Database Articles

Page 241 of 546

Is there any way in MongoDB to get the inner value of json data?

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 236 Views

To get inner value of JSON data, use find() along with dot(.) notation. Let us create a collection with documents −> db.demo235.insertOne( ...   { ...      "id":101, ...      "details":[ ...         { ...            "Name":"Chris Brown", ...            "Age":21 ...         }, ...         { ...            "Name":"David Miller", ...            "Age":24 ...         } ...      ], ...      "otherdetails":[ ...         ...

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Using MongoDB Aggregate and GroupBy to get the frequency of name record

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 202 Views

Let us first create a collection with documents −> db.demo232.insertOne({_id:101, Name:"Chris"}); { "acknowledged" : true, "insertedId" : 101 } > db.demo232.insertOne({_id:102, Name:"Bob"}); { "acknowledged" : true, "insertedId" : 102 } > db.demo232.insertOne({_id:103, Name:"Bob"}); { "acknowledged" : true, "insertedId" : 103 } > db.demo232.insertOne({_id:104, Name:"David"}); { "acknowledged" : true, "insertedId" : 104 } > db.demo232.insertOne({_id:105, Name:"Chris"}); { "acknowledged" : true, "insertedId" : 105 }Display all documents from a collection with the help of find() method −> db.demo232.find();This will produce the following output −{ "_id" : 101, "Name" : "Chris" } { "_id" : 102, "Name" : "Bob" } { "_id" : ...

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Change a unique index to a sparse unique index in MongoDB?

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 249 Views

For sparse index, use sparse:true. Following is the query to create an index −> db.demo229.ensureIndex({"ClientName":1}, {unique: true}); {    "createdCollectionAutomatically" : true,    "numIndexesBefore" : 1,    "numIndexesAfter" : 2,    "ok" : 1 }Following is the query to display indexes −> db.demo229.getIndexes();This will produce the following output −[    {       "v" : 2,       "key" : {          "_id" : 1       },       "name" : "_id_",       "ns" : "test.demo229"    },    {       "v" : 2,       "unique" ...

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Find document in MongoDB where at least one item from an array is not in the other?

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 197 Views

For this, set regex in MongoDB find(). Let us create a collection with documents −> db.demo228.insertOne({"Subjects":["MongoDB", "Java"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3fa51f03d395bdc213473b") } > db.demo228.insertOne({"Subjects":["MongoDB", "Java", "MySQL"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3fa52c03d395bdc213473c") }Display all documents from a collection with the help of find() method −> db.demo228.find();This will produce the following output −{ "_id" : ObjectId("5e3fa51f03d395bdc213473b"), "Subjects" : [ "MongoDB", "Java" ] } { "_id" : ObjectId("5e3fa52c03d395bdc213473c"), "Subjects" : [ "MongoDB", "Java", "MySQL" ] }Following is the query to find documents where at least one item from an array is not in the ...

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Updating a set of documents from a list of key value pairs in MongoDB

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 480 Views

Let us create a collection with documents −> db.demo227.insertOne({"_id":"101", "Name":"Chris"}); { "acknowledged" : true, "insertedId" : "101" } > db.demo227.insertOne({"_id":"102", "Name":"Bob"}); { "acknowledged" : true, "insertedId" : "102" }Display all documents from a collection with the help of find() method −> db.demo227.find();This will produce the following output −{ "_id" : "101", "Name" : "Chris" } { "_id" : "102", "Name" : "Bob" }Following is the query to update a set of documents from a list of key value pairs −> var bulkUpdateValue = [{"_id": "101", "Name": "Robert"}, ...   {"_id": "102", "Name": "Sam"} ...]; > var bulkUpdate = db.demo227.initializeUnorderedBulkOp(); > ...

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MongoDB query to display all the values excluding the id?

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 617 Views

For this, use the $project. The $project takes a document that can specify the inclusion of fields, the suppression of the _id field, the addition of new fields, and the resetting of the values of existing fieldsLet us first create a collection with documents −> db.demo226.insertOne({"Name":"Chris", "Age":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3f9be803d395bdc2134738") } > db.demo226.insertOne({"Name":"Bob", "Age":20}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3f9bf003d395bdc2134739") } > db.demo226.insertOne({"Name":"David", "Age":22}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3f9bf803d395bdc213473a") }Display all documents from a collection with the help of find() method −> db.demo226.find();This will produce the following ...

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How to compare multiple properties in MongoDB?\\n

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 351 Views

To compare multiple properties, use $where in MongoDB. Let us create a collection with documents −> db.demo223.insertOne({"Scores":[56, 78]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee4ca03d395bdc2134730") } > db.demo223.insertOne({"Scores":[88, 45]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee4d103d395bdc2134731") } > db.demo223.insertOne({"Scores":[98, 79]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee4d803d395bdc2134732") }Display all documents from a collection with the help of find() method −> db.demo223.find();This will produce the following output −{ "_id" : ObjectId("5e3ee4ca03d395bdc2134730"), "Scores" : [ 56, 78 ] } { "_id" : ObjectId("5e3ee4d103d395bdc2134731"), "Scores" : [ 88, 45 ] } { "_id" : ObjectId("5e3ee4d803d395bdc2134732"), "Scores" : ...

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MongoDB query to add new array element in document

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 531 Views

To add new array element in a MongoDB document, use $(projection) along with update(). Let us create a collection with documents −>db.demo222.insertOne({"details":[{"StudentName":"Chris", "StudentMarks":78}, {"StudentName":"David", "StudentMarks":89}]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee31703d395bdc213472f") }Display all documents from a collection with the help of find() method −> db.demo222.find().pretty();This will produce the following output −{    "_id" : ObjectId("5e3ee31703d395bdc213472f"),    "details" : [       {          "StudentName" : "Chris",          "StudentMarks" : 78       },       {          "StudentName" : "David",          "StudentMarks" ...

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MongoDB regular expression to fetch record with specific name “John”, instead of “john”

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 113 Views

For searching a specific word, use /searchWord/ with regex. Let us create a collection with documents −> db.demo221.insertOne({"Details":{"StudentName":"Chris", "StudentAge":21}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee15d03d395bdc213472b") } > db.demo221.insertOne({"Details":{"StudentName":"John", "StudentAge":20}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee16503d395bdc213472c") } > db.demo221.insertOne({"Details":{"StudentName":"Bob", "StudentAge":22}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee16b03d395bdc213472d") } > db.demo221.insertOne({"Details":{"StudentName":"john", "StudentAge":24}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3ee17303d395bdc213472e") }Display all documents from a collection with the help of find() method −> db.demo221.find();This will produce the following output −{ "_id" : ObjectId("5e3ee15d03d395bdc213472b"), "Details" : { "StudentName" : "Chris", "StudentAge" : 21 } ...

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Get all embedded documents with “isMarried” status in a MongoDB collection

AmitDiwan
AmitDiwan
Updated on 30-Mar-2020 245 Views

To get all embedded documents, use $project in MongoDB. Let us create a collection with documents −> db.demo220.insertOne({ ...   "id":101, ...   "FullName" : "John Doe", ...   "EmailId" : "john12@gmail.com", ...   "ShippingDate" : new ISODate(), ...   "details" : { "_id" :1001, "isMarried" :true } ...} ...); {    "acknowledged" : true,    "insertedId" : ObjectId("5e3eaf5b03d395bdc213471d") } > db.demo220.insertOne( ...{ ...   "id":102, ...   "FullName" : "John Smith", ...   "EmailId" : "johnsmith@gmail.com", ...   "ShippingDate" : new ISODate(), ...   "details" : { "_id" :1002, "isMarried" :false } ... } ... ); {    "acknowledged" ...

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