Question is very broad without specifics of your application needs.
Flash can be published as a projector (executable) and in its native
capabilities access databases via an http: request either on an internal or
external server. It can also read native files with either XML or Url
encoded data but it cannot write to those files.
It is not the same as having full access to your local computer. For example
no access to making folders or writing to registry.
You also can use third party or your own custom code wrappers to communicate
with a Flash projector to overcome its limitations to communicate with the
operating system - this is a very common approach. Example of a third party
wrapper would be Zinc.

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Lon Hosford
www.lonhosford.com
Flash, Actionscript and Flash Media Server examples:
http://flashexamples.hosfordusa.com
May many happy bits flow your way!
> Hi,
>
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> Thanks
> Crunchy