Introduction to Data Management

Glossary
15873 Tandem Computers Incorporated Glossary-11
Report. In NonStop SQL, a formatted listing of data retrieved by a query; a highly
formatted report can be defined with the SQLCI report writer. In PATHMAKER, a
listing of information from a project's catalog or from an application's database;
standard reports show such information as object types defined in the catalog, service
and server structure, relationships among requesters, and other details.
Report writer. In NonStop SQL, the SQLCI component used to produce reports from
queries.
Requester process. A process that manages the front-end interface to an application by
controlling displays at one or more terminals or workstations; accepting, interpreting,
and validating input from end users; requesting database access through servers; and
returning information to end users. Requesters are often multithreaded processes;
that is, a single requester can handle a complex series of operations from many users,
interleaving the concurrent handling of several requests. In a PATHWAY
environment, the TCP is a requester that executes a SCREEN COBOL program to
process requests to servers for database access. In PATHMAKER, a requester is an
application module corresponding to a SCREEN COBOL program unit; this module
contains presentation logic for a single logical screen (which might include several
pages), manages terminal context associated with that screen, communicates with
services, and contains navigation logic.
Resource queue. Any group of transactions waiting in line for a particular resource,
such as a CPU, communication line, terminal, or disk-handling process. In a system
where many transactions are active at the same time, the intense demand for
particular resources often creates queues. Queues build up when the workload is
heavy and resources are limited.
Response time. The period that the computer system needs to act on your request.
This period begins when you send a request to the system, and ends when the system
responds to that request and prompts you for another.
Rollback. See Autorollback.
Rollforward. A TMF recovery mechanism that returns a NonStop SQL table, a file, or
entire database to its most recent consistent state following a media failure, such as a
disk crash. The rollforward facility first uses a previously provided online dump to
restore the database to disk, and then applies after-images from audit trails to roll the
files forward to their most recent consistent state before the failure occurred.
Row. A record in a relational database; a horizontal component of a table. A row
contains one data value for each column in the table.
Row lock. In NonStop SQL, a lock held by a process on one specific row.
SAFEGUARD security system. The software package that protects system or network
components, including disk files, from access by unauthorized users.
Schema. See Source schema.