VB.Net forms application database table update - sql-server

Question

I am attempting to make a small application allowing users to read the content of a table describing the inventory of a warehouse, search depending on 2 rows indicating which warehouse the item resides in and by it's assigned barcode which i already managed to get to work by using a binding source, and a datagrid view, updating the view trough a query taking the barcode and location as strings from two boxes.
The second part i would need for this application to suit my basic objective would be to have a way to add new lines and store them into the original table on the database so users could add the new items independently from the warehouses directly.
So far i have encountered 2 issues: i need a primary key that would represent a sequential ID but i do not know how to produce a sequentially incrementing ID, i manage to get the first addition ID by using a top 1 order by desc query combination but the data does not get updated after adding the new line, producing an error since it tries to add another line with the same value for the primary key.
The second issue i am encountering is: the gridview gets altered accordingly to the data i input in the textboxes i set up to gather the various values for the table but the table on the database itself is not showing any change, keeping only the test data i inputted at it's creation.
Public Class AddItems
Private Sub AddItems_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'MagazzinoDataSet.LastUsedID' table. You can move, or remove it, as needed.
Me.LastUsedIDTableAdapter.LastUsedID(Me.MagazzinoDataSet.LastUsedID)
'TODO: This line of code loads data into the 'MagazzinoDataSet.Stock' table. You can move, or remove it, as needed.
Me.StockTableAdapter.Fill(Me.MagazzinoDataSet.Stock)
'TODO: This line of code loads data into the 'MagazzinoDataSet.AddWarehouseList' table. You can move, or remove it, as needed.
Me.AddWarehouseListTableAdapter.AddWarehouseList(Me.MagazzinoDataSet.AddWarehouseList)
'TODO: This line of code loads data into the 'MagazzinoDataSet.WarehouseList' table. You can move, or remove it, as needed.
Me.WarehouseListTableAdapter.Fill(Me.MagazzinoDataSet.WarehouseList)
'TODO: This line of code loads data into the 'MagazzinoDataSet.Stock' table. You can move, or remove it, as needed.
Me.StockTableAdapter.Fill(Me.MagazzinoDataSet.Stock)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim R As DataRow = MagazzinoDataSet.Tables("Stock").NewRow()
R("Supplier") = Supplier.Text
R("Producer_code") = ProducerCode.Text
R("Barcode") = Barcode.Text
R("Comp_name") = ComponentName.Text
R("Warehouse") = Warehouse.Text
R("Internal_Code") = InternalCode.Text
R("Description_IT") = ITDescr.Text
R("Description_EN") = ENDescr.Text
'R("ID") = NextID.SelectedValue <- this would be an hidden uneditable multibox containing the product of the query finding the next value to be inserted in the table (basically last ID + 1, nothing fancy)"ID" would be the primary key of this table
R("Quantity") = "0"
MagazzinoDataSet.Tables("Stock").Rows.Add(R)
DataGridView1.DataSource = MagazzinoDataSet.Stock
End Sub
End Class
To sum it up:
How would i go about updating the database table to include the new line?
Is there a smart way to find the last value, incrementing it by 1 to have the next value and updating it when inserting a new line, so as to not end up with 2 lines with the same value for primary key, generating an error?

Answer 1

To set an incremental ID in the Db, assuming you have access to SQL Server Management Studio, in Design of the table, for the ID column, in Column Properties, scroll down to Identity Specification and set (is Identity) to Yes.
To add a new row, I use this code:
Using NotesDS As New DataSet
Using NotesDA As New SqlDataAdapter With {.SelectCommand = New SqlCommand With {.Connection = SQLDBConnection, .CommandText = "SELECT * FROM Notes WHERE ID = " & ID}}
NotesDA.Fill(NotesDS, "Notes")
Using NotesDV As New DataView(NotesDS.Tables("Notes"))
Using NoteBuilder As New SqlCommandBuilder(NotesDA) With {.QuotePrefix = "[", .QuoteSuffix = "]"}
If NotesDV.Count = 0 Then
Dim NoteDRV As DataRowView = NotesDV.AddNew
NoteDRV.Item("UserName") = UserName
NoteDRV.Item("Note") = Note
NoteDRV.Item("NoteDate") = NoteDate
NoteDRV.Item("CompanyCode") = CompanyCode
NoteDRV.EndEdit()
NotesDA.UpdateCommand = NoteBuilder.GetUpdateCommand
NotesDA.Update(NotesDS, "Notes")
End If
End Using
End Using
End Using
End Using
Obviously, amend to make appropriate for your table and column names.
If you need to retrieve the ID for display, you can add a handler to the Update like:
Public Sub GenericOnRowUpdated(sender As Object, e As System.Data.SqlClient.SqlRowUpdatedEventArgs)
Dim newID As Integer = 0
Dim idCMD As SqlClient.SqlCommand = New SqlClient.SqlCommand("SELECT ##IDENTITY", SQLDBConnection)
If e.StatementType = StatementType.Insert Then
newID = CInt(idCMD.ExecuteScalar())
e.Row("ID") = newID
End If
End Sub
and use like:
AddHandler NotesDA.RowUpdated, New SqlRowUpdatedEventHandler(AddressOf GenericOnRowUpdated)
NotesDA.Update(NotesDS, "Notes")
NewID = NoteDRV.Item("ID")
EDIT
First Example amended and explained below:
'Declare you connection to the SQL dB. Connection String looks like "Data Source=192.168.71.10\dBName; Initial Catalog=dBName; User ID=USER; Password='PASSWORD!';MultipleActiveResultSets=true" - You may well already have an open connection, and can use that instead. Not sure what your
StockBindingSource is...
Dim oConn As New SqlConnection("CONNECTION STRING")
'Open the connection
oConn.Open()
'Declare Your DataAdapter and initialise using your connection
Dim DA As New SqlDataAdapter With {.SelectCommand = New SqlCommand With {.Connection = oConn, .CommandText = "SELECT * FROM Stock WHERE ID=0"}}
'Declare you DataSet
Dim DS As New DataSet
'Fill Your DataSet with the Stock table from your DataAdapter
DA.Fill(DS, "Stock")
'Declare a DataView for easy use (really the same as using DS.Tables("Stock").DefaultView)
Dim DV As New DataView(DS.Tables("Stock"))
'Declare a CommandBuilder and initialise with your DataAdapter. This will now watch for changes made to your data and build the appropriate SQL UPDATE/INSERT/DELETE command. the "[" and "]" are in case any column names use reserved words
Dim Builder As New SqlCommandBuilder(DA) With {.QuotePrefix = "[", .QuoteSuffix = "]"}
'Decalre a DataRowView for data population, based on your DataView table structure
Dim R As DataRowView = DV.AddNew()
'Populate the fileds with your Form data
R("Supplier") = Supplier.Text
R("Producer_code") = ProducerCode.Text
R("Barcode") = Barcode.Text
R("Comp_name") = ComponentName.Text
R("Warehouse") = Warehouse.Text
R("Internal_Code") = InternalCode.Text
R("Description_IT") = ITDescr.Text
R("Description_EN") = ENDescr.Text
R("Quantity") = "0"
'Notify that the edit has finished
R.EndEdit()
'Get the SQL command from the CommandBuilder
DA.UpdateCommand = Builder.GetUpdateCommand()
'Execute the update (in this case it will be an INSERT)
DA.Update(DS, "Stock")