MongoDB Text Search – Indexing Single & Multiple Fields

{
"subject":"Joe", 
"content":"best friend", 
"likes": 60, 
"year":2015, 
"language":"english"
}

Let’s add some sample documents in the collection.

db.examples.insert({"subject":"Joe", "content":"best friend", "likes": 60, "year":2015, "language":"english"})

db.examples.insert({"subject":"Dogs", "content":"Cats", "likes": 30, "year":2015, "language":"english"})

db.examples.insert({"subject":"Cats", "content":"Rats", "likes": 55, "year":2014, "language":"english"})

db.examples.insert({"subject":"Rats", "content":"Joe", "likes": 75, "year":2014, "language":"english"})

i. Indexing a Single Field

db.examples.createIndex({"subject":"text"})

Now, if you want to test this newly created text index on the subject field, we will have to find documents using $text operator. We will look for all documents that have keyword dog in their subject field.

db.examples.find({$text: {$search: "dogs"}}, {score: {$meta: "toextScore"}}).sort({score:{$meta:"textScore"}})

Here, we are using {$meta: “textScore” } to get some statistics about how relevant our resultant document is. After that, we will sort all documents by their textScore using sort command. Higher the textScore, more relevant the match is.

db.examples.dropIndex("subject_text") 
db.examples.createIndex({"subject":"text","content":"text"})

After writing this query now write another query to find out all documents with keyword cat.

db.messages.find({$text: {$search: "cat"}}, {score: {$meta: "textScore"}}).sort({score:{$meta:"textScore"}})

This query will give us the following output:

db.messages.createIndex({"$**":"text"})

This query will set up text indexes on any string fields in our documents. For this insert a new document with a new field location in it.

db.examples.insert({"subject":"Birds", "content":"Rats", "likes": 12, "year":2013, location: "Switzerland", "language":"english"})

Now if we try to search with Switzerland keyword then it will show up the current document we inserted.

db.examples.find({$text: {$search: "switzerland"}}, {score: {$meta: "textScore"}}).sort({score:{$meta:"textScore"}})