Rule Definition
Having an SQL query inside a loop is usually the source of performance and scalability problems especially if the number of iterations become very high (for example if it is dependent on the data returned from the database). This iterative pattern has proved to be very dangerous for application performance and scalability. Database servers handle in a much better set-oriented pattern rather than pure iterative ones.

Remediation
The remediation is often to replace the iterative approach based on a loop with a set-oriented one and thus modify the query.

Violation Code Sample

PreparedStatement updateSales;
String updateString = "update COFFEES " +
                      "set SALES = ? where COF_NAME like ?";
updateSales = con.prepareStatement(updateString);

int len = coffees.length;
for(int i = 0; i < len; i++) {
                updateSales.setInt(1, salesForWeek[i]);
                updateSales.setString(2, coffees[i]);
                updateSales.executeUpdate();    // VIOLATION
        }