DB Synchronisation Behavior - Can A User Read The Entry While Other User Is Updating That On Exact Same Time
Jul 25, 2011
I have a oracle database. I use the OracleDataAdapter(Oracle.DataAccess.dll) for select, update, insert, delete operations. I don't set any (table) locks on my own(I only start a transaction). I have a oracle table named "test" with the entry "test1".
Now my question: Can Person A read the entry "test1" while Person B is updating/deleting the entry at the exact same time? What happens in the worst case? An old match/empty match or can it cause any kind of exception/error(e.g. "TableLocked-Exception")?
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Jul 1, 2010
I have a program that allows a user to select a program to run at a certain time for a specific amount of time all choosen by the user. Everything works with the exception of if my program has launched the other program, my program become non-responsive. Meaning I am not able to look at that window again. Not that one really needs too, because when time is up my program closes the program it opened, then closes itself. I just want to be able to see my program when the other program is running. how to do this and perhaps drop me some links, that would be wonderful. This is what I have coded, but like I stated there are no code errors.
[Code]...
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Aug 26, 2009
I am designing a fairly small application to manage a waiting area for a clinical department. There will be a receptionist who books appointments and updates exisiting appointments to say that a patient has "Arrived". In seperate rooms will be nurses who call patients who have "Arrived" and update the appointment as "In Session" and finally as "Discharged". The appointments are viewed in a flexgrid with nurses across the top and time down the left, patient names are displayed at the relevant times and the cells are shaded a colour to represent the current appointment status ("Booked", "Arrived", "In Session" and "Discharged").
I am using SQL Server as the back-end and Visual Basic 6 (I know) as my front-end.I have been told that there will be 2 or 3 nurses plus the receptionist logged in to the system but I would like to cater for growth.My question is what is the best mechanism to use in order to reflect the status change made by one user on the screens of the other users currently logged in?
I have been thinking about using a timer to refresh the data at a set interval but I do not want to keep hitting the server excessively (although what is considered excessive? we would be talking about a call for data every 60 secs per user). Plus the server could be serving data for many other applications so this is another consideration.Alternatively I have been thinking about sending some kind of message via Winsock to the other users notifying them of data changes as they happen. I don't have a lot of experience with this and am concerned about clients not receiving messages and users seeing old data. It also seems strange to me that once the days appointments have been retrieved from the database that "in theory" a client could go the whole day without having to query the database again to pick up changes - kind of scary.Some information on the data:We would probably be looking at around 100 appointments per day We capture patient name, date of birth, date and time of appointment and appointment status.What is the standard approach / best practice for this kind of scenario?
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Sep 25, 2009
writing user info such as user, computer name, date, and time to an acces database using a button click event. Then use a query to check if the user has accepted the aggreement. If the user has accepted the aggreement then call a vb.exe that display the aggrement. I have a login script that runs the vb.exe and uses a button click that records the user info to a csv file, but if the user has already agreed to the policies I do not want it run again.
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May 31, 2012
I thought I postet this yesterday but I can't find my thread so if this is a duplicate please point me at the original one. Background: I need to create a user account and Modify it's registry before the user logs on the first time. Creating the account is done by using the Winnt provider (works great). To create the profile I'm trying to use Process.start to launch a process as the newly created user. With the use of loaduserprofile property the users profile gets created and i can do my regwrites without problem.
[Code]...
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Sep 29, 2011
Using VB.Net and Sql Server. I want to check the user Entry Value. The User is entering the code in the textbox, before saving to the table, I want to check whether code is already exist in the table or not.
Tried Code
cmd = New SqlCommand("Select code from table where code = '" & textbox1.Text & "' ", Con)
dr = cmd.ExecuteReader()
While dr.Read()
End While
If value is exist, then message to the user "Already Exist" other wise save to the table.
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Jul 29, 2010
I want to create a registry entry when the user presses Alt F6 F6
Could someone give me an example of house to do this?
I'm playing with this code
[code]...
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Dec 29, 2011
Im trying to build a user control to enter date as dd/mm/yyyy. I want to create a text box control so the user can enter the date without making a mistake.ex:-Lets assume that the user is trying to enter 31/03/2010 so when the user types 3 first the next number allowed should only be 1 or 0 because there cant be any date more than 31.and if the user enters 31/ then he should only be allowed to enter a month which has 31 days. Im trying to implement this codes in keypress method.So it checks the errors at runtime and prevents the user from typing a wrong value.So far i have got to something like this but Im stuck.Please help
Dim IndexOfCursor As Integer
IndexOfCursor = textbox1.SelectionStart
chr = e.KeyChar
[code]....
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Apr 10, 2011
I am trying to learn VB.NET and I've written a user entry screen to store and retrieve information. I keep getting this error. I understand that I have to either change the ref value from the calling code, but my problem is where is the calling code? Here is the error I'm getting (the program is underscoring udtTrans in the FileGet line in this segment).
Private Sub viewRecords()
'open the file and read fields of the first record into the textboxes
Try
FileOpen(1, strFilename, OpenMode.Random, OpenAccess.ReadWrite, OpenShare.Shared, Len(udtTrans))
FileGet(1, udtTrans, intCurrentRecord) 'gets first record
[Code] .....
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Sep 29, 2009
I don't think this can be that hard but I just can't get my head on it. I have a connection to an Access DB, put three text boxes representing three columns in the DB. Using the DataNavigator everything works. But what I want is to be able to enter text in say textbox1 and have textbox2 and 3 update, like when using the navigator.
Add: I want this to function like when you enter a record number in the Navigator and hit Enter, bam, goes to that record and all the text boxes update. I want to enter a number in textbox1...
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Sep 6, 2009
I have an ASP.NET application with a SQL Server back end. I am storing all my dates in UTC format and doing the appropriate conversions to the local time zone of the browser viewing it. One of the pages asks for a start date and end date (no times).
I am taking the start date and setting the time to 00:00:00 hours (midnight) and I'm taking the End time and adding a time of 23:59:59, so that the date range covers the whole day. Now what I'm trying to do is do a SQL query to do a search for records in this date range. The problem is, the data in SQL is in UTC time and the user is typing their dates and times in their local date and times. My quickest solution was to convert the date and time to UTC, then search the records. However, by doing this, I am to believe ASP.NET converts the given time and date to UTC based on the server time zone. How can I convert a date and time to UTC time based on the time zone of the user?
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Jan 22, 2012
I need to have 4 text boxes and three command buttons. One button should be used for exiting the program, one button should be used for clearing all of the text boxes, and the last button should be used for any calculations/conversions. You should also have a radio button group for the user to choose entry temperature type.
One text box should be used for the entry of an initial temperature. The radio button group will then allow the user to select the entry temperature. When the button is clicked for conversion, the other three text boxes will populate with answers to the conversion. and if I enter 37 degrees Fahrenheit, the Fahrenheit text box should read 37 after the conversion.)
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Mar 8, 2009
I'm presently creating an application which uses Access2007 as the database. No problem there. But Since most use Excel for data-entry, i've created two tables in access linked to excel source file. Any change in excel will reflect in Access database and subsequently in my Application . Until now my application only reads the database and displays records in DataGridView. These records, i then export to excel along with other formatting for direct printing as a report as I have no idea how to make report. Now i want to add data-entry capability to my app using password-protection user-access. So i can directly add new record to source file. Also need to know if There's any way of eliminating Access from the picture entirely....
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May 10, 2011
I need to write a program in VB 2008 express that takes an user entry from a textbox and strips out all the spaces, changes it to either all upper case or all lower case then checks to see if it is a palindrome. I must also include a loop structure and a decision structure. I have seen bits and pieces of code but I do not really know how to put them together. Basically I need it from the button click to the end. ?
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Nov 4, 2009
I have followed a tutorial at url.... It is a very good tutorial but it is also a little dated. Most people who visit it praise it to high heaven so I decided it was a good place to start as an absolute beginner to programming. (I have teamed it up with Dan Mabbut Vis basic tutorial at about.com and joined DreamInCode in order to learn what I can accomplish with Visual Basic 2008 Express ). I am up to part 6 of 7 but keep going back to part 4 because there is one aspect I just cant work out.I am creating a form which logs staff in or out of work and allows staff to include a message with their ( at work /away from work ) status details on the form.The form is supposed to update a users status in a new row when they click a button. In my form the rows per user are being over-written with the updated information - it is not being written in a new row. There is a login form which precedes the staff status form - this has a little relevant code re calling the user info from the database but I think my problem is related to the insert statement in the middle of the below code.[code]
My code has changed quite a bit since the above as the form has progressed but the problem started at the stage above and has not changed with the forms progression. Every other aspect of staff update info is working well in my form - just not in a new row.I am going bald - The tutorial was written for VB2005 Express - I am using VB2008 Express though it has not made too much difference to the tutorial.
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Jan 2, 2010
I know how to read user input using textbox but it only can read character and numbers. Is it possible that I want to read user input equation?
Example:
User type A+B
User put range of A and B.
1.25<A< 3.56
2.45<B< 9.87
I failed to read the equation using textbox. Is it there are other ways that can use to read equation input A+B?I am using VS2005 and VB.Net. I really new in this programming using VB.Net.
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Jan 24, 2012
I'm using
Days = Dat2.Subtract(Dat1).Days
where
Dat2 = today
Dat1 = installed date
to trace the days of a program installed in user's computer.However, the user can changes the system time of his computer to a advancing date. How can I get a SNTP time from internet to solve this problem?
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Jun 21, 2011
I have a problem when updating an entity (User) in my application.
The entity is located in session when the user has been logged. So I made it:
Dim u as User = (From x in ctx.Users).First()
Session("user") = u
[code]...
I got the follow error:
An object with a key that matches the key of the supplied object could not be found in the ObjectState Manager.Verify that the key values of the supplied object match the key values of the object to which changes must be applied.
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May 2, 2008
Alright, let's try this again. I have an mdb file as a database in my program, I need this mdb file to be what my published program reads off of. Is there any way to have Visual Basic (2008 Express) not encode my mdb file to Example.mdb.deploy?
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Jun 15, 2012
I am trying to make a form for an app that will update the current users password to something new of his choice but I cant seem to make it update the database and just says the wrong password statement.
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim connection As New SqlClient.SqlConnection
Dim command As New SqlClient.SqlCommand
Dim adaptor As New SqlClient.SqlDataAdapter
Dim dataset As New DataSet
[Code] .....
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Apr 25, 2012
I have a program that runs fine in the debugger. I started on the project in x86 mode this January and I've always been able to run it outside of the debugger, but this is the first time I've seen this error.The error says "ConfigurationErrorException was unhandled: Configuration system failed to initialize."The InnerException of the error said that the error was in the user.config file, and it gave me the directory of the user.config file that it was using. So I clicked synchronize in the project settings thinking that it would overwrite the current user.config file and that would probably fix the error. When it showed the confirmation dialog that it would delete the user.config file, I noticed that it had "vshost" in the directory.
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Apr 26, 2011
way to update my application executable, and a few other application files for a simple application updater that I am using in my application. The code updates the files (including the executable, manifest, and a few other files), but on Windows Vista and Windows 7 machines you must run the application as Administrator in order for it to update the files in the application folder.
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Oct 11, 2011
When the user open the form a textbox is displayed that picks up data from a table. If they click Change button a combo box is displayed that allows them to change what was originally in the textbox. The combobox is updated with whatever was in the textbox as shown below.This all works fine but the user can add something in the combo box that is not in the list which is bad.
cmbAddBook.Visible = True
cmbAddBook.Text = txtAddBook.Text
txtAddBook.Visible = False
[code]....
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Jan 2, 2012
I have a program written in VB 2010 express under windows xp which does some heavy number crunching combined with serial communication. When it "gets too busy" it does not update the screen anymore (done simply with Textbox.text = "any text") and it does not respond to user input in any text box. Not even to a click on any text box. Is there a way I can get the program to do screen update and respond to user input while it is busy?
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Jan 3, 2011
I've got a VB .NET application that has an auto-updater that updates the exe and manifest files of the application when it finds a new version. For some reason when I update those 2 files, it also clears the user settings, even though Im not replacing the exe.config file.
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Nov 15, 2011
Can I stop updating the user display of a control (rich text box) temporarily? I want it to process what I tell but not change how it looks for just a small piece of code.
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Apr 19, 2011
I'm trying to update a data user using vb.net2008 and sql server management studio express for my backend. the error says "must declare the scalar variable "@username"
Here's the code .
Private Sub btnupdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles btnupdate.Click
Dim connstring = New SqlClient.SqlConnection("Data Source=MISD-
[CODE]...
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Aug 23, 2009
Is there anyway to get the exact time. I know 'Now' Commands get the system time but the system time is not exact to real time, is there way of returning a value from a webpage, even using a webbrowser.
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Feb 24, 2010
I want to put my application on a shared network drive. Do I need to do anything to allow more than once user to use it at a time??
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Mar 20, 2009
i want to make the Grid view Button(Time In) invisible until the User press Time Out Button. Once the user press the Time Out Button,Time in Button must be shown
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