jW. jW. - 6 months ago 13
Java Question

Is there a way to retrieve the autoincrement ID from a prepared statement

Is there a way to retrieve the auto generated key from a DB query when using a java query with prepared statements.

For example, I know AutoGeneratedKeys can work as follows.

stmt = conn.createStatement();

stmt.executeUpdate(sql, Statement.RETURN_GENERATED_KEYS);
if(returnLastInsertId) {
ResultSet rs = stmt.getGeneratedKeys();
rs.next();
auto_id = rs.getInt(1);
}


However. What if I want to do an insert with a prepared Statement.

String sql = "INSERT INTO table (column1, column2) values(?, ?)";
stmt = conn.prepareStatement(sql);

//this is an error
stmt.executeUpdate(Statement.RETURN_GENERATED_KEYS);
if(returnLastInsertId) {
//this is an error since the above is an error
ResultSet rs = stmt.getGeneratedKeys();
rs.next();
auto_id = rs.getInt(1);
}


Is there a way to do this that I don't know about. It seems from the javadoc that PreparedStatements can't return the Auto Generated ID.

Answer

Yes. See here. Section 7.1.9. Change your code to:

String sql = "INSERT INTO table (column1, column2) values(?, ?)";
stmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);


stmt.executeUpdate();
if(returnLastInsertId) {
   ResultSet rs = stmt.getGeneratedKeys();
    rs.next();
   auto_id = rs.getInt(1);
}