SQL/MX Glossary

Glossary
HP NonStop SQL/MX Glossary—523732-002
Glossary-38
timestamp check
timestamp check. A comparison performed by SQL/MX of the current redefinition
timestamp of a table in an SQL statement with the table’s compile-time timestamp to
determine if the table has changed since the last explicit SQL compilation. If the
redefinition timestamp of the table has changed, SQL/MX automatically recompiles the
SQL statement if it fails the similarity check (or if the similarity check is not enabled).
TMF. See Transaction Management Facility (TMF).
TNS/R native. The Tandem NonStop Series/RISC native mode that enables users to write
programs that make full use of the RISC instruction set and processor architecture.
TNS/R native code has significant performance advantages over TNS code.
Embedded SQL/MX is available only on TNS/R native platforms.
token. Additional information about an operator found in the Description column of the
Explain output.
transaction. An operation or a series of operations that transforms a database from one
consistent state to another. The HP NonStop Transaction Management Facility (TMF)
product treats transactions as a single unit. Either all of the changes made by a
transaction are made permanent (the transaction is committed), or none of the
changes are made permanent (the transaction is aborted). If an error occurs while a
transaction is in progress, the TMF product backs out whatever partial changes were
made to the database, leaving it in a consistent state. See also aborted transaction.
transactional queuing. Applications specifying stream access can read and delete entries
with a single operation as part of a transaction. Entries are dequeued after the
associated transaction commits. To prevent concurrent transactions—for example,
multiple applications dequeuing requests—from interfering with each other,
applications use the skip conflict access mode to skip conflicting locks held by
concurrent transactions.
transaction access mode. The mode that determines whether statements in a transaction
can read but cannot insert, delete, or update data in tables (READ ONLY); or whether
statements in a transaction can read, insert, delete, or update data in tables (READ
WRITE).
transaction isolation level. See isolation level.
Transaction Management Facility (TMF). A NonStop product that provides transaction
protection and database consistency. It gives full protection to transactions that access
distributed SQL/MP databases, as well as recovery capabilities for transactions and
entire databases.
translator. See SQLJ translator.
trigger. A set of actions that are executed automatically whenever a delete, insert, or
update operation occurs on a specified base table.