OCA /OCP Oracle Database 11g A ll-in-One Exam Guide- P105 potx

The background process responsible for recording the current redo byte address—the point in time up to which the DBWn has written changed data blocks to disk—and for signaling checkpoint

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ACID Atomicity, Consistency, Isolation, and Durability Four characteristics that a relational database must be able to maintain for transactions

ADDM Automatic Database Diagnostic Monitor A tool that generates performance tuning reports based on snapshots in the AWR

ADR Automatic Diagnostic Repository The default location for the alert log, trace files, and other information useful for fault finding

ADRCI The ADR command-line interface

AES Advanced Encryption Standard A widely used data encryption method

AL16UTF16 A Unicode fixed-width two-byte character set, commonly specified for the NLS character set used for NVARCHAR2, NCHAR, and NCLOB data types

alias In Oracle Net, a pointer to a connect string An alias must be resolved into the address of a listener and the name of a service or instance

ANSI American National Standards Institute A U.S body that defines a number of standards relevant to computing

987

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API Application programming interface A defined method for manipulating data, typically implemented as a set of PL/SQL procedures in a package

ARBn Background processes that perform extent movement between disks in an Automatic Storage Management (ASM) disk group during the rebalancing process triggered by adding a disk to or removing a disk from the group

ASA Automatic Segment Advisor An Oracle advisory tool that can recommend segments (tables or indexes) that are candidates for segment shrink

ASCII American Standard Code for Information Interchange A standard (with many variations) for coding letters and other characters as bytes

ASH Active session history A category of information in the AWR that records details of session activity

ASM Automatic Storage Management A logical volume manager (LVM) provided with the Oracle database

ASMM Automatic Shared Memory Management A technique for automating the allocation of memory to both the SGA and PGA structures

ASSM Automatic segment space management The method of managing space within segments by use of bitmaps

attribute One element of a tuple (aka a column)

AVG A function that divides the sum of a column or expression by the number of nonnull rows in a group

AWR Automatic Workload Repository A set of tables in the SYSAUX tablespace, populated with tuning data gathered by the MMON process

B

background process A process that is part of the instance: launched at startup

BFILE A large object data type that is stored as an operating system file The value

in the table column is a pointer to the file

bind variable A value passed from a user process to a SQL statement at statement execution time

BLOB Binary large object A LOB data type for binary data, such as photographs and video clips BLOBs do not undergo character set conversion when passed between

a session’s user process and server process

block The units of storage into which datafiles are formatted The size can be 2KB, 4KB, 8KB, 16KB, 32KB, or 64KB Some platforms will not permit all these sizes

BMR Block media recovery An RMAN technique for restoration and recovery of

individual data blocks, rather than complete datafiles

C

Cartesian product Sometimes called a cross join A mathematical term that

refers to the set of data created by multiplying the rows from two or more tables

together: every row is joined to every other row

CET Central European Time A time zone used in much of Europe (though not

Great Britain) that is one hour ahead of UTC, with daylight saving time in effect

during the summer months

character set The encoding system for representing data within bytes Different

character sets can store different characters and may not be suitable for all languages

Unicode character sets can store any character

check constraint A simple rule enforced by the database that restricts the values

that can be entered into a column

checkpoint An event that forces the DBWn to write all dirty buffers from the

database buffer cache to the datafiles

CKPT The checkpoint process The background process responsible for recording

the current redo byte address—the point in time up to which the DBWn has written

changed data blocks to disk—and for signaling checkpoints, which force DBWn to

write all changed blocks to disk immediately

client-server architecture A processing paradigm where the application is

divided into client software that interacts with the user and server software that

interacts with the data

CLOB Character large object A LOB data type for character data, such as text

documents, stored in the database character set

cluster A hardware environment where more than one computer shares access to

storage A RAC database consists of several instances on several computers opening

one database on the shared storage

cluster segment A segment that can contain one or more tables, denormalized

into a single structure

COALESCE A function that returns the first nonnull value from its parameter list

If all its parameters are null, then a null value is returned

column An element of a row: tables are two-dimensional structures, divided

horizontally into rows and vertically into columns

commit To make a change to data permanent

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complete recovery Following a restore of damaged database files, a complete recovery applies all redo to bring the database up to date with no loss of data

connect identifier An Oracle Net alias

connect role A preseeded role retained only for backward compatibility

connect string The database connection details needed to establish a session: the address of the listener and the service or instance name

consistent backup A backup made while the database is closed

constraint A mechanism for enforcing rules on data: that a column value must be unique, or may only contain certain values A primary key constraint specifies that the column must be both unique and not null

control file The file containing pointers to the rest of the database, critical

sequence information, and the RMAN repository

CPU Central processing unit The chip that provides the processing capability of a computer, such as an Intel Pentium or a Sun SPARC

CTWR Change Tracking Writer The optional background process that records the addresses of changed blocks, to enable fast incremental backups

D

data blocks The units into which datafiles are formatted, made up of one or more operating system blocks

data dictionary The tables and views owned by SYS in the SYSTEM tablespace that define the database and the objects within it

data dictionary views Views on the data dictionary tables that let the DBA investigate the state of the database

Data Guard A facility whereby a copy of the production database is created and updated (possibly in real time) with all changes applied to the production database

Data Pump A facility for transferring large amounts of data at high speed into, out of, or between databases

database buffer cache An area of memory in the SGA used for working on blocks copied from datafiles

database link A connection from one database to another, based on a username and password and a connect string

Database Replay An Oracle feature that can help assess the performance impact

of a workload captured from one system and replayed on another

datafile The disk-based structure for storing data.

DBA Database administrator The person responsible for creating and managing

Oracle databases—this could be you

DBA role A preseeded role in the database provided for backward compatibility

that includes all the privileges needed to manage a database, except that needed to

start up or shut down

DBCA The Database Configuration Assistant A GUI tool for creating, modifying,

and dropping instances and databases

DBID Database identifier A unique number for every database, visible in the DBID

column of the V$DATABASE dynamic performance view

DBMS Database management system, often used interchangeably with RDBMS

DBWn or DBWR The Database Writer The background process responsible for

writing changed blocks from the database buffer cache to the datafiles An instance

may have up to 20 database writer processes, DBW0 through DBWj

DDL Data Definition Language The subset of SQL commands that change object

definitions within the data dictionary: CREATE, ALTER, DROP, and TRUNCATE

deadlock A situation where two sessions block each other, such that neither

can do anything Deadlocks are detected and resolved automatically by the DIA0

background process

DECODE A function that implements if-then-else conditional logic by testing

two terms for equality and returning the third term if they are equal or, optionally,

returning some other term if they are not

DHCP Dynamic Host Configuration Protocol The standard for configuring

the network characteristics of a computer, such as its IP address, in a changing

environment where computers may be moved from one location to another

DIA0 The diagnosability process that detects hang and deadlock situations

DIAG The diagnosability process that generates diagnostic dumps

direct path A method of I/O on datafiles that bypasses the database buffer cache

directory object An Oracle directory: a object within the database that points to

an operating system directory

dirty buffer A buffer in the database buffer cache that contains a copy of a data

block that has been updated in memory and not yet written back to the datafile

DMnn Data Pump Master process The process that controls a Data Pump job—one

will be launched for each job that is running

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DML Data Manipulation Language The subset of SQL commands that change data within the database: INSERT, UPDATE, DELETE, and MERGE

DNS Domain Name Service The TCP mechanism for resolving network names into

IP addresses

domain The set of values an attribute is allowed to take Terminology: tables have rows; rows have columns with values Or: relations have tuples; tuples have attributes with values taken from their domain

DSS Decision Support System A database, such as a data warehouse, optimized for running queries as opposed to OLTP work

DWnn Data Pump Worker process There will be one or more of these launched for each Data Pump job that is running

E

easy connect A method of establishing a session against a database by specifying the address on the listener and the service name, without using an Oracle Net alias

EBCDIC Extended Binary Coded Decimal Interchange Code A standard developed

by IBM for coding letters and other characters in bytes

environment variable A variable set in the operating system shell that can be used by application software and by shell scripts

equijoin A join condition using an equality operator

F

fact table The central table in a star schema, with columns for values relevant to the row and columns used as foreign keys to the dimension tables

FGA Fine-grained auditing A facility for tracking user access to data, based on the rows that are seen or manipulated

flash recovery area A default location for all recovery-related files

Flashback Data Archive A database container object that retains historical data for one or more database objects for a specified retention period

Flashback Database A flashback feature that recovers the entire database to a prior point in time using Flashback Database logs

Flashback Database logs Changed database blocks that are stored in the flash recovery area and used for Flashback Database

Flashback Drop A flashback feature that makes it easy to recover dropped tables

if they are still in the recycle bin

Flashback Query A flashback feature that enables you to view table rows at a

prior point in time

Flashback Table A Flashback Query that recovers a single table and its associated

objects to a prior point in time

full backup A backup containing all blocks of the files backed up, not only those

blocks changed since the last backup

G

GMT Greenwich Mean Time Now referred to as UTC, this is the time zone of the

meridian through Greenwich Observatory in London

grid computing An architecture where the delivery of a service to end users is

not tied to certain server resources but can be provided from anywhere in a pool of

resources

GROUP BY A clause that specifies the grouping attribute rows must have in

common for them to be clustered together

GUI Graphical user interface A layer of an application that lets users work with the

application through a graphical terminal, such as a PC with a mouse

H

HTTP Hypertext Transfer Protocol The protocol that enables the World Wide Web

(both invented at the European Organization for Nuclear Research in 1989)—this is a

layered protocol that runs over TCP/IP

HWM High water mark This is the last block of a segment that has ever been

used—blocks above this are part of the segment but are not yet formatted for use

I

I/O Input/output The activity of reading from or writing to disks—often the slowest

point of a data processing operation

image copy An RMAN copy of a file

inconsistent backup A backup made while the database was open

incremental backup A backup containing only blocks that have been changed

since the last backup was made

INITCAP A function that accepts a string of characters and returns each word in

title case

inner join When equijoins and nonequijoins are performed, rows from the source

and target tables are matched These are referred to as inner joins

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instance recovery The automatic repair of damage caused by a disorderly shutdown of the database

INSTR A function that returns the positional location of the nth occurrence of a

specified string of characters in a source string

IOT Index-organized table A table type where the rows are stored in the leaf blocks

of an index segment

IP Internet Protocol Together with the Transmission Control Protocol, TCP/IP: the

de facto standard communication protocol used for client/server communication over

a network

IPC Inter-Process Communications protocol The platform-specific protocol, provided by your OS vendor, used by processes running on the same machine to communicate with each other

ISO International Organization for Standardization A group that defines many standards, including SQL

J

J2EE Java 2 Enterprise Edition The standard for developing Java applications

JOIN ON A clause that allows the explicit specification of join columns

regardless of their column names This provides a flexible joining format

JOIN USING A syntax that allows a natural join to be formed on specific columns with shared names

joining Involves linking two or more tables based on common attributes Joining allows data to be stored in third normal form in discrete tables, instead of in one large table

JVM Java Virtual Machine The runtime environment needed for running code written in Java Oracle provides a JVM within the database, and there will be one provided by your operating system

L

large pool A memory structure within the SGA used by certain processes:

principally shared server processes and parallel execution servers

LAST_DAY A function used to obtain the last day in a month given any valid date item

LDAP Lightweight Directory Access Protocol The TCP implementation of the X25 directory standard, used by the Oracle Internet Directory for name resolution,

security, and authentication LDAP is also used by other software vendors, including

Microsoft and IBM

LENGTH A function that computes the number of characters in a string, including

spaces and special characters

LGWR The Log Writer The background process responsible for flushing change

vectors from the log buffer in memory to the online redo log files on disk

library cache A memory structure within the shared pool, used for caching SQL

statements parsed into their executable form

listener The server-side process that listens for database connection requests from

user processes and launches server processes to establish sessions

LOB Large object A data structure that is too large to store within a table LOBs

(Oracle supports several types) are defined as columns of a table but physically are

stored in a separate segment

log switch The action of closing one online logfile group and opening another:

triggered by the LGWR process filling the first group

LRU Least recently used LRU lists are used to manage access to data structures,

using algorithms that ensure that the data that has not been accessed for the longest

time is the data that will be overwritten

LVM Logical Volume Manager A layer of software that abstracts the physical storage

within your computer from the logical storage visible to an application

M

MMAN The Memory Manager background process, which monitors and reassigns

memory allocations in the SGA for automatically tunable SGA components

MML Media Management Layer Software that lets RMAN make use of automated

tape libraries and other SBT devices

MMNL Manageability Monitor Light The background process responsible for

flushing ASH data to the AWR, if MMON is not doing this with the necessary

frequency

MMON The Manageability Monitor is a background process that is responsible for

gathering performance monitoring information and raising alerts

MOD The modulus operation, a function that returns the remainder of a division

operation

MONTHS_BETWEEN A function that computes the number of months between

two given date parameters and is based on a 31-day month