As we know that in order to maintain the Big data and to get the corresponding reports in different ways from this data we use Hadoop which is an Open Source framework from Apache Software Foundation based on Java Programming Language.Now Apache introduces the next version of Hadoop which named as Hadoop 2 so as this post is focusing on differences between both of these versions.Following are the main differences between Hadoop 1 and Hadoop 2.Sr. No.KeyHadoop 1Hadoop 21New Components and APIAs Hadoop 1 introduced prior to Hadoop 2 so has some less components and APIs as compare to that ... Read More

RDBMSRDBMS stands for Relational Database Management System. It stores data in form of entity as tables. It provides multiple layers on information security. Each table may or may not have a primary key which identifies a record uniquely in a table and a foreign key which indentifies the relationship between two tables. RDBMS uses SQL language to query databases. Examples of popular RDBMS are oracle, sql server, mysql etc.MongoDBMongoDB is a NoSQL database. It is open source. It is a document oriented database and it uses BSON which is binary version of JSON. BSON is a document storage format. MongoDB ... Read More

Large volumes of structured and unstructured data are essentially referred to as ‘Big Data;’ and is produced by almost all sources around us such as social media exchange, digital processes, mobile devices, sensors etc. Big Data provides insights into patterns, trends, and correlations with other entities in the business world. Big Data swamps businesses on a regular daily basis, and due to the speed and accuracy with which it is analyzed, it leads to enhanced and accurate decisions via tactical business steps. As it is variable and complex and comes from various sources, it is imperative to connect it and ... Read More

Given ‘n’ numbers the task is to generate the Fibonacci numbers in PL/SQL starting from 0 to n, where the Fibonacci series of integers is in the form 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 Where integers 0 (1st place) and 1 (2nd place) will have a fixed place after that, the previous two digits will be added to get the integer of the next place as shown below. 0+1=1 (3rd place) 1+1=2 (4th place) 2+1=3 (5th place) and So on. Formula Sequence F(n) ... Read More

The process to alter the structure of a database is basically categorized into two ways, one is Normalization and the other is Denormalization. The basic difference between normalization and denormalization is that the database normalization removes the redundancy of data and anomalies in a poorly designed table, while denormalization combines multiple table data into one so that it can be queried quickly. Read through this article to find out more about normalization and denormalization and how they are different from each other. What is Normalization? Normalization is used to remove redundant data from the database and to store non-redundant and ... Read More

To count number of elements in an array, use the aggregate framework. Let us first create a collection with documents −>db.countNumberOfElementsDemo.insertOne({"UserMessage":["Hi", "Hello", "Bye", "Awesome"]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cef8ec2ef71edecf6a1f6a1") }Display all documents from a collection with the help of find() method −> db.countNumberOfElementsDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cef8ec2ef71edecf6a1f6a1"),    "UserMessage" : [       "Hi",       "Hello",       "Bye",       "Awesome"    ] }Following is the query to count number of elements in an array −> db.countNumberOfElementsDemo.aggregate({$project: { NumberOfElements: { $size:"$UserMessage" }}})This will produce ... Read More

Let us first create a collection with documents −> db.queryMongoValueDemo.insertOne(    {       _id:101,       "ScoreDetails":[{Score:80}, {Score:45}, {Score:25}, {Score:70}]    } ); { "acknowledged" : true, "insertedId" : 101 } > db.queryMongoValueDemo.insertOne(    {       _id:102,       "ScoreDetails":[{Score:80}, {Score:24}, {Score:34}]    } ); { "acknowledged" : true, "insertedId" : 102 } > db.queryMongoValueDemo.insertOne(    {       _id:103,       "ScoreDetails":[{Score:99}, {Score:95}]    }   ); { "acknowledged" : true, "insertedId" : 103 }Display all documents from a collection with the help of find() method −> db.queryMongoValueDemo.find().pretty();This will produce the ... Read More

To get distinct first word from a string, you can use distinct(). Let us first create a collection with documents −> db.distinctFirstWordDemo.insertOne(    {       "_id": 100,       "StudentName":"John",       "StudentFeature": "John is a good player",       "Subject":"MongoDB"    } ); { "acknowledged" : true, "insertedId" : 100 } > db.distinctFirstWordDemo.insertOne(    {       "_id": 101,       "StudentName":"Carol",       "StudentFeature": "Carol is not a good player",       "Subject":"MongoDB"    } ); { "acknowledged" : true, "insertedId" : 101 }Display all documents from a collection ... Read More

To query all items, use find(). Let us first create a collection with documents −> db.queryAllItemsDemo.insertOne({"StudentDetails":{"StudentName":"John", "StudentSubject":["MongoDB", "MySQL"], "StudentSubjectPrice":[4000, 6000]}, "OtherDetails":{"UserAge":29, "UserCountryName":"US"}}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cef74ecef71edecf6a1f69f") }Display all documents from a collection with the help of find() method −> db.queryAllItemsDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cef74ecef71edecf6a1f69f"),    "StudentDetails" : {       "StudentName" : "John",       "StudentSubject" : [          "MongoDB",          "MySQL"       ],       "StudentSubjectPrice" : [          4000,         ... Read More

Use $addToSet operator to ensures that there are no duplicate items added to the set. Let us first create a collection with documents −> db.getDistinctDemo.insertOne({"Values":[100, 200]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cef69f9ef71edecf6a1f69d") } > db.getDistinctDemo.insertOne({"Values":[300, 100]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cef6a07ef71edecf6a1f69e") }Display all documents from a collection with the help of find() method −> db.getDistinctDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cef69f9ef71edecf6a1f69d"),    "Values" : [       100,       200    ] } {    "_id" : ObjectId("5cef6a07ef71edecf6a1f69e"),    "Values" : [       300, ... Read More