Appendix B

Glossary

ActiveX control:
A reusable software component that can be added to an application, reducing development time in the process. ActiveX is a Microsoft technology; ActiveX components can be used only by developers who work on Windows development systems.
aggregate function:
A function that produces a single result based on the contents of an entire set of table rows; also called a set function.
alias:
A short substitute or nickname for a table name.
applet:
A small application written in the Java language, stored on a web server that’s downloaded to and executed on a web client that connects to the server.
application program interface (API):
A standard means of communicating between an application and a database or other system resource.
assertion:
A constraint specified by a CREATE ASSERTION statement (rather than by a clause of a CREATE TABLE statement). Assertions commonly apply to more than one table.
atomic:
Incapable of being subdivided.
attribute:
A component of a structured type or relation.
back end:
That part of a database management system (DBMS) that interacts directly with the database.
catalog:
A named collection of schemas. See also schema.
client:
An individual user workstation that represents the front end of a DBMS — the part that displays information on a screen and responds to user input. See also front end.
client/server system:
A multiuser system in which a central processor (the server) is connected to multiple intelligent user workstations (the clients).
cluster:
A named collection of catalogs. See also catalog.
CODASYL DBTG database model:
The network database model. Note: This use of the term network refers to the structuring of the data (network as opposed to hierarchy) rather than to network communications.
collating sequence:
The ordering of characters in a character set. All collating sequences for character sets that have the Latin characters (a, b, c) define the obvious ordering (a, b, c, …). They differ, however, in the ordering of special characters (+, -, <, ?, and so on) and in the relative ordering of the digits and the letters.
collection type:
A data type that allows a field of a table row to contain multiple objects.
column:
A table component that holds a single attribute of the table.
composite key:
A key made up of two or more table columns.
conceptual view:
The schema of a database. See also schema.
concurrent access:
Two or more users operating on the same rows in a database table at the same time.
constraint:
A restriction you specify on the data in a database.
constraint, deferred:
A constraint that isn’t applied until you change its status to immediate or until you COMMIT the encapsulating transaction.
cursor:
An SQL feature that specifies a set of rows, an ordering of those rows, and a current row within that ordering.
Data Control Language (DCL):
That part of SQL that protects the database from harm.
Data Definition Language (DDL):
That part of SQL used to define, modify, and eradicate database structures.
Data Manipulation Language (DML):
That part of SQL that operates on database data.
data redundancy:
Having the same data stored in more than one place in a database.
data source:
A source of data used by a database application. It may be a database, a spreadsheet, or a flat data file.
data sublanguage:
A subset of a complete computer language that deals specifically with data handling. SQL is a data sublanguage.
data type:
A set of representable values.
database:
A self-describing collection of integrated records.
database, enterprise:
A database containing information used by an entire enterprise.
database, personal:
A database designed for use by one person on a single computer.
database, workgroup:
A database designed to be used by a department or workgroup within an organization.
database administrator (DBA):
The person ultimately responsible for the functionality, integrity, and safety of a database.
database engine:
That part of a DBMS that directly interacts with the database (serving as part of the back end). See also back end.
database management system (DBMS):
A set of computer programs that controls the creation, maintenance, and use of databases.
database publishing:
The act of making database contents available on the Internet or over an intranet.
database server:
The server component of a client/server system — the place where the database resides. See also client/server system.
DB2:
A relational database management system (RDBMS) marketed by IBM Corp.
deletion anomaly:
An inconsistency in a multitable database that occurs when a row is deleted from one of its tables.
denial-of-service attack:
An attack on a website mediated by a flood of messages coming in from large numbers of worm-infected computers that have been programmed to send a message to the target site at a specific time, overwhelming the site’s ability to handle the traffic. See also worm.
descriptor:
An area in memory used to pass information between an application’s procedural code and its dynamic SQL code.
diagnostics area:
A data structure, managed by the DBMS, that contains detailed information about the last SQL statement executed and any errors that occurred during its execution.
distributed data processing:
A system in which multiple servers handle data processing.
domain:
The set of all values that a database item can assume.
domain integrity:
A property of a database table column in which all data items in that column fall within the domain of the column.
driver:
That part of a DBMS that interfaces directly with a database.
driver manager:
A component of an ODBC-compliant database interface. On Windows machines, the driver manager is a dynamic link library (DLL) that coordinates the linking of data sources with appropriate drivers. See also Open Database Connectivity (ODBC).
entity integrity:
A property of a database table that is entirely consistent with the real-world object that it models.
exploit:
An action that takes advantage of a security weakness of a software system to penetrate the system for a malicious purpose.
Extensible Markup Language (XML):
A widely accepted markup language used as a means of exchanging data between dissimilar systems.
file server:
The server component of a resource-sharing system. It doesn’t contain any database management software.
firewall:
A piece of software (or a combination of hardware and software) that isolates an intranet from the Internet, allowing only trusted traffic to travel between them.
flat file:
A collection of data records that contains only data — no metadata.
foreign key:
A column or combination of columns in a database table that references the primary key of another table in the database.
forest:
A collection of elements in an XML document.
front end:
That part of a DBMS (such as the client in a client/server system) that interacts directly with the user.
functional dependency:
A relationship between or among attributes of a relation.
hierarchical database model:
A tree-structured model of data.
host variable:
A variable passed between an application written in a procedural host language and embedded SQL.
Hypertext Markup Language (HTML):
A standard formatting language for web documents.
implementation:
A particular RDBMS running on a specific hardware platform.
index:
A table of pointers used to locate rows in a data table rapidly.
information schema:
The system tables, which hold the database’s metadata. See also metadata.
insertion anomaly:
An inconsistency introduced into a multitable database when a new row is inserted into one of its tables.
Internet:
The worldwide network of computers.
intranet:
A network that uses World Wide Web hardware and software but restricts access to users within a single organization.
IPX/SPX:
A local area network (LAN) protocol.
Java:
A platform-independent compiled language designed originally for web application development but now used in many contexts.
Java-Based Database Connectivity (JDBC):
A standard interface between a Java applet or application and a database. The JDBC standard is modeled after the ODBC standard. See also Open Database Connectivity (ODBC).
JavaScript:
A script language that gives some measure of programmability to HTML-based web pages.
join:
A relational operator that combines data from multiple tables in a single result table.
JSON:
An open standard file format used for asynchronous browser/server communication.
logical connectives:
Used to connect or change the truth value of predicates to produce more-complex predicates.
malware:
Software written to accomplish a malicious purpose.
mapping:
The translation of data in one format to another format.
metadata:
Data about the structure of the data in a database.
modification anomaly:
A problem introduced into a database when a modification (insertion, deletion, or update) is made in one of the database tables.
module:
A container for SQL statements.
module language:
A form of SQL in which SQL statements are placed in modules, which are called by an application program written in a host language.
mutator function:
A function associated with a user-defined type (UDT), having two parameters whose definition is implied by the definition of some attribute of the type. The first parameter (the result) is of the same type as the UDT. The second parameter has the same type as the defining attribute.
nested query:
A statement that contains one or more subqueries.
NetBEUI:
A LAN protocol.
network database model:
A way of organizing a database to get minimum redundancy of data items by allowing any data item (node) to be directly connected to any other.
normalization:
A technique that reduces or eliminates the possibility that a database will be subject to modification anomalies.
object:
Any uniquely identifiable thing.
Open Database Connectivity (ODBC):
A standard interface between a database and an application that’s trying to access the data in that database. ODBC is defined by an international (ISO) and a national (ANSI) standard.
Oracle:
An RDBMS marketed by Oracle Corp.
parameter:
A variable within an application written in SQL module language.
phishing scam:
A social-engineering ploy that induces victims to surrender confidential information by claiming to be a trusted source.
precision:
The maximum number of digits allowed in a numeric data item.
predicate:
A statement that may be either logically true or logically false.
primary key:
A column or combination of columns in a database table that uniquely identifies each row in the table.
procedural language:
A computer language that solves a problem by executing a procedure in the form of a sequence of steps.
query:
A question you ask about the data in a database.
rapid application development (RAD) tool:
A proprietary, graphically oriented alternative or supplement to SQL. Several such tools are on the market.
record:
A representation of some physical or conceptual object.
reference type:
A data type whose values are all potential references to sites of one specified data type.
referential integrity:
A state in which all the tables in a database are consistent with one another.
relation:
A two-dimensional array of rows and columns containing single-valued entries and no duplicate rows.
reserved words:
Words that have a special significance in SQL and can’t be used as variable names or in any other way that differs from their intended use (refer to Appendix A).
row:
A sequence of (field name, value) pairs.
row pattern recognition:
A feature of the FROM clause that uses a MATCH_RECOGNIZE clause to retrieve rows that exhibit a pattern.
row value expression:
A list of value expressions enclosed in parentheses and separated by commas.
scale:
The number of digits in the fractional part of a numeric data item.
schema:
The structure of an entire database. The information that describes the schema is the database’s metadata. See also metadata.
schema owner:
The person who was designated as the owner when the schema was created.
SEQUEL:
A data sublanguage, created by IBM, that was a precursor of SQL.
set function:
A function that produces a single result based on the contents of an entire set of table rows; also called an aggregate function.
SQL:
An industry-standard data sublanguage specifically designed to create, manipulate, and control relational databases.
SQL, dynamic:
A means of building compiled applications that doesn’t require all data items to be identifiable at compile time.
SQL, embedded:
An application structure in which SQL statements are embedded within programs written in a host language.
SQL, interactive:
A real-time conversation with a database.
SQL injection attack:
An attempt to penetrate the defenses of an SQL database application to gain control of the underlying database.
SQL/DS:
An RDBMS marketed by IBM Corp.
structured type:
A UDT expressed as a list of attribute definitions and methods instead of being based on a single predefined source type.
subquery:
A query within a query.
subtype:
A subtype of a second data type if every value of the first type is also a value of the second type.
supertype:
A supertype of a second data type if every value of the second type is also a value of the first type.
table:
A relation.
teleprocessing system:
A powerful central processor connected to multiple dumb terminals (combination keyboard/display devices with no internal intelligence).
transaction:
A sequence of SQL statements whose effect isn’t accessible to other transactions until all the statements are executed.
transitive dependency:
A situation in which one attribute of a relation depends on a second attribute, which in turn depends on a third attribute.
translation table:
A tool for converting character strings from one character set to another.
Transmission Control Protocol/Internet Protocol (TCP/IP):
The network protocol used by the Internet and intranets.
trigger:
A small piece of code that tells a DBMS what other actions to perform after certain SQL statements have been executed.
Trojan horse:
A useful program that also has a secret payload. This payload, when activated inside a target computer, does what a malware writer wants rather than what the computer owner wants.
update anomaly:
A problem introduced into a database when a table row is updated.
user-defined type (UDT):
A type whose characteristics are defined by a type descriptor specified by the user.
value expression:
An expression that combines two or more values.
value expression, conditional:
A value expression that assigns different values to arguments, based on whether a condition is logically true.
value expression, datetime:
A value expression that deals with DATE, TIME, TIMESTAMP, or INTERVAL data.
value expression, numeric:
A value expression that combines numeric values using the addition, subtraction, multiplication, or division operator.
value expression, string:
A value expression that combines character strings with the concatenation operator.
value function:
A function that performs an operation on a single character string, number, or datetime.
view:
A database component that behaves exactly like a table but has no independent existence of its own.
virtual table:
A view.
virus:
A self-replicating piece of software that spreads by attaching itself to other programs or to documents.
World Wide Web:
An aspect of the Internet that has a graphical user interface. The web is accessed by applications called web browsers, and information is provided to the web by installations called web servers.
worm:
A self-replicating form of malware that spreads via networks.
zombie spambot:
One of a host of worm-infected computers spewing unsolicited advertising messages to lists of email addresses that the spammers have acquired. See also worm.
..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.
Reset
3.144.238.20