Method and apparatus for managing a document index

An apparatus for managing a document index, comprising:

• at least one processing unit;
• at least one memory coupled to the at least one processing unit and storing instructions to be executed by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the apparatus to:
• determine an independently updatable field in a plurality of documents, the independently updatable field comprising at least one item;
• create an index for an item in the independently updatable field, the index containing an identifier of a document comprising the item, the document being included in the plurality of documents;
• and
• store the identifier of the document in blocks such that the index is updatable without modifying the identifier of the document.