SQL/MX 2.x Reference Manual (G06.24+, H06.03+)

Introduction
HP NonStop SQL/MX Reference Manual—523725-004
1-21
Partition Management
SERIALIZABLE or REPEATABLE READ
This option locks all data accessed through the transaction and holds the locks on data
in audited tables until the end of the transaction.
SERIALIZABLE provides the highest level of data consistency. A transaction executing
with this isolation level does not allow dirty reads, nonrepeatable reads, or phantoms.
For audited tables, SERIALIZABLE uses shared locks for unmodified rows and
exclusive locks for modified rows—but all locks are held by the transaction and not
released until the transaction ends. SERIALIZABLE prevents other users from inserting
or modifying rows in the range of rows examined by the transaction.
For nonaudited tables, SERIALIZABLE does not provide repeatable-read protection.
That is, it does not prevent other users from inserting or modifying rows in the range of
rows examined by the transaction.
Partition Management
You can create SQL/MX tables with multiple physical files, or partitions. Use the
CREATE TABLE Statement on page 2-75 and the CREATE INDEX Statement on
page 2-54 to create tables and indexes that include partitions. Use the MODIFY Utility
to partition tables after they have been created.
For more information, see Partitions on page 6-82 for an overview of partitions in
SQL/MX and SQL/MP files. For information about managing partitioned files see the
SQL/MX Installation and Management Guide.
Internationalization
Users need to be able to display data in formats appropriate to their locale and
language—in English or other Roman-character formats, in Japanese Kanji or Korean
or Chinese characters. In SQL/MX Release 2.x, users can select from one
single-character or three double-byte character sets. See Character Sets on page 6-3
for information on these character sets in addition to restrictions on the use of
character sets.
Using NonStop SQL/MX to Access SQL/MP
Databases
NonStop SQL/MX allows applications to use the SQL/MX engine to access SQL/MP
databases. SQL/MP tables, views, indexes, and catalogs are accessed by using
SQL/MX DML statements. For information on the SQL/MP language, see theSQL/MP
Reference Manual.
In SQL/MX Release 2.x, mixing embedded SQL calls to NonStop SQL/MP and
NonStop SQL/MX from the same application process is not supported.