error handling

22 Jun 2006 5:27 PM

Eugene Anthony

One problem with the code bellow is after this code

conn.qDupUser p1,rs

I added:

set rs = nothing

to test the error handling capability.

What happen is the code bellow gets executed

If rs(0) = 1 then
response.write "<center>Error: Username is
unavailable</center> "
conn.close
set conn = nothing
else

along with the code bellow

If Err.number <> 0 then
Response.Write "<center>" & Err.number & ":" &
Err.Description & "</center> "
end if
on Error goto 0

THE CODE:

If request.queryString("Action") = 2 then
p1 = Trim(request.form("username"))
p2 = Trim(request.form("password"))
p3 = Trim(request.form("type"))
If (p1 <> "" and p2 <> "") AND (Len(p1)<=12 and Len(p2)<=12) then
on error resume next
set conn = Server.CreateObject("ADODB.Connection")
conn.open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
Server.MapPath("/db/upload/stelladb.mdb") & ";"
set rs = Server.CreateObject("ADODB.Recordset")
conn.qDupUser p1,rs
set rs = nothing
If rs(0) = 1 then
response.write "<center>Error: Username is
unavailable</center> "
conn.close
set conn = nothing
else
arParms = Array(p1,p2,p3)
sql = "INSERT INTO Account([Username],[Password],[Type]) VALUES(?,?,?)"
RunQueryString sql, arParms
End if
if Err.number <> 0 then
Response.Write "<center>" & Err.number & ":" &
Err.Description & "</center> "
end if
on Error goto 0
Else
response.write "<center>Error: Invalid username or
password</center> "
End if
End if

How do I solve the problem?

Eugene Anthony

*** Sent via Developersdex http://www.developersdex.com ***

22 Jun 2006 7:40 PM

Mike Brind

Eugene Anthony wrote:
Show quote

> One problem with the code bellow is after this code
>
> conn.qDupUser p1,rs
>
> I added:
>
> set rs = nothing
>
> to test the error handling capability.
>
> What happen is the code bellow gets executed
>
> If rs(0) = 1 then
> response.write "<center>Error: Username is
> unavailable</center> "
> conn.close
> set conn = nothing
> else
>
> along with the code bellow
>
> If Err.number <> 0 then
> Response.Write "<center>" & Err.number & ":" &
> Err.Description & "</center> "
> end if
> on Error goto 0
>
>
> THE CODE:
>
>
> If request.queryString("Action") = 2 then
> p1 = Trim(request.form("username"))
> p2 = Trim(request.form("password"))
> p3 = Trim(request.form("type"))
> If (p1 <> "" and p2 <> "") AND (Len(p1)<=12 and Len(p2)<=12) then
> on error resume next
> set conn = Server.CreateObject("ADODB.Connection")
> conn.open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
> Server.MapPath("/db/upload/stelladb.mdb") & ";"
> set rs = Server.CreateObject("ADODB.Recordset")
> conn.qDupUser p1,rs
> set rs = nothing
> If rs(0) = 1 then

I'm not quite sure what your problem is, because you haven't exactly
described it very well, but in the 4 lines above, you have declared a
recordset object, opened it, set it to nothing and then tried to
reference it.

Obviously, since you have set rs = nothing, anything that belongs to rs
is also set to nothing, including rs(0).

--
Mike Brind

23 Jun 2006 1:48 AM

solomon_13000

I purposely set rs = nothing

to test the error handling capability and what happen is the code
bellow gets executed

If rs(0) = 1 then
response.write "<center>Error: Username is
unavailable</center> "
conn.close
set conn = nothing
else

followed by the code bellow

If Err.number <> 0 then
Response.Write "<center>" & Err.number & ":" &
Err.Description & "</center> "
end if
on Error goto 0

so I am getting two error msg which is wrong. Only one error msg is to
be displayed.

Eugene Anthony wrote:
Show quote

> One problem with the code bellow is after this code
>
> conn.qDupUser p1,rs
>
> I added:
>
> set rs = nothing
>
> to test the error handling capability.
>
> What happen is the code bellow gets executed
>
> If rs(0) = 1 then
> response.write "<center>Error: Username is
> unavailable</center> "
> conn.close
> set conn = nothing
> else
>
> along with the code bellow
>
> If Err.number <> 0 then
> Response.Write "<center>" & Err.number & ":" &
> Err.Description & "</center> "
> end if
> on Error goto 0
>
>
> THE CODE:
>
>
> If request.queryString("Action") = 2 then
> p1 = Trim(request.form("username"))
> p2 = Trim(request.form("password"))
> p3 = Trim(request.form("type"))
> If (p1 <> "" and p2 <> "") AND (Len(p1)<=12 and Len(p2)<=12) then
> on error resume next
> set conn = Server.CreateObject("ADODB.Connection")
> conn.open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
> Server.MapPath("/db/upload/stelladb.mdb") & ";"
> set rs = Server.CreateObject("ADODB.Recordset")
> conn.qDupUser p1,rs
> set rs = nothing
> If rs(0) = 1 then
> response.write "<center>Error: Username is
> unavailable</center> "
> conn.close
> set conn = nothing
> else
> arParms = Array(p1,p2,p3)
> sql = "INSERT INTO Account([Username],[Password],[Type]) VALUES(?,?,?)"
> RunQueryString sql, arParms
> End if
> if Err.number <> 0 then
> Response.Write "<center>" & Err.number & ":" &
> Err.Description & "</center> "
> end if
> on Error goto 0
> Else
> response.write "<center>Error: Invalid username or
> password</center> "
> End if
> End if
>
>
> How do I solve the problem?
>
> Eugene Anthony
>
> *** Sent via Developersdex http://www.developersdex.com ***

23 Jun 2006 7:25 AM

Mike Brind

On Error Resume Next tells the VBScript engine to ignore errors and
continue with the next line of code. Details of the last error
encountered are stored in the Err object. Previous error information
is lost. On Error Goto 0 switches off On Error Resume Next, so code
continues executing normally until it reaches another error.

More information:
http://blogs.msdn.com/ericlippert/archive/2004/08/19/217244.aspx

--
Mike Brind

solomon_13000 wrote:

Show quote

> I purposely set rs = nothing
>
> to test the error handling capability and what happen is the code
> bellow gets executed
>
> If rs(0) = 1 then
> response.write "<center>Error: Username is
> unavailable</center> "
> conn.close
> set conn = nothing
> else
>
> followed by the code bellow
>
> If Err.number <> 0 then
> Response.Write "<center>" & Err.number & ":" &
> Err.Description & "</center> "
> end if
> on Error goto 0
>
> so I am getting two error msg which is wrong. Only one error msg is to
> be displayed.
>
>
> Eugene Anthony wrote:
> > One problem with the code bellow is after this code
> >
> > conn.qDupUser p1,rs
> >
> > I added:
> >
> > set rs = nothing
> >
> > to test the error handling capability.
> >
> > What happen is the code bellow gets executed
> >
> > If rs(0) = 1 then
> > response.write "<center>Error: Username is
> > unavailable</center> "
> > conn.close
> > set conn = nothing
> > else
> >
> > along with the code bellow
> >
> > If Err.number <> 0 then
> > Response.Write "<center>" & Err.number & ":" &
> > Err.Description & "</center> "
> > end if
> > on Error goto 0
> >
> >
> > THE CODE:
> >
> >
> > If request.queryString("Action") = 2 then
> > p1 = Trim(request.form("username"))
> > p2 = Trim(request.form("password"))
> > p3 = Trim(request.form("type"))
> > If (p1 <> "" and p2 <> "") AND (Len(p1)<=12 and Len(p2)<=12) then
> > on error resume next
> > set conn = Server.CreateObject("ADODB.Connection")
> > conn.open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
> > Server.MapPath("/db/upload/stelladb.mdb") & ";"
> > set rs = Server.CreateObject("ADODB.Recordset")
> > conn.qDupUser p1,rs
> > set rs = nothing
> > If rs(0) = 1 then
> > response.write "<center>Error: Username is
> > unavailable</center> "
> > conn.close
> > set conn = nothing
> > else
> > arParms = Array(p1,p2,p3)
> > sql = "INSERT INTO Account([Username],[Password],[Type]) VALUES(?,?,?)"
> > RunQueryString sql, arParms
> > End if
> > if Err.number <> 0 then
> > Response.Write "<center>" & Err.number & ":" &
> > Err.Description & "</center> "
> > end if
> > on Error goto 0
> > Else
> > response.write "<center>Error: Invalid username or
> > password</center> "
> > End if
> > End if
> >
> >
> > How do I solve the problem?
> >
> > Eugene Anthony
> >
> > *** Sent via Developersdex http://www.developersdex.com ***

23 Jun 2006 7:27 AM

Anthony Jones

"solomon_13000" <solomon_13***@yahoo.com> wrote in message
news:1151027326.628285.81850@i40g2000cwc.googlegroups.com...
> I purposely set rs = nothing
>
> to test the error handling capability and what happen is the code
> bellow gets executed
>
> If rs(0) = 1 then

Earlier in your code you set On Error Resume Next.

This line fails but that doesn't imply the whole If ... End If block is
skipped. Code execution just falls into the 'Then' portion and executes
that. I can't say whether it's guaranteed always to behave that way but at
least in VBScript it fairly certain.

Show quote

> response.write "<center>Error: Username is
> unavailable</center> "
> conn.close
> set conn = nothing
> else
>
> followed by the code bellow
>
> If Err.number <> 0 then
> Response.Write "<center>" & Err.number & ":" &
> Err.Description & "</center> "
> end if
> on Error goto 0
>
> so I am getting two error msg which is wrong. Only one error msg is to
> be displayed.
>

Frankly Error handling in VBScript stinks. Using a blanket On Error Resume
Next can often to lead to all sorts of strange an seemingly inexplicable
behaviour.

If you really must use it extract the specific lines that really need this
(there are usually only one or two lines that actually need this) and move
them into their own function. You can place the On Error Resume Next in
those functions.

Show quote

>
> Eugene Anthony wrote:
> > One problem with the code bellow is after this code
> >
> > conn.qDupUser p1,rs
> >
> > I added:
> >
> > set rs = nothing
> >
> > to test the error handling capability.
> >
> > What happen is the code bellow gets executed
> >
> > If rs(0) = 1 then
> > response.write "<center>Error: Username is
> > unavailable</center> "
> > conn.close
> > set conn = nothing
> > else
> >
> > along with the code bellow
> >
> > If Err.number <> 0 then
> > Response.Write "<center>" & Err.number & ":" &
> > Err.Description & "</center> "
> > end if
> > on Error goto 0
> >
> >
> > THE CODE:
> >
> >
> > If request.queryString("Action") = 2 then
> > p1 = Trim(request.form("username"))
> > p2 = Trim(request.form("password"))
> > p3 = Trim(request.form("type"))
> > If (p1 <> "" and p2 <> "") AND (Len(p1)<=12 and Len(p2)<=12) then
> > on error resume next
> > set conn = Server.CreateObject("ADODB.Connection")
> > conn.open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" &
> > Server.MapPath("/db/upload/stelladb.mdb") & ";"
> > set rs = Server.CreateObject("ADODB.Recordset")
> > conn.qDupUser p1,rs
> > set rs = nothing
> > If rs(0) = 1 then
> > response.write "<center>Error: Username is
> > unavailable</center> "
> > conn.close
> > set conn = nothing
> > else
> > arParms = Array(p1,p2,p3)
> > sql = "INSERT INTO Account([Username],[Password],[Type]) VALUES(?,?,?)"
> > RunQueryString sql, arParms
> > End if
> > if Err.number <> 0 then
> > Response.Write "<center>" & Err.number & ":" &
> > Err.Description & "</center> "
> > end if
> > on Error goto 0
> > Else
> > response.write "<center>Error: Invalid username or
> > password</center> "
> > End if
> > End if
> >
> >
> > How do I solve the problem?
> >
> > Eugene Anthony
> >
> > *** Sent via Developersdex http://www.developersdex.com ***
>