public void updateCharacterStream(String columnName, Reader reader, int length) throws SQLException {
        updateCharacterStream(findColumn(columnName), reader, length);
    }
Updates the designated column with a character stream value.
The <code>updateXXX</code> methods are used to update column values
in the current row or the insert row.  The <code>updateXXX</code>
methods do not update the underlying database; instead the
<code>updateRow</code> or <code>insertRow</code> methods are called
to update the database.

@param columnName the name of the column
@param reader the new column <code>Reader</code> stream value
@param length the length of the stream
@throws SQLException if a database access error occurs
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java