|
Please help...I think I'm losing my mind.
I'm using an OleDB connection in C# to connect to a database. The table I'm trying to access tracks user session information, including the date & time of logging in and primary key of the session. I start to run into problems when the user has logged in over 68 times.
Here is the section of code:
int LastLoginRow = userDS.Tables["UserSessionInfo"].Rows.Count - 2;
sring LastLoginDateTime = userDS.Tables["UserSessionInfo"].Rows[LastLoginRow]["SessionDate"].ToString();
I checked, and it does accurately tell me what the LastLoginRow is (i.e. 90). However when it goes to grab the SessionDate information, it ALWAYS grabs row 68.
Before it gets to row 68, it works fine. Does anyone know what is going on? 
~~~~~~~~~~~~
 Over-worked, under-paid, glorified "secretary" 
|
|
|
|
|
The code looks OK. Might help to see the query.
Other than that, maybe all the rows after 68 have the same value in SessionDate?
Perform the query with some other tool and see what you get.
|
|
|
|
|
Here's some more information I've come across. There are two tables in my database, UserInfo & SessionInfo and they are connected through the field UserID, with a one-to-many relationship. When I look at the SessionInfo table alone, the sessions look as they're supposed to, the SessionPkey is ordered correctly.
However, when I expand the UserInfo row to show the related SessionInfo, at some point (around row 68 in SessionInfo) each subsequent sessioninfo is pushed on the top of the table, instead of being inserted into the bottom of the table.
So, when looking at just the SessionInfo table, the sessionPkey looks like this:
227 - 228 - 229 - 230 - ... 321 - 322 - 323 - 324
But when looking at the sessionPkey table as a subtable of the userInfo, it looks like this:
296 - 297 - 298 - 299 ... 321 - 322 - 323 - 324 - 227 - 228 - 229 - 230 ... 293 - 294 - 295
Does anyone know why this happens? I haven't changed the code used to insert into the table. Thanks.
~~~~~~~~~~~~
Over-worked, under-paid, glorified "secretary"
|
|
|
|
|
Hi ..
I want to use DataGridView as a data entry table << and I like to make alot of things like data verificatoin and don't move between rows before complete the existing fow...
I know that it isn't easy to do .. but if any one have any book or site which demonstrate the DataGridView as good .. I will be so happy ..
jooooo
|
|
|
|
|
Hi ..
I'm using SQL Server 2000 with VB6, vb.net ,,, and some times ( rarely ) on add new record , I found that the row is added to the table more than one time ..
and when I go to Edit or Delete this row , the next message is appear:
Key Column is Insufficient or Incorrect
Too many Rows were affected by update.
Notice:
There're no any constraitns or releations between that table and any other table
Really this problem is exhausting me
jooooo
|
|
|
|
|
kindman_nb wrote: Key Column is Insufficient or Incorrect
Too many Rows were affected by update.
The key (primary key) on a row must be unique. If there are no constraints you are not enforcing this most basic requirement of a key. The application is therefore getting confused when the update affects multiple rows.
To fix the problem you need to:
* Remove any existing duplicates from the table
* Put a proper constraint on the primary key (defining the primary key would be enough)
* Find and fix the part of the application that is producing the multiple inserts.
|
|
|
|
|
Hi
Thanks my friend ...
now it's good
jooooo
|
|
|
|
|
In the web site that I am building ( in C# language ), a hypothetic customer who would buy something would then be redirected to a Secure payments company where he would make the payment and then the company would send back to my web site, information about this transaction.
My program would then save this info in a Microsoft SQL database. The problem is that this company uses to send the same info several times repeatedly and I do not want to store the same info more than once.
So I want a SQL procedure where it takes the invoice number of the customer ( contained in the string of info that this company sends back ) and looks inside a table to see if it was already stored there. If it is there ( or not ), it would return a value, which could be false/true or 0/1 so my program could use this value to save a new info ( or not ) and then activate ( or not ) some related tasks.
I am still learning SQL and I tried the below procedure but it is not working. Which alternative procedure could solve the problem ?
~~~~~~~~~~~~~~~~~~~~~~~~~
CREATE PROCEDURE VerifyIfInvoiceExists
(@Invoice VARCHAR(50))
AS
SELECT COUNT(*) FROM IPN_received
WHERE Invoice = @Invoice
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
|
In your stored procedure you can do something like this:
IF NOT EXISTS (SELECT * FROM IPN_received WHERE Invoice = @Invoice)
BEGIN
-- The row does not exist already. Insert the new row here!
END
|
|
|
|
|
Hi Colin
What I really need is the procedure simply returning TRUE if a given invoice is there or FALSE if it is not.
What lines of code should I add after “IF NOT EXISTS (SELECT * FROM IPN_received WHERE Invoice = @Invoice)” ?
( Sorry if my question is too elementar. I am still learning SQL. )
|
|
|
|
|
tedhill13 wrote: What I really need is the procedure simply returning TRUE if a given invoice is there or FALSE if it is not.
You can use something like:
SELECT 1
or
SELECT 0
Then you can pick up the value from your application with ExecuteScalar()
int existsAlready = (int)theSqlCommand.ExecuteScalar()
tedhill13 wrote: Sorry if my question is too elementar. I am still learning SQL.
Then you may wish to lean more about constraints so that SQL Server can handle this scenario itself - that is what it is good at.
|
|
|
|
|
I would likely have a ProcessState column. Initialized to something like a "Pending" code.
When I receive a response (approve or decline), if the transaction is still "Pending" I'd set the ProcessState as appropriate. Then other methods would take the transactions from there.
Technical note: Use integers for the code, not strings; have a separate table to map the values to strings. Then, if you like, add referential integrity.
Extra credit: If you don't know about finite state machines, you might want to do some reading.
|
|
|
|
|
Can someone post a link for some sample app. in vb2005 and with sql db (mdf)
Thanks!
|
|
|
|
|
There are plenty of samples at Microsoft's web site including their "coding4fun" samples. Make a search there.
modified 1-Aug-19 21:02pm.
|
|
|
|
|
Hi All,
I'm calling a SQL2000 SP from my VB.NET app with the following code:
<br />
Dim sqlCmd As SqlCommand<br />
sqlCmd = New SqlCommand("JHU_SAS_IDOC_Process", conn)<br />
sqlCmd.CommandType = CommandType.StoredProcedure<br />
<br />
Dim adapter As SqlDataAdapter = New SqlDataAdapter(sqlCmd)<br />
<br />
adapter.Fill(tableReturned)<br />
This SP performs a SELECT that causes the tableReturned (a DataTable) to be filled. The SP also returns an INT (0 or 1, depending on whether an error occurred). The SP code is basically this (much simplified for this question):
<br />
CREATE PROCEDURE dbo.JHU_SAS_IDOC_Process<br />
<br />
AS<br />
<br />
BEGIN<br />
<br />
SELECT * FROM JHU_SAS_IDOC<br />
<br />
RETURN 1 -- or 0, depending on an error condition<br />
<br />
END<br />
My question is: How do I read that return value in the app? I think I could read it using the SqlCommand.ExecuteScalar() func, but that wouldn't work to fill my table. Any ideas?
Thanks!
Justin
|
|
|
|
|
Justin Cooke wrote: How do I read that return value in the app? I think I could read it using the SqlCommand.ExecuteScalar() func, but that wouldn't work to fill my table.
And it wouldn't work to get the value because ExecuteScalar just retrieves the value in the first column of the first row in the result set and discards anything else.
You need to add a SqlParameter[^] to your SqlCommand object to get the ReturnValue.
For example:
Dim sqlCmd As SqlCommand
sqlCmd = New SqlCommand("JHU_SAS_IDOC_Process", conn)
sqlCmd.CommandType = CommandType.StoredProcedure
Dim parameter As New SqlParameter("ReturnValue", SqlDbType.Int, 4)
parameter.Direction = ParameterDirection.ReturnValue
sqlCmd.Parameters.Add(parameter)After you've got the data you can then check the value of the parameter with parameter.Value
DISCLAIMER: I typed that off the top of my head, and I'm also not a VB.NET developer, so there may be errors
|
|
|
|
|
hi fellows
i'm trying to create triggers in Sql Server 2000 and my query doesn't work.
can anyone plz tell me the query syntax to create trigger for the following operations:
1. Insert
2. Update
3. Delete
awaitng ur replies
Saira
|
|
|
|
|
Saira Tanwir wrote: can anyone plz tell me the query syntax to create trigger
The syntax is here[^]
|
|
|
|
|
Saira Tanwir wrote: 1. Insert
CREATE TRIGGER blah_trigger ON blah1 FOR INSERT AS INSERT INTO blah2 ...
|
|
|
|
|
I have a database that a user can search for using the begins with, exact match, or contains option. I did a request.querystring to pull in that information from the previous page where the user selects one of those options and types is what he is searching for. The problem is that I cannot figure out how to display the users result when they select to search by exact match, begins with, or contains. The following is the code that I used. Can anyone tell me what is wrong with it and give me some leads on how to get it fixed.
<title>Table Display
<%Dim FieldHead, SearchMethod, TextBox, Table, DB, RS, strSql%>
<%'Request the information from the previous page'%>
<%FieldHead = Request.QueryString("fieldhead")
SearchMethod = Request.QueryString("SrchMthd")
TextBox = Request.QueryString("textbox")
Table = Request.QueryString("Table")
%>
<%'search method if the user selects begins with%>
<%If SearchMethod = "begin" Then%>
<%Set DB = Server.CreateObject("ADODB.Connection")
DB.Open ("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE= C:\Inetpub\wwwroot\ASP\ThomasTate\North.mdb")
Set RS = Server.CreateObject("ADODB.Recordset")
strSql = "SELECT * FROM " & Table " WHERE " & FieldHead & " LIKE '" & TextBox & "%'"
RS.Open (strSql), DB
End IF
%>
<%'search method if the user selects contains%>
<%If SearchMethod = "contain" Then%>
<%Set DB = Server.CreateObject("ADODB.Connection")
DB.Open ("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE= C:\Inetpub\wwwroot\ASP\ThomasTate\North.mdb")
Set RS = Server.CreateObject("ADODB.Recordset")
strSql = "SELECT * FROM " & Table " WHERE " & FieldHead & " LIKE '%" & TextBox & "%'"
RS.Open (strSql), DB
End IF%>
<%'search method if the user selects exact match%>
<%If SearchMethod = "exact" Then%>
<%Set DB = Server.CreateObject("ADODB.Connection")
DB.Open ("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE= C:\Inetpub\wwwroot\ASP\ThomasTate\North.mdb")
Set RS = Server.CreateObject("ADODB.Recordset")
strSql = "SELECT * FROM " & Table " WHERE " & FieldHead & = TextBox
RS.Open (strSql), DB
End IF%>
Ty
|
|
|
|
|
Your code should use:
... " WHERE " & FieldHead & " LIKE '" & Replace(TextBox, "'", "''") & "%' Instead of:
... " WHERE " & FieldHead & " LIKE '" & TextBox & "%'" Otherwise it will break if the user enters a single-quote into his search value.
The normal way to show the results is to iterate through each row and column in the result set. However, you might find the following faster:
'Open the recordset and render the data in HTML format.
For Each objField In objRS.Fields
Call Response.Write("<td nowrap><b>" & _
Server.HtmlEncode(objField.Name) & "</b></td>" & vbCRLF)
Next
Call Response.Write("</tr>" & vbCRLF)
Call Response.Write("<tr>")
If Not objRs.eof Then
strData = objRS.GetString( , , "#<#/td#>##<#td#>#", _
"#<#/td#>##<#/tr#>##<#tr#>##<#td nowrap#>#", "#&#nbsp;")
strData = Replace(Replace(Replace(strData, "#&#", Chr(1)), "&", "&"), Chr(1), "&")
strData = Replace(Replace(Replace(strData, "#<#", Chr(1)), "<", "<"), Chr(1), "<")
strData = Replace(Replace(Replace(strData, "#>#", Chr(1)), ">", ">"), Chr(1), ">")
strData = "<td>" & Replace(Left(strData, Len(strData) - 15), "</tr>", "</tr>" & vbCRLF)
Call Response.Write(strData)
Else
Call Response.Write("<td colspan=""" & objRs.Fields.Count & """>No records found.</td></tr>" & vbCRLF)
End If
Call Response.Write("</table>" & vbCRLF)The funny replace stuff is a quick way to get it to render each field as a separate HTML table cell.
Andy
|
|
|
|
|
hi there,
I've got a table like this:
CREATE TABLE [dbo].[one_Messages] (
[ID] [int] IDENTITY (1, 1) NOT NULL ,
[RecipientID] [int] NOT NULL ,
[SenderID] [int] NOT NULL ,
[DateTimeSent] [datetime] NOT NULL ,
[IsRead] [bit] NOT NULL ,
[Body] [varchar] (1024) COLLATE Latin1_General_CI_AS NOT NULL
) ON [PRIMARY]
Now please consider that I want to allow only 20 Messages per conversation (SenderID/RecipientID combination). In my stored procedure, I'd like to INSERT a new conversation-record first and then DELETE the oldest messages which exceed the number of 20. It's quite hard for me to explain this in english, do you get the point? After every INSERT, I'd like make sure to keep a maximum number of 20 messages and DELETE the rest. How can this be done with a DELETE statement?
Any help is greatly appreceated. Thanks in advance.
/matthias
I love deadlines. I like the whooshing sound they make as they fly by.
[Douglas Adams]
|
|
|
|
|
Do the insert then do the delete based on the DateTimeSend, or you could do it on the ID (because it will be ever increasing)
e.g.
DELETE one_Messages
WHERE RecipientID = @RecipientID
AND SenderID = @SenderID
AND ID NOT IN (SELECT TOP 20 ID FROM one_Messages
WHERE RecipientID = @RecipientID
AND SenderID = SenderID
ORDER BY ID DESC)
The inner select gets the most recent 20 items.
Does this help?
|
|
|
|
|
Perfect. Thanks a bunch!
/matthias
I love deadlines. I like the whooshing sound they make as they fly by.
[Douglas Adams]
|
|
|
|
|
Place the delete code in a trigger.
Grady Booch: I told Google to their face...what you need is some serious adult supervision. (2007 Turing lecture)
http:\\www.frankkerrigan.com
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
