Empty table in a dataset

[pmelanso@uwaterloo.ca]

Hello,
What would be the statement to see if a table in a dataset has no rows
( i.e. is empty)??? What I need this for is if an sql statement doesn't
return anything... I need to know when that happends.

Pam

[Chris]

Re: Empty table in a dataset

pmelanso@uwater loo.ca wrote:[color=blue]
> Hello,
> What would be the statement to see if a table in a dataset has no rows
> ( i.e. is empty)??? What I need this for is if an sql statement doesn't
> return anything... I need to know when that happends.
>
> Pam
>[/color]

if not DataSet.Tables( 0) is nothing then
DataSet.Tables( 0).Rows.Count
end if

[Marina]

Re: Empty table in a dataset

Actually, I would expect that code to throw an index out of bounds
exception.

It should be something like:

If myDS.Tables.Cou nt = 0 Then
' there are no tables
End If

"Chris" <no@spam.com> wrote in message
news:%23Q09DpU6 FHA.2816@tk2msf tngp13.phx.gbl. ..[color=blue]
> pmelanso@uwater loo.ca wrote:[color=green]
>> Hello,
>> What would be the statement to see if a table in a dataset has no rows
>> ( i.e. is empty)??? What I need this for is if an sql statement doesn't
>> return anything... I need to know when that happends.
>>
>> Pam
>>[/color]
>
> if not DataSet.Tables( 0) is nothing then
> DataSet.Tables( 0).Rows.Count
> end if[/color]

[Chris]

Re: Empty table in a dataset

Marina wrote:[color=blue]
> Actually, I would expect that code to throw an index out of bounds
> exception.
>
> It should be something like:
>
> If myDS.Tables.Cou nt = 0 Then
> ' there are no tables
> End If
>
> "Chris" <no@spam.com> wrote in message
> news:%23Q09DpU6 FHA.2816@tk2msf tngp13.phx.gbl. ..
>[color=green]
>>pmelanso@uwat erloo.ca wrote:
>>[color=darkred]
>>>Hello,
>>>What would be the statement to see if a table in a dataset has no rows
>>>( i.e. is empty)??? What I need this for is if an sql statement doesn't
>>>return anything... I need to know when that happends.
>>>
>>>Pam
>>>[/color]
>>
>>if not DataSet.Tables( 0) is nothing then
>>DataSet.Table s(0).Rows.Count
>>end if[/color]
>
>
>[/color]

You are right... I was thinking but didn't type along the lines of:

if not MyDS.Tables("Ta bleName") is nothing then
....
end if

because if the ds has two tables in it your way isn't valid for his needs

[datatable row count sample]

RE: Empty table in a dataset

'note the test can be done in one line of code like in the commented out line
'below
'If mydataset.table s("TableName"). Rows.Count < 1 Then MsgBox("Zero datarows
exist", , "No Data")

'declare objects outside of the block so you can dispose of them in
finally
Dim tbl As DataTable
Dim ds As DataSet
Dim iRows As Integer
Try
'set objects inside of try to trap exceptions
ds = New DataSet("ds")
tbl = New DataTable("t")
tbl.Columns.Add ("ID")
ds.Tables.Add(t bl)
'returns 0(zero) if there are no datarows in the table referenced
iRows = ds.Tables("t"). Rows.Count

MsgBox(iRows, , "Number of datarows: iRows")
'test the value of iRow
If iRows > 0 Then
'No datarows present
Else
'at least one datarow present
End If

Catch ex As Exception
MsgBox(ex.Messa ge.ToString, , "System Exception")
Finally
tbl.Dispose() : ds.Dispose()
End Try

"pmelanso@uwate rloo.ca" wrote:
[color=blue]
> Hello,
> What would be the statement to see if a table in a dataset has no rows
> ( i.e. is empty)??? What I need this for is if an sql statement doesn't
> return anything... I need to know when that happends.
>
> Pam
>
>[/color]

[datatable row count sample]

RE: datatable row count sample.

'note the test can be done in one line of code like in the commented out line
'below
'If mydataset.table s("TableName"). Rows.Count < 1 Then MsgBox("Zero datarows
exist", , "No Data").

'declare objects outside of the block so you can dispose of them in
finally
Dim tbl As DataTable
Dim ds As DataSet
Dim iRows As Integer
Try
'set objects inside of try to trap exceptions
ds = New DataSet("ds")
tbl = New DataTable("t")
tbl.Columns.Add ("ID")
ds.Tables.Add(t bl)
'returns 0(zero) if there are no datarows in the table referenced
iRows = ds.Tables("t"). Rows.Count

MsgBox(iRows, , "Number of datarows: iRows")
'test the value of iRow
If iRows > 0 Then
'No datarows present
Else
'at least one datarow present
End If

Catch ex As Exception
MsgBox(ex.Messa ge.ToString, , "System Exception")
Finally
tbl.Dispose() : ds.Dispose()
End Try

"pmelanso@uwate rloo.ca" wrote:
[color=blue]
> Hello,
> What would be the statement to see if a table in a dataset has no rows
> ( i.e. is empty)??? What I need this for is if an sql statement doesn't
> return anything... I need to know when that happends.
>
> Pam
>
>[/color]