92 High-Function Business Intelligence in e-business
2.11 Materialized view limitations
The limitations applying to materialized views fall into the categories and
subcategories shown in Figure 2-15.
Figure 2-15 Materialized view limitation categories
The following sections describe the restrictions in each of the above categories.
2.11.1 REFRESH DEFERRED and REFRESH IMMEDIATE
The following fullselect restrictions apply to both REFRESH DEFERRED and
REFRESH IMMEDIATE materialized views:
? References to a materialized view, declared temporary table, or typed table in
any FROM clause.
? References to a view where the fullselect of the view violates any of the listed
restrictions on the fullselect of a materialized view.
? Expressions that are a reference type or DATALINK type (or distinct type
based on these types).
? Functions that have external action.
? Functions written in SQL.
Materialized VIew Limitations
Restrictions that ONLY apply to
REFRESH IMMEDIATE materialized views
and
REFRESH DEFERRED materialized views
associated with a staging table
General restrictions
Restrictions related to the requirement
that there can be NO DUPLICATES in the
materialized view
Restrictions when
there is no GROUP
BY clause defined
Restrictions that apply to
BOTH
REFRESH IMMEDIATE
and
REFRESH DEFERRED
materialized views
Restrictions when
a GROUP BY
clause is defined
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