how to delete a row from a datatable?

[Mark Moge]

Hi.
I want to delte row from the dataTable. I have a java class called Book and the datatable on jsp page. How can I write a delete method? Can you tell me how to get an IdBook from the table (when I get id I will be able to delete the correct row from the database). Or maybe you have a better idea.

                <h:dataTable value='#{book.result}' var = 'item' border = '1'>
                    <h:column>
                        <h:outputText value="#{item.title}" />
                    </h:column>
                    <h:column>
                        <h:outputText value="#{item.author}" />
                    </h:column>
                    <h:column>
                        <h:outputText value="#{item.idBook}" />
                    </h:column>
                    <h:column>
                        <h:commandButton value="delete" action="book.delete()"/> // don't know how to get id of current book 
                    </h:column>
                </h:dataTable>
      

  
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Book {

    //connect to database
    public Connection connectDB() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/db", "root", "admin");
            return conn;
        } catch (Exception ex) {
            ex.printStackTrace();
            return null;
        }
    }
    //get data from database
    public ResultSet getData() throws SQLException {
        Connection conn = connectDB();
        String query = "SELECT title, author, idBook FROM book";
        Statement stmt = conn.createStatement();
        result = stmt.executeQuery(query);
        return result;
    }
   
    private ResultSet result;

    public ResultSet getResult() throws SQLException {
        getData();
        return result;
    }

    public void setResult(ResultSet result) {
        this.result = result;
    }  
  

[Tim Holloway]

The DataTable is only a View component for a DataModel. The DataModel is the backing data for the view, and isn't supposed to actually be the Domain Model. In fact, at best, it can only wrap a Domain Model.

In order to "delete a row from a datatable", therefore, you must remove it from the DataModel. You MAY also choose to remove it from the Domain Model (that is, delete the row from the database), but that's up to you. If the DataModel doesn't contain the row, the row won't display. Conversely, you can include rows in the DataModel that aren't necessarily in the Domain model, since you're the one that determines the difference.

[Mark Moge]

I have solved my problem by binding the datatable with a HtmlDataTable.

  <h:dataTable value='#{book.result}' var = 'item' binding ="#{book.dataTable}" border = '1'>   

then in the book class

  private HtmlDataTable dataTable; // + getter & setter 

and after that i could get data from a selected row by using

dataTable.getRowData();    

[Tim Holloway]

Er, you do realize that that just retrieves the row and doesn't actually delete it, don't you?

[Mark Moge]

Tim Holloway wrote:Er, you do realize that that just retrieves the row and doesn't actually delete it, don't you?

Yes I do.
With data from a row I have an id of a book so I can write a SQL query to delete this book from a database.

[Tim Holloway]

Just checking.

Ironically enough, I'm coding almost that exact same sequence myself right now. I'm working on a generic database table editor for a client, since I couldn't seem to find any viable ones in open source. If I'm not too revolted by the final results, you may see it on SourceForge someday soon.