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To change header background color, at first get the header background −JTableHeader tableHeader = table.getTableHeader();Now, set the background color using set Background() −tableHeader.setBackground(Color.black);Above, we have used the Color class to set the color.The following is an example to change the header background color of a JTable −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, ... Read More
The stripos() equivalent in MySQL is INSTR(), which returns the position of the first occurrence of a string in another string. Following is the syntax −select instr(yourColumnName, yourWord) As anyAliasName from yourTableName;Let us first create a table −mysql> create table DemoTable -> ( -> Title text -> ); Query OK, 0 rows affected (1.22 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('MySQL is my favourite subject'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('MongoDB is not my favourite subject'); Query OK, 1 row affected (0.20 sec)Display ... Read More
Here we will see one program that can tell whether two strings are rotation of each other or not. The rotation of strings is like −Suppose two strings are S1 = ‘HELLO’, and S2 = ‘LOHEL’ So they are rotation of each other. By rotating HELLO three position to the left it will be LOHEL.To solve this problem, we will concatenate the first string with itself, then check whether the second one is present in the concatenated string or not. So for HELLO, it will be HELLOHELLO. Then this concatenated string contains the LOHEL. [HELLOHELLO].AlgorithmisRotation(str1, str2)begin if lengths of ... Read More
The feclearexcept() function is used to clear the supported floating point exceptions represented by the excepts.This function returns 0, if all exceptions are cleared, or the exception value is 0. And returns nonzero value for some exceptions.To use this function, we have to enable the FENV_ACCESS. This will give our program to access the floating point environment to test the exception raised.Example#include #include #include #pragma STDC FENV_ACCESS on using namespace std; main() { feclearexcept(FE_ALL_EXCEPT); sqrt(-5); if (fetestexcept(FE_INVALID)) cout >> "sqrt(-5) will generate FE_INVALID" >> endl; }Outputsqrt(-5) will generate FE_INVALIDRead More
In computer networks, when more than one station tries to transmit simultaneously via a shared channel, the transmitted data is garbled. This event is called collision. The Medium Access Control (MAC) layer of the OSI model is responsible for handling collision of frames. Collision – free protocols are devised so that collisions do not occur. Protocols like CSMA/CD and CSMA/CA nullifies the possibility of collisions once the transmission channel is acquired by any station. However, collision can still occur during the contention period if more than one stations starts to transmit at the same time. Collision – free protocols resolves ... Read More
You can create a table in a database using the CREATE TABLE query.SyntaxCREATE TABLE table_name( column1 datatype, column2 datatype, column3 datatype, ..... columnN datatype, PRIMARY KEY( one or more columns ) );To create a table in a database using JDBC API you need to −Register the Driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement ... Read More
To get the size of all the documents in a query, you need to loop through documents. Let us first create a collection with documents −> db.sizeOfAllDocumentsDemo.insertOne({"StudentFirstName":"John", "StudentSubject":["MongoDB", "Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5cd3c0c1edc6604c74817cd7") } > db.sizeOfAllDocumentsDemo.insertOne({"StudentFirstName":"Larry", "StudentSubject":["MySQL", "PHP"], "StudentAge":21}); { "acknowledged" : true, "insertedId" : ObjectId("5cd3c0d9edc6604c74817cd8") } > db.sizeOfAllDocumentsDemo.insertOne({"StudentFirstName":"Chris", "StudentSubject":["SQL Server", "C#"], "StudentAge":23, "StudentCountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5cd3c0fbedc6604c74817cd9") }Following is the query to display all documents from a collection with the help of find() method −> db.sizeOfAllDocumentsDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd3c0c1edc6604c74817cd7"), ... Read More
To create two borders for a single component, use the createCompoundBorder() method in Java. Here, we have created LineBorder nd TitledBorder −LineBorder lineBorder = new LineBorder(Color.red); TitledBorder titleBorder = new TitledBorder("Demo Title"); Border border = BorderFactory.createCompoundBorder(lineBorder, titleBorder);Now, set both the borders for a single component −JButton button = new JButton("two borders"); button.setBorder(border);The following is an example to create two borders for a single component −Examplepackage my; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.border.Border; import javax.swing.border.EtchedBorder; import javax.swing.border.LineBorder; import javax.swing.border.TitledBorder; public class SwingDemo { public static void main(String args[]) { ... Read More
To set the margins i.e. row and columns margins between cells of a table, use the setIntercellSpacing() method −Dimension dim = new Dimension(50, 2); table.setIntercellSpacing(new Dimension(dim));Above, we have used the Dimension class −The following is an example to set margins between cells of a JTable cell −Examplepackage my; import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JRootPane; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.DefaultTableModel; public class SwingDemo { public static void main(String[] argv) throws Exception { JFrame frame = new JFrame("Demo"); JPanel panel = new JPanel(); String data[][] = { ... Read More
While creating a table, in certain scenarios, we need values to column such as ID, to be generated/incremented automatically. Various databases support this feature in different ways.In MySQL database you can declare a column auto increment using the following syntax.CREATE TABLE table_name( ID INT PRIMARY KEY AUTO_INCREMENT, column_name1 data_type1, column_name2 data_type2, column_name3 data_type3, column_name4 data_type4, ............ ........... );While inserting records in a table there is no need to insert value under the auto-incremented column. These will be generated automatically.Setting the initial valueBy default, the initial value of the auto-incremented column will be 1. You ... Read More