Oracle7 Getting Started for Windows NT

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Product

Contents

Index

Glossary

admin privileges The authorization to perform certain administrative procedures on a system.

alias (1)An alternative name for an existing network object, such as a host (server), or a set of parameters. (2) In SQL, a temporary name assigned to a table, view, column, or value within a SQL statement, used to refer to that item later in the same statement or in associated SQL*Plus commands. (3) In SQL*Net version 2.3, a nickname for a string by which a remote database can be accessed.

application One or more program modules used to achieve a specific result. Applications can be nested within other applications.

application system A name given to a collection of business functions, entities, programs, and tables that can be further described by system documentation of various forms. It is typically used to describe a unit of related work such as in a project, subsystem, or data subject area. The status of an application system may change (for example, it may be frozen), and new versions may be created. It is also a unit of access control to the collection of elements that it contains. Elements may be shared between application systems.

argument An independent variable whose value can be used to modify a command.

attribute (1) A property or characteristic of an object that determines the behavior or appearance of that object. (2) Any detail that serves to qualify, identify, classify, quantify, or express the state of an entity or object.

attribute descriptor A data structure that stores the attributes of an entity.

authenticate The process of verifying the identity of a user, device, or other entity in a computer system, often as a prerequisite to allowing access to resources in a system.

authorization Access permission given to a user, program, or process.

bitmap Definition of a physical bit image in terms of a coordinate plane. A bitmap has a height, width, and vertical and horizontal resolution.

call interface (1) A set of standard software routines used to access an Oracle database. Also called the OCI for Oracle Call Interface. (2) An interface that allows RUNREP and/or SQLREP to be linked with a user or other Oracle program.

child An object that is a member of a group, and is immediately below that group object in its group tree. The objects that compose a group object are children of that group. Every object is a child of its parent.

clause A part of a SQL statement that does not constitute the full statement; for example, a WHERE clause.

client-server architecture Software architecture based on a separation of processing between two CPUs, one acting as the client in the transaction, requesting and receiving services, and the other as the server that provides services in a transaction.

cursor (1) A handle for a context area that allows you to access and manipulate data in the context area. (2) A handle (a name or pointer) for the memory associated with a specific statement. Although most Oracle users rely on the automatic cursor handling of the Oracle utilities, the programmatic interfaces offer application designers more control over cursors. For example, in precompiler application development, a cursor is a named resource available to a program and can be specifically used for the parsing of SQL statements embedded within the application. The application developer can code an application so that it controls the phases of SQL statement execution and thus improve application performance.

data dictionary A comprehensive set of tables and views automatically created and updated by Oracle Server, which contains administrative information about users, data storage, and privileges.

domain A division of names guaranteed to be unique. Domains are related hierarchically in a naming model.

domestic domains The set of domains that are managed within a given administrative region.

dump file See trace file. dynamic data dictionary An online data dictionary is an integral part of the data source and always reflects the current definition of the data source. Data structures can be changed while the data source is being accessed. See also data dictionary.

DLL Data Link Libraries. Microsoft Windows operating systems executable files.

expression A formula, such as SALARY + COMMISSION, used to calculate a new value from existing values. An expression can be made up of column names, functions, operators, and constants. Formulas are found in commands or SQL statements.

forward type definition Similar to a forward declaration in a programming language such as C.

identifiers Not synonymous with REF, which contains an object identifier as well as other information necessary to locate an object. An identifier cannot be used independently to locate an object.

instance Combination of processes and threads that begins each time a database is started. Identified with a unique SID. A default instance, ORCL, is installed during installation of Oracle7. The background processes and memory areas required to access an Oracle database. A database system requires one instance and one database. Every Oracle instance has a single system global area (SGA); a multiple-user instance also requires several background processes.

instance recovery Recovery of an instance in the event of software or hardware failure, so that the database is again available to users. If the instance terminates abnormally, then instance recovery automatically occurs at the next instance startup.

instance failure Failure that occurs when a problem arises that prevents a database instance (SGA and background processes) from continuing work. Instance failure may result from a hardware problem such as a outage, or a software problem such as an operating system crash. When an instance failure occurs, the data in the buffers of the SGA is not written to the data files.

instance identifier A name or ID used to distinguish one instance from another when multiple instances exist on one CPU. The identifier is specified in a operating system specific manner.

instantiate The first time a PL/SQL package is called, it is instantiated. The package is read into memory. Memory is allocated for any variables defined in the package. Each session will have its own copy of packaged variables.

LOB The term LOB locator refers to the pointer to the LOB stored in the database column or object attribute. The locator is retrieved into a program variable in host-language programming environments and subsequently used in calls to access the LOB data.

LOB value refers to the actual value of the LOB stored out-of-line.

listener The server process that listens for and accepts incoming connection requests from client applications. Oracle listener processes start up Oracle database processes to handle subsequent communications with the client.

LISTENER.ORA A configuration file that describes one or more TNS listeners on a server.

library datatype Datatypes provided to the end-user by Oracle Corporation or a third-party developer.

logon string A user-specified command line, used to run an application that is connected to either a local or remote database. The logon string either explicitly includes a connect string or implicitly uses a default connect string.

long column Each entry in a long column can be up to 65,535 characters long. Users cannot apply SQL functions to long columns, nor use long columns in the CONDITIONS and SORT regions of the screen.

LONG datatype A standard Oracle datatype. A LONG column may contain any printable character, such as A, 3, &, or blanks, and can be any length from 1 to 65K characters; alternatively it can be null.

LONG RAW datatype A standard Oracle datatype similar to LONG, but which contains raw binary data. Values entered into LONG RAW columns must be in hexadecimal notation.

login account A username and password to use Oracle Server. This account is usually separate from an operating system account.

map To make a view visible on the display screen.

memory structures There are several basic memory structures associated with Oracle: the System Global Area (SGA) which includes the database and redo log buffers, and the shared pool, and the program global areas. Memory structures complete several jobs. For example, memory is used to store program code being executed and to store data that is shared among database users.

mode An indicator of the type of operator action allowed at any particular time. The runtime modes are normal, Enter Query, Edit, Insert, Replace, and Debug.

mount To associate a database with a started instance, in order to perform maintenance on the database or to open it and make it accessible to database users

multi-site update An update (DML statement) that affects multiple data tables (local or remote). Currently, a multi-site update in Oracle requires multiple statements; one statement can update one node only.

multi-user mode An Oracle Server operation in which many users may simultaneously access the database and thus share common data. This mode requires the background virtual computers, whereas single-user mode does not.

multi-instance mode A database that has been started (mounted and opened) in Shared mode, in the expectation that multiple instances will access it.

mounted database A database associated with an Oracle instance. The database may be opened or closed. A database must be both mounted and opened to be accessed by users. A database that has been mounted but not opened can be accessed by DBAs for some maintenance purposes.

major objects Major objects are collections of minor objects; for example, the DBA_USERID, BACKGROUND_MACHINES, and SHARED_SEGMENTS.

NLS National Language Support. Data can be entered, stored, and displayed in the language of the administrator's choice.

named object A user-accessible entity, uniquely identified by name, that contains data. Access to a named object implies the potential ability to read, write, or execute its contents. For example, named object could be a table.

named parameter A type of PL/SQL parameter. You can use named parameters in any order.

nested object An object whose datatype is a column or an attribute of another object type.

nested tables Use the CREATE TYPE statement to define a table type that can be nested within other object types or in one or more columns of a relational table.

nesting In programming or writing SQL statements, the placement of a structure within a like structure, as in placing a query within another query. In SQL, a nested query refers to one query that includes another.

network listener A listener on a server that listens for connection requests for one or more databases on one or more protocols.

network service In an Oracle application network, a service performs tasks for its service consumers; for example, a MultiProtocol Interchange provides protocol conversion services for clients, and a Names Server provides name resolution services for clients.

null The absence of a value for a given item. A null implies nothing more than "a value is not applicable" or " the value is unknown." Nulls are not equal to any other value, even to each other. Comparisons with nulls are always false. To prohibit null values, define a column as NOT NULL.

NULL Empty; describes an item, object, variable, etc. that has no value. Note that a NULL character text item is not the same as a blank text item or a text item whose value is zero characters long; similarly, a NULL numerical text item is not the same as a numerical text item whose value is zero.

NULL value The absence of a value.

NUMBER datatype A standard Oracle datatype. A NUMBER column can contain a number, with or without a decimal point and a sign, and can have from 1 to 105 decimal digits (only 38 digits are significant).

numerics Numbers 0-9, represented as text strings, unless specified otherwise.

\ORANT Default Oracle Home directory where the Oracle Installer installs Oracle7 Server.

OSI Stands for Open Systems Interconnection, a 7-layer abstract reference model for communications protocols in which each layer performs a specific task. The intent of the model is to allow different vendors on different hardware to communicate with each other at the same layer. The seven layers are physical, data link, network, transport, session, presentation, and application.

object In Oracle7, an instance of an object type. Objects can be persistent or transient datatypes (stored in the database vs. PL/SQL or OCI variables). Objects stored in rows of a database table have identifiers which allow the object to be referenced and shared. A named structure in the Oracle database, such as a table, index, or form. A group of data in a form that you can copy, move, or delete in a single operation.

object auditing The auditing of accesses to specific schema objects without regard to user. Object auditing monitors the statements permitted by object privileges, such as SELECT or DELETE statements on a given table.

object privileges Privileges granted (assigned) to end-users so that they can use a database application to accomplish specific tasks. Object privileges perform a particular action on a specific object. For example, the privilege to delete rows of a specific table is an object privilege.

open systems System components that implement standard non-proprietary interfaces, permitting communication with other systems implementing the same standards (interoperability).

object view Synthesizes (row) objects based on queries of (relational or object) tables. May expose an object identifier for each of the objects.

off-line redo log A redo log file that has been archived.

online redo log Redo log files that have not been archived, but are either available to the instance for recording database activity or are filled and waiting to be archived or reused.

online redo log file File that records all committed changes made to the database. Whenever a transaction is committed, the corresponding redo entries temporarily stored in redo log buffers of the SGA are written to an online redo log file by the background process LGWR. An online redo log file can be individual or mirrored; in the latter case, it is an online redo log group, made up of online redo log members.

Oracle Call Interface (OCI) An optional Oracle product that allows users to embed Oracle calls directly into high-level languages. It is the program call interface to an Oracle database. See also call interface.

Oracle7 Server A host system that runs a multi-user Oracle7 Relational Database Management System (RDBMS) and maintains at least one database that can be shared by remote clients. The term Oracle7 Server refers to the RDBMS that is using SQL*Net version 2.3 and is capable of serving Oracle clients.

Oracle7 Database The software used to create and maintain the database system, as well as the actual data stored in the database.

Oracle7 RDBMS The Oracle Relational Database Management System. Oracle7 Server for Windows NT is an Oracle RDBMS.

Oracle Protocol Adapters A set of products in which each one maps the functions of a given network protocol into TNS, so that TNS can act as an interface among all protocols. For example, there is a TCP/IP protocol adapter and a DECnet adapter. SQL*Net version 2.3 requires protocol adapters; the equivalent in SQL*Net V1 was the protocol driver component of SQL*Net version 2.3.

Oracle service Created and associated with Oracle7 database. Similar to Windows NT services.

Oracle System Identifier (SID) A unique name for an Oracle instance. To switch between Oracle databases, users must specify the desired SID. The SID is included in the CONNECT DATA parts of the connect descriptors in a TNSNAMES.ORA file, and in the definition of the TNS listener in the LISTENER.ORA file.

Oracle Tool Any Oracle application tool (such as SQL*Plus), an Oracle end-user tool (such as Oracle Forms), or a third-party software program that interfaces with an Oracle7 Server.

Oracle7 Server Utilities Oracle7 Server Utilities are included in the server software of your Oracle7 Server for Windows NT package. Oracle7 Server Utilities include: Server Manager, Import, Export, and SQL*Loader (all Windows NT versions).

outer join A type of join that returns rows from one table that do not satisfy the join condition, in addition to those that do satisfy the condition. Each additional row is joined to an imaginary row in the other table in which all the fields are null.

PL/SQL The Oracle procedural language extension of SQL. PL/SQL combines the ease and flexibility of SQL with the procedural functionality of a structured programming language, such as IF ...THEN, WHILE, and LOOP. Even when PL/SQL is not stored in the database, applications can send blocks of PL/SQL to the database rather than individual SQL statements, thereby reducing network traffic.

packages A method of encapsulating and storing related procedures, functions, and other package constructs together as a unit in the database. While packages provide the database administrator or application developer organizational benefits, they also offer increased functionality and database performance.

packet Information, including data and control elements, that is switched and transmitted as a whole unit of information. The data and control elements (and any error control information) are arranged in a specified format.

parallel mode An Oracle instance running in parallel mode can share access to the database with other instances in the same Oracle Parallel Server.

Parallel Server Some hardware architectures (for example, loosely coupled processors) allow multiple computers to share access to data, software, or peripheral devices. With systems that have the parallel server option, Oracle can take advantage of such hardware platforms by running multiple database instances that share a single physical database. In appropriate applications, the Oracle Parallel Server allows access to a single database by the users on multiple computers with increased database performance.

parameter (1) Object of a command. A parameter can be a file specification, a symbol value passed to a command procedure, or a word defined by the operating system. (2) In SQL*Plus, a substitution variable consisting of an ampersand followed by a numeral (&1, &2, etc.). See also argument. (3) A global variable that you can change at runtime.

parameter file File that contains information to initialize the database and instance.

parent An object that is immediately above another object in its group tree. A group object is the parent to each of the objects that compose it. Every object is the parent of its children.

parent-child relationship Way in which to define the relationship of a "primary key to foreign key" connection between two different tables.

parent (GUI Definition) Views within a window are related hierarchically, with a view's position within the hierarchy expressed relative to its parent. The parent may be a drawn view, scroll bar alley, or client-defined view. The parent is passed to the view creation function as an argument whenever one of its children is created.

parent group (Query Definition) A group that owns a query or another group.

parent key The unique key or primary key of the same or different table that is referenced by a foreign key. Individual values in a key are called key values.

parent query The outermost query (the one that displays a result) in a query containing a subquery. See also nesting.

parse A phase of SQL statement execution in which a SQL statement is examined and validated to make sure it is properly formed (it meets syntax rules) and that all necessary information is accessible, so Oracle Server can execute it. A parse error can occur because of incorrect syntax or naming of non-existent database objects.

parse lock A shared dictionary lock, acquired on behalf of a user who is referencing one or more tables in a SQL statement. Contrast to DDL lock.

password (1) A secondary identification word (or string of alphanumeric characters) associated with a username. A password is used for data security and known only to its owner. Passwords are entered in conjunction with an operating system login ID, Oracle username, or account name in order to connect to an operating system or software application (such as the Oracle database). Whereas the username or ID is public, the secret password ensures that only the owner of the username can use that name, or access that data.

port (1) One point of access to a CPU. (2) In TCP/IP, an address associated with a specific application. See also socket. (3) An operating system that supports Oracle Server. While much information regarding Oracle products is the same for all ports, some information necessarily varies depending on the operating system; this information is usually called port-specific or operating system dependent.

port parameters The set of parameters that defines the communications information for the local port.

portability The concept of being able to work under different operating systems in the same way. Applications developed for Oracle can be ported to any operating system with little or no modification.

precompiler A tool that allows a user to embed any SQL statement in a 3GL (host language) program. The precompiler takes this program as input and produces as output another program, in the same 3GL, in which all the embedded SQL calls are translated into host language procedure calls. This resulting program can be compiled, linked, and executed. Oracle supports precompilers for the languages C, FORTRAN, Pascal, PL/I, COBOL, and Ada.

predicate A portion of a SQL statement, typically the WHERE clause, which imposes a set of criteria on the data to be returned by a query. See also expression.

primary index An index used to improve performance on the combination of columns most frequently used to access rows in a table.

primary key In a database table, a set of columns used to enforce uniqueness of rows. The combination of column values is unique for each row in the table. The primary key is the most frequently-used means of accessing rows.

privilege A right to successfully execute a particular type of SQL statement. Some examples of privileges include rights to connect to the database (create a session), to create a table in your schema, to select rows from someone else's table, and to execute someone else's stored procedure. The privileges of an Oracle database can be divided into two distinct categories: system privileges and object privileges.

Pro*C An Oracle precompiler product that allows developers of C programs to embed standard database calls to an Oracle database in C programs to manipulate Oracle data.

Pro*COBOL An Oracle precompiler product that allows developers of COBOL programs to embed standard database calls to an Oracle database in COBOL programs to manipulate Oracle data.

procedure A set of SQL and PL/SQL statements grouped together as an executable unit to perform a very specific task. Procedures and functions are nearly identical; the only difference between the two is that functions always return a single value to the caller, while procedures do not return a value to the caller.

procedural gateway A gateway that is accessed using Oracle PL/SQL.

process (1) A thread of control in an operating system; that is, a mechanism in an operating system that can execute a series of steps. Some operating systems use the terms job or task. A process normally has its own private memory area in which it runs. An Oracle Server has two general types of processes: user processes and Oracle processes. (2) A synonym for "user," a single entity performing a set of tasks in an operating system environment or in a database.

process failure A failure in a user process accessing Oracle, such as an abnormal disconnection or process termination. The failed user process cannot continue work, although Oracle and other user processes can. Oracle background process PMON automatically detects the aborted user process (or is informed of it by SQL*Net version 2.3) and resolves the problem by rolling back the uncommitted transaction of the user process (if one was in progress) and releasing any resources that this process was using.

process-to-process communication Communication between two tasks, or processes, in which they coordinate to guarantee reliable data transmission. Same as task-to-task or peer-to-peer communication.

process-to-process protocol A communications protocol that provides services for programs on one computer to initiate processes on another computer, thus establishing a dialogue.

programmatic interface A procedural interface to the database that provides access to Oracle Server for user application programs. Examples are Pro*C and Pro*FORTRAN. The program interface is divided into two halves: the UPI and the OCI.

Process Monitor (PMON) One of five background tasks used by an Oracle instance. Process Monitor performs recovery when a process accessing a database terminates abnormally.

Protocol Adapter The software component of the Oracle Transparent Network Substrate (TNS) architecture that translates TNS function calls into requests to the underlying network protocol.

public Visible or available to all users. Though by default all objects are private, many database objects can be made public. An object that is not public is visible or available only to its creator. While only DBAs can create public synonyms or database links, any user may GRANT PUBLIC access to that user's own objects.

public synonym A synonym for a database object created by a DBA to make access to that object more convenient for all database users. Contrast with private synonym.

query A SQL SELECT statement that retrieves data, in any combination, expression, or order. Queries are read-only operations; they do not change any data, they only retrieve data.

query field A field on a screen that the user may enter solely for the purpose of qualifying a query on the database.

query language Defined syntax for the specification of queries. Language employed by the user to specify search criteria.

queue A file that stores requests until the system is ready to process them.

quota A limit on a resource, such as a limit on the amount of database storage used by a database user. A DBA can set tablespace quotas for each Oracle username.

RAW datatype A standard Oracle datatype, a RAW data column may contain data in any form, including binary. You can use RAW columns for storing binary (non-character) data.

raw mode A mode in which data is transmitted "as is," i.e., 8-bit data characters are directly transmitted across the link. Raw mode is only suitable for direct, computer-to-computer links.

read consistency A feature of all versions of Oracle Server that guarantees that the results of any query are a consistent set of data as of the time the query was executed. A read-consistent view of the data can be thought of as a "snapshot" of the data at the time the query began. See integrity (data).

redo log A sequential log of all changes made to the data. The redo log is written and used in the event that a failure caused the changes to fail to be written to disk; it is used to reapply the changes to disk. The redo log consists of two or more redo log files; one is optionally being saved while the other is being written by Oracle Server. When the file currently being written fills, the other file is reused. See also online redo log and off-line redo log.

redo log buffer Buffer that stores redo entries a log of changes made to the database. The redo entries stored in the redo log buffers are written to an online redo log file, which is used if database recovery is necessary. Its size is static.

redo log file A file containing records of changes to the databases. These files are used for recovery purposes. See also redo log.

redo log sequence number A number used to identify a redo log. It is used when applying the redo log files during recovery.

redo server An optional process that writes redo entries to the online redo log file for multiple instances of the Oracle Parallel Server on the nCUBE 2 supercomputer.

referenced object An object whose properties are used as the basis for creating one or more similar objects.

referential integrity A condition that guarantees that the values in one column also exist in another column. This guarantee is enforced through the use of integrity constraints.

referential integrity constraints A set of validation rules applied to an entity or table such as uniqueness constraints, domain validation of columns or correspondence of foreign keys to the primary key of their related table.

referential integrity rule A particular integrity constraint rule defined by a user to enforce referential integrity.

relation Synonym for table.

relation, relationship indication Hierarchical relationship between terms in the thesaurus structure. The relationship is expressed in: preferred term; non-preferred terms; synonyms, quasi-synonyms, abbreviations, acronyms; top term; broader term; related term.

relation object An object that defines the relationship between blocks in a master-detail relationship.

remark In SQL*Plus, a Comment you can insert into a command file with the REMARK command.

remote computer A computer on a network other than the local computer.

remote database A database on a computer other than the local database. Usually a computer on the same network, but at a different node (that is, a database that you use through a database link).

replication A database feature in which identical (and updateable) copies of a table are stored in the database, on more than one node. Table replicates are called synchronized copies.

role A list of usernames that can be granted privileges to use form and/or menu modules.

roles Named groups of related privileges that are granted to users or other roles.

root (1) In a table with tree-structured data (row data with an implicit hierarchy), the top of the tree; that is, a row that has no parent row, and whose descendant rows constitute the entire tree. (2) In a tree-structured query (one using CONNECT BY), the row specified by the START WITH clause.

root administrative region The highest level administrative region in a distributed administration installation. The root administrative region contains the root domain.

root domain The highest level domain in a hierarchical naming model.

rollback (noun) The second half of the recovery procedures. After the roll forward, any changes that were not committed must be undone. After the redo log files have been applied, then the rollback segments are used to identify and undo transactions that were never committed, yet were recorded in the redo log. Oracle completes this step automatically.

rollback (verb) (1) To discard some or all pending changes made to data in the current transaction, using the SQL statement ROLLBACK. You can roll back a portion of a transaction by rolling back to a savepoint. (2) As a part of recovery, to undo changes made to a database that were never committed by users.

SQL Structured Query Language--the internationally accepted standard for defining and manipulating relational databases.

SID A unique name for an Oracle database instance. To switch between Oracle databases, users must specify the desired SID. The SID is included in the CONNECT DATA parts of the connect descriptors in a TNSNAMES.ORA file, and in the definition of the network listener in the LISTENER.ORA file. Also known as system ID.

schema A collection of table definitions.

schema objects A collection of related objects. Schema objects are the logical structures that directly refer to the database's data. Schema objects include such structures as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links (there is no relationship between a tablespace and a schema: objects in the same schema can be in different tablespaces, and a tablespace can hold objects from different schemas).

select (1) To fetch rows from one or more database tables using a query (the SQL statement SELECT).

server (1) The provider of services requested by a client. (2) A process providing services to other cooperating processes.

Server Oracle software that handles the functions required for concurrent, shared data access to an Oracle database. The server portion receives and processes SQL and PL/SQL statements originating from client applications. The computer that manages the server portion must be optimized for its duties.

server computer Performs database work on behalf of the user. The server computers are used by networking and two-task users.

service An executable process installed in the Windows NT Registry database and administered by Windows NT. Once created and started, it can run even while no user is logged on to the Oracle7 server.

service name The name used to identify a SQL*Net version 2.3 server process. The services file on client and server computers maps each service name to a port number and protocol.

session (1) The time after a username connects to an Oracle database and before disconnecting, and the events that happen in that time. (2) The name for the connection between a PC emulating a mainframe terminal and the mainframe when they are communicating.

snapshot Information stored in rollback segments to provide transaction recovery and read consistency. Rollback segment information can be used to recreate a snapshot of a row before an update.

snapshots Read-only copies of a master table located on a remote node. A snapshot can be queried, but not updated; only the master table can be updated. A snapshot is periodically refreshed to reflect changes made to the master table.

socket A TCP/IP port number associated with a specific application.

SQL*Net The Oracle client/server communication software that offers transparent operation to Oracle tools or databases over any type of network protocol and operating system.

starter database The starter database Oracle is the core of the Oracle7 Server for Windows NT database system. Database creation is an advanced function. Oracle Corporation recommends that you use the starter database and modify it to suit your needs.

statement (SQL) A SQL statement, and analogous to a complete sentence, as opposed to a phrase. Portions of SQL statements or commands are called expressions, predicates, or clauses. See also SQL statement.

static data dictionary A data dictionary that contains data definitions that are not an integral part of the data source. Changes to data structures require the data source to be rebuilt. See also dynamic data dictionary.

storage object The passive repositories in which database named objects are stored. Storage objects are labeled based on the sensitivity of the information contained in the object.

stored query expression (SQE) A query expression that is stored along with the results obtained by performing that query. Each SQE can be named.

static record group A record group whose columns and rows are defined at design time; it cannot be modified programmatically at runtime. A static record group cannot be defined programmatically.

substitution parameter A variable in a dialogue file for which you can assign a string. At runtime the string is substituted into the dialogue.

substitution variable In SQL*Plus, a variable name or numeral preceded by one or two ampersands (&). Substitution variables are used in a command file to represent values to be provided when the command file is run.

synonym An alias for a table, view, sequence, or program unit; a synonym is not actually an object itself, it is a direct reference to its base object. Synonyms are used to mask the real name and owner of an object, provide public access to an object, provide location transparency for tables, views, or program units of a remote database, and simplify the SQL statements for database users. A synonym can be public or private.

SYSDBA A special database administer role that contains all system privileges with the ADMIN OPTION, and the SYSOPER system privilege. SYSDBA also permits CREATE DATABASE and time-based recovery.

SYSOPER A special database administer role that permits a database administrator to perform STARTUP, SHUTDOWN, ALTER DATABASE OPEN/MOUNT, ALTER DATABASE BACKUP, ARCHIVE LOG, and RECOVER, and includes the RESTRICTED SESSION privilege.

system ID A synonym for instance identifier. Often abbreviated to SID.

SYSTEM username One of two standard DBA usernames automatically created with each database (the other is SYS). The Oracle user SYSTEM is created with the password MANAGER. The SYSTEM username is the preferred username for DBAs to use when performing database maintenance.

TNSNAMES.ORA A file that contains connect descriptors mapped to service names. The file may be maintained centrally or locally, for use by all or individual clients.

table The basic unit of storage in a relational database management system. A table represents entities and relationships, and consists of one or more units of information (rows), each of which contains the same kinds of values (columns). Each column is given a column name, a datatype (such as CHAR, DATE, or NUMBER), and a width (the width may be predetermined by the datatype, as in DATE). Once a table is created, valid rows of data can be inserted into it. Table information can then be queried, deleted, or updated. To enforce defined business rules on a table's data, integrity constraints and triggers can also be defined for a table. See also synonym and view.

table alias A temporary substitute name for a table, defined in a query and only good during that query. If used, an alias is set in the FROM clause of a SELECT statement and may appear in the SELECT list. See also alias.

table constraint An integrity constraint that applies to multiple columns of the same table.

table list Contains the tables and views that users have access to. You can specify the Table List for different users in different ways using the Table List definition scripts.

tablespace A logical portion of an Oracle database used to allocate storage for table and index data. Each tablespace corresponds to one or more physical database files. Every Oracle database has a tablespace called SYSTEM and may have additional tablespaces. A tablespace is used to group related logical structures together. For example, tablespaces commonly group all of an application's objects to simplify certain administrative operations.

tablespace quotas A mechanism that limits the collective amount of disk space available to the objects in a schema. Quotas (space limits) can be set for each tablespace available to a user. The tablespace quota security feature permits selective control over the amount of disk space that can be consumed by the objects of specific schemas.

thread The cross memory services connection from CICS to an Oracle for MVS subsystem for a particular Oracle userid.

trace file A file created when a problem or exceptional condition is encountered while using a software program. Also called a dump file, the file contains information useful in diagnosing or locating the problem.

truncate To discard or lose one or more characters from the beginning or end of a value, whether intentionally or unintentionally.

user-defined datatypes Object types and/or collection types the application developer creates to solve specific problems.

value A single value, as in the data for a column or field.

variable A named object that can be assigned a value and whose assigned value may change over time. SQL*Plus uses substitution, system, and user variables.

variable parameters (1) Parameters whose value may change or can be reset. (2) The INIT.ORA parameters whose values may vary and whose values may affect the performance of a database. DBAs may wish to "tune" or experiment with the variable parameter values in order to optimize their database's performance.

view (1) A rectangular section of a window that exists outside the area of the scroll bar alleys and window decoration such as borders and title bars. (2) A custom tailored presentation of the data in one or more tables. A view can also be thought of as a "stored query." Views do not actually contain or store data; rather, they derive their data from the tables on which they are based, called base tables. Base tables can in turn be actual tables or can themselves be views. Views can be queried, updated, inserted into, and deleted from, with restrictions. All operations performed on a view actually affect the base tables of the view.

view tree The hierarchy of related views within a window, usually descending from the content view.

virtual column A column in a query result whose values do not exist in the underlying tables. Instead, the values are calculated from the value(s) of other column(s).

WAN (Wide Area Network) Similar to a LAN except that the computers can be separated by great distances. An example of a WAN is the telephone cabling system that covers the entire globe. Computers can use this network to exchange data just as humans use it to communicate by voice.

width (Column and Parameter Properties, layout objects) The width of a column, parameter, or layout object. Width is measured in characters; a space is a character.

workgroup The name given to the members of the same LAN, sharing the same programs and files, and, most likely, coordinating tasks and workload. Usually associated with PC LANs.

workstation Name given to a client PC on a LAN.

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