Updating database with BindingSource data - vb.net

Question

This is my first post in here, but this forum already helped me a lot.
First, sorry for my English, i'm from Brazil and i'm trying to write without a translator.
I'm developing a software for a supermarket, but i'm having problems with the connection to the database. I'm trying to make all the connections and transactions programmatically (DataSets, BindingSources and so).
I've already managed to connect with SQL Server Express 2008, using a Function ("consulta") inside a Module ("db"):
Dim ad As SqlDataAdapter = New SqlDataAdapter
Function consulta(ByVal tabela As String, Optional opt As Boolean = False, Optional optparam As String = "") As DataSet
Dim ds As New DataSet
Try
Dim connstring As String = "Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=SysMarket;Persist Security Info=True;User ID=admin;Password=XXXXXX"
Dim conObj As New SqlConnection(connstring)
Dim sql As String
If opt = True Then
sql = "SELECT * FROM " & tabela & " " & optparam
Else
sql = "SELECT * FROM " & tabela
End If
Dim cmd As SqlCommand = New SqlCommand(sql, conObj)
ad.SelectCommand = cmd
conObj.Open()
ad.Fill(ds, tabela)
ad.Dispose()
cmd.Dispose()
conObj.Close()
Return ds
Catch ex As Exception
MessageBox.Show("Erro na consulta" & vbCrLf & ex.InnerException.ToString, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error)
ds.Clear()
Return ds
End Try
End Function
And this is a part of the main code where I make a SelectQuery and put into a BindingSource:
Dim ds As DataSet = db.consulta("departamentos")
Private Sub cad_departamento_Load(sender As Object, e As EventArgs) Handles MyBase.Load
BindingSource1.DataSource = ds
BindingSource1.DataMember = "departamentos"
TextBox1.DataBindings.Add("Text", BindingSource1, "id")
TextBox2.DataBindings.Add("Text", BindingSource1, "departamento")
End Sub
But my problem is when I have to Update the database, by adding, editing or deleting some item from BindingSource. Because in the Module I've closed the connection to the SQL Server. So I will need reopen this connection and then, somehow "read" the DataSet with the change and Update the database?
Someone could explain this to me or show me a example?
Thank you.

Answer 1

You will use a data adapter to save the data, just as you used one to retrieve the data. You will have to create an InsertCommand if you want to insert new records, an UpdateCommand if you want to update existing records and a DeleteCommand if you want to delete existing records. You can write those yourself or, if the conditions are right, you can use a command builder to do it for you.
If your query is based on a single table and you want to insert/update all the columns you retrieve back to that same table then a SqlCommandBuilder may be your best bet. You simply pass in the query and the command builder will use it to generate the action commands. That gives you limited flexibility but if you're just doing single-table operations then you don't need that added flexibility.
Such a method might look something like this:
Public Sub SaveChanges(tableName As String, data As DataSet)
Dim query = "SELECT * FROM " & tableName
Using adapter As New SqlDataAdapter(query, "connection string here")
Dim builder As New SqlCommandBuilder(adapter)
adapter.Update(data, tableName)
End Using
End Sub

Answer 2

I did what you said, but when I open the Form again, the new data are not there.
I made some changes in the code, perhaps because it did not work
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
BindingSource1.EndEdit()
ds.AcceptChanges()
db.SaveChanges("departamentos", "INSERT INTO departamentos VALUES('', " & TextBox2.Text & ")", ds)
ds = db.consulta("departamentos")
End Sub
And the code in the Module
Function SaveChanges(tableName As String, query As String, data As DataSet)
Using adapter As New SqlDataAdapter(query, "Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=SysMarket;Persist Security Info=True;User ID=admin;Password=XXXXX")
Dim builder As New SqlCommandBuilder(adapter)
adapter.Update(data, tableName)
Return True
End Using
End Function