SQL/MP Programming Manual for C

Program Invalidation and Automatic SQL
Recompilation
HP NonStop SQL/MP Programming Manual for C—429847-008
8-11
Preventing Automatic Recompilations
table-name or view-name
is the Guardian name or DEFINE name of the table or protection view. The name
cannot be a shorthand view. For the ALTER TABLE statement with the
SIMILARITY CHECK clause, table-name cannot be an SQL catalog table.
SIMILARITY CHECK ENABLE | DISABLE
enables or disables the similarity check for the specified table or protection view.
DISABLE is the default.
For the complete syntax of these statements, see the SQL/MP Reference Manual.
If you use the ALTER TABLE or ALTER VIEW statement to change the similarity check
attribute, the SQL catalog manager invalidates any programs, as identified in the
USAGES table, that reference the table or protection view. If the ALTER TABLE or
ALTER VIEW statement sets the similarity check attribute to its current value,
programs are not invalidated.
If you enable the similarity check for a protection view, the operation does not enable
the check for any underlying tables. You must explicitly enable the similarity check for
the underlying table. If you enable the similarity check for an underlying table, the
operation does not enable the check for a protection view defined on the table.
The SIMILARITYCHECK column in the TABLES table indicates whether a table or
protection view has the similarity check enabled:
A table or protection view that has the similarity check enabled is version 310 (or later).
All SQL/MP components, including the executor, catalog manager, and compiler, must
be version 310 (or later) to access the table or protection view. An SQL catalog that
supports the similarity check must have a catalog version of 310 (or later). For more
information, see the SQL/MP Version Management Guide.
Similarity Rules for Tables
For two tables to be similar, the characteristics and attributes of the tables must be the
same, except for the following listed differences. These tables are used to describe
these differences:

COMPILE-TIME-TABLE is the table SQLCOMP uses to generate the execution
plan during explicit SQL compilation. COMPILE-TIME-TABLE must have the
similarity check enabled for the COMPILE INOPERABLE PLANS option. (If the
similarity check is not enabled for COMPILE-TIME-TABLE, the CHECK
INOPERABLE PLANS option returns SQL warning 4315.)

RUN-TIME-TABLE is the table the program accesses at run time.
RUN-TIME-TABLE must have the similarity check enabled for the CHECK
ENABLED The similarity check is enabled.
DISABLED The similarity check is disabled.