clarify a subclass-superclass
relationship. Instances of a subclass must also be instances of a
superclass. [ p400]
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Language
– SQL-3 keyword. Used as part of the syntax for ‘external’
to indicate what language the external function is written in. [
p426]
Last
- SQL keyword. Used in a ‘fetch’ statement to retrieve
the last row of a query. [ p140]
Late
Binding – a feature of an OO system, where the method to be
used is only decided at runtime, not at compile time. Allows method
overloading and overriding to work nicely. Also called ‘dynamic
lookup’ [ p413]
Left
outer join – an outer join r1 LEFT
r2 where dangling tuples from r1 are padded with blanks and inserted
into the join. [ p53]
Left
[Outer] Join – SQL keyword: used to join two tables before
selecting from them. See join. [ p109]
Legal
Extension – an extension of a relation schema that
satisfies the (functional dependency) constraints. Also called Legal
Relation State. [ p477]
Legal
Relation State – see ‘Legal Extension’.
Like
– SQL keyword: Used as an operator to construct the where
clause of a query. Specifies that a string attribute must match (be
like) a certain pattern. [ p105
Link
Attribute – An attribute of an association. [ p285]
Link
Tables – a menu item in Microsoft Access allowing the
access database to gain access to external sources of data. See also
DAO. [ p179]
List
– an ordered collection of objects of the same type, allowing
duplicates. [ p399]
List-of
– O2 keyword allowing the construction of lists. [ p399]
Local
– SQL keyword. Used to indicate that a ‘check option’
on a view should only apply to the view itself, not to pther views
that were used to define it. [ p134]
Logical
Data Model – any data model where a particular method of
organisation is used to organise data. Examples are the Relational,
Hierarchical, Network and Object data models. [ p6]
Logical
Independence – (see Data Independence) the interaction with
the data does not depend on the logical arrangement of data within
the database. [ p8]
Logical
Schema – a description of a database according to the
appropriate logical data model. [ p7]
Lossless
Join Property – a vital property of a database schema, that
joins do not introduce spurious tuples. Also called the non-additive
join property. [ p484, 505]
Lost
– some functional dependencies are lost if the
dependency preservation property is not satisfied by a decomposition.
[ p504]
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Many-to-Many
association – an association between two classes A and B,
where each A can be associated with many B’s, and vice versa.
See Multiplicity. [ p282]
Materialized
view – a derived relation whose data is actually stored in
the database. Contrast with virtual relation (view) [ p65]
Max
– SQL keyword. Used to perform an aggregate query that returns
the maximum value of an attribute. [ p114]
Merge-scan
– a ‘join method’ useful when both tables are
pre-sorted on the join attributes. [ p338]
Member
(of a class) – an object contained in the class. The object
will also simultaneously be members of all the classes superclasses.
Contrasted with ‘instance’ [ p410]
Metadata
– data about the structure of data. See reflexivity,
dictionary. [ p99]
Method
– an action that may be performed on an object. [ p404]
Method
Body – See method implementation.
Method Implementation
- the (code describing the) operations that a method performs. [
p403,404]
Method
Invocation – the act of performing the action on the
object. May be seen as an act of sending a message to an object. [
p406]
Method
Overloading – the situation where the same method name (but
different signatures) is used more than once in a given class. [
p413]
Method
Overriding – the situation where a method defined in a
superclass is redefined (with the same signature, but different
implementation) in a subclass. [ p412]
Method
Signature – a description of the parameter types and return
type of a method. [ p402,404]
Microsoft
Access – an example of a database development tool,
produced by Microsoft. [ p178]
Microsoft
Jet – a driver for a Microsoft Access database. [ p179]
Middleware
– Software that waits for requests from database clients,
reinterprets the requests, and passes them on to a DBMS. [ p176]
Migration
– the event of an object moving from a superclass to a subclass
(specialization) or vice-versa (generalization). [ p409]
Min
– SQL keyword. Used to perform an aggregate query that returns
the minimum value of an attribute. [ p114]
Minimal
– a set F of function dependencies is minimal if (i) Every
function dependency in F is of the form X
A where A is a single attribute, (ii) If any X
A in F is replaced by Y A,
where Y is a proper subset of X, the new set of functional
dependencies is not equivalent to F, and (iii) if any X
A is removed from F, the new set of functional dependencies is not
equivalent to F. [ p482]
Minimal
Cover – a minimal cover Fmin for a set of
functional dependencies F is a minimal set of functional dependencies
that covers F. [ p482]
Minute –
SQL keyword. Used to specify Interval attributes. [ p90]
Modification Anomaly
– an inconsistency introduced into a badly designed database
when data values are changed without taking into account the bad
design. [ p472]
Month
– SQL keyword. Used to specify Interval attributes. [ p90]
Multidetermine
– X multidetermines Y means X
Y. (see MVD). [ p514]
Multiple
Inheritance – the situation where a class is a subclass of
more than one superclass. [ p291, p410]
Multiplicity
– characteristic of a role. It indicates how many objects of
one type fulfil the role for the object at the other end of the
association. [ p157]
Multi-target
method – a method which can be applied to any of a number
of objects. [ p404]
Multivalued
Domain – a data type where the variable may take on more
than one value at a time. [ p282]
Multivalued
Dependency – see MVD.
Multivalued
Fact – information about something that may take on more
than one value simultaneously. For example, InvoiceNumber for
Customer. See ‘independent multivalued fact’, ‘fourth
normal form’. [ p122]
MVD
– multivalued dependency. Occurs when two or more independent
multivalued facts are stored in a single table. Formally, a
multivalued dependency X
Y specifies the following constraint: if tuples t1 and t2 exist with
t1[X] = t2[X], then there should also exist tuples t3, t4 with (*)
t3[X] = t4[X] = t1[X] (=t2[X]), (*) t3[Y] = t1[Y] and t4[Y]=t2[Y],
(*) t3[Z] = t2[Z] and t4[Z] = t1[Z] (where Z = R – (X
Y)). [ p514]
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Name
– SQL-3 keyword. Part of the syntax for ‘external’.
[ p426]
Name
Conflicts – a problem with multiple inheritance, where two
superclasses of a class use the same name for different properties.
[ p411]
Natural
Join – an operator combining tuples of two relations r1 and
r2 on sets of attributes X1 and X2. The new tuples are formed on
X1X2 by combining tuples
from r1 and r2 for which X1X2
match. r1r2 = {t
on X1X2 : t[X1]
r1 and
t[X2]r2}. See complete and
incomplete join. [ p49]
Nested
Loop – a ‘join method’ where the attributes of
one table are looped through once for each tuple in the other. [
p337]
Nested
Query – A select statement (SQL query) used as part of the
with clause of another query, and used as a source of data against
which to compare attributes. [ p122-128]
Nested
Relation – a relation stored within the tuples of another
relation. [ p487]
Nesting
– in SQL-3 – taking data on the same level, and (for
example by means of the ‘set’ aggregate operator)
returning a more multi-levelled data structure from a query. [
p428]
Network
Data Model – A data model using graphs to organise data
[ p5]
New
– an O2 keyword used to invoke the method that creates an
object. [ p406]
next –
a method of ResultSet that moves the ResultSet’s (inbuilt)
cursor to the next row of the table (or to the first row when next is
called for the first time) It returns true if successful, or false if
all rows of the ResultSet have already been read.
Next
– SQL keyword. Used in a ‘fetch’ statement to
retrieve the next row of a query. [ p140]
Nil
– O2 keyword for the null value. [ p399]
No
action – SQL keyword. Indicates behaviour of the RDBMS when
an object is modified (deleted or changed) when there are other
objects dependent on it. See cascade, set null, set default, no
action, on update, on delete. [ p96]
No-information
– a null value indicating that it is not known whether
information exists, and even if it does, the value is unknown. Eg.
“Phone Number” for a person who may or may not have a
phone. In practice the situation faced by users of databases with
null values. [ p23]
Non-additive
join property – see Lossless Join Property.
Non-existent
value – a null value indicating that the information does
not exist, for example “Phone Number” for a person who
has no phone. [ p23]
Nonprime
attribute – an attribute which does not form part of any
candidate key. Contrast with ‘prime attribute’. [
p485]
Nontrivial
functional dependency – a functional dependency X
Y where Y is not a subset of X. [ p479]
Nontrivial
MVD – a MVD which is not trivial. That is, X
Y where Y is not a subset of X, nor is X
Y equal to R. [ p516]
Normal
Form – a convention for good database design. See First
Normal Form, Second Normal Form, etc up to Fifth Normal Form. Also
Boyce-Codd Normal Form. [ p120] Also: The Normal Form of a
relation is the highest normal form it satisfies. [ p484]
Normalization
– the process of changing a database design to comply with the
various normal forms. [ p121]
Normalization
Algorithm – an algorithm for taking an unnormalized
relation and putting it into a higher normal form. [ p501]
Not
exists – SQL keyword. Used with nested queries. Not exists
(Query) returns true if Query returns no rows at all.
[ p126]
Not in
– SQL keyword. Used with nested queries. Attr not in
(Query) is equivalent to Attr <> all (Query).
[ p127]
Not
null – SQL keyword. Constraint that the given attribute may
not be null. [ p93] Part of a where clause of a query. See ‘is’.
[ p106]
Noun-phrase
analysis – a tool for identifying concepts, where noun
phrases in the requirements documents are sought. [ p135]
Null
– SQL keyword indicating a null value. See also ‘not
null’ [ p92] Part of a where clause of a query. See ‘is’
[ p106] Used with update…set to change the value of an
attribute to null. [ p130]
Null
Value – a special value a tuple can assume on an attribute,
denoting an absence of information. See Unknown Value, Non-existent
Value and No-information. [ p26]
Numeric
– SQL keyword: domain of exact numbers, either integral or with
a given number of decimal places. See also decimal. [ p88]
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O2
– a specific example of an OODBMS. [ p299]
Object
Data Model – A data model encapsulating an object-oriented
approach. [ p5]
Object
Identifier – see OID.
Object
Identity – the property of OODBMSs that Objects have OIDs.
[ p416]
Object-Oriented
Analysis – an analysis of a problem domain that divides it
according to objects and classes, that is, things and types. [
p132]
Object-Valued
– an object valued property is a property whose value is an
instance of an object, that is, an OID of an object. [ p401]
ODBC
– ‘Other Database Connectivity’. A standard
protocol that allows applications to communicate with databases
without having to know in advance which particular database server
products it will need to connect to. [ p179]
Of
– SQL keyword. Part of the syntax used to declare (create)
cursors. See ‘cursor for’ [ p140]
Of
Type - SQL-3 keyword used to define a table whose rows are of a
predefined tuple type. [ p423]
OID
– Object Identifier. A key used to uniquely identify an object.
[ p399]
OODBMS
– Object-Oriented DBMS. [ p398]
On
– SQL keyword. See On delete, On update [ p96]. SQL keyword:
Used to specify conditions on how a join should be performed [
p109] Used to specify the resource in a grant or revoke statement.
[ p137,138] Used to specify the table and attributes in ‘create
index’. [ p343]
On
Delete – SQL keyword. The beginning of a clause indicating
the behaviour of the RDBMS when an object is deleted when there are
other objects dependent on it. See cascade, set null, set default, no
action, on update, on delete. [ p96]
One-to-Many
Association – an association between two classes A and B,
where each A may be associated with many B’s, but each B is
only associated with one A. See Multiplicity. [ p283]
One-to-One
Association – an association between two classes A and B,
where each A is associated with only one B, and vice-versa. See
Multiplicity. [ p283]
On
Update – SQL keyword. The beginning of a clause indicating
the behaviour of the RDBMS when an object is changed when there are
other objects dependent on it. See cascade, set null, set default, no
action, on update, on delete. [ p96]
Open
– SQL keyword. Used to run the query associated with a cursor,
and begin to manipulate the data. See ‘cursor’. Syntax:
open cursorname. [ p140]
Optimisation
– the process of choosing “the best” of several
equivalent forms of a query, for example (in ‘cost-based’
optimisation) choosing the form with the lowest estimated cost (see
‘cost model’). [ p333]
Or
– SQL keyword: Used as a Boolean operator to construct the
where clause of a query. [ p105]
ORDBMS
– Object-Relational DBMS. An RDBMS with some Object-Oriented
concepts added. An example is SQL-3. [ p423]
Order
by – SQL keyword: Used to sort the output of a query. See
asc, desc. [ p113]
Ordered
– UML keyword: Used to denote that objects associated with
another are to be kept in some order. [ p423]
Ordered
Association – an association where the Ordered keyword is
applied. [ p286]
Orthogonal
– the constructors for various data types in O2 and SQL are
‘orthogonal’, meaning they can be arbitrarily nested.
[ p399]
Other
Database Connectivity – see ODBC.
Outer
Join – a natural join augmented with tuples derived from
tuples of r1 or r2 for which no matching tuple in the other relation
exists. New tuples are padded with blanks for the missing values. See
left outer join, right outer join and full outer join. [ p53]
Output
parameter – the data that a method returns back to the
caller. That is, the return value. [ p405]
Overloading
– see Method Overloading.
Overriding
– see Method Overriding.
Ownership
– a package ‘owns’ a class if the package contains
the class. [ p424]
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Package
– used to group together classes which are similar or related
in some way, to ease the software development process. [ p424-425]
Page
– a block of memory. [ p321]
Parameter
– see Input parameter, Output parameter. [ p405]
Partial
Dependency – a functional dependency X
Y where X’ Y also
holds for some proper subset X’ of X. See also ‘full
functional dependency’ [ p488]
Partition
– see Conceptual Class Partition.
Persistent
– the lifespan of a database extends beyond that of the program
using it. [ p4] The lifespan of an object extends beyond the
execution of the program using it. [ p411-412]
Pipelining
– a memory-saving technique of performing several operations
tuple by tuple, and so not storing intermediate tables. [ p341]
Physical
Independence – (see Data Independence) the interaction with
the DBMS does not depend on how the data is physically stored on the
disk (or elsewhere). [ p7]
PL/SQL
– an extension of SQL marketed by Oracle. [ p146]
Pointer-based
model – a logical data model where pointers are used to
refer to data in different parts of the database. [ p21]
Polymorphic
value – a value that may belong to any of a number of
types. An example is ‘nil’ (the null value). [ p399]
Predicate
– a function associating a value True or False with an instance
of a database [ p29]
Prepare
- SQL keyword. Used to prepare an SQL command from a string for
later use. Syntax: prepare CommandName from SQLString.
See also ‘deallocate prepare’ [ p144]
PreparedStatement
– a class in java.sql that represents a precompiled SQL
command. [ p182]
Primary
Key – a key (in the second sense) that is constrained to
not contain null values [ p33] An arbitrarily selected Candidate
Key used for identification of tuples in a relation. [ p485]
Primary
key – SQL keyword. A constraint that the given attribute(s)
form the primary key of the table. [ p94]
Prime
Attribute – an attribute which is a member of some
candidate key. Contrast with ‘nonprime attribute’ [
p485]
Privacy
– Each user is qualified to perform only certain actions on the
database. [ p4]
Private
method – a method that may only be called by other methods
of the same class. See ‘public method’ [ p405]
Privilege
– a ‘permission’ to do something on some component
of a database (some ‘resource’) [ p136]
Procedure
– SQL keyword. Used to define a procedure. Under standard SQL,
a procedure may only contain a single SQL statement. Many DBMSs relax
this restriction. [ p145]
Projection
– An operator that takes a relation and returns a new relation
whose attributes are a subset of the original. [ p47-48] The
projection of a set F of functional dependencies onto a relation
schema R is the set of all X
Y in F+ such that X and Y are subsets of R. Denoted pR(F).
[ p503]
Projective
Rule – An inference rule for functional dependencies. Also
called Decomposition Rule. If X
YZ then X Y (and X
Z). [ p479]
Proof
by Contradiction – a method of proof where one assumes the
opposite of the thing one is trying to prove, and deduces a
contradiction. [ p479]
Properties
– The properties of an object are the data members that make up
the object, that is, the attributes of the type of the object. [
p400]
Pseudotransitive
Rule – an inference rule for functional dependencies. If X
Y and WY
Z, then WX Z.
Public
method – a method that is accessible by any component of
the system. See ‘private method’ [ p405]
Push
(up or down) – a term used by Blaha to indicate a strategy
where a subclass or a superclass is not represented in the RDBMS, and
its attributes are stored in the superclass or subclass table
instead. [ p290]
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Read
only – SQL keyword. Used in the creation of a cursor to
indicate that the data returned by the query may not be modified.
[ p140]
Real
– SQL keyword. Domain of lower precision values. See double
precision, float. [ p89]
Record
– an ordered sequence of values of possibly different types.
[ p399]
Record-of
– O2 keyword allowing the construction of records. [ p399]
Record
source – Microsoft Access keyword. The property of a form
that indicates the source of the data it displays. [ p178]
Ref
– SQL-3 keyword. Used to define an attribute to have values
that reference a particular type of tuple. [ p424]
References
– SQL keyword: specifying a referential constraint. The
values of the given attribute(s) match values of other attributes in
other table. [ p95] SQL keyword denoting the privilege of being
able to use a table or attribute as a foreign key in ones own tables.
[ p137] In Object-Oriented Analysis: a class references another if
it uses or is associated with it. A package references a class if any
of its classes do. See dependency. [ p424]
Referential
Constraint – (also: foreign key constraint). A constraint
ensuring, for a set of attributes A of a relation r1, and a
corresponding set of attributes B of r2, and is a key (the primary
key?) for r2, that for every tuple t1 of r1, there exists a tuple t2
of r2 for which t1[A] = t2[B]. [ p34,35]
Refinement
– properties and a method’s input parameters can be
refined by giving them new types which are subtypes (or in some
cases, supertypes) of the original types. See ‘covariance’
and ‘contravariance’ [ p414]
Reflexive
Association – an association of a concept with
itself. [ p423]
Reflexive
Rule – An inference rule for functional dependencies. If Y
is a subset of X, then Y is functionally dependent on X. An
alternative (but not equivalent) definition: X is functionally
dependent on X. [ p479]
Reflexivity
– the property of a DBMS that it can store, as data, data about
data. See Metadata, Dictionary. [ p99]
Relation
– a subset of a Cartesian product [ p16] More usually, in
database theory, a collection of tuples [ p19,22]
Relation
Instance – a relation, in the second sense. [ p22]
Relational
Data Model – a data model using tables (relations) to
organise data. [ p5, 15]
Relational
Synthesis Algorithm – an algorithm for decomposing a
(universal) relation schema into a decomposition with the dependency
preservation property. Examples are algorithms 15.1 and 15.4 of
Elmasari. Contrast with Decomposition Algorithm. [ p504, 505, 509]
Relation
Profile – statistical information about a relation, such as
the number of tuples, the number of bytes per tuple, etc. Used in
cost-based optimisation to estimate the cost. [ p333-334]
Relation
Schema – the name of the relation R, and a set X of names
of the attributes. Normally denoted R(X). [ p22]
Relative
– SQL keyword. Used in a ‘fetch’ statement to move
a given number of rows forwards or backwards in the query. [ p141]
Reliability
– the DBMS is able to preserve the contents of the DB. [ p4]
Even if some components or operations fail. [ p417]
Renaming
– an operator on a relation that changes the name of an
attribute. It may be used to allow unions etc of relations with
similar but differently-named schemas. [ p44]
Replication
Rule – an inference rule for MVDs and FDs. {X
Y} 
X Y. [
p517]
Resource
– a component of a database (usually a table, view or
attribute) on which privileges may be granted or revoked to or from
users. [ p136]
Restrict
– SQL keyword. Used to disallow a drop command if components
exist that depend on the “dropped’ component. [ p98]
SQL keyword. Causes a revoke command to fail if the revocation would
cause other privileges to also be revoked. [ p138]
ResultSet
– a class in java.sql containing the results of the execution
of a select command. [ p182]
ResultSetMetaData
– a class in SQL containing information (attribute names and
types) about a ResultSet [ p182]
Returns
– SQL-3 keyword. Used to denote the type and/or value that a
function returns. [ p426]
Revoke
– SQL keyword. Used to remove privileges from users. Syntax:
revoke priv on res from users [restrict |
cascade]. [ p138]
Right
outer join – an outer join r1 RIGHT
r2 where dangling tuples from r2 are padded with blanks and inserted
into the join. [ p53]
Right
[Outer] Join – SQL keyword: used to join two tables before
selecting from them. See join. [ p109]
Role
– one end of an association. May have a name, multiplicity and
navigability. [ p157]
Row
type – SQL-3 keyword used to create and manipulate tuple
types. [ p423]
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Scan
Operation – a sequential access to all tuples of a table,
perhaps performing various operations on the tuples along the way.
[ p336]
Schema
– the characteristics of the data (not the data itself) within
the database. [ p6]
Schema
(of a relation or table) – its heading (or name), followed by
(in brackets) the names of its attributes. Eg “TEACHING(Course,
Tutor)” [ p6]
Schema
– SQL keyword specifying that an operation acts on a database
schema object. [ p90]
Scope
for – SQL-3 keyword. Used to specify that the give
attribute must take values from a given table. Syntax: ‘scope
for Attr is Table’ [ p425]
Scroll
– SQL keyword. Used when creating a cursor to indicate that a
program should be allowed to move freely across the results of a
query. See ‘cursor for’ [ p140]
Second
– SQL keyword. Used to specify interval attributes. [ p90]
Secondary
Key – a Candidate Key which was not selected to be the
Primary Key. [ p485]
Second
Normal Form – a nonkey field in a table must be information
about the whole key, not just part of the key. [ p121] Every
nonprime attribute is fully functionally dependent on the primary
key. [ p488] Alternatively, on some cadidate key (not just the
primary key). [ p491]
Select
– SQL keyword. Used to construct a query. Specifies what
attributes to select. [ p101] SQL keyword denoting the privilege
of being able to query a table, view or attribute via a select
statement. [ p137]
Selection
– an operator that takes a relation and returns a new relation
on the same attributes, with only those rows satisfying a given
Boolean expression (prepositional formula). [ p45,46]
Semantics
– the semantics of a schema gives its meaning, that is, how the
tables and attributes correspond to real-world things. [ p467]
Sequence
– Oracle SQL Keyword: ‘create sequence SequenceName’
creates a “sequence” of integers. If a record is inserted
with SequenceName as the data value, the next interger in the
sequence will be inserted. See Identifier Domain. [ p278]
Sequentially
ordered organisation – a way data may be arranged in memory
(primary or secondary). The sequence of tuples is dictated by values
assumed by attributes in the tuples. [ p324]
Set
– SQL keyword. Used with ‘update’ to modify the
data in a table. Specifically, ‘set’ identifies the
attribute(s) to be modified, and their new values. [ p130] An
unordered collection of objects of the same type, with no duplicates.
[ p399] SQL-3 keyword. An aggregate operator that returns a set of
the grouped data. [ p428]
Set
constraints – SQL keyword. Used to specify whether a given
constraint should be checked every time an operation is performed on
the database, or only at the end of a ‘transaction’. See
immediate, deferred. [ p133]
Set
default – SQL keyword. Indicates behaviour of the RDBMS
when an object is modified (deleted or changed) when there are other
objects dependent on it. See cascade, set null, set default, no
action, on update, on delete. [ p96]
Set
null – SQL keyword. Indicates behaviour of the RDBMS when
an object is modified (deleted or changed) when there are other
objects dependent on it. See cascade, set null, set default, no
action, on update, on delete. [ p96]
Setof
- SQL-3 keyword allowing the construction of sets. [ p424]
Set-of
– O2 keyword allowing the construction of sets. [ p399]
Set-oriented
approach – the manipulation of data in sets, as in SQL. See
tuple-oriented approach, impedance mismatch. [ p139]
Shared
Aggregation – An aggregation where the ‘part’
may belong to more than one ‘whole’. Contrast with
Composition. [ p416]
Show
plan – SQL keyword. Used to identify how a particular query
will be executed. In particular this will show what indexes (if any)
are being used. [ p343]
Signature
– see ‘Method Signature’.
Simple
Attribute – basic data type such as text, number, date,
time, Boolean, enumerated type, and so on. [ p168]
Smallint
– SQL keyword. Domain of small integers. See also integer.
[ p88]
Software
Class Hierarchy – a class hierarchy implemented in
software. [ p409]
Sort
Operation – the action of sorting the data stored in the
database. [ p336]
Specification
Class – a class used to contain information about objects
of another class. [ p141]
Specialization
– The process where from a general concept, more specific
concepts are derived. See Generalization, Subclass. [ p396] A form
of migration, where an object moves from a superclass to a subclass.
[ p410]
Spurious
Tuple – a tuple in a join between two (badly designed)
relations that contains wrong information, even though the original
relations contained correct information. See also ‘lossless
join property’ [ p473-475]
SQL
– a standard language, the “structured query language”,
incorporating DDL and DML features, used to manipulate databases.
Available in most commercial RDBMSs. [ p85]
SQLException
– an exception thrown by the executeXXX methods of Statement if
there are problems with the statement. [ p189]
Sum
– SQL keyword. Used to perform an aggregate query that adds up
the values of an attribute. [ p114]
State
(of a database) – see Instance.
State
(of an object) – the values of its attributes. [ p402]
Statement
– a class in java.sql that includes methods for sending SQL
commands to the database server. [ p182]
Static
properties – that part of a class or type definition
describing the structure of the objects (that is, the data). See
dynamic properties. [ p399]
Structural
Complexity (of objects) – the fact that objects can be of
types formed from arbitrarily nested complex data type constructors.
[ p400]
Structured
Analysis – an analysis of a problem domain that divides it
according to functions and procedures. [ p132]
Structured
Domain – A data type that has a complex structure, eg
Address. [ p281]
Structured
Query Language – See SQL.
Subclass
– a specialization of a superclass. Related to the superclass
via an ‘is-a’ relationship. The <subclass>
is a <superclass> [ p396]
Superclass
– a generalization of a subclass. Related to the subclass via
an ‘is-a’ relationship. The <subclass> is a
<superclass> [ p396]
Superficial
Equality – Two objects are superficially equal if they have
the same state. Superficial equality implies deep equality, but not
vice versa. See also identical. [ p402]
Superkey
– a set of attributes A for a relation r for which there are no
two distinct tuples t1 and t2 in r for which t1[A] = t2[A]. (see also
key). [ p31]
Symbol
– words or images used to represent a conceptual class [
p131]
Symmetric
Association – a Reflexive Association where the two Roles
are interchangeable. Example: Person is-a-friend-of Person. See
Reflexive Association, Role. [ p286]
Synthesis
Algorithm – see ‘relation synthesis algorithm’.
System
– see ‘_system’.
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Table
– SQL keyword specifying that an operation acts on a table
object. [ p91]
Target
– the object to which a method is applied. [ p404]
Ternary
Association – an association between three different
classes. [ p285]
Theta-join
– the selection of a cartesian product. [ p54]
Third
Normal Form – A nonkey field must be information about the
key, not about other nonkey fields. [ p121] The relation must
satisfy 2NF, and there must be no nonprime attribute which is
transitively dependent on the primary key. [ p490] Alternatively,
if a nontrivial dependency X
A holds, either X is a superkey, or A is a prime attribute. [
p491] That is, every nonprime attribute is fully functionally
dependent and nontransitively dependent on every key. [ p493]
Three-tiered
architecture – a system architecture where user
applications (databse clients) do not communicate directly with a
DBMS (Database server) directly, but rather, communicate with other
software (middleware) as an intermediary. [ p177]
Time
– SQL keyword. Domain of time values. See also timestamp, time
zone.
Timestamp
– SQL keyword. Domain of date+time values. See also date, time,
time zone. [ p89]
Time
Zone – SQL keyword. See ‘with time zone’. [
p89]
To
– SQL keyword. Used to specify interval attributes. [ p90]
Used to specify the user in a ‘grant’ statement. [
p137]
Top-down
design – a design methodology that begins by creating a
conceptual model (a domain model), and translates this into a
collection of tables. [ p501]
Transformer
– a method used to change the data stored in an object. [
p405]
Transitive
Dependency – a functional dependency X
Y is a transitive dependency if there exists a set of attributes Z
which is not a subset (or equal to) any key, with X
Z and Z Y. See ‘third
normal form’ [ p489]
Transitive
Rule – An inference rule for functional dependencies. If X
Y and Y
Z, then X Z. [ p479]
for MVDs: {X
Y, Y Z}
X (Z-Y).
[ p517]
Trivial
Functional Dependency – a functional dependency X
Y where Y is a subset of X. [ p479]
Trivial
MVD – a MVD X
Y where either Y is a subset of X or X
Y = R. [ p516]
Tuple
– a function from a set of attributes to a collection of
elements from the domains of the attributes. Conceptually similar to
an ordered pair or triple etc. [ p19]
Tuple Constraint
– a form of intra-relational integrity constraint which may be
evaluated indivisually on single tuples of the relation. [ p29,30]
Tuple-oriented
approach – the manipulation of sets of data tuple by tuple,
as in a typical procedural language. See set-oriented approach,
impedance mismatch. [ p139]
Tuple
Type – in an ORDBMS, a type that describes the data in a
row. See also ‘row type’. [ p423]
Type
– a description of data and method signatures for an object.
Sometimes called ‘class’. [ p399]
Type
Constructor – syntax allowing complex types to be described
in terms of simpler ones. [ p399]
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UML –
a notation used for software and conceptual modelling. [ p10]
Unavoidable
Redundancy – a situation in a database schema where data
must be replicated and there is no way to modify the schema and
remove the redundancy. [ p125]
Under
– SQL-3 keyword used to link tables or types in a class
hierarchy. [ p425]
Unified
Modeling Language – see UML.
Uniform
Resource Locator – see URL.
Union
(of two relations) – the union of two relations r1 and r2 is
the set of tuples that belong to either r1 or r2. Note that r1 and r2
must be on the same schema for this to make sense in terms of
databases. [ p42] SQL keyword. Used to find the ‘union’
of the rows returned by a ‘select’ statement (query).
[ p120]
Union
Rule – see Additive Rule.
Unique
– SQL keyword. A constraint that the given attribute(s) must
take on unique values in the table. Cf. primary key. [ p93] SQL
keyword. Used to create an index for a key. See ‘index’.
[ p343]
Universal
Relation Schema – A (schema for a) single relation
containing all the attributes in the database, representing all the
information in the database. May be obtained by joining all the
tables in the database. [ p476, p502]
Universal
Relation Assumption – the assumption that every attribute
in the universal relation schema has a unique name. [ p502]
Unknown
Value – a null value indicating that the information exists
but is unknown. Eg, the unknown phone number for a person who is
known to have a phone. [ p23]
Unnesting
– flattening out a complex data structure, bringing some data
up from one level together with data on higher levels. [ p428]
Separating nested relations into separate tables so that the schema
complies with the first normal form. [ p488]
Update
– SQL keyword. Used with ‘set’ to modify data in a
table. Specifically, update identifies the table to be modified. [
p130] SQL keyword denoting the privilege of being able to modify
(update) the data in a table, view or attribute. [ p137] SQL
keyword indicating that a cursor may be used to modify the data
returned in a query. [ p140]
Update
Anomalies – inconsistencies that arise when the data in a
badly designed database is modified. See ‘insertion anomalies’,
‘deletion anomalies’, ‘modification anomalies’.
[ p470]
URL
– a text string giving the unique location of a resource on a
network (typically, on the internet) [ p177]
Usage
– SQL keyword. Denotes the privilege of being able to use a
domain in the definition of a table or schema. [ p137]
User
– someone who employs the database for his or her own
activities. [ p9]
User
– SQL keyword. In a default specification, indicates that the
defaults value is to be the username of the database user. [ p92]
Using
– SQL keyword. Used in an ‘execute’ statement to
indicate parameters to be fed into the wildcards of a previously
prepared SQL command. [ p144] Can also be used for the same
purpose when opening a cursor. [ p145]
was the major
text. It's a good book. I still refer to it.
r2}
C,D(r1)
B=”Fish”(r1)
