How to Select a Database
In MySQL, selecting a database means choosing the database that you want to work with on the database server (such as MySQL or SQL Server) before executing SQL queries.
Example: Selecting a database in Java.
Source Code:
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import java.sql.*;
import javax.swing.*;
Connection con;
public DatabaseSelector() {
initComponents();
loadDatabases(); // load DBs into combo when form opens
}
private void loadDatabases() {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
// Connect to MySQL server (no specific DB yet)
con = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/?useSSL=false&serverTimezone=Asia/Phnom_Penh",
"root", // your MySQL username
"root" // your MySQL password
);
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SHOW DATABASES");
// Clear old items first
comboDatabases.removeAllItems();
while (rs.next()) {
comboDatabases.addItem(rs.getString(1)); // add DB name
}
rs.close();
stmt.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(this, "Error: " + e.getMessage());
}
}
private void btnSelectActionPerformed(java.awt.event.ActionEvent evt) {
String dbName = (String) comboDatabases.getSelectedItem();
if (dbName != null) {
// Example: connect to that database
try {
Connection dbCon = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/" + dbName + "?useSSL=false&serverTimezone=Asia/Phnom_Penh",
"root",
"root"
);
JOptionPane.showMessageDialog(this, "You selected database: " + dbName);
dbCon.close();
} catch (Exception ex) {
JOptionPane.showMessageDialog(this, "Connection failed: " + ex.getMessage());
}
}
}
Result:
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