An obvious way to implement the Boolean search is through the inverted file. We store a list for each keyword in the vocabulary, and in each list put the addresses (or numbers) of the documents containing that particular word. Suppose that The keyword CAT indexes D1 (Document #1), D2, D3, D4; DOG indexes D1, D2; COLLAR indexes D1, D2, D3; and LEASH indexes : D1. Create an inverted file for these four keywords and four documents.

Keyword/Do cument # Document #1 Document #2 Document #3 Document #4 CAT++++ DOG++ COLLAR+++ LEASH+

Create inverted fileSort inverted file

Dictionary file Postings file

OR

CAT DOG COLLAR LEASH