Java应用程序的SQL数据库中结果集错误的列数

Question

I'm having an issue with adding data to a sql database through Java on Netbeans.

String bladeSerial;
String bladeType;
LocalTime startTime1;

private void startButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                             

    Connection conn = null; 
    Statement st = null;
    try {
        conn = DriverManager.getConnection ("jdbc:derby://localhost:1527/db01", "Administrator", "admin"); //run procedure getConnection to connect to the database - see below
        st = conn.createStatement(); //set up a statement st to enable you to send SQL statements to the database.
    } catch (SQLException ex) {
        Logger.getLogger(FormTwo1.class.getName()).log(Level.SEVERE, null, ex);
    }

    System.out.println ("Successful Connection");


    String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values ('+bladeSerial+', '+itemText+', '+(String.valueOf(startTime1))+')";
    try (PreparedStatement pstmt = conn.prepareStatement(query)) {
        pstmt.setString(1, bladeSerial);
        pstmt.setString(2, bladeType);
        pstmt.setString(3, String.valueOf(startTime1));
        pstmt.executeUpdate();
    } catch (SQLException ex) {
        Logger.getLogger(FormTwo1.class.getName()).log(Level.SEVERE, null, ex);
    }

I get the error The column position '1' is out of range. The number of columns for this ResultSet is '0'. The column position '1' is out of range. The number of columns for this ResultSet is '0'.

In the database, Serial is VARCHAR(5) , Bladetype is VARCHAR(80) and StartT1 is VARCHAR(12)

The startTime1 variable is saved in the format HH:mm:ss.SSS.

I appreciate any help on this error

Answer 1

You need to give placeholder in your query. Change your code as given here...

String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values (?, ?, ?)";
PreparedStatement pstmt = conn.prepareStatement(query);
pstmt.setString(1, bladeSerial);
pstmt.setString(2, bladeType);
pstmt.setString(3, String.valueOf(startTime1));
pstmt.executeUpdate();

Answer 2

You don't need to give column names in query when you are using Prepared statement. Do the following changes:

 String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values (?, ?, ?)";

Hope it helps!!

Answer 3

Here you are forming query like simple statement and used it in prepared statement which is not possible, so change your query with place holder like below.

String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values (?, ?, ?)";
PreparedStatement pstmt = conn.prepareStatement(query);
pstmt.setString(1, bladeSerial);
pstmt.setString(2, bladeType);
pstmt.setString(3, String.valueOf(startTime1));
pstmt.executeUpdate();

Answer 4

If you want to directly use variables names like bladeSerial , then you should use these String variables as if you're adding multiple Strings.

String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values ("+bladeSerial+", "+itemText+", "+(String.valueOf(startTime1))+")";

But this is strictly not recommended as it would introduce serious security issues.

The recommended way is to use PreparedStatement . The query you've written is correct, it's just that you have to use placeholders instead of variable names.

String query = "insert into TB01(SERIAL,BLADETYPE,STARTT1) values (?, ?, ?)";
try (PreparedStatement pstmt = conn.prepareStatement(query)) {
    pstmt.setString(1, bladeSerial);
    pstmt.setString(2, bladeType);
    pstmt.setString(3, String.valueOf(startTime1));
    pstmt.executeUpdate();
} catch (SQLException ex) {
    // Exception handling
    Logger.getLogger(FormTwo1.class.getName()).log(Level.SEVERE, null, ex);
}