Database Primary Key Won't Hide And Some Other Stuff?
Aug 17, 2011
So Im making a program with 2 different data tables where different columns from those tables are used in different tabs in the same form. This all works good and well so far, but I have one issue which just drives me mad, and a couple minor ones.
1. I have an ID column in each data table marked as Primary Key, Unique and Identity. Problem is that even if I choose to hide this column it just randomly decides if it actually is visible or not. Most often its visible. I dont get it, doesnt this function work? Do I use it wrong? Im not using any code for this, just right click on the data grid, press Edit Columns... And change the Visible to False. It works for all other columns all the time as far as I can tell, but for my ID column its just random.
2. Im wondering if its possible to align the text in some of the columns of my data table to the right, note I only want some of them, not all of them.
3. Is it possible to do maths with the values from the columns in a table on the same row? Like for example having column 3 = column1 + column2?
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Feb 22, 2011
I have noticed that whilst in the past using MS Access you could have a primary key field on a form and have it not visible. You could still use it for Dlookups etc using the value in the field no problem even though it is not visible. In Vb if i hide a textbox that is bound to a PK field in a datasource and try to use its value in code i get an error. Making the field visible again prevents the error. My goal is to use a PK bound textbox not visible to the user but still read its contents.
Also, what is the equivalent of a simple DLOOKUP in VS2010? EG. You have the PK and want to know, say 3 other pieces of information from the record based upon the PK you have.
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Nov 18, 2011
Okay what I have saves my stuff to the database. However, when I rebuild my application the previous data is gone. The data is loaded into datagridview using
[Code]...
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May 29, 2010
I'm quite new to databases so this might be a very basic question: How does one replace a table in a local MS Access database with a new dataset?
I'm able to read the contents from the database into the dataset DatabaseDataset, change it so it looks perfect, but when I update the Access database, it only adds the dataset instead of replacing the existing contents. I tried to clear the contents of the database, but that doesn't work either.
[Code]...
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Apr 29, 2009
how to do a delegate for my lstView1 to display the stuff that taken out from the database? I keep display the error on ListView1.Items.Add(myReader("Int_Name" )).Error: System.InvalidOperationException: Cross-thread operation not valid: Control 'ListView1' accessed from a thread other than the thread it was created on.
Private Sub DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim strSql As String
[code]....
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Jul 1, 2009
I seem to have a major problem. when I add a typed dataset to my project and go back to my sql server and click on the databse I use it doesn't open. the tables and stuff just vanish. using the wizard, it creates this connectionstring:
<add name="Schenectady.My.MySettings.SISQL2ConnectionString"
connectionString="Data Source=.SQLEXPRESS;AttachDbFilename="C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLDataSISQL3.mdf";Integrated Security=True;Connect Timeout=30;User Instance=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
It connects fine. but after I try opening it in sql server i get an error. It doesnt let me restore or anything. i tried restarting my pc incase the db was locked but it is still gone. now my app cant connect. Just for clarity, is user instance supposed to be set to true. and what is the purpose of it. also when the wizard asks to make a copy of the file that will be copied accross each time I run my project I select No.
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May 6, 2009
I'm using a background worker to read a XML file and do stuff in a database i get nothing in debugger but when i run it i get this error... how can i find out where and what is wrong? Exception has been thrown by the target of an invocation.
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Aug 23, 2011
On a client i have an anonymous list containing a multi-column primary key previously selected from the DB.Then i need to select all the records from the DB that equals the primary key list i have stored in the memory.[code]
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Mar 2, 2012
How i can import row from TABLE1 to TABLE2 without primary keyfield or adding correct value to primary key
i tried with two different codes, but result is same, it says: "In the column "Key"a constraint on the uniqueness.[code]...
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Apr 19, 2011
I have finally got my code all working, but there is just a quick query really. At the moment I have all the database stuff in each form seperatly. When I place it in a global module, it looks like the dataset is being duplicated I was wondering why this happens when I place it in a global module?
This the code I use and the code I would put in a global module
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
[CODE]...
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May 26, 2006
I want to be able to get some data from my database table, given the value of the primary key. This is what I have so far:
projectName = DbDataSet.Projects.FindByid(projectId).name
where projectName is a String, and DbDataSet is my dataset. The variable projectId is the ID of the row I want to extract the data from, but every time I run my code I get a NullReferenceException.
I know that the row with the primary key value of projectId exists because I can see it when I view through server explorer.
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Dec 15, 2011
I'm creating a form that will be used to update fields in a table. I don't want the user to be able to update primary keys though, so I'm trying to disable the textbox so it can't be edited.
The textboxes are created during runtime, so I'm trying to create an If loop that will see if it is on the primary key column, but i'm unsure of how to do this. I tried doing this:
If dt.Columns(i).Unique = True Then
t(i).Enabled = False
End If
But this didn't work. I found an option called PrimaryKey which would go dt.PrimaryKey... something (I'm guessing) but just unsure of how to use it.
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Jan 21, 2009
I'm using vb2005express for forms (front-end) and ms access database. I have a form with a master-detail setup. The problem I'm having is that when I set the primary key column to autonumber, I don't get the pk value generated in ms access database into my master datatable in forms when a new record is created. Then I tried setting the AutoIncreament to True in the pk column of the datatable in my dataset (forms). This generates a number in my pk column but its not the number generated in the database (since I think because the pk column is still set to AutoNumber). So I change the field property of my pk to Number in the access database and on my dataset (forms), i still have AutoIncrement to True.
This works okay since what it seems to be doing is getting the max value for the pk column when the datatable is filled upon form load. The problem now is that I normally don't do tableadapter.fill(datatable) at form load since I think there would be a performance issue if record counts around millions. What happens now is that when I create a new record, the pk generated is still 1 which will cause duplicate violation when saving to database. I'm not quite familiar with access features but in oracle, what I do is I create a sequence in database then I create a function that gets the next value of the sequence. Then at form load I set the datatable.column.default_value = get_sequence. How do I do this in ms access?
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Jul 21, 2009
i am wondering if it is possible to get the source code for the following:
1. use vb.net code to set on/off primary key when connected to Access database
2. update a particular data.
for e.g: hostname: AES-19 *use source code to check data in Microsoft Access database
if hostname is new, insert into Access. if hostname already exist, update into Access
*so that i will not have duplicate data in Access.
[Code]...
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Feb 3, 2012
How do I fetch the loginID and display the student data on the textbox?E.g. I login with loginID of 18 but it only display the data of 12
Private Sub frmLibrary_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'LibraryDataSet.Student' table. You can move, or remove it, as needed.
Me.StudentTableAdapter.Fill(Me.LibraryDataSet.Student)
End Sub
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May 21, 2011
I have managed to successfully create a logon page and have created a form to insert data into one of my tables using text boxes and a "Save" button, however the first field in the table is the named "CustomerID" and is set to Autonumber, this is the primary key of the table. If I enter a record into the table in Access it automatically enters the next valid ID however when I can't seem to make this happen when entering data via my VB form!
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Aug 9, 2011
I am trying to append multiple rows in a SQL Server.I have connected to the MS SQL Server and with a DataAdapter, I have downloaded the Table into a DataTable and displayed it in DataGridView.I now want to programatically enter multiple rows into the DataTable and later to update the SQL Table.
I am trying to build an application to do this generically.The problem I have is that the Table and DataTable has an 'ID' Field. In the SQL DB, i is an Auto-incrementing field.When the code loops through creating new rows and entering field values, how do I handle the ID Field that is the Primary Key?
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Aug 3, 2010
When I add a new row to an access database, I would like the primary key to be automatically incremented and entered. I've got this to work using a sql database, but it doesn't work with access for some reason. The following code works if I give the code a value for "@key" which is my primary key column. If I leave it out I get the error "Number of query values and destination fields are not the same". I don't want to have to supply the primary key, I want it to generate automatically.
[Code]...
In the database the primary key is type "AutoNumber". Does anyone know what I'm doing wrong?
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Aug 1, 2011
Im trying to develop a frontend for a database project I have been working on, I am using a combobox to select a meal_name and need the primary key to update another table for orders, How can I retreive the primary key using the meal name selected.below is the code I am using to add meal names to the combobox
Private Sub ComboBox1_MouseEnter(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.MouseEnter
Dim myRow As DataRow
Dim CmdStr As String[code].........
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Apr 9, 2010
when i will enter form no. in the text box this should check the on the lost focus event either this form no. is already exsist or not.if exist show msgbox?
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Mar 16, 2012
How do I increment a primary key that is in integer digit format to a record when adding or pressing an "Add New" button that I have on my form. In other words, I have a 'Add New' Button that has the code following:
[code]...
As you can see from the above code, that most of the textboxes are cleared so that a enduser can insert his or her values and information. Currently, I do have the OrderNumber which is the primary key cleared, however, I would rather have this field auto incremented to the next digit. For some reason, at the moment, I just do not know where to begin to set this field so that a digit canbe inserted and incremented rather than cleared.
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Nov 10, 2011
i need a functionality that adodb.recordset have on ado.net right now im developing my project in school but seem to difficult for me to handle give me an idea what should im going to use here can i hindrance that made me stock.i what to retrieve the last row on the database to be able to automate my primary key code that been a varchar(10).i know some basic stuff on connecting thru ado.net,inserting,updating,deleting could you have some advice or post some example that might use of it..
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Nov 13, 2009
I'm using Visual Studio 2008 and MS Access 2007.
I have linked the database to vs2008.
The first problem I have now is how to add all the data to the combobox from access 2007? [I have solved this myself accidentally.]
The second problem I have is I cannot save the primary key.
Assume that I have these:
Table name: tCustomer
Fields:
ID Datatype [Text]
[Code]....
Now, the user fills in the form. The ID cannot be edited by them where it's automatically counts the number of customer in database and give the id. For example, I already have 3 customers in the database so when I add new Customer, it will be 4 for the ID.
When I click save, it shows me the message of "Index or primary key cannot contain a Null value." I have set an input mask for my Customer. So, can I make it to save in a format like CT001, CT002, CT003 automatically?
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Aug 5, 2011
Lets say we have an Access file in a well known path (i.e. "C:MyFolderMyFile.mdb"). That file does not have a primary key set on the table we are interested in . Is it possible to set one of the fields as a primary key (for example the "ID" field , which is also an AutoNumber data) ? And one more thing : I'd like to change the name of a field on that table . For example , lets say there is a field called "My Field 1" (note the space characters) and we want it to be renamed as "My_Field_1" . If it's possible , I'd like both these changes to be permanent in the data base file itself , not just in the imported DataSet ,
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Aug 5, 2009
I have the error Server: Msg 5171, Level 16, State 1, Line 1Database.mdf is not a primary database file.
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Feb 15, 2012
Is there a way to hide the password of your database inside the source code? [code] As you can see the password is exposed, increasing the risk for the database to be compromise. Is there anything you can suggest how can I work around this one?
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May 5, 2012
I'm curious if it is possible to hide a group of text boxes from view in a form until a particular condition is met, and to have a custom set of text boxes for that condition. To give an example; I want radio buttons offering choices for a manner of searching records, the user selects one and then a specific set of text boxes are displayed for the user to utilize, if a different option is chosen a different set of text boxes will be shown. Is this something that can be done?
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Mar 5, 2012
how to hide exe into task-manager in windows 7 using vb.net windows application?I want exe is hide into task-manager in windows 7 & windows vista machine using vb.net(windows application)
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Apr 20, 2009
Is there a way to to hide the taskbar o.o and unhide it?
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Dec 4, 2011
Is there anything like STL in Visual Basic , e.g a binary tree , quick sort Do I have to implement those algorithms myself , does Microsoft provide any useful interface ?
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