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.
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
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!
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]
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?
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.
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?
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.
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?
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?
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].........
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?
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.
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..
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?
I am new at asp.net, so I would be glad, if anybody could help me in this case... I scanned already the internet for answers, unfortunately with no success..I have a grid view, and this is loaded by a sql data table, this table has 2 keys (RezeptNr and Zutatnr). When I wanna update a row in the data grid, the RowUpdating event fires, so I need to read the Basket Session, what has the complete object stored. I put this in a DataTable (dt1), so far so good..The problem is line: Dim dr As System.Data.DataRow = dt1.Rows.Find(id) Here the compiler alerts, that I have two keys, and he cannot select the data sentence with the find method. I tried it with datatable.select command, that works, but then I have the data sentence in an array, but I need to update the data row of the data table.
I have created a form that enables me to enter data for adding a new customer. so far i am able to save the data as a line and separte each field with a "#", with out any problem but the thing is i am not sure how to assin a primary key to the data, every time i add a new customer to my txt file i want the primary key to be one number higher than the previous.
so that i can l8r enter the primary key to search for the costumer and view that data
I would like someone to modify the following code to save data to generate the primary key for each record automatically. In the database,the ID column is the primary key and the Is Identity is set Yes.
The primary key of the table is generated automatically using the Is Identity and I want to update based on the primary key. There is certainly something wrong with the following code, so I'd like someone to modify it for me.
Try Dim qry As String qry = "Update StudentDetails.Programmes set Programme=@Programme,Form=@Form,AcademicYear=@AcademicYear,Class=@Class where ID=ID" cmd = New SqlCommand(qry, cn)
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 ,
i have a project where I need to concatenate strings from 4 different tables based on a sequence of numbers. I created a 5th table that holds the number sequence and dictates in what order the strings get appended. I have created primary keys on the tables, but 3 of the tables are composite primary keys. I have written up to where I start referencing the primary keys, but am not sure how I should reference the keys on the actual tables. I saw some examples for creating composite keys from an array which I did. The main questions are did I declare the composite keys correctly, am I creating the composite key reference from the array correctly, and how should I reference it all to append to the stringbuilder variable.
[Code]...
And yes I kn ow it would be easier if I used Strongly Typed Dataset, but this is a clr sql stored procedure and have not found any examples on how to add a .XSD to a stored procedure. The add item option is not available, besides a bunch of typing
I defined a database using SQL Server 2008 R2 Express, and connected to it using Visual Basic 2010 Express. For some reason though, when I use the database in the program, it wants to start off using a negative primary key.Is there any way to make the primary key only a positive number?
I have made several posts on here lately regarding master/detail or parent/child data setups but no one has been able to help. It seems like a subject people don't like to tackle BUT I really need help.
I'm having a real hard with the DataView.RowFilter functionality and it is driving me insane.
For the most part, I have the basic master/detail functionality working. When you select a record in the first grid, it shows the correct data in the second grid. When you enter a record in the first grid, you can enter related data in the second grid. I accomplish this by using a dataview and row filter bound to the 2nd grid. When you change the record in the first grid, the rowfilter for the 2nd grid is restated and reapplied.
The problem arises when I overwrite the primary field value in the first grid and the detail records become orphaned. You would think all I have to do is change the ID in the 2nd grid to match the new ID in the 1st grid but this is where I am having problems. I wrote a loop to change the ID of each record currently loaded in the 2nd grid to match the newly changed ID in the first grid. The code is here:
Code: Dim I As Integer
For I = AuthorizationGroupsDGV.Rows.Count - 2 To 0 Step -1 AuthorizationGroupsDGV.Rows(I).Cells(0).Value = StrEmployeeID Next
I have used this code before and it works great. It has to step backwards through the grid because when the ID's are changed, they no longer match the RowFilter criteria and they disappear from the grid. They still exist in the dataset. The problem is, while the code "works" the intended effect does not. Some of the records completely disappear from the dataset and do not reload when I restate the row filter against the new ID number.
I want to see if anyone has used one table that has a primary key (not displayed) in the DataGridView. Then use a text box on the same form to call and group what if viewed in the DataGridView table. I want to group the displayed data of the DataGridView by the primary key of both tables.
I got a system which i want to insert, delete, update the data into my database and the data from database will be display using datagrid. The below is the coding for one of my button, delete.
Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click Try btnSearchEmpNo.Enabled = False[code].....
Now I wanna set when user click on this button to delete a employee (for example) then the datagrid that i have in my application will not show the data of the deleted employee but in the background, the employee haven't been deleted from database.The employee only will be deleted from database when the user click on SAVE button.I know this application have to use RowState but how?
What I want to happen is that the button from my system will remove the previous data from database and then insert new data to database from text file. Im done with inserting new data. The thing is that I dont how to control or where to put the Delete Command from my code.
