public double getDouble(String columnName) throws SQLException {
      return getDouble(getColIdxByName(columnName));
   }
Retrieves the value stored in the designated column
of the current row of this <code>StreamingRowSetImpl</code> object
as a <code>double</code> value.

@param columnName a <code>String</code> object giving the SQL name of
       a column in this <code>StreamingRowSetImpl</code> object
@return the column value; if the value is SQL <code>NULL</code>,
        the result is <code>0</code>
@throws SQLException if (1) the given column name is not the name of
a column in this rowset, (2) the cursor is not on one of
this rowset's rows or its insert row, or (3) the designated
column does not store an SQL <code>TINYINT, SMALLINT, INTEGER
BIGINT, REAL, <b>FLOAT</b>, <b>DOUBLE</b>, DECIMAL, NUMERIC, BIT, CHAR,
VARCHAR</code> or <code>LONGVARCHAR</code> value. The bold SQL type
designates the recommended return types.
@see #getDouble(int)
src/main/java/org/replicadb/rowset/StreamingRowSetImpl.java