Glossary
O
object
(1) Anything that can be created or
manipulated with SQL--for example, tables, views, indexes, or packages.
(2) In object-oriented design or programming,
an abstraction consisting of data and operations associated with that data.
(3) For NetWare**, an entity that is defined
on the network and thus given access to the file server.
object property
A property that identifies a category of
information associated with an object. A NetWare** bindery object can be
assigned one or more properties. The DB2 server instance object has an object
property NET_ADDR, which denotes the location of the record within the object.
object type
(1) A 2-byte number that classifies an object
in the bindery on a NetWare** file server. 062B represents the DB2 database
server object type.
(2) A categorization or grouping of object
instances that share similar behaviors and characteristics.
ODBC
Open Database Connectivity.
ODBC driver
A driver that implements ODBC function
calls and interacts with a data source.
offline backup
A backup of the database or table space
that was made when the database or table space was not being accessed by
applications. The Backup Database utility acquires exclusive use of the
database until the backup is complete. Contrast with online backup.
offline restore
A restoration of a copy of a database or
table space from a backup. The Backup Database utility has exclusive use of
the database until the restore is completed.
online backup
A backup of the database or table space
that is made while the database or table space is being accessed by other
applications. Contrast with offline backup.
online monitor
See Snapshot Monitor.
online restore
A restoration of a copy of a database or
table space while the database or table space is being accessed by other
applications. Contrast with offline restore.
Open Database Connectivity (ODBC)
An API that allows access to database
management systems using callable SQL, which does not require the use of a SQL
preprocessor. The ODBC architecture allows users to add modules, called
database drivers, that link the application to their choice of database
management systems at run time. Applications do not have to be linked directly
to the modules of all the supported database management systems.
operand
An entity on which an operation is
performed.
optimized SQL text
SQL text, produced by the Explain
facility, based on the query actually used by the optimizer to choose the
access plan. This query has been supplemented and rewritten by the various
components of the SQL compiler during statement compilation. The text has been
reconstructed from its internal representation, and differs from the original
SQL text. The optimized statement produces the same result as the original
statement.
optimizer
A component of the SQL compiler that
chooses an access plan for a DML statement by modelling the execution cost of
many alternative access plans and choosing the one with the minimal estimated
cost.
ordinary identifier
In SQL, a letter, which might be followed
by zero or more characters, each of which is a letter (a-z and A-Z), a symbol,
a number, or the underscore character, used to form a name.
ordinary token
A numeric constant, an ordinary
identifier, a host identifier, or a keyword.
outer join
A join method in which a column that is
not common to all of the tables being joined becomes part of the resultant
table. Contrast with inner join.
output file
A database or device file that is opened
with the option to allow the writing of records.
overflow record
(1) On an indirectly addressed file, a record
whose key is randomized to the address of a full track or to the address of a
home record.
(2) In DB2, an updated record that is too
large to fit on the page it is currently stored in. The record is copied to a
different page and its original location is replaced with a pointer to the new
location.
(3) In Database Monitor, a record inserted in
the event monitor data stream to indicate that records were discarded because
the named pipe was full and records were not processed in time. An overflow
record indicates how many records were discarded.
overloaded function name
A function name for which there are
multiple functions within a function path or schema. Those within the same
schema must have different signatures.
[ Top of Page | Previous Page | Next Page | Table of Contents ]
[ DB2 List of Books |
Search the DB2 Books ]