CODEWITHSUNDEEP
javasqljdbcprepared-statement
Pierre
Pierre

Reputation: 11633

INSERT SQL in Java

I have a Java application and I want to use SQL database. I have a class for my connection :


public class SQLConnection{
    private static String url = "jdbc:postgresql://localhost:5432/table";
    private static String user = "postgres";
    private static String passwd = "toto";
    private static Connection connect;
    public static Connection getInstance(){
        if(connect == null){
            try {
                connect = DriverManager.getConnection(url, user, passwd);
            } catch (SQLException e) {
                JOptionPane.showMessageDialog(null, e.getMessage(), "Connection Error", JOptionPane.ERROR_MESSAGE);
            }
        }       
        return connect; 
    }
}

And now, in another class I succeeded to print my values but when I attempt to insert a value nothing is happening ...

Here's my code :


try {
Statement state = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
Statement state2 = SQLConnection.getInstance().createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
state2.executeUpdate("INSERT INTO table(field1) VALUES (\"Value\")"); // Here's my problem
ResultSet res = state.executeQuery("SELECT * FROM table");

Upvotes: 3

Views: 2875

Answers (3)

BalusC
BalusC

Reputation: 1108632

You need to commit (and close) the connection (and statement) after use. You also need to ensure that you aren't swallowing any SQLExceptions which may cause that you see "nothing" to happen.

That said,

private static Connection connect;

This is a terribly bad idea. You should never declare external resources as static in your application. Your application will break when the other side decides to close the resource because it's been released for a too long time. You really need to acquire and close those resources (Connection, Statement and ResultSet in the shortest possible scope. I.e. inside the very same method block as where the query is to be executed.

Also, I strongly recommend to use PreparedStatement instead of Statement since that will prevent your code from SQL injection attacks.

You may find this article useful to learn more about how to do basic JDBC interaction the right way.

Upvotes: 3

Tommy
Tommy

Reputation: 39807

Copuld just be a copy over to SO error, but looking but shoulding INSERT INTO table(field1) be INSERT INTO plateau(field1)?

Upvotes: 0

Klaus Byskov Pedersen
Klaus Byskov Pedersen

Reputation: 120917

state2.executeUpdate("INSERT INTO table(field1) VALUES (\"Value\")");

should be:

state2.executeUpdate("INSERT INTO plateau(field1) VALUES (\"Value\")");

Upvotes: 1

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