{"componentChunkName":"component---src-pages-author-author-yaml-id-js","path":"/author/anil-gupta/","result":{"data":{"allMarkdownRemark":{"edges":[{"node":{"id":"c6611215-4458-5540-a382-1ff1548299c9","html":"

One of the leading NoSQL databases, MongoDB is well known for its fast performance, versatile schema, scalability and great capabilities for indexing. Let us look at some context before we get into some details. Full-text search is an essential feature when we talk about finding content on the internet. A google search is the best example for this when we see the content using the phrases or keywords. In this article, we will learn about full-text search capabilities in MongoDB based on text index.

\n

Create a Sample Database

\n

Before we begin, we will create a sample database that will be used during the tutorial.

\n

We will create a database with the name myDB and create a collection with the name books. For this, the statement would be as follows.

\n
> use myDB\n> db.createCollection("books")\n>
\n

Let's insert some documents by using the following statement.

\n
> db.books.insert([\n\t{\n      "title": "Eloquent JavaScript, Second Edition",\n      "subtitle": "A Modern Introduction to Programming",\n      "author": "Marijn Haverbeke",\n      "publisher": "No Starch Press",\n      "description": "JavaScript lies at the heart of almost every modern web application, from social apps to the newest browser-based games. Though simple for beginners to pick up and play with, JavaScript is a flexible, complex language that you can use to build full-scale applications."\n    },\n    {\n      "title": "Learning JavaScript Design Patterns",\n      "subtitle": "A JavaScript and jQuery Developer's Guide",\n      "author": "Addy Osmani",\n      "publisher": "O'Reilly Media",\n      "description": "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you."\n    },\n    {\n      "title": "Speaking JavaScript",\n      "subtitle": "An In-Depth Guide for Programmers",\n      "author": "Axel Rauschmayer",\n      "publisher": "O'Reilly Media",\n      "description": "Like it or not, JavaScript is everywhere these days, from browser to server to mobile and now you, too, need to learn the language or dive deeper than you have. This concise book guides you into and through JavaScript, written by a veteran programmer who once found himself in the same position."\n    },\n    {\n      "title": "Programming JavaScript Applications",\n      "subtitle": "Robust Web Architecture with Node, HTML5, and Modern JS Libraries",\n      "author": "Eric Elliott",\n      "publisher": "O'Reilly Media",\n      "description": "Take advantage of JavaScript's power to build robust web-scale or enterprise applications that are easy to extend and maintain. By applying the design patterns outlined in this practical book, experienced JavaScript developers will learn how to write flexible and resilient code that's easier-yes, easier-to work with as your codebase grows."\n    },\n    {\n      "title": "Understanding ECMAScript 6",\n      "subtitle": "The Definitive Guide for JavaScript Developers",\n      "author": "Nicholas C. Zakas",\n      "publisher": "No Starch Press",\n      "description": "ECMAScript 6 represents the biggest update to the core of JavaScript in the history of the language. In Understanding ECMAScript 6, expert developer Nicholas C. Zakas provides a complete guide to the object types, syntax, and other exciting changes that ECMAScript 6 brings to JavaScript."\n    }\n])
\n

Creating a Text Index

\n

We need to create a text index on the fields to perform the text search. We can create this on single or multiple fields. The following statement will create a text index on a single field.

\n
>db.books.createIndex({"description":"text"})
\n

We will create a text index on the description and subtitle fields for this tutorial. We can create only one text index per collection in MongoDB. So We will create a compound text index using the following statement.

\n
>db.books.createIndex({"subtitle":"text","description":"text"})
\n

$search

\n

Now we will try to search documents that have the keywords 'ECMAScript' in the description and subtitle fields. For this, we can use the below statement.

\n
db.books.find({$text: {$search: "ECMAScript"}})
\n

Example

\n
>db.books.find({$text: {$search: "ECMAScript"}},{ subtitle: 1, description: 1 })\n\t{\n    "_id" : ObjectId("602b09cb3cb6144ada1c62fe"),\n    "subtitle" : "The Definitive Guide for JavaScript Developers",\n    "description" : "ECMAScript 6 represents the biggest update to the core of JavaScript in the history of the language. In Understanding ECMAScript 6, expert developer Nicholas C. Zakas provides a complete guide to the object types, syntax, and other exciting changes that ECMAScript 6 brings to JavaScript."\n\t}\n>
\n

Phrases

\n

You can search for phrases using the text index. By default, text search performs an OR search for all words in the phrase. If you want to search 'modern design patterns', it will search for documents with the keywords either modern, design, or patterns.

\n

Example

\n
>db.books.find({$text: {$search: "modern design patterns"}},{ subtitle: 1, description: 1 })\n\t{\n    "_id" : ObjectId("602b098f3cb6144ada1c2ea1"),\n    "subtitle" : "A JavaScript and jQuery Developer's Guide",\n    "description" : "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you."\n\t},\n\t{\n    "_id" : ObjectId("602b09b93cb6144ada1c4bca"),\n    "subtitle" : "Robust Web Architecture with Node, HTML5, and Modern JS Libraries",\n    "description" : "Take advantage of JavaScript's power to build robust web-scale or enterprise applications that are easy to extend and maintain. By applying the design patterns outlined in this practical book, experienced JavaScript developers will learn how to write flexible and resilient code that's easier-yes, easier-to work with as your code base grows.",\n\t},\n\t{\n    "_id" : ObjectId("602b095c3cb6144ada1c1028"),\n    "subtitle" : "A Modern Introduction to Programming",\n    "description" : "JavaScript lies at the heart of almost every modern web application, from social apps to the newest browser-based games. Though simple for beginners to pick up and play with, JavaScript is a flexible, complex language that you can use to build full-scale applications."\n\t}\n>
\n

If you want to search for exact phrases like documents with 'modern design patterns' together, you can do so by specifying double quotes in the search text.

\n

Example

\n
>db.books.find({$text: {$search: "\\"modern design patterns\\""}},{ subtitle: 1, description: 1 })\n\t{\n    "_id" : ObjectId("602b098f3cb6144ada1c2ea1"),\n    "subtitle" : "A JavaScript and jQuery Developer's Guide",\n    "description" : "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you."\n}
\n

Negations

\n

If you want to exclude the documents containing a particular word, you can use a negation search. For example if you're going to search all documents with the 'JavaScript' but not 'HTML5' or 'ECMAScript', you can search as the below example.

\n

Example

\n
>db.books.find({$text: {$search: "JavaScript -HTML5 -ECMAScript"}},{ subtitle: 1, description: 1 })\n\t{\n    "_id" : ObjectId("602b098f3cb6144ada1c2ea1"),\n    "subtitle" : "A JavaScript and jQuery Developer's Guide",\n    "description" : "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you."\n\t},\n\t{\n    "_id" : ObjectId("602b09a83cb6144ada1c4973"),\n    "subtitle" : "An In-Depth Guide for Programmers",\n    "description" : "Like it or not, JavaScript is everywhere these days, from browser to server to mobile and now you, too, need to learn the language or dive deeper than you have. This concise book guides you into and through JavaScript, written by a veteran programmer who once found himself in the same position."\n\t},\n\t{\n    "_id" : ObjectId("602b095c3cb6144ada1c1028"),\n    "subtitle" : "A Modern Introduction to Programming",\n    "description" : "JavaScript lies at the heart of almost every modern web application, from social apps to the newest browser-based games. Though simple for beginners to pick up and play with, JavaScript is a flexible, complex language that you can use to build full-scale applications."\n\t}
\n

Text Search Score

\n

The text search provides a score to each document representing the relevancy of the document with the search query. This score can be used to sort all the records returned in the search result. A higher score will indicate a most relevant match.

\n

Example

\n
>db.books.find({$text: {$search: "JavaScript "}},{score: {$meta: "textScore"}, subtitle: 1, description: 1 }).sort({score:{$meta:"textScore"}})\n\t{\n    "_id" : ObjectId("602b098f3cb6144ada1c2ea1"),\n    "subtitle" : "A JavaScript and jQuery Developer's Guide",\n    "description" : "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you.",\n    "score" : 1.43269230769231\n\t},\n\t{\n    "_id" : ObjectId("602b09cb3cb6144ada1c62fe"),\n    "subtitle" : "The Definitive Guide for JavaScript Developers",\n    "description" : "ECMAScript 6 represents the biggest update to the core of JavaScript in the history of the language. In Understanding ECMAScript 6, expert developer Nicholas C. Zakas provides a complete guide to the object types, syntax, and other exciting changes that ECMAScript 6 brings to JavaScript.",\n    "score" : 1.42672413793103\n\t},\n\t{\n    "_id" : ObjectId("602b09a83cb6144ada1c4973"),\n    "subtitle" : "An In-Depth Guide for Programmers",\n    "description" : "Like it or not, JavaScript is everywhere these days, from browser to server to mobile and now you, too, need to learn the language or dive deeper than you have. This concise book guides you into and through JavaScript, written by a veteran programmer who once found himself in the same position.",\n    "score" : 0.818181818181818\n\t},\n\t{\n    "_id" : ObjectId("602b095c3cb6144ada1c1028"),\n    "subtitle" : "A Modern Introduction to Programming",\n    "description" : "JavaScript lies at the heart of almost every modern web application, from social apps to the newest browser-based games. Though simple for beginners to pick up and play with, JavaScript is a flexible, complex language that you can use to build full-scale applications.",\n    "score" : 0.801724137931034\n\t},\n\t{\n    "_id" : ObjectId("602b09b93cb6144ada1c4bca"),\n    "subtitle" : "Robust Web Architecture with Node, HTML5, and Modern JS Libraries",\n    "description" : "Take advantage of JavaScript's power to build robust web-scale or enterprise applications that are easy to extend and maintain. By applying the design patterns outlined in this practical book, experienced JavaScript developers will learn how to write flexible and resilient code that's easier-yes, easier-to work with as your codebase grows.",\n    "score" : 0.792857142857143\n\t}
\n

Stop Words

\n

The $text operator filters out the language-specific stop words, such as a, an, the and in English. The below search will not return any document in the result.

\n

Example

\n
>db.books.find({$text: {$search: "is"}},{subtitle: 1, description: 1 })\n\tFetched 0 record(s)
\n

Stemmed Words

\n

The $text operator matches on the complete stemmed word. So if some document field contains the word learning or learn, a search on the term learning or learn would result in the same.

\n

Example

\n
>db.books.find({$text: {$search: " learn"}},{subtitle: 1, description: 1 }) or >db.books.find({$text: {$search: " learning"}},{subtitle: 1, description: 1 })\n\t{\n    "_id" : ObjectId("602b098f3cb6144ada1c2ea1"),\n    "subtitle" : "A JavaScript and jQuery Developer's Guide",\n    "description" : "With Learning JavaScript Design Patterns, you'll learn how to write beautiful, structured, and maintainable JavaScript by applying classical and modern design patterns to the language. If you want to keep your code efficient, more manageable, and up-to-date with the latest best practices, this book is for you."\n\t},\n\t{\n    "_id" : ObjectId("602b09a83cb6144ada1c4973"),\n    "subtitle" : "An In-Depth Guide for Programmers",\n    "description" : "Like it or not, JavaScript is everywhere these days, from browser to server to mobile and now you, too, need to learn the language or dive deeper than you have. This concise book guides you into and through JavaScript, written by a veteran programmer who once found himself in the same position."\n\t},\n\t{\n    "_id" : ObjectId("602b09b93cb6144ada1c4bca"),\n    "subtitle" : "Robust Web Architecture with Node, HTML5, and Modern JS Libraries",\n    "description" : "Take advantage of JavaScript's power to build robust web-scale or enterprise applications that are easy to extend and maintain. By applying the design patterns outlined in this practical book, experienced JavaScript developers will learn how to write flexible and resilient code that's easier-yes, easier-to work with as your codebase grows."\n\t}
\n

Conclusion

\n

I hope you learned something new today. Here is an interesting article on Self-Hosted MongoDB. I also invite you to try stuff on your own and share your experience in the comment section. Furthermore, if you face any problems with any of the above definitions, please feel free to ask me in the comments section below.

\n","frontmatter":{"title":"How to do Full-Text Search in MongoDB","author":{"id":"Anil Gupta","github":"anilswm","avatar":null},"date":"February 16, 2021","updated_date":null,"tags":["MongoDB"],"coverImage":{"childImageSharp":{"fluid":{"aspectRatio":1.5037593984962405,"src":"/static/f4c86ce656fbbcd1cebd60b0c6606d53/58556/coverImage.webp","srcSet":"/static/f4c86ce656fbbcd1cebd60b0c6606d53/61e93/coverImage.webp 200w,\n/static/f4c86ce656fbbcd1cebd60b0c6606d53/1f5c5/coverImage.webp 400w,\n/static/f4c86ce656fbbcd1cebd60b0c6606d53/58556/coverImage.webp 800w,\n/static/f4c86ce656fbbcd1cebd60b0c6606d53/99238/coverImage.webp 1200w,\n/static/f4c86ce656fbbcd1cebd60b0c6606d53/7c22d/coverImage.webp 1600w,\n/static/f4c86ce656fbbcd1cebd60b0c6606d53/25f09/coverImage.webp 1920w","sizes":"(max-width: 800px) 100vw, 800px"}}}},"fields":{"authorId":"Anil Gupta","slug":"/engineering/full-text-search-in-mongodb/"}}},{"node":{"id":"29ac238e-b3d9-5f78-83c0-ec97abe366ad","html":"

In this article, we will address how to perform basic query operations in MongoDB. We are producing data at an unparalleled pace now following the global spread of the internet. Since it will require us to collect/request the required data from the database to conduct some kind of analysis, it is of utmost importance that we choose the right tool to query the data.

\n

This is where MongoDB comes in, specifically. MongoDB is an unstructured database which, in the form of documents, stores data. In addition, MongoDB is very effective in handling enormous amounts of data and is the most commonly used NoSQL database as it provides rich query language and versatile and easy data access.

\n

Create a Sample Database

\n

Before the start, we will create a sample DB with some sample data to perform all operations.

\n

We will create a database with name myDB and will create a collection with name orders. For this, the statement would be as follows.

\n
> use myDB\n> db.createCollection("orders")\n>
\n

MongoDB doesn't use the rows and columns. It stores the data in a document format. A collection is a group of documents.

\n

You can check all collections in a database by using the following statement.

\n
> use myDB\n>show collections\norders\nsystem.indexes\n>
\n

Let's insert some documents by using the following statement.

\n
> db.orders.insert([\n\t{\n\t\tCustomer: "abc",\n\t\tAddress:{"City":"Jaipur","Country":"India"},\n\t\tPaymentMode":"Card",\n\t\tEmail:"abc@mail.in",\n\t\tOrderTotal: 1000.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":10},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"journal","Price":"200.00","Qty":2},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\t\t\n\t},\n\t{\n\t\tCustomer: "xyz",\n\t\tAddress:{"City":"Delhi","Country":"India"},\n\t\tPaymentMode":"Cash",\n\t\tOrderTotal: 800.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\t\t\n\t},\n\t{\n\t\tCustomer: "ron",\n\t\tAddress:{"City":"New York","Country":"USA"},\n\t\tPaymentMode":"Card",\n\t\tEmail:"ron@mail.com",\n\t\tOrderTotal: 800.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":00}\n\t\t]\t\t\n\t}\n])
\n

A document is the equivalent of an RDBMS row. It doesn't need to have the same schema in each document. It means a document might not have any field that doesn't have any value.

\n

Query Documents

\n

find() method

\n

You need to use the find() method to query documents from MongoDB collections. The following statement will retrieve all documents from the collection.

\n
> db.orders.find()\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tAddress:{"City":"Jaipur","Country":"India"},\n\t\tPaymentMode":"Card",\n\t\tEmail:"abc@mail.com",\n\t\tOrderTotal: 1000.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":10},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"journal","Price":"200.00","Qty":2},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\t\t\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tAddress:{"City":"Delhi","Country":"India"},\n\t\tPaymentMode":"Cash",\n\t\tOrderTotal: 800.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tAddress:{"City":"New York","Country":"USA"},\n\t\tPaymentMode":"Card",\n\t\tEmail:"ron@mail.com",\n\t\tOrderTotal: 600.00,\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":00}\n\t\t]\n\t}\n>
\n

Projection

\n

If you want to fetch only selected fields then you can use the projection. Following statement will fetch only Customer and Email field.

\n
> db.orders.find( { }, { Customer: 1, Email: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tEmail:"abc@mail.com"\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz"\t\t\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tEmail:"ron@mail.com"\t\t\n\t}\n>
\n

Filter the Documents by Specifying a Condition

\n

Now we will learn how we can fetch the documents that match a specified condition. MongoDB provides many comparison operators for this.

\n

1. $eq Operator

\n

The $eq operator checks the equality of the field value with the specified value. To fetch the order where PaymentMode is 'Card' you can use the following statement

\n
>db.orders.find( { PaymentMode: { $eq: "Card" } } )
\n

This query can be written also like below

\n
>db.orders.find( { PaymentMode: "Card" } )
\n

A similar SQL statement would be as follows

\n
SELECT * FROM orders WHERE PaymentMode="Card"
\n

Example

\n
>db.orders.find( { PaymentMode: "Card" }, { Customer: 1, PaymentMode: 1 } )\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tPaymentMode":"Card"\t\t\t\t\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tPaymentMode":"Card"\n\t}\n>
\n

$eq Operator with embedded document

\n

You may have noticed that we inserted an embedded document Address in the Orders collection. If you want to fetch the order where Country is 'India' you can use a dot notation like the following statement.

\n
>db.Orders.find( { "Address.Country": { $eq: "India" } } )
\n

This query can be written also like below

\n
>db.Orders.find( { "Address.Country":"India" } )
\n

Example

\n
>db.Orders.find( { "Address.Country": { $eq: "India" } } , { Customer: 1, Address: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tAddress:{"City":"Jaipur","Country":"India"}\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tAddress:{"City":"Delhi","Country":"India"}\n\t}\n>
\n

$eq Operator with array

\n

$eq operator will retrieve all the documents if the specified condition is true for any item in an array. We have an OrderItems array in the document. If you want to filter the documents where 'paper' were also ordered then the statement would be as follows.

\n
>db.Orders.find( { "OrderItems.ItemName": { $eq: "paper" } } )
\n

This query can be written also like below

\n
>db.Orders.find( { "OrderItems.ItemName": "paper"  } )
\n

Example

\n
>db.Orders.find( { "OrderItems.ItemName": { $eq: "paper" } } , { Customer: 1, OrderItems: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":10},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"journal","Price":"200.00","Qty":2},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\t\t\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\n\t}\n>
\n

2. $gt Operator

\n

You can use the $gt operator to retrieve the documents where a field’s value is greater than the specified value. The following statement will fetch the documents where OrderTotal is greater than 800.

\n
>db.orders.find( { OrderTotal: { $gt: 800.00 } } )
\n

A similar SQL statement would be as follows

\n
SELECT * FROM orders WHERE OrderTotal>800.00
\n

Example

\n
>db.Orders.find( { "OrderTotal": { $gt: 800.00 } } , { Customer: 1, OrderTotal: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tOrderTotal: 1000.00\n\t}\n>
\n

3. $gte Operator

\n

You can use the $gte operator to retrieve the documents where a field’s value is greater than or equal to the specified value. The following statement will fetch the documents where OrderTotal is greater than or equal to 800.

\n
>db.orders.find( { OrderTotal: { $gte: 800.00 } } )
\n

A similar SQL statement would be as follows

\n
SELECT * FROM orders WHERE OrderTotal>=800.00
\n

Example

\n
>db.Orders.find( { "OrderTotal": { $gte: 800.00 } } , { Customer: 1, OrderTotal: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tOrderTotal: 1000.00\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tOrderTotal: 800.00\n\t}\n>
\n

4. $lt Operator

\n

You can use the $lt operator to retrieve the documents where a field’s value is less than the specified value. The following statement will fetch the documents where OrderTotal is less than 800.

\n
>db.orders.find( { OrderTotal: { $lt: 800.00 } } )
\n

A similar SQL statement would be as follows

\n
SELECT * FROM orders WHERE OrderTotal<800.00
\n

Example

\n
>db.Orders.find( { "OrderTotal": { $lt: 800.00 } } , { Customer: 1, OrderTotal: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tOrderTotal: 600.00\n\t}\n>
\n

4. $lte Operator

\n

You can use the $lte operator to retrieve the documents where a field’s value is less than or equal to the specified value. Following statement will fetch the documents where OrderTotal is less than or equal to 800.

\n
>db.orders.find( { OrderTotal: { $lte: 800.00 } } )
\n

A similar SQL statement would be as follows

\n
SELECT * FROM orders WHERE OrderTotal<=800.00
\n

Example

\n
>db.Orders.find( { "OrderTotal": { $lte: 800.00 } } , { Customer: 1, OrderTotal: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tOrderTotal: 800.00\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tOrderTotal: 600.00\n\t}\n>
\n

5. $ne Operator

\n

You can use the $ne operator to retrieve the documents where a field’s value is not equal to the specified value.

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>db.orders.find( { PaymentMode: { $ne: "Card" } } )
\n

A similar SQL statement would be as follows

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SELECT * FROM orders WHERE PaymentMode != "Card"
\n

Example

\n
>db.Orders.find( { "PaymentMode": { $ne: "Card" } } , { Customer: 1, PaymentMode: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tPaymentMode":"Cash"\n\t}\n>
\n

6. $in Operator

\n

You can use the $in operator to retrieve the documents where a field’s value is equal to any value in the specified array.

\n
>db.orders.find( { OrderItems.ItemName: { $in: ["journal","paper"] } } )
\n

Example

\n
>db.Orders.find( { OrderItems.ItemName: { $in: ["journal","paper"] } } , { Customer: 1, OrderItems: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607534c")\n\t\tCustomer: "abc",\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":10},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"journal","Price":"200.00","Qty":2},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\t\t\n\t},\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607544c"),\n\t\tCustomer: "xyz",\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"paper","Price":"10.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":500}\n\t\t]\n\t}\n>
\n

7. $nin Operator

\n

You can use the $nin operator to retrieve the documents where a field’s value is not equal to any value in the specified array. It will also select the documents where the field does not exist.

\n
>db.orders.find( { OrderItems.ItemName: { $nin: ["journal","paper"] } } )
\n

Example

\n
>db.Orders.find( { OrderItems.ItemName: { $nin: ["journal","paper"] } } , { Customer: 1, OrderItems: 1 })\n\t{\n\t\t"_id" : ObjectId("5dd4e2cc0821d3b44607644c"),\n\t\tCustomer: "ron",\n\t\tOrderItems:[\n\t\t\t{"ItemName":"notebook","Price":"150.00","Qty":5},\n\t\t\t{"ItemName":"postcard","Price":"10.00","Qty":00}\n\t\t]\n\t}\n>
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Indexing

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We know that indexing is very important if we are performing the queries on a large database. Without indexing execution of a query can be expensive. We can add a simple ascending index on a single field by using the following statement.

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>db.Orders.createIndex({"Customer":1})
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MongoDB creates a unique index on ‘_id’ field by default. A unique index will prevent insertion of two documents with the same value for that field. If you want to create a unique index then the statement would be as follows.

\n
db.Orders.createIndex( { "OrderId": 1 }, { unique: true } )
\n

Conclusion

\n

I hope you learned something new today, If you want to learn few more stuff on MongoDB, here is an interesting article on Self-Hosted MongoDB I also invite you to try stuff on your own and share your experience in the comment section. Furthermore, if you face any problems with any of the above definitions, please feel free to ask me in the comments below.

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