TS/MP System Management Manual (G06.24+, H06.03+)

Glossary
NonStop TS/MP System Management Manual—541819-001
Glossary-5
database management system (DBMS)
application, which establishes the values and relationships of database fields and
records.
database management system (DBMS). A product, such as NonStop SQL/MP or
Enscribe, that serves as the interface between a user or program (for example, a
Pathway server) and the database. Among its many functions, the DBMS controls
access to and organization of data within the database.
Data Definition Language (DDL). (1) The set of data definition statements within the
Structured Query Language (SQL). (2) A Tandem product for defining data objects in
Enscribe files and translating object definitions into source code.
data integrity. The condition of a database when its data values are accurate, valid, and
consistent according to rules established for changing the database. See also
database consistency.
DBCS. See double-byte character set (DBCS).
DDL. See Data Definition Language (DDL).
deadlock. (1) A situation in which two processes cannot proceed because each is waiting
for a reply from the other. (2) A situation in which two transactions cannot proceed
because each is waiting for the other to release a lock.
dedicated device. A term formerly used for a terminal or other input/output device
controlled by a configured TERM object, so that a Pathway application always ran on
that device without having to be started from PATHCOM with a RUN PROGRAM
command. (No new term replaces this term; instead, the manual text now refers to
such devices as those associated with configured TERM objects.) See
also nondedicated device and configured TERM object.
default value. The value that the system uses for a particular attribute or parameter when a
value has not been supplied by the user.
DEFINE. A named set of attributes and associated values. In a DEFINE (as with an
ASSIGN command), users can specify information to be communicated to processes
they start.
definition files. A set of files containing data declarations for items related to SPI messages
and their processing. The core definitions required to use SPI are provided in a DDL
file and in several language-specific definition files, one for each programming
language that supports SPI. The Tandem DDL compiler generates the language-
specific files from the DDL file. Subsystems that support SPI provide additional
definition files containing subsystem-specific definitions.
delimiters. Characters that make it possible for a SCREEN COBOL requester and an
external device or front-end process to exchange compact variable-length messages
efficiently; delimiters can be message delimiters or field delimiters.