SQL/MX Glossary

Glossary
HP NonStop SQL/MX Glossary—523732-002
Glossary-32
session attribute
session attribute. One of a set of attributes consisting of parameters and options whose
values describe the current MXCI session.
set function. A function that operates on a group or groups of rows retrieved by the
SELECT statement or the subquery in which the set function appears. Also called an
aggregate function.
shared lock. A lock exclusion mode that allows any number of processes to read the same
data but prevents any process from writing to the locked unit or reading it with intent to
rewrite. Contrast with exclusive lock.
similarity check. A comparison made by SQL/MX to determine whether two tables (the
previous compile-time table and the new run-time table) are sufficiently similar so that
an access plan compiled for the previous table is also an operable plan for the new
table. A successful similarity check preserves the original access plan and avoids
recompilation.
simple hash join. A hash join method in which the inner table is read into a memory-
resident hash table. The order of the outer table is preserved. See also hybrid hash
join.
skip conflict access. Access mode used by Publish/Subscribe that allows transactions to
skip rows locked in a conflicting mode by another transaction.
SMD. See system metadata (SMD).
sort merge join. A join method that first sorts the base tables by join attributes, then
merges the sorted tables, and returns rows for matching attribute values.
SPJ. See stored procedure in Java (SPJ).
SPJ method. The static Java method associated with a stored procedure in Java (SPJ).
SQL. Structured query language. A non-procedural relational database language used to
define, manipulate, and control databases. SQL statements can be embedded in
programs or entered as commands through MXCI. See also statement atomicity.
SQL compile. To use the SQL compiler to generate an SQL module.
SQL compile time. The date and time when a program is explicitly compiled by the SQL
compiler (mxcmp). Contrast with SQL statement execution time.
SQL compiler. The SQL/MX component that compiles a set of SQL source statements
extracted from a source program by the SQL preprocessor (for C and COBOL
programs) or by the SQLJ translator and SQLJ customizer (for Java programs),
generates SQL object code for each statement, forms a plan for executing each
statement against the database, and stores the code and plan in an SQL module. The
SQL compiler also processes SQL statements entered dynamically through MXCI.