WHERE some_col > ''
Since null > '' produces unknown, this has the effect of filtering out both null and empty strings.
@JoshPinter: coalesce(some_col, '') = ''
REQUEST: Only when the request comes directly from the client
FORWARD: Only when the request has been forwarded to a component (see Transferring Control to Another Web Component)
INCLUDE: Only when the request is being processed by a component that has been included (see Including Other Resources in the Response)
ERROR: Only when the request is being processed with the error page mechanism (see Handling Servlet Errors)
You can direct the filter to be applied to any combination of the preceding situations by selecting multiple dispatcher types. If no types are specified, the default option is REQUEST.
Der rechtlich einwandfreie Umgang mit Spam erhitzt die Gemüter: Es gilt nicht nur, den täglich wachsenden Schaden durch unerwünschte E-Mail-Massen zu begrenzen, sondern auch durch geeignete Gestaltung der Gegenmaßnahmen keinen Straftatbestand zu erfüllen – ein Spagat.
The order the container uses in building the chain of filters to be applied for a particular request URI is as follows:
First, the <url-pattern> matching filter mappings in the same order that these elements appear in the deployment descriptor.
Next, the <servlet-name> matching filter mappings in the same order that these elements appear in the deployment descriptor.