public void setCommand(String command) throws SQLException {

       if (getCommand() != null) {
          if(!getCommand().equals(command)) {
             super.setCommand(command);
             ps = null;
             rs = null;
          }
       }
       else {
          super.setCommand(command);
       }
    }
Sets this <code>JdbcRowSet</code> object's <code>command</code> property to
the given <code>String</code> object and clears the parameters, if any,
that were set for the previous command. In addition,
if the <code>command</code> property has previously been set to a
non-null value and it is
different from the <code>String</code> object supplied,
this method sets this <code>JdbcRowSet</code> object's private fields
<code>ps</code> and <code>rs</code> to <code>null</code>.
(The field <code>ps</code> is its <code>PreparedStatement</code> object, and
the field <code>rs</code> is its <code>ResultSet</code> object.)
<P>
The <code>command</code> property may not be needed if the <code>RowSet</code>
object gets its data from a source that does not support commands,
such as a spreadsheet or other tabular file.
Thus, this property is optional and may be <code>null</code>.

@param command a <code>String</code> object containing an SQL query
           that will be set as this <code>RowSet</code> object's command
           property; may be <code>null</code> but may not be an empty string
@throws SQLException if an empty string is provided as the command value
@see #getCommand
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java