Data from DB into webMethods

1) if it's blank space in DB (after trim service), it will be equal to '';

    

    

2) if convert empty to null, it will reach $null statement;

    

    

3) 如果在webmethods裏面，在最開始直接輸入的是nothing, leave it blank, it will be considered as $null; it will be evaluated as $null.

    

    

4) 如果在中途輸入nothing, leave it blank, it will considered as NOT null, it will be evaluated as ''.