public void setMatchColumn(int columnIdx) throws SQLException {
        // validate, if col is ok to be set
        if(columnIdx < 0) {
            throw new SQLException(resBundle.handleGetObject("cachedrowsetimpl.matchcols1").toString());
        } else {
            // set iMatchColumn
            iMatchColumns.set(0, columnIdx);
            //strMatchColumn = null;
        }
    }
Sets the designated parameter to the given <code>int</code>
object.  This forms the basis of the join for the
<code>JoinRowSet</code> as the column which will form the basis of the
join.
<P>
The parameter value set by this method is stored internally and
will be supplied as the appropriate parameter in this rowset's
command when the method <code>getMatchColumn</code> is called.

@param columnIdx the index into this rowset
       object's internal representation of parameter values; the
       first parameter is 0, the second is 1, and so on; must be
       <code>0</code> or greater
@throws SQLException if an error occurs or the
                        parameter index is out of bounds
src/main/java/org/replicadb/rowset/sun/rowset/CachedRowSetImpl.java