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

Managing Database Applications
HP NonStop SQL/MX Installation and Management Guide—523723-004
11-10
Maintaining Local Autonomy for Programmatic
Queries
catalog that contains the objects must be visible from the local node before you can
process and run the program. Use the REGISTER CATALOG statement to create an
empty catalog reference on the local node that enables local programs to query the
catalog’s objects on a remote node or nodes. Use the UNREGISTER CATALOG
statement to remove the empty catalog reference from the local node.
From an SQL program, you can create, alter, or drop an SQL/MX object that resides
entirely on one remote node or is partitioned across several remote nodes. To create,
alter, or drop an entire object located on one or more remote nodes, the catalog for the
object must be registered on the node from which the SQL program runs.
Before issuing a REGISTER CATALOG or UNREGISTER CATALOG statement,
consider these requirements:
•
Make sure that a catalog with an identical name does not already exist on the node
from which you run the program.
•
To execute the REGISTER CATALOG or UNREGISTER CATALOG statement from
the local node, you must be the owner of the catalog or the super ID user.
•
Before executing REGISTER CATALOG and UNREGISTER CATALOG for a
remote node, you must establish remote password access from the local node to
the local node and from the remote node to the local node. For information about
this and other aspects of security in a distributed SQL/MX database environment,
see Security Guidelines on page 13-6.
For more information about using the REGISTER CATALOG and UNREGISTER
CATALOG statements, see Section 13, Managing an SQL/MX Distributed Database,
the SQL/MX Reference Manual, the SQL/MX Programming Manual for Java, and the
SQL/MX Programming Manual for C and COBOL.
Maintaining Local Autonomy for Programmatic Queries
The ability of local programs to successfully query objects on remote nodes in a
distributed SQL/MX database depends on the operations they perform and the
availability of remote nodes that contain the queried object data and its metadata.
•
Local programs that perform DDL or dynamic DML operations must have access to
the node that contains the metadata for each referenced object. If the node where
object metadata is located becomes unavailable, local programs cannot perform a
DDL or dynamically compiled DML operations on those objects, even if the objects
reside on available nodes.
•
For local programs that perform late name resolution of ANSI names or automatic
recompilation of static DML operations, object metadata must be on an available
node. However, local programs with static DML statements that do not use ANSI
names, late name resolution of ANSI names, or automatic recompilation can
execute successfully, even when the object metadata node is unavailable, provided
that the node or nodes that contain the objects remain available.