SQL/MX 2.x Reference Manual (G06.24+, H06.03+)

SQL/MX Language Elements
HP NonStop SQL/MX Reference Manual—523725-004
6-14
SQL/MX Object Namespaces
You cannot use DEFINE names to refer to SQL/MX tables, views, partitions, or stored
procedures.
The advantages of using DEFINEs rather than Guardian physical names are:
•
DEFINE names are easier to understand than Guardian names.
For example, the name =CUSTOMERS is simpler than the physical name
\SYS.$VOL2.SALES.CSTMERS. See ADD DEFINE Command on page 4-3.
•
DEFINE names provide location independence.
If you use DEFINE names, you can change the physical file location without
changing the SQL statement. See ALTER DEFINE Command on page 4-5. For
more information on DEFINEs and late name resolution, see the SQL/MX
Programming Manual for C and COBOL or the SQL/MX Programming Manual for
Java.
SQL/MX Object Namespaces
SQL/MX objects are organized in a hierarchical manner. Database objects exist in
schemas, which are themselves contained in catalogs. Catalogs are collections of
schemas. Schema names must be unique within a given catalog.
Multiple objects with the same name can exist provided that each belongs to a
different namespace. NonStop SQL/MX supports these namespaces:
Objects in one schema can refer to objects in a different schema. Objects of a
given namespace are required to have unique names within a given schema.
Considerations for Database Object Names
OBJECTS Table
The OBJECTS table is created at SQL/MX installation time and is used to store
mappings from logical object names to physical Guardian locations. See OBJECTS
Table on page 10-18.
Namespace Description
CN Constraint
IX Index
LK Lock
MD Module
TA Table value object (table, view, stored procedure, MP Alias)
TR Trigger
TT Trigger temporary table