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Reverse Index

Reverse Index
In database systems, a reverse index is an index created on the mirror (or reverse) of the key value. For example, if a key field contained the value "ID100023" then the index would be created on the value "320001DI". Reverse Indexes are useful where key values in a table typically have similar leading data, but different trailing data. They are easier to visualise for string data, but the same logic applies to binary data although its may only be the byte order that is reversed and not the bit order.