Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
In JDBC there are two scrollable ResultSets namely, scrollable sensitive and, scrollable insensitive.In the TYPE_SCROLL_INSENSITIVE ResultSet the cursor moves in forward or backward directions. This type of ResultSet is insensitive to the changes that are made in the database i.e. the modifications done in the database are not reflected in the ResultSet.Which means if we have established a connection with a database using JDBC program and retrieved a ResultSet holding all the records in a table named SampleTable. Meanwhile if we have added some more records to the table (after retrieving getting the ResultSet), these recent changes will not be reflected ... Read More
Use unique and set it to TRUE. Let us implement the same by creating index and setting two columns to unique −>db.keepTwoColumnsUniqueDemo.createIndex({"StudentFirstName":1, "StudentLastName":1}, {unique:true}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 }Now you can insert documents in the above collection −>db.keepTwoColumnsUniqueDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentAge":21}); { "acknowledged" : true, "insertedId" : ObjectId("5cd30fd7b64f4b851c3a13e5") } >db.keepTwoColumnsUniqueDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Doe", "StudentAge":23}); { "acknowledged" : true, "insertedId" : ObjectId("5cd30fe5b64f4b851c3a13e6") } >db.keepTwoColumnsUniqueDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentAge":24}); 2019-05-08T22:50:42.803+0530 E QUERY [js] WriteError: E11000 duplicate key error collection: sample.keepTwoColumnsUniqueDemo index: StudentFirstName_1_StudentLastName_1 dup key: { : "John", : "Smith" } ... Read More
To change the table header font, you need to first get the header -JTableHeader tableHeader = table.getTableHeader();Now, use the Font class to set the new font. Here, we have set the font face to be Verdana, style as PLAIN and font size as 14 -Font headerFont = new Font("Verdana", Font.PLAIN, 14);Now, set this font to table header -tableHeader.setFont(headerFont);The following is an example to change the header font -Examplepackage my; import java.awt.Color; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.JTableHeader; public class SwingDemo { public static void main(String[] argv) throws Exception { Integer[][] marks = ... Read More
You can use $where operator for this. Let us first create a collection with documents −>db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Doe", "StudentAge":23}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bcdb50a6c6dd317adb8") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Larry"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bdbb50a6c6dd317adb9") } >db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"David", "StudentLastName":"Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4becb50a6c6dd317adba") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bfbb50a6c6dd317adbb") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Bob", "StudentLastName":"Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4c6db50a6c6dd317adbc") }Following is the query to display all documents from a collection with the help of find() method −> db.veryStrictDocumentDemo.find();This will produce the following output ... Read More
A tetrahedron is a pyramid with triangular base i.e. it has a base that is a triangle and each side has a triangle. All the three triangles converge to a point. As in the figure, Code Logic − The code to find the area and volume of tetrahedron uses the math library to find the square and square-root of a number using sqrt and pow methods. For calculating the area we take a floating point and the value of the expression “((sqrt(3)*a*a))” is given to it. Another variable get the value of volume of the tetrahedron that is evaluated by ... Read More
The HTML DOM Input Date min property returns/sets min attribute of Input date type.SyntaxFollowing is the syntax −Returning string valueinputDateObject.minSetting min to string valueinputDateObject.min = YYYY-MM-DDString ValuesHere, “YYYY-MM-DD” can be the following −stringValueDetailsYYYYIt defines year (eg:1998)MMIt defines month (eg: 05 for May)DDIt defines Day (eg: 24)ExampleLet us see an example of Input Date min property − Live Demo Input Date Min Date Select: Change Min Date var inputDate = document.getElementById("date"); var divDisplay = document.getElementById("divDisplay"); divDisplay.textContent = 'Min of date input: '+inputDate.min; function getMinDate() { var oldInputDate = inputDate.max; inputDate.min = '1998-07-01'; divDisplay.textContent = 'Min of date input: ... Read More
The wcstoll() function is used to convert the wide character string to long long integers. It sets the pointer to point to the first character after the last one. The syntax is like below.long long wcstoll(const wchar_t* str, wchar_t** str_end, int base)This function takes three arguments. These arguments are like below −str: This is the starting of a wide string.str_end: The str_end is set by the function to the next character, after the last valid character, if there is any character, otherwise null.base: This specifies the base. The base values can be of (0, 2, 3, …, 35, 36)This function ... Read More
Here we will see, why we should use the strict aliasing in C. Before discussing that part, let us see one code, and try to analyze the output.Example#include int temp = 5; int* var = &temp; int my_function(double* var) { temp = 1; *var = 5.10; //this will change the value of temp return (temp); } main() { printf("%d", my_function((double*)&temp)); }Output1717986918If we call the function my_function, then it will return 1. We can also call this using my_function((double*)&temp). This is supposed to return 1, but here we can see that this is returning something else. This code was made to return constant 1 only. To fix this problem, we can use Strict ... Read More
Let us first create a collection with a document −>db.replacingEntireDocumentDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentCountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5cd3119bb64f4b851c3a13e8") }Following is the query to display document from a collection with the help of find() method −> db.replacingEntireDocumentDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd3119bb64f4b851c3a13e8"), "StudentFirstName" : "John", "StudentLastName" : "Smith", "StudentCountryName" : "US" }Following is the query to update a MongoDB document while replacing the entire document −>db.replacingEntireDocumentDemo.update({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentCountryName":"US"}, {"StudentFirstName":"David", "StudentLastName":"Miller", "StudentCountryName":"AUS"}); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Let us display all the records from the collection ... Read More
Yes, we can hide the header from a table. Use the setTableHeader() method and set it to null -table.setTableHeader(null);Above, the table is our JTable -JTable table = new JTable(marks, col)The following is an example to hide the table header -Examplepackage my; import java.awt.Color; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.JTableHeader; public class SwingDemo { public static void main(String[] argv) throws Exception { Integer[][] marks = { { 70, 66, 76, 89, 67, 98 }, { 67, 89, 64, 78, 59, 78 }, ... Read More