H06.20 Release Version Update Compendium

4 Database and Transaction Processing Products
SQL/MX 2.3.4 Enhancements
The NonStop SQL/MX 2.3.4 release includes the following new features:
• You can now specify one of the following ACTION clauses as part of the referential integrity
constraint feature:
— CASCADE
When this clause is specified with the ON DELETE referential triggered action, a row
from the referencing table that relates to the row deleted from the referenced-table is
deleted. When CASCADE is specified with the ON UPDATE referential triggered action,
a row in the referencing table that relates to the row updated in the referenced-table is
updated.
— SET NULL
When this clause is specified with the ON DELETE referential triggered action, and if
a row from the referencing table relates to the row deleted from the referenced-table,
the referencing column(s) of the referencing row from the referencing table is set to
NULL. When SET NULL is specified with the ON UPDATE referential triggered action,
and if a row in the referencing table relates to the row updated in the referenced-table,
the referencing column(s) of the referencing row from the referencing table is set to
NULL.
— SET DEFAULT
When this clause is specified with the ON DELETE referential triggered action, and if
a row from the referencing table relates to the row deleted from the referenced-table,
the referencing column(s) of the referencing row from the referencing table is set to its
default value. When SET DEFAULT is specified with the ON UPDATE referential
triggered action, and if a row in the referencing table relates to the row updated in the
referenced-table, the referencing column(s) of the referencing row from the referencing
table is set to its default value.
The CREATE TABLE and ALTER TABLE statements support the ACTION
clauses—CASCADE, SET NULL, and SET DEFAULT.
• SQL/MX now displays the query execution plans in a more readable format using the
EXPLAIN statement. The EXPLAIN statement generates and displays the result of the
EXPLAIN function, and describes the access plan for a SELECT, INSERT, DELETE, UPDATE,
or CALL statement. It also displays the plans from modules created by the SQL/MX compiler.
It can be accessed from JDBC or ODBC applications as any other SQL/MX statement.
An MXCI command called DISPLAY_EXPLAIN is discontinued and its functionalities are
available through the EXPLAIN statement.
• SQL/MX enables you to embed SQL statements in DLLs and to build more modular and
manageable products. The SQL statements can be embedded in both Guardian and OSS
DLLs. For efficient management of the module files, SQL/MX allows modules to be located
with the corresponding DLLs.
• MXCI provides a more versatile LOG command, which allows you to choose the information
to be logged. The LOG command can now log only the commands or only the results with
and without success, or error or row count information.
• The GTACL command enables you to run the TACL commands, TACL macros, programs,
and utilities from the MXCI interface.
SQL/MX 2.3.4 Enhancements 15