How to get the exact match of using DSL - elasticsearch

Question

How mapping have role to find the search??
GET courses/_search
return is below
{
"took" : 2,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : 1.0226655,
"hits" : [
{
"_index" : "courses",
"_type" : "classroom",
"_id" : "7",
"_score" : 1.0226655,
"_source" : {
"name" : "Computer Internals 250",
"room" : "C8",
"professor" : {
"name" : "Gregg Va",
"department" : "engineering",
"facutly_type" : "part-time",
"email" : "payneg#onuni.com"
},
"students_enrolled" : 33,
"course_publish_date" : "2012-08-20",
"course_description" : "cpt Int 250 gives students an integrated and rigorous picture of applied computer science, as it comes to play in the construction of a simple yet powerful computer system. "
}
},
{
"_index" : "courses",
"_type" : "classroom",
"_id" : "4",
"_score" : 0.2876821,
"_source" : {
"name" : "Computer Science 101",
"room" : "C12",
"professor" : {
"name" : "Gregg Payne",
"department" : "engineering",
"facutly_type" : "full-time",
"email" : "payneg#onuni.com"
},
"students_enrolled" : 33,
"course_publish_date" : "2013-08-27",
"course_description" : "CS 101 is a first year computer science introduction teaching fundamental data structures and algorithms using python. "
}
}
]
}
}
mapping is below
{
"courses" : {
"mappings" : {
"properties" : {
"course_description" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"course_publish_date" : {
"type" : "date"
},
"name" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"professor" : {
"properties" : {
"department" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"email" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"facutly_type" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"name" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
}
}
},
"room" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
},
"students_enrolled" : {
"type" : "long"
}
}
}
}
}
I need to return the exact match phrase professor.name=Gregg Payne
I tried below query as per direction from https://www.elastic.co/guide/en/elasticsearch/guide/current/_finding_exact_values.html
GET courses/_search
{
"query" : {
"constant_score" : {
"filter" : {
"term" : {
"professor.name" : "Gregg Payne"
}
}
}
}
}

Answer 1

Based on your mapping, here is the query that shall work for you -
POST http://localhost:9200/courses/_search
{
"query" : {
"constant_score" : {
"filter" : {
"term" : {
"professor.name.keyword" : "Gregg Payne"
}
}
}
}
}
Answering your question in the comments - search is always about mappings :) In your case you use Term query which is about searching for exact values and it needs a keyword field. Text fields get analyzed:
Avoid using the term query for text fields.
By default, Elasticsearch changes the values of text fields as part of
analysis. This can make finding exact matches for text field values
difficult.
To search text field values, use the match query instead