MongoDB - Text Search

 Starting from version 2.4, MongoDB started supporting text indexes to search inside string content. The Text Search uses stemming techniques to look for specified words in the string fields by dropping stemming stop words like a, an, the, etc. At present, MongoDB supports around 15 languages.

Enabling Text Search

Initially, Text Search was an experimental feature but starting from version 2.6, the configuration is enabled by default.

Creating Text Index

Consider the following document under posts collection containing the post text and its tags −

> db.posts.insert({
   "post_text": "enjoy the mongodb articles on tutorialspoint",
   "tags": ["mongodb", "tutorialspoint"]
}
{
	"post_text" : "writing tutorials on mongodb",
	"tags" : [ "mongodb", "tutorial" ]
})
WriteResult({ "nInserted" : 1 })

We will create a text index on post_text field so that we can search inside our posts' text −

>db.posts.createIndex({post_text:"text"})
{
	"createdCollectionAutomatically" : true,
	"numIndexesBefore" : 1,
	"numIndexesAfter" : 2,
	"ok" : 1
}


Using Text Index

Now that we have created the text index on post_text field, we will search for all the posts having the word tutorialspoint in their text.

> db.posts.find({$text:{$search:"tutorialspoint"}}).pretty()
{
	"_id" : ObjectId("5dd7ce28f1dd4583e7103fe0"),
	"post_text" : "enjoy the mongodb articles on tutorialspoint",
	"tags" : [
		"mongodb",
		"tutorialspoint"
	]
}

The above command returned the following result documents having the word tutorialspoint in their post text −

{ 
   "_id" : ObjectId("53493d14d852429c10000002"), 
   "post_text" : "enjoy the mongodb articles on tutorialspoint", 
   "tags" : [ "mongodb", "tutorialspoint" ]
}


Deleting Text Index

To delete an existing text index, first find the name of index using the following query −

>db.posts.getIndexes()
[
	{
		"v" : 2,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "mydb.posts"
	},
	{
		"v" : 2,
		"key" : {
			"fts" : "text",
			"ftsx" : 1
		},
		"name" : "post_text_text",
		"ns" : "mydb.posts",
		"weights" : {
			"post_text" : 1
		},
		"default_language" : "english",
		"language_override" : "language",
		"textIndexVersion" : 3
	}
]
>

After getting the name of your index from above query, run the following command. Here, post_text_text is the name of the index.

>db.posts.dropIndex("post_text_text")
{ "nIndexesWas" : 2, "ok" : 1 }

Comments

Post a Comment

Popular posts from this blog

Java : Variables Declaring

[1]. Java Variables Variables are containers for storing data values. In Java, there are different types of variables, for example: String - stores text, such as "Hello". String values are surrounded by double quotes int - stores integers (whole numbers), without decimals, such as 123 or -123 float - stores floating point numbers, with decimals, such as 19.99 or -19.99 char - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes boolean - stores values with two states: true or false [2]. Declaring (Creating) Variables To create a variable, you must specify the type and assign it a value: Syntax type variable = value ; Where type is one of Java's types (such as int or String), and variable is the name of the variable (such as x or name). The equal sign is used to assign values to the variable. To create a variable that should store text, look at the following example: Example Create a variable called  name  of type  Stri...
Read more

SQL Self JOIN

SQL Self JOIN A self JOIN is a regular join, but the table is joined with itself. Self JOIN Syntax SELECT column_name(s) FROM table1 T1, table1 T2 WHERE condition; T1 and T2 are different table aliases for the same table.
Read more