The simplest form of view is to create an index against a single field from the documents stored in your database.

For example, given the document structure:

{
    "firstname": "Martin",
    "lastname": "Brown"
}

A view to support queries on the firstname field could be defined as follows:

function(doc, meta) 
{
  if (doc.firstname) 
  {
     emit(doc.firstname.toLowerCase(),null);
  }
}

The view works as follows for each document:

Queries can now be specified by supplying a string converted to lowercase. For example:

?key="martin"

Will return all documents where the firstname field contains 'Martin', regardless of the document field capitalization.