public void setMatchColumn(String columnName) throws SQLException {
        // validate, if col is ok to be set
        if(columnName == null || (columnName= columnName.trim()).equals("")) {
            throw new SQLException(resBundle.handleGetObject("jdbcrowsetimpl.matchcols2").toString());
        } else {
            // set strMatchColumn
            strMatchColumns.set(0, columnName);
            //iMatchColumn = -1;
        }
    }
Sets the designated parameter to the given <code>String</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 columnName the name of the column into this rowset
       object's internal representation of parameter values
@throws SQLException if an error occurs or the
 parameter index is out of bounds
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java