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Static Hashing

 

Let K denote all the search-key values.

Let B represent the set of all bucket addresses.

A bucket is a unit of storage that contains some records.

 

Here, h is a ‘hash function’ from K to B. 

‘Hash function’ is used to avoid ‘index structure’.

  

Bucket Overflow :

This will occur only in two ways.

  1.  Insufficient buckets.
  2. Skew in distribution of records. Some buckets are given more records than others, so a bucket can overflow even though the other buckets still have space. This situation is called ‘bucket skew’.

Overflow Chaining :

The overflows of a given bucket are chained together in a linked list. This is called ‘Closed Hashing’.

In ‘Open Hashing’, the set of buckets are fixed, and there are no overflow chains. Here, if a bucket is full, the system inserts records in some other bucket in the initial set of buckets.

A hash index arranges the search keys, with their associated pointers, into a hash file structure. In this, one applies a hash function on a search key to helping identify a bucket, and store the key and its associated pointers in the bucket. 

 

Reference Link

Static Hashing