Indexes are critical objects separate from tables; they vastly increase the performance of a database application. Your index architecture should be well planned, implemented, and maintained. Carefully choose which tables and columns are indexed. Although indexes dramatically increase the speed of queries, indexes can slow down DML statement because the index has to be maintained as the table data changes. Indexes also consume disk space and thus should be created only when required.
Oracle's B-tree index is the default index type and is sufficient for most applications. However, you should be aware of other index types and their uses. Specific features such as bitmap and function-based indexe...
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