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To delete the documents from a collection in MongoDB, you need to use remove() method. The syntax is as follows:db.yourCollectionName.remove(yourDeleteValue);Here, let us create a collection with some documents. The query is as follows:>db.deleteDocuments.insert({"UserId":1, "UserName":"Bob", "UserTechnicalSubject":"Introducti on to PL/SQL"}); WriteResult({ "nInserted" : 1 }) >db.deleteDocuments.insert({"UserId":2, "UserName":"Carol", "UserTechnicalSubject":"Introduction to MongoDB"}); WriteResult({ "nInserted" : 1 }) >db.deleteDocuments.insert({"UserId":3, "UserName":"John", "UserTechnicalSubject":"Introduction to MySQL"}); WriteResult({ "nInserted" : 1 }) >db.deleteDocuments.insert({"UserId":4, "UserName":"Maxwell", "UserTechnicalSubject":"Introduction to SQL Server"}); WriteResult({ "nInserted" : 1 })You can display all documents from the collection we created above with the help of find() command. The query is as follows:> db.deleteDocuments.find().pretty();The following ... Read More
A scriptlet can contain any number of JAVA language statements, variable or method declarations, or expressions that are valid in the page scripting language.Following is the syntax of Scriptlet −You can write the XML equivalent of the above syntax as follows − code fragment Any text, HTML tags, or JSP elements you write must be outside the scriptlet. Following is the simple and first example for JSP − Hello World Hello World!
The setBinaryStream() method of the PreparedStatement interface accepts an integer representing the index of the parameter and an InputStream object and sets the parameter to the given InputStream object. Whenever you need to send very large binary value you can use this method.And SQL databases provide a datatype named Blob (Binary Large Object) in this you can store large binary data like images.Storing image using JDBCIf you need to store an image in a database using the JDBC program create a table with a Blob datatype as shown below:CREATE TABLE Tutorial(Name VARCHAR(255), Type INT NOT NULL, Logo BLOB);Now, using JDBC, connect ... Read More
The day of the week for a particular LocalDateTime can be obtained using the getDayOfWeek() method in the LocalDateTime class in Java. This method requires no parameters and it returns the day of the week.A program that demonstrates this is given as follows −Example Live Demoimport java.time.*; public class Demo { public static void main(String[] args) { LocalDateTime ldt = LocalDateTime.parse("2019-02-18T11:30:15"); System.out.println("The LocalDateTime is: " + ldt); System.out.println("The day of the week is: " + ldt.getDayOfWeek()); } ... Read More
The summaryStatistics() method in the LongStream class in Java returns a LongSummaryStatistics describing various summary data about the elements of this stream.The syntax is as follows −LongSummaryStatistics summaryStatistics()Here, LongSummaryStatistics is a state object for collecting statistics such as count, min, max, etc.To use the LongStream class in Java, import the following packageimport java.util.stream.LongStream;Create LongStream and add some elements −LongStream longStream = LongStream.of(30000L, 15000L, 20000l, 25000l, 30000l);Now, get the statistics −LongSummaryStatistics info = longStream.summaryStatistics(); The following is an example to implement LongStream summaryStatistics() method in Java −Example Live Demoimport java.util.stream.LongStream; import java.util.LongSummaryStatistics; public class Demo { public static ... Read More
The syntax is as follows to rename a field for all documents. Here, we have used $renameLdb.yourCollectionName.update({}, {$rename:{"yourOldFieldName":"yourNewFieldName"}}, false, true);To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.renameFieldDemo.insertOne({"StudentName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5c7ee6c7559dd2396bcfbfbb") } > db.renameFieldDemo.insertOne({"StudentName":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5c7ee6cb559dd2396bcfbfbc") } > db.renameFieldDemo.insertOne({"StudentName":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5c7ee6cf559dd2396bcfbfbd") } > db.renameFieldDemo.insertOne({"StudentName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5c7ee6d3559dd2396bcfbfbe") } > db.renameFieldDemo.insertOne({"StudentName":"Maxwell"}); { "acknowledged" : true, "insertedId" ... Read More
You can use $in operator for this. Let us first create a collection with a document. The query to create a collection with a document is as follows −> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":1, "StudentName":"Larry"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9010215705caea966c557f") } > db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":2, "StudentName":"Mike", "hasAgeGreaterThanOrEqualTo18":true}); { "acknowledged" : true, "insertedId" : ObjectId("5c90106a5705caea966c5580") } > db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":3, "StudentName":"Carol", "hasAgeGreaterThanOrEqualTo18":false}); { "acknowledged" : true, "insertedId" : ObjectId("5c9010795705caea966c5581") } > db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":4, "StudentName":"Sam", "hasAgeGreaterThanOrEqualTo18":null}); { "acknowledged" : true, "insertedId" : ObjectId("5c9010865705caea966c5582") } > db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":5, "StudentName":"David", "hasAgeGreaterThanOrEqualTo18":false}); { "acknowledged" : true, "insertedId" : ObjectId("5c9010945705caea966c5583") } > db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":6, "StudentName":"Chris", ... Read More
This is a C++ Program to Implement the Edmonds-Karp algorithm to calculate maximum flow between source and sink vertex.Algorithm:Begin function edmondsKarp() : initiate flow as 0. If there is an augmenting path from source to sink, add the path to flow. Return flow. EndExample Code#include #include #include #include #include using namespace std; int c[10][10]; int flowPassed[10][10]; vector g[10]; int parList[10]; int currentPathC[10]; int bfs(int sNode, int eNode)//breadth first search { memset(parList, -1, sizeof(parList)); memset(currentPathC, 0, sizeof(currentPathC)); queue q;//declare queue vector q.push(sNode); parList[sNode] = -1;//initialize parlist’s ... Read More
This example demonstrate about How to create firebase account for android applicationRegister with firebase account using https://firebase.google.com/Click on Sign in button, it will ask gmail user name and pass word as shown below –Give proper user name and pass word. After successful login process, it will redirect to main page as shown below –Now click on go to console, it will redirect to create project as shown below –Now click on add project, it will ask project details as shown belowGive project name and accept all terms and conditions as shown below –After enter all details click on create project.it ... Read More
For converting array to 1D and 2D arrays, let us first create a one-dimensional and two-dimensional array −One-DimensionalString str[] = {"p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};Two-Dimensionaldoubled [][]= { {1.2, 1.3, 2.1, 4.1}, {1.5, 2.3}, {2.5, 4.4}, {3.8}, {4.9}, {3.2, 2.1, 3.2, 7.2} };Converting array to string for one-dimensional array −Arrays.toString(str);Converting array to string for two-dimensional array −Arrays.deepToString(d);Exampleimport java.util.Arrays; public class Demo { public static void main(String args[]) { String str[] = {"p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"}; ... Read More