Inverted Files


An inverted file is a list of sorted words, each one having a set of pointers to the pages where it occurs.

Advantages
It is the index found in most commercial library systems. The use of an inverted file improves search efficiency by several orders of magnitude.

Disadvantages
The need to store a data structure that ranges from 10%–100% or more of the size of the text itself, and a need to update that index as the data set changes.

State-of-the-art techniques can reduce an inverted file to about 20% of the text.

Some Restrictions


      I’d tell you if you were going around the bend (crazy).