DB/Reporting :: Get Value That SQL Command MAX() Returns?
Jan 21, 2010
the sub I right now is this:
Code:
Private Sub DetermineTicketNumber()
Dim objConnection As SqlConnection = New SqlConnection(strConnectionString)
Dim objDataAdapter As New SqlDataAdapter
[code]....
My question is, how do I access the value that MAX() is returning from my SQL query?
The new command text returns data with schema different from the schema of the main query. Check your query's command text if this is not desired. I am getting this warning, whenever I add a query in a Strongly Typed DataSet which returns a single column.
Ex SELECT DISTINCT Building FROM Room ORDER BY Building
When I give this query it will show me a warning. Because warning leads to a constraint error when ever i call the same function in a windows form.
I am building a vb.net application for a client, and there is a problem. I am connecting to a mySQL server, and using the UPDATE command to update certain fields to the specified values, however, once I run this code, the fields on the mySQL server turn EMPTY. Here is my code :
Sub updateresidents() 'MAKES NO SENSE; UPDATES EMPTY FIELDS ON mySQL SIDE??!!!!!!!!!!!!!!!!!! Dim connection As MySqlConnection
I will have to perform updates/inserts/... on several relational tables of an Access database but I know that the Command builder usage is limited only to one table at a time.
i'm using this code to try and write a value to a table in an access database. when i try to write oledb.oledbcommandbuilder, intellisense doesn't recognize this but it doesn't throw an error up for that line either. when i try to execute this code i get the error "syntax error in UPDATE statement"
Code: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUPdate.Click Dim myConnection As OleDb.OleDbConnection Dim ds As New DataSet
I need to filter a measurements table that consists of 63 measurement objects that may or may not be tested more then once. The entries are put in a Batch table on a SQL server in the following fashion:
ID: | Serie | Test object | Min Amps | Max Amps | OK? DateTime| String | Integer | Double | Double | Boolean
So there may be multiple entries in my database with the same series and testobject number but with (slightly) different results.
Currently I just select: SELECT * FROM Measurements WHERE Serie = 'XXXX' and use a datareader object to fill a datatable and then I let loose a routine on it that will either: Get the last result that produced a good measurement, so OK = 1 and max ID. Or the last result that produced a bad measurement if there are no good ones. I then end up with a list of 63 either good or bad measurement objects with the last good result, and if there isn't one then the last bad result.
Now I know that SQL is quite powerfull and I suppose that it must be possible to directly query for these results without a programatical routine re-filtering the results. I suppose it's like Selecting within a select statement..
I'm experimenting with the sql command builder and it seems to do nothing when trying to update existing rows. If I create a new row and then add it then it works fine but I cant seem to update an existing record.
Heres what I have at the moment
Code: Dim strConnection As String = "Server=myServerSQLExpress;AttachDbFilename=C:databasepath estdb.mdf;" & _ "Database=testdb; Trusted_Connection=False;User Id=sa;Password=test;"
[CODE]...
But I'd really like to find out why its not working when using the command builder. I'm working with VB.net 2010 express and SQL server express.
Currently working on a web-service with Oracle10g as back-end. Here is my problem.
1. The table I need to populate has 100 columns. I have no control over the design of the table.
2. I wanted to use the "deriveparameters" method of OracleCommandBuilder, but found out that this is "costly" in terms of performance. What I initially planned to do was to derive the parameters from an open connection, close the connection, then maybe cache the parameters obtained but I don't know if this is possible.
I am unsure how big of a hit the performance will get if I continue using the "deriveparameters" method WITHOUT caching the parameters driven. The environment is as follows
-intranet -around 2000 users -users spread out in different parts of the country
I am not familiar where they will put the web pages of the application, the web service and the database. I don't know if they'll be putting it in different servers or on one server, but that's something we cannot control too, that's why I am looking for the best approach.
I just don't want to hard-code all that parameters and if, for instance, we need to change some properties/parameters, it will be a pain to maintain the code. It would be nice if someone here can point a way to automate the whole thing w/o the performance of the system taking a hit.
I created a report viewer app that takes a command line parameter, the report filename, and opens the report. I also created a ODBC File DSN that I want to redistribute. However, currently, the DSN needs to reside in 'c:program filescommon filesodbcdata sources'. Is there a way for the report to look for the DSN in the application directory? Also, what components besides .NET 3.5 are required to redistribute the report and report viewer app?
i left timeout to none because the user didnt log out yet but when I try to hit logout I use this statement
Code: str = "Update login set timeout = '" & DateAndTime.TimeOfDay & "' and remarks = '" & _ remarks & "' where userid = '" & txt_user_id.Text & _ "' and YEAR(ldate) = " & DateAndTime.Today.Year & _
[code]....
were I set timeout = currenttime but instead of saving the time to the database it saves only "0" and I dont know why it update statement returned zero and supposed to be the currenttime. I user Oledb and MS Access 2007 as database?
First let me say that I am not sure whether or not this should go in this section or the API section, and if it needs to be moved I apologize. My issue is fairly straight forward, but for some reason I cannot get it to work.
I am trying to send a command to a command line and then submit the command. I have been trying without success to get this to work in v2008 Express and v2010 Express, Here is the code I am trying to us:
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" ( _ ByVal lpClassName As String, _ ByVal lpWindowName As String _
I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu If menuData.Children IsNot Nothing Then menuData.Children.AddRange(GetChildren(menuData)) End If Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu menuData.Children.AddRange(GetChildren(menuData)) Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
I am currently using psexec.exe from PsTools to send a command to a remote system to fire a command through a command prompt however I am finding that the shell I am doing does not seem to like the spaces in the path.
Any ideas on how I handle the following error thrown in the SqlDataAdapter.Fill as a result of the BeginTrans in the callee?
System.InvalidOperationException = {"ExecuteReader requires the command to have a transaction when the connection assigned to the command is in a pending local transaction.The Transaction property of the command has not been initialized."}
I want to add a new select command to my dataset. To do that, I have added a new partial class to my project. Because we have to use partial class if we want to extend generated dataset codes. [code]...
I am using a CheckedListBox that is populated with Filenames (full path, i.e. C:TestTest.jpg)When I have the files that I want in the CheckedListBox I wish to click a Start Button which will process the list one at a time using an exe program that runs on the Command Line. There are arguments that need to pass to the command line as well as the file location in order for the program to process.I currently have it working but the issue is the loop finishes quickly and it is left up to the CMD.exe to finish the process. What I would like is for the LOOP to wait until each file completes processing before passing the command for the next file in the CheckedListBox.There some reasons I wish for it to work this way.
1) I would like to have a button that can Pause/Restart the Loop.
2) I would like to have a button that can Stop the Loop so the whole process can end.
3) I would like to have the Loop remove each file one by one from the CheckedListBox after it has been processed.
4) I would like to display a Message once all the files have been processed.
5) And if it were possible I would like to report the status either by text or a progress bar showing where it is at in the process.
6) And the ability to add some error handling if possible.
Since the Loop finishes so quickly as it just passes the command to the command line using the & as a seperator it is the command line that is handling the rest of the process. Because of this there is not control over it in the GUI.The code I am using allows the Command Line text to display in the Form so it won't open up a seperate window to run CMD.exe. This is the desired affect as I would like everything to appear to run from within the Form itself.
User need to select their prefferable data to show in report. What i did is i have a clear command first to delete the temporary table. The temporary table is basically a table to stored user selection parameter data. After the clear command, i have a insert command to insert user selection data into the temporary table. What happened now is when i run the program exe, first run of the report is work fined, but not the second and the following times of execution. It will return null or blank report. The weird thing is when i execute it from development environment, it seem like the report is able to pick up user selection parameter and run the report for the first times and the subsequent execution.
i have seen this in many codes, just not sure where to start and how to call the command. what i'm talking about is having code as such (this is for save file dialog):
In the Windows Shell, there is a command that looks like this: copy /b fileA.zip + fileB.jpg fileC.jpg..Is there any equivalent function in VB.NET? I already know this works: [code] But I would much rather have a built-in function to work with. Here is what I am trying to do: url...Also, this doesn't just work for pictures. It works for any binary file. Is there any way in VB.NET to tell if a file is binary or text?
I am struggling to pass a parameter to a VB.NET application via a Windows scheduled task. It works perfectly in Visual Studio (passing a command line arguement via project properties).If I am calling a VB6 application, then I will supply the following parameters and it works:
Run: c:progra~1TestTest.exe TestParameter Start In: c:progra~1Test However, if I supply the same parameters in VB.NET, the program throws an exception when it tries to create an instance of a class in the Form.Load: System.NullReferenceException cannot create instance of object.
I have also tried the following:Run: c:program filesTestTest.exe TestParameter Start In: "c:program filesTest" This time the status of the scheduled task changes to "cannot start".What is the correct way to specify command line parameters in a scheduled task for a VB.NET program?UPDATE I found the solution on this web page:[URL}.. I am still confused as to why the program would not create an instance of an object when I used the 8 bit paths (i.e. progra~1)
I have beginner skills using VB (am using the Express edition to learn). I would like to know how to set up a conditional statement in a Windows Form (WF) app that would check if a specific command line has been passed by another separate app that launchesthe Windows Form app using command lines, and if not passed, then the Windows Form app would shut down (exit, close).So far, I can use:
For Each s As String In My.Application.CommandLineArgs If s <> "xyz" Then Me.Close()
In the Windows Shell, there is a command that looks like this:copy /b fileA.zip + fileB.jpg fileC.jpgIs there any equivalent function in VB.NET? I already know this works:Shell("cmd copy /b fileA.zip + fileB.jpg fileC.jpg")