Java FXML - NetBeans - Delete from Table - MySQL - mysql

Question

I get the following error when I attempt to delete a row from TableView:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '[value: 3]' at line 1
What I want: Once a row from TableView is selected, I want to delete it from database.
#FXML
void delete(ActionEvent event) {
try {
int pos;
pos = (int) tabelCustomers.getSelectionModel().getSelectedIndex();
Customers c;
c = tabelCustomers.getItems().get(pos);
SimpleIntegerProperty idc = c.idc;
String query;
query = "DELETE FROM customers WHERE customers.idc = " + idc;
try (Statement stm = cnx.createStatement()) {
stm.executeUpdate(query);
}
} catch (SQLException ex) {
Logger.getLogger(CustomersTableController.class.getName()).log(Level.SEVERE,
null, ex);
}
}
What am I missing? I have tried a lot of possible solutions, nothing works.
Basically, when a user clicks on the row in a table and then clicks on the "remove" button, that row should be deleted from table and DB.
Thanks in advance.

Answer 1

SimpleIntegerProperty idc = c.idc;
String query = "DELETE FROM customers WHERE customers.idc = " + idc;
When an Object (that is not a String) is used in string concatenation it is automatically converted into a String by calling toString() on it. The string representation of SimpleIntegerProperty is not simply its value, which means your query ends up looking something like:
DELETE FROM customers WHERE customers.idc = IntegerProperty [bean: <some_instance>, name: idc, value: 42]
Which is obviously not valid SQL. You need to extract the value of the property and use that as part of the query. However, you should not use string concatenation when creating SQL queries in the first place. You should instead be using a PreparedStatement with parameters. For example:
String query = "DELETE FROM customers WHERE customers.idc = ?";
try (PreparedStatement ps = cnx.prepareStatement(query)) {
ps.setInt(1, idc.get());
ps.executeUpdate();
}