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You can remove a particular record from a table in a database using the DELETE query.SyntaxDELETE FROM table_name WHERE [condition];To delete a record from a table 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 to 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 object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the executeUpdate() method of the ... Read More
To check if a field in MongoDB is [] or {}, you can use the following syntax −db.yourCollectionName.find({ "yourOuterFieldName": { "$gt": {} }, "yourOuterFieldName.0": { "$exists": false } });Let us first create a collection with documents -> db.checkFieldDemo.insert([ ... { _id: 1010, StudentDetails: {} }, ... { _id: 1011, StudentDetails: [ { StudentId: 1 } ] }, ... { _id: 1012, StudentDetails: [ {} ] }, ... { _id: 1013 }, ... { _id: 1014, StudentDetails: null}, ... { _id: 1015, StudentDetails: { StudentId: 1 } } ... ]); BulkWriteResult({ "writeErrors" ... Read More
To display the default font of the tabs, you need to use the Font class. Let’s say we created a JTabbedPane in Java −JTabbedPane tabbedPane = new JTabbedPane();Now, set the Font with font face, style and font size −Font font = new Font("Arial", Font.CENTER_BASELINE, 20); tabbedPane.setFont(font);The following is an example to change the default font of the JTabbedPane tabs −package my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Technologies"); JTabbedPane tabbedPane = new JTabbedPane(); JPanel panel1, panel2, panel3, panel4, ... Read More
To set the the color of a single tab’s text, use the setForegroundAt() method. This gives an option to mention the index and the color. The index here is the index of the specific tab you want to color the text.Let us first create a JTabbedPane −JTabbedPane tabbedPane = new JTabbedPane();Now, set the background color for one of the tabs with index 2 −tabbedPane.setForegroundAt(2, Color.RED);The following is an example wherein we will update the foreground color of a single tab in the JTabbedPane −Examplepackage my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { ... Read More
No, you need to use open and close parenthesis like this ( ) while creating a table. Use the below syntax −CREATE TABLE IF NOT EXISTS yourTableName ( yourColumnName1 dataType1, . . . . . N );Let us first create a table −mysql> CREATE TABLE IF NOT EXISTS DemoTable ( CustomerId int, CustomerName varchar(20), CustomerAge int , PRIMARY KEY(CustomerId) ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1, 'Chris', 25); Query OK, 1 row ... Read More
The start attribute of the element is used to set the start value of the first list item.. Following is the syntax−Above, num is the number set for the start value of the first list item. Let us now see an example to implement the start attribute of the element−Example Live Demo Last Semester MCA Result Rank from 1-5 Steve David Kane William John Rank from 5-10 Tom Jack Will ... Read More
The java.sql.Types class represents the SQL datatype in integer format. The valueOf() method of the enumeration JDBCType accepts an integer value representing the java.sql.Type and, returns the JDBC type corresponding to the specified value.ExampleLet us create a table with name MyPlayers in MySQL database using CREATE statement as shown below −CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), PRIMARY KEY (ID) );Following JDBC program establishes connection with the MySQL database retrieves the contents of the MyPlayers table into a ResultSet object, obtains its metadata, obtains the column ... Read More
For this, use the aggregate function SUM(). Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> € int -> ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(€) values(10); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(€) values(200); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(€) values(190); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from ... Read More
The HTML DOM option defaultSelected property returns the default value of option element in an HTML document.SyntaxFollowing is the syntax −object.defualtSelectedExampleLet us see an example of defaultSelected property − Live Demo html{ height:100%; } body{ text-align:center; color:#fff; background: linear-gradient(62deg, #FBAB7E 0%, #F7CE68 100%) center/cover no-repeat; height:100%; } p{ font-weight:700; font-size:1.2rem; } .drop-down{ width:35%; border:2px solid #fff; font-weight:bold; padding:8px; ... Read More
In this section we will see how to count how many of elements whose absolute values are distinct? Suppose in an array there are few elements like {5, 5, 6, -5, 8, 2, -2, 1}, so there are 8 elements. But there are 5 elements {5, 6, 8, 2, 1} which are distinct. The -5 and 5 are not considered as different, they are same as their absolute value is same.To solve this problem, we will use the Set data-structure. In set duplicate elements are not allowed. And when we are inserting item into the set, we will push only ... Read More