Delete record from a java interface

[Gunner 1]

Hi,
I wanted to delete the record of the database from a java interface . But the removal of the record does not work. This is the code of the request:

String query ="DELETE FROM users WHERE (Code = '"+ + CNTCODE" ', Name ='"+ + cntNom" ', FirstName ='"+ + cntnm"');

This code of adding works:

String query ="insert into user values ( '"+ + CNTCODE"','"+ + cntNom"','"+ + cntnm"','"+ + cntLogin"','"+ + cntPassword"','"+ + cntpass"')";

So how do I delete the record? or is there a problem in my program?
Note - I am using database a Access.

[opaper]

Hi,
I think your syntax for DELETE is wrong. The various elements of the clause "WHERE" are separated by logical operators (AND, OR, etc.). And not by commas.

String query ="DELETE FROM users WHERE (Code = '"+ + CNTCODE" ', Name ='"+ + cntNom" ', FirstName ='"+ + cntnm"');

In addition, Java uses readily available PreparedStatement class to give the driver the task of the DBMS to manage its peculiarities (escape characters, etc..). This allows for example to have strings containing with no problems. I think you should read some book or documents on sql, so that you can get familiar with the syntax.

[Gunner 1]

Hey,
The syntax is correct now, the program compiles with 0 errors. But the removal is not done, I do not understand why and it does not display the error message that I specify. This is the code if you can still help me,

if(B == VSupprim)
		{
			if((SCode.getText().equals(""))||(Snom.getText().equals(""))||(SPrenom.getText().equals("")))
				{/ / Error message.
					JOptionPane.showMessageDialog(null, "All fields must be filled","Standard", JOptionPane.ERROR_MESSAGE);
				}
			else
			{
			String ccd = sCode.getText();
String = CNOM Snom.getText();
String cpnm = SPrenom.getText();

String query ="DELETE FROM users WHERE code = '"+ + ccd" 'AND name ='"+ + CNOM" 'AND FirstName ='"+ + cpnm"'";
			try
			{/ / connection to the database and execute statement
				Class.Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

  Connection conn = DriverManager.getConnection("jdbc: odbc: Database");
 Statement st = conn.createStatement();
 				
				  int nb = st.executeUpdate(query);
				  if (nb ==0)
  					{/ / Error message.
  						JOptionPane.showMessageDialog(null, "Error while deleting","Message", JOptionPane.WARNING_MESSAGE);
  					}
  				else
				  	{
  						JOptionPane.showMessageDialog(null, "User deleted successfully","Message", JOptionPane.INFORMATION_MESSAGE);
  					}					
					 st.close();
conn.close();
  			}
  			
  			catch(Exception eb){
				}
			}
		}

[MindSpace]

Hello,
I think you are over committing your transactions, I mean to say, I just reread your code.

  			catch(Exception eb){
				}

Just watch the above part of the code, I think you have used it too much in your code and the code has become more complicated. I think you should minimize the use of such things from your code.

[Gunner 1]

Hey

catch(Exception eb){
}

Sorry, I do not understand what you want to say. I can not find the error, is it in the syntax of my program? When I replace the line by removing a motion to add it turns normally but does not delete the record. But, still I did not understand what you are trying to say with the catch block in my code. Is it wrongly placed in the program.

[Modifier]

Hello,
You should also make sure that the connection will be released in all cases, just look at the sample code below, I would recommend this to you first.

Connection connection = null;
try
{
   connection = DriverManager.getConnection(...);
   ...
}
catch (Exception e)
{
   ...
}
finally
{
   if (connection! = null) connection.close();
}