SQL/MX Glossary

Glossary
HP NonStop SQL/MX Glossary—523732-002
Glossary-15
host language
host language. Any programming language whose statements can be combined with SQL
statements in the same source program. SQL/MX supports C, C++, COBOL, and Java
as host languages.
host language compiler. The C, C++, COBOL or Java compiler.
host program. A source program that contains both host language statements and
embedded SQL statements.
host variable. A data item declared in the host language program that can be used by both
host language statements and embedded SQL statements in the same source
program. A host variable provides communication between these two types of
statements. An input host variable transfers data from a program to a database, and an
output host variable transfers data from a database to a program. A host variable has a
corresponding SQL data type.
hybrid hash join. A hybrid hash join joins the data from its children. It creates a hash table
for the inner child and joins the outer table by hashing each outer row and looking for
matches in the hash table. This operator can overflow to disk when the inner table is
too large to fit in memory. Equijoins and cross-products are supported by hybrid hash
join.
I
implicit correlation name. A table or view name for which no correlation name is specified
in the FROM clause of a SELECT statement. Contrast with explicit correlation name.
IN parameter mode. The mode of a parameter that passes data to a user-defined routine
(UDR). In an SQLJ program, this mode specifies a host variable or expression that
passes data to an SQLJ clause. It is the default mode if the host expression is not part
of an INTO list or an assignment expression. Contrast with INOUT parameter mode
and OUT parameter mode.
independent parallelism. An inherent feature of SQL/MX where two or more operators can
execute simultaneously and independently. Also called operator parallelism.
index. An alternate access path (alternate key) to a table that differs from the primary
access path (clustering key) defined for the table at creation time. An index, stored in a
key-sequenced file, includes columns for the clustering key and the alternate key.
index predicate. A predicate evaluated on rows in an index by the Data Access Manager.
indicator variable. An exact numeric data item associated with a host variable and
declared in an SQL declare section. A C, C++ or COBOL program uses an indicator
variable to insert null into a column, to pass a null value into or out of a user-defined
routine, or to indicate whether a target host variable (of any data type) contains null or
whether the target host variable (of character data type) is smaller than the source
character string.