
10.4 Performance and the MODEL Clause 313
Chapter 10
10.4.2 Understanding MODEL Clause Query Plans
An Oracle SQL MODEL clause query is accessed as ORDERED,
CYCLIC, or ACYCLIC. Any of the three aforementioned options can be
accessed as FAST. The different access methods are used by the optimizer in
generating a query plan, depending on the structure of the MODEL clause
RULES clause.
Figure 10.32 shows an example of an ORDERED FAST MODEL
clause query where expressions on both sides of the rules are all simple cell
expressions.
Figure 10.33 shows an example of an ORDERED MODEL clause
query where expressions in the rules have multiple cell references and not ...