The access plan is the method that the database server uses to access a table. The database server can either read the table sequentially (full table scan) or use any one of the indexes on the table. The following directives influence the access plan:
Use the index specified to access the table. If the directive lists more than one index, the optimizer chooses the index that yields the least cost.
Do not use any of the indexes listed. You can use this directive with the AVOID_FULL directive.
Perform a full table scan.
Do not perform a full table scan on the listed table. You can use this directive with the AVOID_INDEX directive.
In some cases, forcing an access method can change the join method that the optimizer chooses. For example, if you exclude the use of an index with the AVOID_INDEX directive, the optimizer might choose a hash join instead of a nested-loop join.
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