SQL/MX Database Distribution White Paper

NonStop SQL/MX Database Distribution White Paper 22 November 2004
Hewlett-Packard Company – 529627-001 Page 12 of 12
b) A partitioned read-only table with replicated rows would be complicated to use from SQL/MX
conversational interface (MXCI) and other ad-hoc queries. This issue could be overcome by using a
suitable view.
However, Alternative 4 is the only alternative that offers a single, globally visible ANSI name for a
replicated table.
The other three alternatives differ in how they preserve the original catalog and schema structure:
• Alternative 1, Application-Managed Node-Specific Names, preserves the original catalog and
schema names and implements replicated” tables by having different table names within the same
catalog and schema. This alternative is generally useful. However, it requires more application
changes than Alternatives 2 and 3. For a description of the use of prototype names, see Support
Note S04098, “USING SQL/MX NAMES WITH NO GUARDIAN DEFINE SUPPORT.”
• Alternative 2, Node-Specific Default Schema Names, preserves the original catalog names and
table names. Replicated tables are implemented by having different schemas within the catalog.
Alternative 2 uses a default catalog and schema name, and there can be only one such set of
defaults. Therefore, this alternative is not useful if read-only tables must reside in more than one
schema.
• Alternative 3, Individual Catalogs, introduces separate catalogs for read-only tables. Replication
is implemented by having identically named individual catalogs on the involved nodes. This
alternative is not useful if read-only tables must be related to tables in the globally visible
application catalog or if application programs must perform updates to all copies.