{"id":51296,"date":"2019-03-06T11:00:36","date_gmt":"2019-03-06T05:30:36","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=51296"},"modified":"2021-05-09T13:07:10","modified_gmt":"2021-05-09T07:37:10","slug":"interview-questions-for-mongodb","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/interview-questions-for-mongodb\/","title":{"rendered":"Top 30 Interview Questions and Answers for MongoDB"},"content":{"rendered":"<p>Earlier we discussed the <strong>part 1 of\u00a0the MongoDB interview questions<\/strong> and answers. Now we will be looking at some more questions that will help you to prepare for your MongoDB interview.<\/p>\n<p>Let&#8217;s explore the best MongoDB interview questions and answers.<\/p>\n<h2><\/h2>\n<h2>Core MongoDB Interview Questions and Answers<\/h2>\n<p>Here is the list of frequently asked interview questions for MongoDB.<\/p>\n<p><strong>Q1. How can db.ClockTime.update() convert these text-based values to a date datatype?<\/strong><\/p>\n<p><strong>Ans.<\/strong> There can be two solutions for the problem given over here:<\/p>\n<ul>\n<li><strong>First solution<\/strong>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">&gt; var cursor = db.ClockTime.find()\r\n&gt; while (cursor.hasNext()) {\r\n\u2026 var doc = cursor.next();\r\n\u2026 db.ClockTime.update({_id : doc._id}, {$set : {ClockInTime : new Date(doc.ClockInTime)}})\r\n\u2026 }<\/pre>\n<\/li>\n<li><strong>Second solution<\/strong>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.ClockTime.find().forEach(function(doc) {\r\ndoc.ClockInTime=new Date(doc.ClockInTime);\r\ndb.ClockTime.save(doc);\r\n})<\/pre>\n<p>&nbsp;<\/li>\n<\/ul>\n<p>So using any of these you can convert text-based values to date datatype.<\/p>\n<p><strong>Q2. How can you use map-reduce for grouping more than 10000 unique keys?<\/strong><\/p>\n<p><strong>Ans.<\/strong> For <strong>using MapReduce<\/strong> for grouping, use version 2.2. The db.collection.group() method&#8217;s returned array can contain up to 20,000 elements; that means at up to 20,000 unique groupings.<\/p>\n<p>For the group by operations that are having more than 20,000 unique groupings, MapReduce&#8217;s previous versions had a limit of 10,000 elements.<\/p>\n<p><strong>Q3. In what way will you query live MongoDB data?<\/strong><\/p>\n<p><strong>Ans.<\/strong> By using the following utilities you can handle live MongoDB data.<\/p>\n<ul>\n<li>MongoHub is moved to a native Mac version.<\/li>\n<li>This is useful for tree and document views.<\/li>\n<li><strong>genghisapp<\/strong> &#8211; This is a web-based GUI that is clean, light-weight, straight-forward, offers keyboard shortcuts, and works awesomely well. It also supports GridFS. It\u2019s all a single script.<\/li>\n<\/ul>\n<p><strong>Q4. How to update a specific key\/value of an array field with MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> For this let us suppose a collection content, as it contains articles, news, etc. These articles contain another array called the author which contains all the information about the author.<\/p>\n<pre class=\"EnlighterJSRAW\">db.content.update({\u2018authors.abc\u2019:\u2019xyz\u2019},{$set:{\u2018authors.$.address\u2019:\u2019Address That I wanted\u2019}},false,true);<\/pre>\n<p>It updates all the records properly.<\/p>\n<p><strong>Q.5 How to use the primary key in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> _id field is reserved for the primary key in MongoDB, and that is a unique value. If you don\u2019t set anything to _id it will automatically fill it with \u201cMongoDB Id Object\u201d. But you can put any unique info in that field.<\/p>\n<p><strong>Q6. How to delete everything from the MongoDB database?<\/strong><\/p>\n<p><strong>Ans.<\/strong> For <strong>deleting everything from the MongoDB database<\/strong>, you can use the following code:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">use [database];\r\ndb.dropDatabase();\r\nRuby code should be pretty similar.\r\nAlso, from the command line:\r\nmongo [database] \u2013eval \u201cdb.dropDatabase();\u201d\r\nUse\r\n[databaseName]\r\ndb.Drop+databaseName();\r\ndrop collection\r\nuse databaseName\r\ndb.collectionName.drop();\r\n\r\n<\/pre>\n<p><strong>Q7. How to use $set in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> For a detailed explanation about how it works dynamically, I\u2019ll give an example in PHP:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">$action = array(\u201ccolumns.$colNum.panels.$panelNum\u201d =&gt; $newValue);<\/pre>\n<p>Yes there is the positional operator, but it does not appear to be advanced enough to change arrays within arrays, this might have changed in MongoDB 1.7.0<\/p>\n<p>There is an alternative for this. Try to flatten it out. We can make a collection that contains panel &amp; column objects:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">column object:\r\n{\r\n_id: \/\/ MongoId\r\ntype: \u2018column\u2019,\r\nuser: \u2018username\u2019,\r\norder: 1,\r\nwidth: 30,\r\n}\r\npanel object:\r\n{\r\n_id: \/\/MongoId\r\ntype: \u2018panel\u2019,\r\nuser: \u2018username\u2019,\r\nparentColumn: \/\/the columns _id string\r\ntop: 125,\r\nleft: 100\r\n}<\/pre>\n<p>Then find all columns that belong to a user:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">find({ type: \u2018column\u2019, user:\u2019username\u2019});<\/pre>\n<p>We can detect all panels for a particular column by doing:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">find({type: \u2018panel\u2019, columnOwner:\u2019ownerID\u2019});<\/pre>\n<p>Since each column and panel will contain a unique ID given by MongoDB to it, we can query easily and atomically set options.<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">update({\u2018_id\u2019: ObjectId(\u2018idstring\u2019)}, {$set : { \u2018top\u2019 : 125}});<\/pre>\n<p><strong>Q8. Using what can you print more than 20 items in MongoDB\u2019s shell?<\/strong><\/p>\n<p><strong>Ans.<\/strong><\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.example.find().toArray()\r\ndb.example.find().forEach(printjson)<\/pre>\n<p>It will both print out a very expanded view of each document instead of the 1-line version for find():<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">DBQuery.shellBatchSize = 300<\/pre>\n<p><strong>Q9. How to perform join operations in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> From MongoDB 3.2 onwards we can perform join operation. The new $lookup operator added with the aggregation pipeline is essentially similar to a left outer join. This is an example of the same:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">{\r\n$lookup:\r\n{\r\nfrom: &lt;collection to join&gt;,\r\nlocalField: &lt;field from the input documents&gt;,\r\nforeignField: &lt;field from the documents of the \"from\" collection&gt;,\r\nas: &lt;output array field&gt;\r\n}\r\n}<\/pre>\n<p><strong>Q10. Explain oplog.<\/strong><\/p>\n<p><strong>Ans.<\/strong> The operational log(oplog) is a special type of capped collection that keeps a rolling record of all operations that modify the data stored in your databases.<\/p>\n<p>Firstly it applies database operations on the primary and then records these operations on the primary\u2019s oplog. Then, the secondary members copy and implement these operations in an asynchronous process.<\/p>\n<p><strong>Q11. When should the data be normalized in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> It depends on your goals. Normalization will provide an update efficient data representation. Denormalization will make data reading efficiently.<\/p>\n<p>In general, use embedded data models (denormalization) when:<\/p>\n<ul>\n<li>When you have \u201ccontains\u201d relationships between entities.<\/li>\n<li>When you have one-to-many relationships between entities. In these relationships, the \u201cmany\u201d or child documents always display with or are seen in the context of the \u201cone\u201d or parent documents.<\/li>\n<\/ul>\n<p>In general, use normalized data models:<\/p>\n<ul>\n<li>When embedding leads to duplication of data but will not give sufficient read performance benefits to outweigh the implications of the duplication.<\/li>\n<li>To represent more complex many-to-many relationships.<\/li>\n<li>To model large hierarchical data sets.<\/li>\n<\/ul>\n<p><strong>Q12. Comparison between MongoDB and Cassandra.<\/strong><\/p>\n<p><strong>Ans.<\/strong><\/p>\n<p><strong>MongoDB<\/strong>:<\/p>\n<ul>\n<li>Data mode are the document<\/li>\n<li>Database scalability is read-only<\/li>\n<li>Query of the data is multi-index<\/li>\n<\/ul>\n<p><strong>Cassandra<\/strong>:<\/p>\n<ul>\n<li>Data mode are a big table like<\/li>\n<li>Database scalability is write only<\/li>\n<li>Query of the data by using scan or key<\/li>\n<\/ul>\n<p><strong>Q13. What does ObjectId consist of?<\/strong><\/p>\n<p><strong>Ans.<\/strong> It consists of the following:<\/p>\n<ul>\n<li>Timestamp<\/li>\n<li>Client machine ID<\/li>\n<li>Client process ID<\/li>\n<li>Byte incremented counter<\/li>\n<\/ul>\n<p><strong>Q14. Explain about replication and when should we use it?<\/strong><\/p>\n<p><strong>Ans.<\/strong>\u00a0<strong>Replication is the process of synchronizing data across multiple servers<\/strong> so that data is not lost in any condition. It gives redundancy and rises data availability with many copies of data on other database servers.<\/p>\n<p>We can use it for various purposes like for keeping the data safe, for high availability of data, disaster recovery and in no downtime for maintenance.<\/p>\n<p><strong>Q15. When and up to what extent does data get extended to multi-slice?<\/strong><\/p>\n<p><strong>Ans.<\/strong> The MongoDB scrap stands on a collection. So all substances are kept in a lump or mass.<\/p>\n<p>When there is an additional time slot only then there will be more than a few slice data achievement choices, but at the time, when there is more than 1 lump, data gets extend to many slices and it can further extend to 64 MB.<\/p>\n<p><strong>Q16. Enlist the limitations of the 32-bit version of MongoDB.<\/strong><\/p>\n<p><strong>Ans.<\/strong> MongoDB uses memory-mapped files. When we run a 32-bit build of MongoDB, the total size of storage for the server, including indexes and data, is 2 gigabytes. Due to this, don\u2019t deploy MongoDB to production on 32-bit machines.<\/p>\n<p>And in the 64-bit build of MongoDB, there\u2019s virtually no limit to storage size. For production deployments, we strongly recommend 64-bit builds and operating systems<\/p>\n<p><strong>Q17. What is the NoSQL database? Is MongoDB a NoSQL database?<\/strong><\/p>\n<p><strong>Ans.<\/strong> From the advent of social media, the internet is being loaded with big data, big users, big complexity etc. and also becoming more complex day by day.<\/p>\n<p>NoSQL is the answer to all these problems; it is not a traditional database management system, not even a<strong> relational database management system (RDBMS)<\/strong>. NoSQL stands for \u201cNot Only SQL\u201d.<\/p>\n<p>NoSQL is a kind of database that can handle and segregate all types of messy, unstructured, and complicated data. It is just a new way to describe the database. Yes, MongoDB is a NoSQL database.<\/p>\n<p><strong>Q18. How to find values in the array with multiple criteria?<\/strong><\/p>\n<p><strong>Ans.<\/strong> Suppose you have the following document:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">{_id : 1, numbers : [-1000, 1000]}\r\n{_id : 2, numbers : [5]}\r\n\r\n<\/pre>\n<p>After this, if you write the following command :<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.example.find( { numbers : { $elemMatch : { $gt : -10 , $lt : 10 } } } );<\/pre>\n<p>It will return the _id: 2 document.<\/p>\n<p><strong>Q19. How to use select * group by MongoDB aggregation?<\/strong><\/p>\n<p><strong>Ans.<\/strong> Suppose you want to select all attributes and groups by name across records. Let&#8217;s take an example:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">{ Name: George, x: 5, y: 3 }\r\n{ Name: George, z: 9 }\r\n{ Name: Rob, x: 12, y: 2 }<\/pre>\n<p>And now do the <strong>MongoDB aggregation<\/strong> as follows:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.example.aggregate(\r\n{ $group : {\r\n_id : \u201c$Name\u201d,\r\nx: { $addToSet: \u201c$x\u201d },\r\ny: { $addToSet: \u201c$y\u201d },\r\nz: { $addToSet: \u201c$z\u201d },\r\n}}\r\n)<\/pre>\n<p><strong>Q20. How is sorting performed and what is a projection in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> Whenever we have to find any data from MongoDB, find() method is being used. This method will return the documents of the collection on which this is invoked.<\/p>\n<p>Now we can have where clause in MongoDB query so that we can <strong>limit the output by MongoDB projection<\/strong>. Whenever we will execute the find() method MongoDB will return all documents related to that specific collection. Below is the syntax for same:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.&lt;collection_name&gt;.find({},{&lt;Key_Name&gt;:&lt;Flag to display&gt;})\r\n<\/pre>\n<p>Here flag will have two values as 0 or 1. Here 1 indicates that the corresponding values will be displayed and 0 indicates that the corresponding values will not be displayed.<\/p>\n<p><strong>Q21. Is it necessary to call \u201cgetLastError\u201d to make a write durable?<\/strong><\/p>\n<p><strong>Ans.<\/strong> No, it is not necessary to call \u201cgetLastError\u201d(Safe Mode). Here the server behaves as if it has been called. The \u201cgetLastError\u201d simply allows one to get confirmation that write operation is successfully committed. Here you will want the confirmation, but the safety of write and its durability is independent.<\/p>\n<p><strong>Q22. For how long does the replica set failover take?<\/strong><\/p>\n<p><strong>Ans.<\/strong> It takes around 10 \u2013 30 seconds for the primary to be dropped down by the other members and a new primary to be elected.<\/p>\n<p>During this time span, the cluster is down for primary operations i.e writes and reads. Eventually, consistent queries can execute to secondaries at any time (in slaveOk mode), including during this window.<\/p>\n<p><strong>Q23. What does the \u201c_v\u201d field correspond to in Mongoose?<\/strong><\/p>\n<p><strong>Ans.<\/strong> When the mongoose is created for the first time the version key is a property set on each and every document. The value of this key has the internal revision of the document. It is understood that the name of this document is configurable. The default key is __v<\/p>\n<p><strong>Q24. Tell about composition\/structure of ObjectId in MongoDB? Explain each composing element.<\/strong><\/p>\n<p><strong>ObjectId in MongoDB<\/strong> is very special. It associates with _id field, and MongoDB uses objectid as the default value of _id in documents. To generate objectid(), the following is the syntax:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">ObjectId([SomeHexaDecimalValue])\r\n<\/pre>\n<p>Let\u2019s take an example to understand it better:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">obj_id = new ObjectId()\r\n<\/pre>\n<p>The above query will give us the following output:<br \/>\nObjectId(&#8220;6549h6hgt8721s97u45798j7&#8221;)<\/p>\n<p>There are some methods and details for the same are as follows:<\/p>\n<ul>\n<li><strong>str<\/strong>\u00a0&#8211; It provides a string representation of object id.<\/li>\n<li><strong>valueOf()<\/strong> &#8211; It returns the hexadecimal representation of ObjectId.<\/li>\n<li><strong>getTimeStamp()<\/strong> &#8211; It returns the creation timestamp of objected.<\/li>\n<li><strong>toString()<\/strong> &#8211; It returns the string representation of ObjectId in the \u201cObjectId(haxstring)\u201d .<\/li>\n<\/ul>\n<p><strong>Q25. Tell about the capped collection. How we create them in MongoDB?<\/strong><\/p>\n<p><strong>Ans. Capped collection is a special type of collection in MongoDB<\/strong>. That means in this collection we can restrict the size of collection or we can put the limit on the size of the collection, these special type of collection is named as the capped collection. Here is the syntax for creating collections:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.createCollection(&lt;Collection_Name&gt;, {capped: Boolean, autoIndexId: Boolean, size: Number, max : Number})<\/pre>\n<p>Let\u2019s understand the syntax.<\/p>\n<ul>\n<li><strong>Collection_Name<\/strong> &#8211; Name of the collection that we create as the capped collection.<\/li>\n<li><strong>capped<\/strong> &#8211; Capped is the Boolean flag, true if the collection is to create as the capped collection, by default the value is false.<\/li>\n<li><strong>autoIndexId<\/strong> &#8211; The Boolean flag that we use for auto indexing. If true indexes will create automatically, false will say indexes will not create automatically.<\/li>\n<li><strong>size<\/strong> &#8211; Size parameter depicts the maximum size of documents in bytes. It is a mandatory field in terms of capped collections.<\/li>\n<li><strong>max<\/strong>\u00a0&#8211; max parameter depicts the maximum number of documents that allow in a collection. Size gets preference over size.<\/li>\n<\/ul>\n<p>Here is the syntax for isCapped() method:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.&lt;Collection_Name&gt;.isCapped()<\/pre>\n<p><strong>Q 26. How can MongoDB simulate join or subquery?<\/strong><\/p>\n<p><strong>Ans.<\/strong> We are trying to figure out the best way to structure data in Mongo to simulate what would be a simple join or subquery in SQL.<\/p>\n<p>Say we have the classic Users and Posts example, with Users in one collection and Posts in another. We want to find all posts by users who\u2019s city is \u201cMumbai\u201d.<\/p>\n<p>We have simplified things in this question, in real-world scenario storing posts as an array in the user document won\u2019t work as we have 1,000\u2019s of \u201cposts\u201d per user constantly inserting.<\/p>\n<p><strong>Q27. How can you sort a user-defined function; e.g. suppose x and y are integers, and the difference is (x-y)?<\/strong><\/p>\n<p><strong>Ans.<\/strong> It is not possible directly.<br \/>\nServer-side sort:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.eval(function() {\r\nreturn db.scratch.find().toArray().sort(function(doc1, doc2) {\r\nreturn doc1.a \u2013 doc2.a\r\n})\r\n});\r\nVersus the equivalent client-side sort:\r\ndb.scratch.find().toArray().sort(function(doc1, doc2) {\r\nreturn doc1.a \u2013 doc2.b\r\n});<\/pre>\n<p>Note that it\u2019s also possible to sort via an aggregation pipeline and by the $orderby operator (i.e. in addition to .sort()) however neither of these ways lets you provide a custom sort function either.<\/p>\n<p><strong>Q28. How to update _id of one MongoDB Document?<\/strong><\/p>\n<p><strong>Ans.<\/strong> If you want to update _id then you will get something like this:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.clients.update({\u2018_id\u2019:ObjectId(\u201c4cc45467c55f4d2d2a000002\u201d)}, {\u2018$set\u2019:{\u2018_id\u2019:ObjectId(\u201c4c8a331bda76c559ef000004\u201d)}});<\/pre>\n<p>Mod on _id not allowed<\/p>\n<p>And the <strong>update of the document <\/strong>is not made. You cannot update it by the given code. You\u2019ll have to save the document using a new _id, and then remove the old document.<\/p>\n<p>Skip code block<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">\/\/ store the document in a variable\r\ndoc = db.clients.findOne({_id: ObjectId(\u201c4cc45467c55f4d2d2a000002\u201d)})\r\n\/\/ set a new _id on the document\r\ndoc._id = ObjectId(\u201c4c8a331bda76c559ef000004\u201d)\r\n\/\/ insert the document, using the new _id\r\ndb.clients.insert(doc)\r\n\/\/ remove the document with the old _id\r\ndb.clients.remove({_id: ObjectId(\u201c4cc45467c55f4d2d2a000002\u201d)})\r\n\r\n<\/pre>\n<p>To do it for your whole collection you can also use a loop<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">db.status.find().forEach(function(doc){ var id=doc._id; doc._id=doc.UserId; db.status.insert(doc); db.status.remove({_id:id}); })<\/pre>\n<p>In this case, UserId was the new ID I wanted to use<\/p>\n<p><strong>Q29.\u00a0 How to get MongoDB database in JavaScript array?<\/strong><\/p>\n<p><strong>Ans.<\/strong> To get this use the following code:<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"null\">use admin\r\ndbs = db.runCommand({listDatabases: 1})\r\ndbNames = []\r\nfor (var i in dbs.databases) { dbNames.push(dbs.databases[i].name) }\r\nHopefully this will help.\r\nThe below will create an array of the names of the database:\r\nvar connection = new Mongo();\r\nvar dbNames = connection.getDBNames();<\/pre>\n<p><strong>Q30. How to create a database in MongoDB?<\/strong><\/p>\n<p><strong>Ans.<\/strong> When I was trying to <strong>create a database in MongoDB<\/strong>, I got one error:<\/p>\n<p>:~$ mongo<br \/>\nMongoDB shell version: 1.6.5<br \/>\nconnecting to: test<br \/>\nError: couldn\u2019t connect to server 127.0.0.1 (anon):1154<br \/>\nexception: connect failed<\/p>\n<p>A solution to the above issue:<\/p>\n<ol>\n<li>cd \/var\/lib\/mongodb\/<\/li>\n<li>Remove mongod.lock file from this folder<\/li>\n<li>Sudo start mongodb (in console)<\/li>\n<li>Mongo (in console)<\/li>\n<\/ol>\n<p>And it runs fine.<\/p>\n<p>First, you\u2019ll need to run mongod on one terminal. Then fire up another terminal and type mongo. This shall open the mongo shell. You also need to create \/data\/db\/ where mongo will store your databases.<\/p>\n<p>This comes to the end of MongoDB interview questions and answers. We hope you liked our explanation.<\/p>\n<h2>Summary &#8211; Questions and Answers for MongoDB Interview<\/h2>\n<p>Hence, we have seen some questions\u00a0for the MongoDB interview. These interview questions for\u00a0MongoDB will surely help you with your interview preparation.<\/p>\n<p>We tried to cover all the questions for MongoDB interview, still, if you have any queries or feedbacks related to <strong><a href=\"https:\/\/www.mongodb.com\/\">MongoDB<\/a><\/strong>\u00a0interview questions and answers article, you can enter in the comment section.<span hidden class=\"__iawmlf-post-loop-links\" data-iawmlf-links=\"[{&quot;id&quot;:1630,&quot;href&quot;:&quot;https:\\\/\\\/www.mongodb.com&quot;,&quot;archived_href&quot;:&quot;http:\\\/\\\/web-wp.archive.org\\\/web\\\/20251209094318\\\/https:\\\/\\\/www.mongodb.com\\\/&quot;,&quot;redirect_href&quot;:&quot;&quot;,&quot;checks&quot;:[{&quot;date&quot;:&quot;2025-12-09 14:17:42&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2025-12-17 07:08:07&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-01-15 20:47:49&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-01-27 04:21:30&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-02-23 07:23:46&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-03-06 10:09:35&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-03-11 16:28:10&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-03-15 11:37:26&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-03-24 14:08:12&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-04-30 02:34:30&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-05-12 12:25:35&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-02 08:52:39&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-06 05:28:10&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-14 06:24:06&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-17 14:53:23&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-22 12:21:04&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-06-30 14:59:57&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-07-04 08:21:37&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-07-07 16:43:13&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-07-11 21:54:44&quot;,&quot;http_code&quot;:206},{&quot;date&quot;:&quot;2026-07-15 14:18:13&quot;,&quot;http_code&quot;:206}],&quot;broken&quot;:false,&quot;last_checked&quot;:{&quot;date&quot;:&quot;2026-07-15 14:18:13&quot;,&quot;http_code&quot;:206},&quot;process&quot;:&quot;done&quot;}]\"><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Earlier we discussed the part 1 of\u00a0the MongoDB interview questions and answers. Now we will be looking at some more questions that will help you to prepare for your MongoDB interview. Let&#8217;s explore the&#46;&#46;&#46;<\/p>\n","protected":false},"author":6,"featured_media":51374,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38],"tags":[19158,19156,19155,19157],"class_list":["post-51296","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mongodb","tag-crack-mongodb-interview","tag-interview-questions-for-mongodb","tag-mongodb-interview-questions","tag-mongodb-interview-questions-and-answers"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Top 30 Interview Questions and Answers for MongoDB - DataFlair<\/title>\n<meta name=\"description\" content=\"Explore top interview questions and answers for MongoDB which help you to crack MongoDB interview and give an edge over your interview preparation.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/data-flair.training\/blogs\/interview-questions-for-mongodb\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Top 30 Interview Questions and Answers for MongoDB - 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