Bug 416703 Mongodb : Display correctly the Number data type
data/org.eclipse.birt.data.oda.mongodb/src/org/eclipse/birt/data/oda/mongodb/impl/MDbResultSet.java
* @see org.eclipse.datatools.connectivity.oda.IResultSet#wasNull()
     */
    public boolean wasNull() throws OdaException
    {
        return m_wasNull;
    }
    /*
     * @see org.eclipse.datatools.connectivity.oda.IResultSet#findColumn(java.lang.String)
     */
    public int findColumn( String columnName ) throws OdaException
    {
        return m_metadata.getColumnNumber( columnName );
    }
    private String findFieldName( int columnNumber ) throws OdaException
    {
        return getMetaData().getColumnName( columnNumber );
    }
    private Object getFieldValue( String columnName ) throws OdaException
    {
        Object fieldValue = doGetFieldValue( columnName );
        m_wasNull = ( fieldValue == null );
        return fieldValue;
    }
    
    private Object doGetFieldValue( String columnName ) throws OdaException
    {    
        if( ! projectsFlattenedRows() )
        {   
            FieldMetaData fieldMD = m_metadata.getColumnMetaData( columnName );
            return ResultDataHandler.fetchFieldValues( columnName, fieldMD, m_currentRow );