DATA STUCTURE

Definition:

Hashing index is used to retrieve data. We can find, insert and delete data by using the hashing index and the idea is to map keys of a given file. A hash means a 1 to 1 relationship between data. This is a common data type in languages. A hash algorithm is a way to take an input and always have the same output, otherwise known as a 1 to 1 function. An ideal hash function is when this same process unique

Hash Function

Choosing a hash function that minimizes the number of collisions and also hashes uniformly is another critical issue. It is also used in Main formula for hashing index is H(k) means that where is the location of that key

Explanation:

So far, to find something in a tree, or in a list, we have searched. However, there is another technique called hashing. Assume we are looking for some element e in a set S, where S may be implemented as a vector. We apply some function to e, hash (e), and this delivers the position of e in S, and we can then go directly to that location to get e or information on e. For example, e might be the key to a record, such as someone's name, and we wish to extract details/info on that person. e might be a telephone number and we want to know address, or e might be address and we want telephone number.

A hashing algorithm takes a variable length data message and creates a fixed size message digest. 

A tree is a disjointed data structure that programmers mostly use to store data in a hierarchical structure. In this discussion, we examine two types of trees, B-tree and binary tree. A binary tree is a tree structure that has a firm computational characteristic that provides for an efficient operation. Programmers recognise a binary tree as a tree structure where each node can consist of two or more children. By assigning a minimum value of children to two, we can come up with programs for manipulating the data in a binary tree. A binary tree is balanced if it is not “heavy” on either sub-trees. There are three traversal algorithms available in a binary tree. These are sometimes referred as pre order, in order, and post order traversal. In order is where the left sub-tree is visited first, then the node and the right sub-tree. Pre order is where the node is visited then the left sub-tree followed by the right sub-tree. For post order, the left sub-tree followed by the right sub-tree and later the node is traversed (McMillan, 2007).

Unlike a binary tree structure, each node of a b-tree may consist of variable values of keys as well as children. B-tree is an efficient data structure, which is used to manipulate large amount of data for a faster access. A b-tree is normally used for column manipulations in expressions that employ the use of the =, ≥, ≥=, ≤, operators. B-trees are used in databases such as Oracle. In addition, it is used in file-structures to enable faster random retrieval of an arbitrary block in a certain file (Alapati, 2008).

Hashing algorithm is a function that takes a variable string input and changes it into a constant numeric code. It is normally used in cryptography, fast data storage and error corrections cryptograms.

A hashing algorithm can cause problems if there are various strings with the same hash value. This is especially when there is a wider range of strings. To prevent these problems, a larger hash table should be provided .

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KRISHNA.P