Hash Indices

1. A hash index organizes the search keys with their associated pointers into a hash file structure.
2. We apply a hash function on a search key to identify a bucket, and store the key and its associated pointers in the bucket (or in overflow buckets).
3. Strictly speaking, hash indices are only secondary index structures, since if a file itself is organized using hashing, there is no need for a separate hash index structure on it.