The single purpose of creating an index or record is to retrieve the information stored in the easiest, fastest and most efficient way. Although there are many ways in which this index is built, one of the most effective way is by building a hash table. In hashing, a formula is applied to attach a numerical value to each word. The formula is designed to evenly distribute the entries across a predetermined number of divisions.
Let us explain how this works and why it is important. In English, there are some letters that begin many words, while others begin fewer. For example, the "M" section of the dictionary is much thicker than the "X" section. This inequity means that finding a word beginning with a very "popular" letter could take much longer than finding a word that begins with a less popular one. Hashing evens out the difference, and reduces the average time it takes to find an entry. It also separates the index from the actual entry. The hash table contains the hashed number along with a pointer to the actual data. This combination of efficient indexing and effective storage makes it possible to get results quickly, even when the user creates a very complicated search.
In fact, when you search using a major search engine you are not actually searching the web, but are searching a slightly outdated index of Web content which roughly represents the content of the web. This makes an efficiently made and a searchable index all the more important.