{"id":55948,"date":"2018-03-09T15:00:52","date_gmt":"2018-03-09T13:00:52","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=55948"},"modified":"2018-03-09T12:35:37","modified_gmt":"2018-03-09T10:35:37","slug":"mongodb-hasnext-and-next-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/software-development\/mongodb\/mongodb-hasnext-and-next-example\/","title":{"rendered":"MongoDB hasNext() and next() Example"},"content":{"rendered":"<p>Hello readers, in this tutorial, we will see the <code>hasNext()<\/code> and the <code>next()<\/code> methods available in the Mongo database.<\/p>\n<h2>1. Introduction<\/h2>\n<p>If you have installed the MongoDB application (<em>version 3.6<\/em>) on Windows or Ubuntu operating system and you wish to learn the <code>hasNext()<\/code> and the <code>next()<\/code> methods then follow the below steps. It is very simple, but before moving further let&#8217;s take a look at the Mongo database and its characteristics.<\/p>\n<h3>1.1 What is MongoDB?<\/h3>\n<ul>\n<li>MongoDB is a high-performance <em>NoSQL database<\/em> where each database has collections which in turn has documents. Each document has a different number of fields, size, content, and is stored in a JSON-like format (i.e. Binary JSON (<a href=\"https:\/\/en.wikipedia.org\/wiki\/BSON\" target=\"_blank\" rel=\"noopener\">BSN<\/a>))<\/li>\n<li>The documents in MongoDB doesn\u2019t need to have a schema defined beforehand. Instead, the fields (i.e. <em>records<\/em>) can be created on the go<\/li>\n<li>Data model available within the MongoDB allows developers to represent the hierarchical relationships, store arrays, and other more complex structures easily<\/li>\n<li>This NoSQL solution often comes with embedding, auto-sharding, and onboard replication for better scalability and high availability<\/li>\n<\/ul>\n<h4>1.1.1 Why MongoDB?<\/h4>\n<ul>\n<li>As a NoSQL type database, MongoDB stores the data in the form of a document. Thus, MongoDB offers more flexibility<\/li>\n<li>This database supports search by field-name, range queries, and the regular expressions. It often provides queries to return the particular fields inside the documents<\/li>\n<li>MongoDB offers <em>indexes<\/em> to improve the <em>search performance<\/em> within the NoSQL database<\/li>\n<li>To offer horizontal scalability, MongoDB uses sharding by splitting the data across the many MongoDB occurrences<\/li>\n<li><strong>Replication<\/strong>: MongoDB can give high availability with the replica sets<\/li>\n<\/ul>\n<h3>1.2 What is a Cursor in MongoDB?<\/h3>\n<p>In Mongo world, a <strong>cursor<\/strong> is an object that allows developers to iterate through the documents of a Mongo collection. The behavior of cursor allows an automatic iteration across the results of the query; however, developers can explicitly go through the items returned in the cursor object. The below diagram lists <code>4<\/code> documents where the Mongo <em>cursor<\/em> will point to the first document and then iterate through all the other documents of a collection.<\/p>\n<p><figure id=\"attachment_55950\" aria-describedby=\"caption-attachment-55950\" style=\"width: 673px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-archi-guide-1.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55950\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-archi-guide-1.jpg\" alt=\"Fig. 1: Pictorial representation of a Cursor in Mongo collection\" width=\"673\" height=\"492\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-archi-guide-1.jpg 673w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-archi-guide-1-300x219.jpg 300w\" sizes=\"(max-width: 673px) 100vw, 673px\" \/><\/a><figcaption id=\"caption-attachment-55950\" class=\"wp-caption-text\">Fig. 1: Pictorial representation of a Cursor in Mongo collection<\/figcaption><\/figure><\/p>\n<h4>1.2.1 Why Cursor in MongoDB?<\/h4>\n<p>Cursor offers:<\/p>\n<ul>\n<li>A true snapshot of a system i.e. it returns the data in batches and increases the database performance<\/li>\n<li>It saves system memory by allowing batch inserts and updates<\/li>\n<li>Intelligibility and Clarity on the ad-hoc and complex queries of the sequential nature having large result sets and low consistency requirements<\/li>\n<li>Openness to work on small batches of data as developers don\u2019t need to wait for the processing and download of the complete record-set<\/li>\n<\/ul>\n<h2>2. MongoDB hasNext() and next() Example<\/h2>\n<p>In this tutorial, we will learn how to handle the <code>hasNext()<\/code> and the <code>next()<\/code> methods provided by the Mongo database.<\/p>\n<h3>2.1 hasNext() method in the Mongo database<\/h3>\n<p>In the Mongo universe, the <code><a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/method\/cursor.hasNext\/\" target=\"_blank\" rel=\"noopener\">hasNext()<\/a><\/code> method returns <code>true<\/code> if the cursor object returned by the <code><a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/method\/db.collection.find\/#db.collection.find\" target=\"_blank\" rel=\"noopener\">db.collection.find()<\/a><\/code> query has more documents to return. If <strong>not<\/strong>, the <code>hasNext()<\/code> method will return a Boolean <code>false<\/code>. This method has the following prototype form:<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Mongo database &#8216;hasNext()&#8217; Syntax<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.collection_name.find(&lt;query_string&gt;).hasNext()\r\n<\/pre>\n<p>Where:<\/p>\n<ul>\n<li>The <code>query_string<\/code> is an optional input argument that retrieves the documents from the collection on the basis of a specified selection criteria<\/li>\n<\/ul>\n<p>Do <em>remember<\/em>, this method returns a <code>Boolean<\/code> output.<\/p>\n<h3>2.2 next() method in the Mongo database<\/h3>\n<p>In the Mongo universe, the <code><a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/method\/cursor.next\/\" target=\"_blank\" rel=\"noopener\">next()<\/a><\/code> method returns the next document in a cursor object returned by the <code><a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/method\/db.collection.find\/#db.collection.find\" target=\"_blank\" rel=\"noopener\">db.collection.find()<\/a><\/code> query. This method has the following prototype form:<div style=\"display:inline-block; margin: 15px 0;\"> <div id=\"adngin-JavaCodeGeeks_incontent_video-0\" style=\"display:inline-block;\"><\/div> <\/div><\/p>\n<p><span style=\"text-decoration: underline;\"><em>Mongo database &#8216;next()&#8217; Syntax<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.collection_name.find(&lt;query_string&gt;).next()\r\n<\/pre>\n<p>Where:<\/p>\n<ul>\n<li>The <code>query_string<\/code> is an optional input argument that retrieves the documents from the collection on the basis of a specified selection criteria<\/li>\n<\/ul>\n<p>Do <em>remember<\/em>, this method returns an exception if the <code>next()<\/code> method has no document in the cursor object.<\/p>\n<h3>2.3 Practical usage<\/h3>\n<p>Let&#8217;s understand the implementation of these methods with the help of the sample snippets.<\/p>\n<h4>2.3.1 Start MongoDB<\/h4>\n<p>Start a standalone <a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/program\/mongod\/#bin.mongod\" target=\"_blank\" rel=\"noopener\">mongod<\/a> instance as shown below.<\/p>\n<p><figure id=\"attachment_55951\" aria-describedby=\"caption-attachment-55951\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-1.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55951\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-1.jpg\" alt=\"Fig. 2: Start Mongo instance\" width=\"849\" height=\"613\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-1.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-1-300x217.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-1-768x555.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55951\" class=\"wp-caption-text\">Fig. 2: Start Mongo instance<\/figcaption><\/figure><\/p>\n<h4>2.3.2 Connect to the Mongo Instance<\/h4>\n<p>Connect with the <a href=\"https:\/\/docs.mongodb.com\/manual\/reference\/program\/mongo\/#bin.mongo\" target=\"_blank\" rel=\"noopener\">mongo<\/a> shell to make a connection with the MongoDB instance on the port <code>27017<\/code> as shown below.<\/p>\n<p><figure id=\"attachment_55952\" aria-describedby=\"caption-attachment-55952\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-2.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55952\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-2.jpg\" alt=\"Fig. 3: Connect to Mongo database\" width=\"849\" height=\"362\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-2.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-2-300x128.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-2-768x327.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55952\" class=\"wp-caption-text\">Fig. 3: Connect to Mongo database<\/figcaption><\/figure><\/p>\n<h4>2.3.3 Create Mongo database and collection<\/h4>\n<p>To begin with the implementation, we will need to create a sample database and collection. The below script creates a database called <code>warehouse<\/code> with a collection of <code>products<\/code>. Open the Mongo terminal and execute the script.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Database &amp; Collection creation script<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; use warehouse\r\n\r\n&gt; db.products.insertMany( [\r\n\t{ \"_id\" : \"1001\", \"name\" : \"AC3 Phone\", \"brand\" : \"ACME\", \"type\" : \"phone\", \"price\" : 200, \"warranty_years\" : 1, \"available\" : \"true\" },\r\n\t{ \"_id\" : \"1002\", \"name\" : \"AC7 Phone\", \"brand\" : \"ACME\", \"type\" : \"phone\", \"price\" : 320, \"warranty_years\" : 1, \"available\" : \"false\" },\r\n\t{ \"_id\" : \"1003\", \"name\" : \"AC3 Series Charger\", \"type\" : [ \"accessory\", \"charger\" ], \"price\" : 19, \"warranty_years\" : 0.25, \"for\" : [ \"ac3\", \"ac7\", \"ac9\" ] },\r\n\t{ \"_id\" : \"1004\", \"name\" : \"AC3 Case Green\", \"type\" : [ \"accessory\", \"case\" ], \"color\" : \"green\", \"price\" : 12, \"warranty_years\" : 0 },\r\n\t{ \"_id\" : \"1005\", \"name\" : \"Phone Extended Warranty\", \"type\" : \"warranty\", \"price\" : 38, \"warranty_years\" : 2, \"for\" : [ \"ac3\", \"ac7\", \"ac9\", \"qp7\", \"qp8\", \"qp9\" ] },\r\n\t{ \"_id\" : \"1006\", \"name\" : \"AC3 Case Black\", \"type\" : [ \"accessory\", \"case\" ], \"color\" : \"black\", \"price\" : 12.5, \"warranty_years\" : 0.25, \"available\" : \"false\", \"for\" : \"ac3\" },\r\n\t{ \"_id\" : \"1007\", \"name\" : \"AC3 Case Red\", \"type\" : [ \"accessory\", \"case\" ], \"color\" : \"red\", \"price\" : 12, \"warranty_years\" : 0.25, \"available\" : \"true\", \"for\" : \"ac3\" },\r\n\t{ \"_id\" : \"1008\", \"name\" : \"Phone Service Basic Plan\", \"type\" : \"service\", \"monthly_price\" : 40, \"limits\" : { \"voice\" : { \"units\" : \"minutes\", \"n\" : 400, \"over_rate\" : 0.05 }, \"data\" : { \"units\" : \"gigabytes\", \"n\" : 20, \"over_rate\" : 1 }, \"sms\" : { \"units\" : \"texts sent\", \"n\" : 100, \"over_rate\" : 0.001 } }, \"term_years\" : 2 },\r\n\t{ \"_id\" : \"1009\", \"name\" : \"Phone Service Core Plan\", \"type\" : \"service\", \"monthly_price\" : 60, \"limits\" : { \"voice\" : { \"units\" : \"minutes\", \"n\" : 1000, \"over_rate\" : 0.05 }, \"data\" : { \"n\" : \"unlimited\", \"over_rate\" : 0 }, \"sms\" : { \"n\" : \"unlimited\", \"over_rate\" : 0 } }, \"term_years\" : 1 },\r\n\t{ \"_id\" : \"1010\", \"name\" : \"Phone Service Family Plan\", \"type\" : \"service\", \"monthly_price\" : 90, \"limits\" : { \"voice\" : { \"units\" : \"minutes\", \"n\" : 1200, \"over_rate\" : 0.05 }, \"data\" : { \"n\" : \"unlimited\", \"over_rate\" : 0 }, \"sms\" : { \"n\" : \"unlimited\", \"over_rate\" : 0 } }, \"sales_tax\" : true, \"term_years\" : 2 },\r\n\t{ \"_id\" : \"1011\", \"name\" : \"Cable TV Basic Service Package\", \"type\" : \"tv\", \"monthly_price\" : 50, \"term_years\" : 2, \"cancel_penalty\" : 25, \"sales_tax\" : \"true\", \"additional_tariffs\" : [ { \"kind\" : \"federal tariff\", \"amount\" : { \"percent_of_service\" : 0.06 } }, { \"kind\" : \"misc. tariff\", \"amount\" : 2.25 } ] }\r\n] )\r\n<\/pre>\n<p>The script gives the below output.<\/p>\n<p><figure id=\"attachment_55953\" aria-describedby=\"caption-attachment-55953\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-3.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55953\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-3.jpg\" alt=\"Fig. 4: Database &amp; Collection creation\" width=\"849\" height=\"366\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-3.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-3-300x129.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-3-768x331.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55953\" class=\"wp-caption-text\">Fig. 4: Database &amp; Collection creation<\/figcaption><\/figure><\/p>\n<h4>2.3.4 Check Mongo database and collection<\/h4>\n<p>If the script works well, the database and the collection will be shown in the Mongo Workbench. Using the <code>db.collection_name.find()<\/code> or the <code>db.collection_name.find().pretty()<\/code> command the documents of a collection will be shown as below.<\/p>\n<p><figure id=\"attachment_55954\" aria-describedby=\"caption-attachment-55954\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-4.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55954\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-4.jpg\" alt=\"Fig. 5: Mongo database &amp; collection\" width=\"849\" height=\"206\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-4.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-4-300x73.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-4-768x186.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55954\" class=\"wp-caption-text\">Fig. 5: Mongo database &amp; collection<\/figcaption><\/figure><\/p>\n<h4>2.3.5 Implementation of &#8216;hasNext()&#8217; method<\/h4>\n<p>Now, go back to the Mongo shell and use the <code>hasNext(&lt;query_string&gt;)<\/code> method to check if the cursor object has more documents to return.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Query 1<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.products.find().hasNext()\r\n<\/pre>\n<p>This command will return a Boolean <code>true<\/code> because the <code>db.products.find()<\/code> cursor object has more documents to return.<\/p>\n<p><figure id=\"attachment_55955\" aria-describedby=\"caption-attachment-55955\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-5.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55955\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-5.jpg\" alt=\"Fig. 6: Mongo database hasNext() method\" width=\"849\" height=\"38\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-5.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-5-300x13.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-5-768x34.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55955\" class=\"wp-caption-text\">Fig. 6: Mongo database hasNext() method<\/figcaption><\/figure><\/p>\n<p>Let\u2019s say developers want to return the documents that match criteria. They can achieve this by simply appending the selection criteria in the <code>find()<\/code> method. Let\u2019s understand this with the help of an example.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Query 1(a)<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.products.find( { \"available\" : \"true\", \"brand\": \"ACME_NEW\" } ).hasNext()\r\n<\/pre>\n<p>This command will return a Boolean <code>false<\/code> because the criteria specified in the <code>db.products.find()<\/code> cursor object has <strong>no<\/strong> documents to return.<\/p>\n<p><figure id=\"attachment_55956\" aria-describedby=\"caption-attachment-55956\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-6.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55956\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-6.jpg\" alt=\"Fig. 7: Mongo database hasNext() method with selection criteria\" width=\"849\" height=\"45\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-6.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-6-300x16.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-6-768x41.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55956\" class=\"wp-caption-text\">Fig. 7: Mongo database hasNext() method with selection criteria<\/figcaption><\/figure><\/p>\n<h4>2.3.6 Implementation of &#8216;next()&#8217; method<\/h4>\n<p>Refresh the Mongo shell and use the <code>next(&lt;query_string&gt;)<\/code> method to return the next document in a cursor.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Query 2<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.products.find().next()\r\n<\/pre>\n<p>This command will return the next document from the <code>products<\/code> collection.<\/p>\n<p><figure id=\"attachment_55957\" aria-describedby=\"caption-attachment-55957\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-7.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55957\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-7.jpg\" alt=\"Fig. 8: Mongo database next() method\" width=\"849\" height=\"96\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-7.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-7-300x34.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-7-768x87.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55957\" class=\"wp-caption-text\">Fig. 8: Mongo database next() method<\/figcaption><\/figure><\/p>\n<p>Let\u2019s say developers want to retrieve the documents from a collection that matches criteria. They can modify the Query 2 as shown below.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Query 2 (a)<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.products.find( { \"available\" : \"false\", \"brand\": \"ACME\" } ).next()\r\n<\/pre>\n<p>This command will return the output as shown in Fig. 9.<\/p>\n<p><figure id=\"attachment_55958\" aria-describedby=\"caption-attachment-55958\" style=\"width: 849px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-8.jpg\"><img decoding=\"async\" class=\"size-full wp-image-55958\" src=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-8.jpg\" alt=\"Fig. 9: Mongo database next() method with selection criteria\" width=\"849\" height=\"96\" srcset=\"https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-8.jpg 849w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-8-300x34.jpg 300w, https:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/mongodb-nhn-project-guide-8-768x87.jpg 768w\" sizes=\"(max-width: 849px) 100vw, 849px\" \/><\/a><figcaption id=\"caption-attachment-55958\" class=\"wp-caption-text\">Fig. 9: Mongo database next() method with selection criteria<\/figcaption><\/figure><\/p>\n<p>Do <em>remember<\/em>, this method will return an exception if the <code>next()<\/code> method has no document in the cursor object. Let\u2019s understand this with the help of an example.<\/p>\n<p><span style=\"text-decoration: underline;\"><em>Exception Trace<\/em><\/span><\/p>\n<pre class=\"brush:bash;wrap-lines:false;\">&gt; db.products.find( { \"available\" : \"false\", \"brand\": \"PHILIP\" } ).next()\r\n\r\n2018-03-07T21:14:45.096+0530 E QUERY    [thread1] Error: error hasNext: false :\r\nDBQuery.prototype.next@src\/mongo\/shell\/query.js:305:1\r\n@(shell):1:1\r\n<\/pre>\n<p>That\u2019s all for this post. Happy Learning!!<\/p>\n<h2>3. Conclusion<\/h2>\n<p>In this tutorial, we learned about the <code>hasNext()<\/code> and the <code>next()<\/code> methods of the Mongo database. Developers can download the sample commands in the <a href=\"#projectDownload\">Downloads<\/a> section.<\/p>\n<h2><a name=\"projectDownload\"><\/a>4. Download the Eclipse Project<\/h2>\n<p>This was an example of the <code>hasNext()<\/code> and the <code>next()<\/code> methods available in the Mongo database.<\/p>\n<div class=\"download\"><strong>Download<\/strong><br \/>\nYou can download the full source code of this example here: <a href=\"http:\/\/examples.javacodegeeks.com\/wp-content\/uploads\/2018\/03\/CodeSnippet-1.zip\" target=\"_blank\" rel=\"noopener\"><strong>CodeSnippet<\/strong><\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Hello readers, in this tutorial, we will see the hasNext() and the next() methods available in the Mongo database. 1. Introduction If you have installed the MongoDB application (version 3.6) on Windows or Ubuntu operating system and you wish to learn the hasNext() and the next() methods then follow the below steps. It is very &hellip;<\/p>\n","protected":false},"author":119,"featured_media":36154,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1447],"tags":[1194,1708],"class_list":["post-55948","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mongodb","tag-mongodb","tag-mongodb-cursor-methods"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>MongoDB hasNext() and next() Example - Java Code Geeks<\/title>\n<meta name=\"description\" content=\"Hello readers, in this tutorial, we will see the hasNext() and the next() methods available in the Mongo database.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" 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