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Articles by Krantik Chavan
Page 13 of 18
How to handle action event for JComboBox in Java?
The following is an example to handle action event for JComboBox in Java:Exampleimport java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JFrame; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComboBox combo = new JComboBox(new String[] { "One", "Two", "Three", "Four", "Five", "Six" }); JButton add = new JButton("Add"); add.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { ...
Read MoreFind document with array that contains a specific value in MongoDB
You can use find() method to find document with array that contains a specific value. The syntax is as follows:db.yourCollectionName.find({"yourArrayFieldName":"yourValue"}, .......N).pretty();To understand the above syntax, let us create a collection with documents. The query to create a collection with documents is as follows:>db.findSpecificValue.insertOne({"StudentId":1, "StudentName":"Larry", "FavouriteSubject":["C", "C++", "Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6e8996140577d89182b8d0") } >db.findSpecificValue.insertOne({"StudentId":2, "StudentName":"Larry", "FavouriteSubject":["MongoDB", "MySQL", "SQL Server"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6e89b1140577d89182b8d1") }Display all documents from a collection with the help of find() method. The query is as follows:> db.findSpecificValue.find().pretty();The following is the output:{ "_id" : ObjectId("5c6e8996140577d89182b8d0"), "StudentId" ...
Read MoreWhat are Lob Data Types? What are the restrictions on these datatypes in JDBC?
A BLOB is binary large object that can hold a variable amount of data with a maximum length of 65535 charactersThese are used to store large amounts of binary data, such as images or other types of files.A CLOB stands for Character Large Object in general, an SQL Clob is a built-in datatype is used to store large amount of textual data. Using this datatype, you can store data up to 2, 147, 483, 647 characters.Blob and Clob data types together are known as LOB (Large Object) datatypes. Following are the restrictions on these datatypes.Cannot compare: We cannot compare CLOB ...
Read MoreGet the count of only unique rows in a MySQL column?
In MySQL, COUNT() will display the number of rows. DISTINCT is used to ignore duplicate rows and get the count of only unique rows.Let us first create a table:mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(10) ); Query OK, 0 rows affected (0.47 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(FirstName) values('Larry'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(FirstName) values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(FirstName) values('Sam'); Query OK, 1 row affected (0.13 sec) ...
Read MoreCan I use SUM() with IF() in MySQL?
Yes, you can use SUM() with IF() in MySQL. Let us first create a demo table:mysql> create table DemoTable ( Value int, Value2 int ); Query OK, 0 rows affected (0.51 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable values(100, 400); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(100, 400); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(400, 100); Query OK, 1 row affected (0.14 sec)Following is the query to display records from the table using select command:mysql> select *from DemoTable;This ...
Read MoreHow to multiply columns and then sum the rows with similar records like customer name?
To understand this, let us create a table with fields like ID, Customer Name, Items, Price. We will first multiply the items with price. After that the rows with similar records i.e. same customer name will get added.Let us first create a table:mysql> create table DemoTable ( CustomerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, CustomerName varchar(100), CustomerItems int, CustomerPrice int ); Query OK, 0 rows affected (0.54 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(CustomerName, CustomerItems, CustomerPrice)values('Larry', 3, 450); Query OK, 1 row affected (0.24 sec) mysql> ...
Read MoreGet count of values that only appear once in a MySQL column?
To get number of values that only appear once in a column, use GROUP BY HAVING. Let us first create a table:mysql> create table DemoTable ( Name varchar(20) ); Query OK, 0 rows affected (0.55 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable values('Larry'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Larry'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into ...
Read MoreHow can I get maximum and minimum values in a single MySQL query?
To get maximum and minimum values in a single query, use the aggregate function min() and max(). Let us first create a table:mysql> create table DemoTable ( FirstValue int, SecondValue int ); Query OK, 0 rows affected (0.66 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable values(10, 30); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(30, 60); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(100, 500); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(50, 80); Query OK, ...
Read MoreCreate KeyValue Tuple from a List collection in Java
To create KeyValue tuple from List collection, use the fromCollection() method. Let us first see what we need to work with JavaTuples. To work with KeyValue class in JavaTuples, you need to import the following package:import org.javatuples.KeyValue;Note: Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file. Refer the below guide for all the steps to run JavaTuples:Steps: How to run JavaTuples program in EclipseThe following is an example to create KeyValue Tuple from List ...
Read MoreSelect first element of a commaseparated list in MySQL?
To select first element of a comma-separated list, you can use SUBSTRING_INDEX(). Let us first create a table:mysql> create table DemoTable ( CSV_Value varchar(200) ); Query OK, 0 rows affected (0.81 sec)Following is the query to insert some records in the table using insert command. We have inserted records in the form of comma-separated integer list:mysql> insert into DemoTable values('10, 20, 50, 80'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('100, 21, 51, 43'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('1, 56, 103, 1090'); Query OK, 1 row affected (0.26 ...
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