SQL/MX Programming Manual for Java

SQL/MX Programming Considerations
HP NonStop SQL/MX Programming Manual for Java—523726-003
4-24
Distributed Database Considerations
the similarity check; otherwise, the plan is inoperable. See Similarity Checks and
Automatic Recompilation on page 4-26.
Distributed Database Considerations
The SQL statements in an SQLJ program can refer to SQL/MX and SQL/MP database
objects on remote nodes.
Remote SQL/MX Objects
To refer to remote SQL/MX database objects in an SQLJ program, you need not
change the database object names in the source code. However, the catalog that
contains the SQL/MX objects must be visible (that is, registered) on the local node
before you customize and run the SQLJ program. For information about registering
catalogs and managing an SQL/MX distributed database, see the SQL/MX Installation
and Management Guide.
Remote SQL/MP Objects
To refer to remote SQL/MP objects by Guardian name in an SQLJ program, you should
fully qualify the SQL/MP object name, including the name of the remote node.
If the SQLJ program uses a class MAP DEFINE or SQL/MP alias name for a remote
SQL/MP object, you should specify a fully qualified SQL/MP object name when you
add the DEFINE or create the SQL/MP alias. The SQL/MP aliases must be in SQL/MX
user catalogs that are visible on the node where the program executes. For information
about registering catalogs to make them visible in an SQL/MX distributed database
environment, see the SQL/MX Installation and Management Guide.
For information about managing an SQL/MP distributed database, see the SQL/MP
Installation and Management Guide.
RDF Considerations
The Remote Database Facility (RDF) subsystem monitors changes to a production
database on a local (primary) system and maintains a copy of the database on a
remote (backup) system. RDF stores a backup of the database objects in a different
catalog on the backup node than on the primary node. For more information, see the
RDF/IMP, IMPX, and ZLT System Management Manual.
An SQLJ application must be able to run on both the primary and backup nodes.
Because RDF stores database objects in different catalogs on the primary and backup
nodes, SQLJ applications in an RDF environment should not refer to hard-coded
database object names that refer to a specific node or catalog.
Note. SQL/MX Release 2.x applications cannot query remote SQL/MP objects on a node that
has SQL/MX Release 1.8 installed. To query these remote objects, you must upgrade the node
to SQL/MX Release 2.x. For more information, see the SQL/MX Installation and Management
Guide.