1. A method for indexing a product identifier and logical parts thereof, comprising: receiving a product identifier; splitting the product identifier into logical parts; indexing the product identifier and the individual logical parts in association with a particular document or portion thereof in an index; and storing the index, wherein the index is created by encoding context information into the particular document, wherein the context information includes the product identifier and the individual logical parts of the product identifier, wherein each of the product identifier and the individual logical parts of the product identifier are stored in separate fields in the context information, wherein different weights are assigned to separate fields based on the field types such as product identifier or logical parts of the product identifier field, wherein different weights are assigned to words based on the word types including bi-words, wherein the fields and weights are encoded to word positions in the particular document, wherein the weights affect a context score generated upon performing a query using the index.
2. The method as recited in claim 1 , wherein if the product identifier comprises multiple logical parts separated by a space, the context information further comprises at least some of the logical parts separated by a space as a single consecutive character string without a space.