Predefined Term Mapping - mongodb

Question

I have not yet used Elasticsearch so please excuse the bad description. I would like to know if it is possible to configure Elasticsearch to do the following - I had some issues in MongoDB with this as the full text search functionalities seem to be a little limiting.
Here's my problem - when I do a search for the term Korea I do not
want it to match North Korea or N. Korea in the document.
The assumption is that a search for Korea is about South Korea. This is obviously different from a synonym as it is kind of the opposite. A phrase search for South Korea is out of the question here as it isn't applicable in my problem. Is this possible?
I will accept answers for either MongoDB or Elasticsearch.

Answer 1

What if you use a query like this one:
{
"query": {
"bool": {
"should": [
{
"match": {
"some_field": "korea"
}
},
{
"query_string": {
"query": "-some_field:(\"north korea\")"
}
},
{
"query_string": {
"query": "-some_field:(\"n. korea\")"
}
}
]
}
}
}
What it does is like this:
if that field content matches "korea" then it's receiving a score
if that field isn't matching "north korea" again it's getting some score boost
again, if it doesn't match "n. korea" is getting some additional score.
Basically, the score increases if it matches "korea", if it doesn't match "north korea" and if it doesn't match "n. korea".
For example, for documents like this
POST /my_index/test/1
{
"text": "North Korea"
}
POST /my_index/test/2
{
"text": "Korea"
}
POST /my_index/test/3
{
"text": "N. Korea"
}
POST /my_index/test/4
{
"text": "South Korea"
}
The query above will return this:
"hits": [
{
"_index": "korea",
"_type": "test",
"_id": "2",
"_score": 1.4471208,
"_source": {
"text": "Korea"
}
},
{
"_index": "korea",
"_type": "test",
"_id": "4",
"_score": 1.4227209,
"_source": {
"text": "South Korea"
}
},
{
"_index": "korea",
"_type": "test",
"_id": "1",
"_score": 0.48779577,
"_source": {
"text": "North Korea"
}
},
{
"_index": "korea",
"_type": "test",
"_id": "3",
"_score": 0.48779577,
"_source": {
"text": "N. Korea"
}
}
]
The highest scores are for documents that are not about north korea.