SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Introduction to SQL/MX Database Management
HP NonStop SQL/MX Installation and Management Guide—523723-004
1-15
SQL/MX Environment
back from Release 2.1 to Release 2.0, you must recompile all version 1400 user
modules.
•
You cannot determine the version of a user module. However, when you run a
program with a user module that was compiled on a later release, you get a
versioning error indicating that the module is of a later version and needs to be
recompiled.
For more information about falling back from Release 2.1 to Release 2.0, see
Appendix A, Falling Back From NonStop SQL/MX Release 2.1 or Release 2.0.
SQL/MX Applications
•
An application that is compiled on a Release 2.1 system can query database
objects on Release 2.1 nodes and Release 2.0 nodes. An application compiled on
a Release 2.0 system can query database objects on Release 2.0 nodes and
Release 2.1 nodes.
•
If you compile an application from an SQL/MX Release node that queries a
Release 2.1 node, the query plan version is the same as the earliest node version
in the distributed database (1200).
•
When you compile an embedded SQL/MX application, a query execution plan has
a plan version equal to the earliest MXV of all its referenced nodes, or it has a plan
version equal to the MXV of the node where you compile the application if that
MXV is earlier than the referenced node’s MXV.
•
If you fall back a remote node from Release 2.1 to Release 2.0 after compiling
embedded SQL/MX applications, any applications compiled on a Release 2.1 node
and referring to database objects on the Release 2.0 node will fail to execute and
will return an error at run time stating that the application cannot access database
objects on the Release 2.0 system. This happens because version 1400 query
execution plans cannot run on a Release 2.0 system. To run the application, you
must explicitly recompile the application to generate version 1200 plans for queries
that refer to the Release 2.1 node that fell back to a Release 2.0 node.
SQL/MX Database Objects
In a mixed Release 2.1 and Release 2.0 distributed database, there are no Release
2.1 and Release 2.0 objects per se. All database objects there have a version of 1200
and are accessible from Release 2.1 nodes and Release 2.0 nodes, regardless of
where the objects reside on the network.
SQL/MX Environment
The SQL/MX query compiler and executor operate on SQL/MX database objects and
SQL/MP database objects. From the SQL/MX conversational interface, MXCI, you can
perform DDL and DML operations and most SQL/MX commands on SQL/MX objects.
From MXCI, you can also perform DML operations—but not DDL operations—on