Querying DB Continuously for Update - java

Question

I have a query to fetch the name and id of companies. I am able to fetch all the companies but my issue is with the id of the companies. I have a combo box to display list of companies and another label which displays the id of the company selected in the combo box.

Here is my issue, when i change the selected company in the combo box, the label showing the id still remains displays the id of the initial company selected. Is there a way that i could continuously query the database to update the id?

PS I display companies in the combo box with reference no.

public AssignCompanies() {
    initComponents();
    conn = DBConnection.ConnectDB();

    FindCompanyID();
}

public void FindCompanyID() {
    String sql = "Select * from Company where ID = "+FindSelectedCompany.getSelectedItem();

    try {
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(sql);
        while(rs.next()) {
            String getSelectedCompany = rs.getString("Reference Number");
            seats.setText(getSelectedCompany);
        }
    }
}

*Continuously* query the database? Why? Why not just update the label when the combo box changes? Doesn't the combo box (or at least an in-memory list) contain the value you're looking for? — David, Aug 20 '17 at 10:35

score 0 · Accepted Answer · answered Aug 20 '17 at 10:34

You don't need to query the database everytime a user changes the selection in combo box, you can do the following:

Get ids and names of all the companies, and dynamically add option elements into combo box with value being id and label being name of the company
Configure an onchange event on that combo box, here's an example
Write a javscript function to update the value in another combo box in the onchange event configured in previous step (here's an example of how to update the value)

Querying DB Continuously for Update - java

1 Answers1