Solution:

Hashing

• Hashing technique is used to calculate the direct location of a data record on the disk without using index structure.
• That is used to index and retrieve items in a database as it is faster to search that specific item, using the shorter hashed key instead of using its original value.

• A hash function is a simple mathematical function to any complex mathematical function.

Types of Hashing Techniques:

There are two types of SQL hashing techniques:

(I) Static Hashing

(II) Dynamic Hashing

(I) Static Hashing Techniques:

• Static hashing is the number of data buckets in memory remains constant throughout.
• That is a method of hashing, or shortening a string of characters in computer programming, in which the set of shortened characters remains the same length to improve the ease with which data can be accessed.

Static Hash Functions:

• Inserting a record:

When a new record requires to be inserted into the table, you can generate an address for the new record using its hash key and record is stored in that location.

• Searching a record:

When you need to retrieve the record, the same hash function should be helpful to retrieve the address of the bucket where data should be stored.

• Update a Record:

we will first search it using a hash function, and then the data record is updated.

This situation in the static hashing is known as bucket overflow, This is a critical situation in this method.

(II) Dynamic Hashing:

• In dynamic hashing, the hash function helps you to create a large number of values.

• This method is used to overcome the problems of static hashing like bucket overflow.

• This hashing is provides a mechanism, in which data buckets are added and removed dynamically and on-demand.

• Dynamic hashing is also known as extended hashing.