SQL/MX Glossary

Glossary
HP NonStop SQL/MX Glossary—523732-002
Glossary-6
compiled module
compiled module. See module.
concurrency. Access to the same data at the same time by two or more processes.
concurrent access. The ability of two or more processes to gain access to the same data
at the same time. See also read uncommitted access and read committed access
configuration client library. An administrative library for MXCS with a programmatic
interface. It connects to MXCS components and passes administrative commands and
responses back and forth.
configuration server. The component of the SQL/MX connectivity service (MXCS) that
manages the MXCS configuration database for the MXCS subsystem The
configuration server also supplies information about the current configuration of the
MXCS subsystem.
connection context. A Java object that associates the execution of each embedded SQL
statement (or SQLJ clause) in a Java program with a particular connection to a
database. Each SQLJ clause in a Java program is implicitly or explicitly associated
with a connection context.
constraint. An object that protects the integrity of data in a table by restricting the values in
a particular column or set of columns to those that meet specified conditions. SQL/MX
supports the constraints NOT NULL, UNIQUE, PRIMARY KEY, CHECK,
REFERENCES, and LOGGABLE.
correlated subquery. A subquery that references values retrieved by the outer query. A
correlated subquery requires repeated evaluation of the subquery for each row
satisfying the outer query. Contrast with noncorrelated subquery.
correlation name. An SQL identifier you can associate with a table reference in a SELECT
statement. You use a correlation name to distinguish a table or view from another table
or view referred to in the statement, to distinguish different uses of the same table, or
to make the text of the query shorter. A correlation name can be explicit or implicit; the
implicit name is the table or view name.
crash-label state. A file state in which file label operations set the state of the file to crash-
label until the file label operation is committed. If a total system crash occurs or the
disk becomes unavailable, the file label state remains set to crash-label until recovery
occurs.
crash-open state. A file state in which a file is open in the same circumstances as a file in
the crash-label state.
cursor. A named pointer used by an application program to indicate the current or next row
within a set of rows selected by an SQL query.
cursor name. An SQL identifier used to identify a cursor.