Hash File Organization

1. Hashing involves computing the address of a data item by computing a function on the search key value.
2. A hash function h is a function from the set of all search key values K to the set of all bucket addresses B.
   • We choose a number of buckets to correspond to the number of search key values we will have stored in the database.
   • To perform a lookup on a search key value , we compute , and search the bucket with that address.
   • If two search keys i and j map to the same address, because , then the bucket at the address obtained will contain records with both search key values.
   • In this case we will have to check the search key value of every record in the bucket to get the ones we want.
   • Insertion and deletion are simple.

• Hash Functions
• Handling of bucket overflows