JAVA DATABASE PROGRAMMING - Introduction to Java Programming: Comprehensive Version - page 1198

11 public class FindGradeUsingPreparedStatement extends Application {
12

// PreparedStatement for executing queries

13 private PreparedStatement preparedStatement;

14 private TextField tfSSN = new TextField();

15 private TextField tfCourseId = new TextField();

16 private Label lblStatus = new Label();

17
18 @Override // Override the start method in the Application class
19 public void start(Stage primaryStage) {
20 // Initialize database connection and create a Statement object
21 initializeDB();
22
23 Button btShowGrade = new Button( "Show Grade" );
24 HBox hBox = new HBox( 5 );
25 hBox.getChildren().addAll( new Label( "SSN" ), tfSSN,
26 new Label( "Course ID" ), tfCourseId, (btShowGrade));

27
28 VBox vBox = new VBox( 10 );
29 vBox.getChildren().addAll(hBox, lblStatus);
30
31 tfSSN.setPrefColumnCount( 6 );
32 tfCourseId.setPrefColumnCount( 6 );
33 btShowGrade.setOnAction(e -> showGrade());
34
35 // Create a scene and place it in the stage
36 Scene scene = new Scene(vBox, 420 , 80 );
37 primaryStage.setTitle( "FindGrade" ); // Set the stage title
38 primaryStage.setScene(scene); // Place the scene in the stage
39 primaryStage.show(); // Display the stage
40 }
41
42 private void initializeDB() {
43 try {
44 // Load the JDBC driver
45 Class.forName( "com.mysql.jdbc.Driver" );
46 // Class.forName("oracle.jdbc.driver.OracleDriver");
47 System.out.println( "Driver loaded" );
48
49 // Establish a connection
50 Connection connection = DriverManager.getConnection
51 ( "jdbc:mysql://localhost/javabook" , "scott" , "tiger" );
52 // ("jdbc:oracle:thin:@liang.armstrong.edu:1521:orcl",
53 // "scott", "tiger");
54 System.out.println( "Database connected" );
55
56

load driver

connect database

String queryString = "select firstName, mi, " +

57 "lastName, title, grade from Student, Enrollment, Course " +

58 "where Student.ssn = ? and Enrollment.courseId = ? " +

placeholder

59 "and Enrollment.courseId = Course.courseId" ;

60
61 // Create a statement

62 preparedStatement = connection.prepareStatement(queryString); prepare statement

63 }
64 catch (Exception ex) {
65 ex.printStackTrace();
66 }
67 }
68
69 private void showGrade() {
70 String ssn = tfSSN.getText();