Database

Re: How to avoid double Rows

2-Jul-05 10:39

I have two tables, one having only 4 records the other many.
The first called Speelzalen is indexed on Speelzaalnummer.
The second one called Groepen has at least one column called Speelzaalnummer but is not indexed on that Column. I retrieve data from boyh by:

sqlCommand = New SqlCommand("Select * from Speelzalen INNER JOIN Groepen ON Speelzalen.Speelzaalnummer = Groepen.Speelzaalnummer", sqlConnection)

After this i bind the result to two datalist and use them like this:

<td width="125"><asp:listbox id="DataList3" runat="server" Rows="1" DataTextField="SpeelzaalNaam" DataValueField="SpeelzaalNaam" /></td>

and

<td><asp:listbox id="DataList2" runat="server" Rows="1" DataTextField="Groep" DataValueField="Groep" /></td>

It all works fine with one exception: for all the records in Groepen there is alse a entry in the SpeelzaalNaam listbox, but there should only be four.

The question is two folded, one; is there a Select construction to be used to undouble the exces records, or second; is there a way to show only those records from the group database that are connected to the row in the Speelzalen table.

toxcct3-Jul-05 20:37

toxcct

3-Jul-05 20:37

if you want to avoid multiple lines with the same datas, replace select with select distinct

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: How to avoid double Rows

gharryh4-Jul-05 2:56

Re: How to avoid double Rows

4-Jul-05 2:56

No success, this is the SQL Line i use:

sqlCommand = New SqlCommand("SELECT DISTINCT Speelzalen.SpeelzaalNaam, Groepen.Groep, Groepen.Dagdelen FROM Speelzalen INNER JOIN Groepen ON Speelzalen.Speelzaalnummer = Groepen.Speelzaalnummer", sqlConnection)

gharryh4-Jul-05 5:01

Puzzles me how to check a columns value

4-Jul-05 5:01

I should mention that in the table Groepen there is more than one Row that contains a same PeuterzaalNummer

gharryh1-Jul-05 10:49

1-Jul-05 10:49

Hi there,

I have selected a single row from a database and put it in a DataList.

One column has a Integer and i cant display that on a form so i want to change it to certain string value first. It looks like:

If DataList.Column("Gender") = 1 Then
Gender = "Boy"
ElseIf DataList.Column("Gender") = 2 Then
Gender = "Girl"
Else
Gender = "Unknown"
End If

But this doenst work. Can anyone tell me why.

Christian Graus1-Jul-05 20:25

1-Jul-05 20:25

Does VB not test equality with == ?

Try putting DataList.Column("Gender") into an object, and looking at it in the debugger. I'd have thought you'd need to wrap it in Convert.ToInt16. I'd also use a switch here, rather than if/else. Only because it's nicer code.

And for future reference, 'it doesn't work' is useless. How doesn't it work ? What's happening ?

Christian Graus - Microsoft MVP - C++

gharryh1-Jul-05 21:31

1-Jul-05 21:31

Christian Graus wrote:
Does VB not test equality with == ?

No, when i put in that extra = i get the error expression expected.

Now the compiler output. I must be doing something wrong, and i am more used programming things in PHP than .NET Smile | :)

). I am a old guy that has to learn some new tricks.

Compiler Error Message: BC30456: 'Column' is not a member of 'System.Web.UI.WebControls.DataList'.

Source Error:

Line 50: DataList1.DataBind()
Line 51:
Line 52: If DataList1.Column("Geslacht") = 1 Then
Line 53: Geslacht = "Jongen"
Line 54: 'ElseIf DataList1.Column("Geslacht") = 2 Then

Christian Graus1-Jul-05 21:58

1-Jul-05 21:58

gharryh wrote:
Compiler Error Message: BC30456: 'Column' is not a member of 'System.Web.UI.WebControls.DataList'.

Gosh - well, where did you get DataList1.Column from ? The error appears to be telling you it's not valid code. DataList1.Items will give you the rows in the datalist.

However, as you were supposed to be going through a data source, I wonder if you've got the wrong variable ? A DataListItem or a Row on a table seem more likely to be the place you'd look for this sort of info. I think they both have an indexer for column names, so MyDataItem("Geslacht") would be what you want.

Christian Graus - Microsoft MVP - C++

gharryh1-Jul-05 23:34

1-Jul-05 23:34

Christian Graus wrote:
Gosh - well, where did you get DataList1.Column from ? The error appears to be telling you it's not valid code. DataList1.Items will give you the rows in the datalist.

Well thinking that DataList1.Rows.Count is a valid statement there should be something similair to check on a Column value.

Christian Graus3-Jul-05 11:23

3-Jul-05 11:23

OK - is your intellisense broken ? The IDE should show you what is available in a list when you hit the '.'. In any case, I think the indexer solution I suggested would work, have you tried it ?

Christian Graus - Microsoft MVP - C++

gharryh3-Jul-05 20:08

3-Jul-05 20:08

Christian thanksfor the answer.
But i thinki wil stop programming. Something that can be done simple in PHP looks like hell in .NET if one is not used to it. And for me as a old 47 year old dog learning a new trick Smile | :)

I hoped to find more direct answers and not something like Indexer and have you tryed it. Dont even know wat the indexer is.

But anyhow thanks for all the help

Christian Graus4-Jul-05 13:10

4-Jul-05 13:10

Sorry, I didn't mean to confuse, I gave you the code, the indexer works like this : MyDataRow("columnName").

Christian Graus - Microsoft MVP - C++

toxcct1-Jul-05 21:32

toxcct

1-Jul-05 21:32

Christian Graus wrote:
Does VB not test equality with == ?

nop, this operator doesn't exist in vb...

the assign operator is the same as the equality one...

you so understand that you cannot assign in an if statement as we could do in C/C++ with : if ((var1 = var2) == 3) ...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

toxcct1-Jul-05 21:35

toxcct

1-Jul-05 21:35

gharryh wrote:
But this doenst work. Can anyone tell me why.

well, have you tried using breakpoints ?

does it enter into the first if ?

is the DataList correctly populated ?

use the debugger to see...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

gharryh1-Jul-05 23:29