ACCESS FEED: Re: [MS_AccessPros] Tracking user profile

Selasa, 27 November 2012

Re: [MS_AccessPros] Tracking user profile

Adam-

Yes, in general Public variables (variables declared Public in a Standard
module) stay set as long as the database is open. But they can get reset
and reloaded back to their default values if there's an untrapped error.
Note that the example I provided is not a Public variable because I used
Dim.

If the permissions can change while the user is running the app, then you
should use DLookup every time. If you're OK with them remaining static
with the values set when the app loads, then use my technique. You
certainly can run code to load them all at startup, but my technique loads
them on first reference. However, my technique won't work with Bit or
Integer variables because those will both have a default value of 0 when
loaded. You could use the Variant data type like this:

Option Compare Database
Option Explicit
Dim pvarDeleteAllowed As Variant

Public Function GetDeleteAuth() As Integer

If IsEmpty(pvarDeleteAllowed) Then
pvarDeleteAllowed = DLookup("DeleteAllowed", "ztblUserData")
End If
GetDeleteAuth = CInt(pvarDeleteAllowed)

End Function

A Variant data type can hold any type of data (including Null) and is
"Empty" when first defined.

Note that you can also add a filter as the third parameter in DLookup to
fetch the data for a specific user.

John Viescas, Author
Microsoft Access 2010 Inside Out
Microsoft Access 2007 Inside Out
Microsoft Access 2003 Inside Out
Building Microsoft Access Applications
SQL Queries for Mere Mortals
http://www.viescas.com/
(Paris, France)

-----Original Message-----
From: AdamF <runuphillracing@yahoo.com>
Reply-To: <MS_Access_Professionals@yahoogroups.com>
Date: Tuesday, November 27, 2012 10:52 PM
To: <MS_Access_Professionals@yahoogroups.com>
Subject: Re: [MS_AccessPros] Tracking user profile

John,

So are public variables then kept (assuming the front end) and accessible
as long as the user is logged in? So that if I have a bunch of boolean
variables (e.g. OrderApprove), I can the use code like
If OrderApprove = True then
code to hide, lock, enable different fields
End If

A One issue with the approach of writing separate "wrapper" functions is
that the different types of permissions do change. I maintain the list of
permissions in a table tblPermissions. Is there a way to generate these
variables from the list in that table?

Adam

--- In MS_Access_Professionals@yahoogroups.com, John Viescas <JohnV@...>
wrote:
>
> Adam-
>
> I prefer to use a table in combination with Public variables to do this.
> It's a known fact that stuff stored in memory can "disappear" of there's
> an error. And a "hidden" form may not always be hidden and is slower to
> reference.
>
> Here's what I do in a Standard module:
>
> Option Compare Database
> Option Explicit
>
> Dim pstrLoginName As String
>
> Public Function GetUser() As String
>
> If Len(pstrLoginName) = 0 Then
> pstrLoginName = DLookup("UserName", "ztblUserData")
> End If
>
> GetUser = pstrLoginName
>
> End Function
>
> Of course, this assume you stored the user name at login in ztblUserData.
>
> You can write as many "wrapper" functions as you like to grab / populate
> the module variables.
>
> John Viescas, Author
> Microsoft Access 2010 Inside Out
> Microsoft Access 2007 Inside Out
> Microsoft Access 2003 Inside Out
> Building Microsoft Access Applications
> SQL Queries for Mere Mortals
> http://www.viescas.com/
> (Paris, France)
>
>
>
> -----Original Message-----
> From: AdamF <runuphillracing@...>
> Reply-To: <MS_Access_Professionals@yahoogroups.com>
> Date: Tuesday, November 27, 2012 9:56 PM
> To: <MS_Access_Professionals@yahoogroups.com>
> Subject: [MS_AccessPros] Tracking user profile
>
> Currently, when a user logs in, I open an unbound, hidden form, and write
> their profile info (from a table using their login name) to that form
> (frmUser). I then refer to that form on numerous pages to customize the
> view and edit/delete/add authorities. I did this because it seems a lot
> quicker to look up in a form than using dlookup to tblUserProfile.
>
> Is there a better way?
>
> I've thought about creating a set of two local (front end) tables with
> this info, in lieu of an unbound form.
>
> I think I recall somewhere about tracking properties in VB. I have no
>idea
> how that works.
>
> Adam
> Denver, CO
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>

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