analyzed v not_analyzed or ...?
By setting not_analyzed, you are only allowing exact matches (e.g. "SOMECODE/FRED" only, including case and special characters).
My guess is that you are using the standard analyzer (It is the default analyzer if you don't specify one). If that's the case, Standard will treat slashes as a token separator, and generate two tokens [somecode] and [fred]:
$ curl -XGET 'localhost:9200/_analyze?analyzer=standard&pretty' -d 'SOMECODE/FRED'{ "tokens" : [ { "token" : "somecode", "start_offset" : 0, "end_offset" : 8, "type" : "<ALPHANUM>", "position" : 1 }, { "token" : "fred", "start_offset" : 9, "end_offset" : 13, "type" : "<ALPHANUM>", "position" : 2 } ]}If you don't want this behavior, you need to change to a tokenizer that doesn't split on special characters. However, I would question the use-case for this. Generally, you'll want to split those types of characters.