SQL/MP Glossary

Glossary
Compaq NonStop™ SQL/MP Glossary—429832-001
Glossary-20
older version
older version. A version that has a lower version number than another version.
OLTP (online transaction processing) application. An application in which many users
can update data simultaneously, recording the changes in the database as they are
entered.
online dump. A copy of an audited database file written to disk or tape when a TMF DUMP
FILES command is issued. If the database is damaged, the file recovery process can
restore the online dump files to disk and then apply the audit trail images to reconstruct
the files. Online dumps can be made while transactions are being processed by database
applications; that is, while the TMF subsystem is running.
online transaction processing application. See OLTP (online transaction processing)
application.
Open System Services (OSS). An open system environment available for interactive or
programmatic use with the Compaq Tandem NonStop Kernel. Processes that run in the
OSS environment use the OSS application program interface; interactive users of the
OSS environment use the OSS shell for their command interpreter. Contrast with
Guardian operating system
.
operable execution plan. An execution plan in an SQL program that is semantically correct
and can execute correctly without recompilation, although the plan might not be
optimal. Contrast with inoperable execution plan
.
operating system name. A name formed according to the operating system rules for naming
a disk file, tape file, process, or device. See also file ID
, file name, node name, and
process name
.
optimization. See query optimization
.
optimizer. A component of the SQL compiler that chooses query execution plans for
retrieving data from a database.
OSS (Open System Services). See Open System Services (OSS)
.
outer join. A query that returns all rows from one of the tables being joined, whether or not
the rows satisfy the join predicate. Rows that do not satisfy the join predicate have
information missing in all the columns corresponding to the other table being joined.
The three types of outer joins are left, full, and right; NonStop SQL/MP currently
supports left outer joins. Contrast with inner join. See also left join.
outer query. A statement containing a subquery or a subquery containing another subquery.
See also inner query
and subquery.
outer reference. A reference from an inner query to a table or view defined in an outer query.
See also inner query
and outer query.
outer table. In the evaluation of a join, the table that the optimizer accesses first.