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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to write a MySQL stored function that inserts values in a table?
As we know that function is best used when we want to return a result. Hence, when we will create stored functions for manipulating tables like to Insert or Update values then it would be more or less like stored procedures.ExampleIn the following example we are creating a stored function named ‘tbl_insert’ which will insert the values in a table named ‘student_marks’.mysql> Create Function tbl_insert(S_name Varchar(50), M1 INT, M2 INT, M3 INT, M4 INT) -> RETURNS INT -> DETERMINISTIC -> BEGIN -> INSERT INTO student_marks values(S_name, M1, M2, M3, M4); ...
Read MoreCan we explicitly define datatype in a Python Function?
Yes, in Python, you can explicitly define the datatype of function parameters and return values using type hints or type annotations. Even if you specify the data types using type hints, Python will still run the code even when the wrong types are passed. The execution of the program will not be interrupted, and an error will not be raised.To find these type-related mistakes, you can use tools like mypy or pyright that check your code before it runs. Using Type Hints in Python Functions To add type hints to a parameter of a function, you need to specify the ...
Read MoreHow can we create MySQL stored procedure to calculate the factorial?
mysql> DELIMITER // mysql> CREATE PROCEDURE get_factorial(IN N INT) -> BEGIN -> SET @@GLOBAL.max_sp_recursion_depth = 255; -> SET @@session.max_sp_recursion_depth = 255; -> -> CALL factorial_recursive (N, @factorial); -> -> SELECT @factorial; -> END // Query OK, 0 rows affected (0.00 sec) mysql> DELIMITER // mysql> CREATE PROCEDURE factorial_recursive(IN N INT, OUT factorial INT) -> BEGIN -> IF N = 1 THEN -> SET factorial := 1; -> ...
Read MoreHow to validate if JTable has an empty cell in Java?
A JTable is a subclass of JComponent class for displaying complex data structures. A JTable can follow the Model View Controller (MVC) design pattern for displaying the data in rows and columns. A JTable will generate TableModelListener, TableColumnModelListener, ListSelectionListener, CellEditorListener and RowSorterListener interfaces.We can validate whether the JTable cell is empty or not by implementing the getValueAt() method of JTable class. If we click on the "Click Here" button, it will generate an action event and display a popup message like "Field is Empty" to the user.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.table.*; public class JTableEmptyValidateTest extends JFrame { ...
Read MoreHow can we write MySQL handler, in a stored procedure, that throws an error message and continues the execution?
As we know that whenever an exception occurred in MySQL stored procedure, it is very important to handle it by throwing proper error message because if we do not handle the exception, there would be a chance to fail application with that certain exception in a stored procedure. MySQL provides a handler that throws an error message and continues the execution. To demonstrate it, we are using the following example in which we are trying to insert a duplicate value in a Primary key column.Examplemysql> DELIMITER // mysql> Create Procedure Insert_Studentdetails(S_Studentid INT, S_StudentName Varchar(20), S_Address Varchar(20)) -> BEGIN ...
Read MoreHow can we filter a JTable in Java?
A JTable provides a very flexible possibility to create and display tables. The TableModel interface defines methods for objects that specify the contents of a table. The AbstractTableModel class is typically extended to provide a custom implementation of a model table. A JTable class provides the ability to edit tables using the method setCellEditor() allows an object of the TableCellEditor interface.We can filter a table using the setRowFilter() method of TableRowSorter class.Exampleimport java.awt.*; import java.awt.event.*; import java.util.regex.*; import javax.swing.*; import javax.swing.table.*; public class FilterTableTest extends JFrame { private JTable table; private TableModel model; ...
Read MoreHow can we write MySQL stored procedure to select all the data from a table?
To demonstrate it we are creating a procedure named ‘selectdetails()’ which will fetch all the records from table ‘student_detail’.mysql> Delimiter // mysql> Create Procedure selectdetails() -> BEGIN -> Select * from student_detail; -> END// Query OK, 0 rows affected (0.00 sec)Now, after invoking this procedure, we will get all the records from ‘student_detail’ table.mysql> Delimiter ; mysql> CALL selectdetails(); +-----------+-------------+------------+ | Studentid | StudentName | address | +-----------+-------------+------------+ | 100 | Gaurav | Delhi | | 101 | Raman | Shimla | | 103 | Rahul | Jaipur | | 104 | Ram | Chandigarh | | 105 | Mohan | Chandigarh | +-----------+-------------+------------+ 5 rows in set (0.00 sec) Query OK, 0 rows affected (0.01 sec)
Read MoreHow to implement the mouse right-click on each node of JTree in Java?
A JTree is a subclass of JComponent class that can be used to display the data with the hierarchical properties by adding nodes to nodes and keeps the concept of parent and child node. Each element in the tree becomes a node. The nodes are expandable and collapsible. We can implement the mouse right-click on each node of a JTree using the mouseReleased() method of MouseAdapter class and need to call show() method of JPopupMenu class to show the popup menu on the tree node.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.tree.*; public class JTreeRightClickTest extends JFrame { ...
Read MoreC++ Program to Sort an Array of 10 Elements Using Heap Sort Algorithm
Heap Sort is based on the binary heap data structure. In the binary heap the child nodes of a parent node are smaller than or equal to it in the case of a max heap, and the child nodes of a parent node are greater than or equal to it in the case of a min heap.An example that explains all the steps in Heap Sort is as follows.The original array with 10 elements before sorting is −207154101590237725This array is built into a binary max heap using max-heapify. This max heap represented as an array is given as follows.907720542515123710The root ...
Read MoreHow to display "No records available" text in a JTable in Java?
A JTable is a subclass of JComponent class and it can be used to create a table with information displayed in multiple rows and columns. When a value is selected from a JTable, a TableModelEvent is generated, which is handled by implementing a TableModelListener interface.In the below program, we can display "No records available" text if the rows are not available in a JTable.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.table.*; public class NoRecordTableTest extends JFrame { private JPanel panel; private JTable table; private JScrollPane scrollPane; public NoRecordTableTest() { panel = new JPanel(); panel.setLayout(new BorderLayout()); ...
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