A simple question about Indexes

For what kind of tables are Indexes inappropriate? Is it for an INSERT-intensive or UPDATE-intensive table?

Almost every table requires some set of indexes... I suppose it would be inappropriate to create an index on a table you only inserted into, never read from, never updated, and never deleted from. I can't imagine the utility, however, of this sort of write-only table.
Maintaining indexes adds some overhead to INSERT transactions and may or may not improve the performance of UPDATEs (depending on whether the index helps you find the row to update more efficiently or whether it just requires maintenance after the update happens). Similarly, it may or may not slow down DELETE operations. Indexes are generally designed, though, to improve query performance.
Justin

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