SQL/MP Glossary

Glossary
Compaq NonStop™ SQL/MP Glossary—429832-001
Glossary-16
key-sequenced merge join
key-sequenced merge join. A join method that can apply a merge join to key-sequenced
tables without doing a sort or using a temporary file. The method involves an inner table
and either a single outer table or a composite table with matching order.
key-sequenced table. A table stored in a key-sequenced file and whose primary key is
defined by the user (user-defined primary key), by both the user and the
NonStop SQL/MP system (clustering key), or by the system alone (SYSKEY column).
Columns can be added to the table, rows can be updated or deleted, and variable-length
values can be shortened or lengthened. Contrast with entry-sequenced table
and relative
table.
KSC6501 character set. A double-byte character set for the Korean language; the Korean
industry-standard character set.
layout option. One of a set of options that control the appearance of a report on a screen or
printed page. Layout options include specification of page length, margins, and spacing
between lines. A layout option can apply to more than one report developed in a session.
left join. A join that returns from a table all rows that satisfy a given search condition plus
those rows that fail to satisfy the condition. NonStop SQL/MP extends each row from
the table on the left of the keywords LEFT JOIN with as many null values as there are
columns from the table on the right in the result. See also null-augmented row
and outer
join.
licensed process. A process authorized by the File Utility Program (FUP), through the super
ID, to perform particular tasks.
literal. A constant in an expression or statement. A literal has a data type and can have an
associated character set or collation. An SQL literal can be a date-time literal,
INTERVAL literal, national character string literal, numeric literal, or string literal.
local autonomy. The principle that users of a node in a network can perform operations on
objects on that node even when other nodes are not available.
lock. A mechanism that coordinates concurrent access to the same data. See also exclusive
lock, lock granularity, and shared lock.
lock duration. The period of time during which a lock is held.
lock escalation. The replacement of all the row locks on a partition or table by a single
partition lock or table lock when the number of row locks approaches a limit. See also
lock granularity
.
lock exclusion mode. A lock attribute that determines whether any process except the lock
holder can access the locked data. See also exclusive lock
and shared lock.
lock granularity. The size of a lockable unit. A lockable unit can be a single row (row lock),
a subset of the rows in a table (generic lock), a partition of a table or a nonpartitioned
table (partition lock), or an entire partitioned table (table lock).