Code below works fine without opening a connection object
explicitly. I mean objConn.Open() Why?

**
Dim objConn As New SqlConnection ("server=localhost;uid=sa;pwd=;database=pubs;")

        Dim strSQL As String = "SELECT * FROM Authors"
        Dim objCommand As New SqlCommand(strSQL, objConn)

        Dim objDA As New SqlDataAdapter
        objDA.SelectCommand = objCommand

        Dim objDS As New DataSet
        objDA.Fill(objDs)

        dgAuthors.DataSource = objDS
        dgAuthors.DataBind()
***

Hello,

The SQLDataAdapter handles the opening and closing of the connection. You don't need to do anything with the connection manually.

Brian

Brian,
I migrating from classic asp to asp.net

Please correct me, if i have understand your answer

When you use SQLDataAdapter object it handles opening and closing of the connection implicitly, but when you use command object (executenonquery() or executereader() ) you have
to open and close your connection in your code explicitly.

Thanks in advance.

Hello,

Yep, that about sums it up. I'm not sure the reasoning for the architecture, but that's what happens.

Brian

Hello,

I probably should also explain that the SQLDataReader object requires an active connection to the database, as well as executing with no results or a scalar value. It requires a connected environment.

In addition, the SQLDataAdapter passing to the DataSet/DataTable doesn't require an active connection when reading/writing to the objects, and is therefore in a disconnected environment.

Hope that helps,

Brian

DataAdapter is new in .NET! so powerfull Obj to work with DataBase & DataSet. It has contained 4 Objects for SELECT, Insert, Update & Delete. but u work much with 2 miracle Methods of that for all of there 4. [u]DataAdapter.fill(DataSet)</u> means SELECT Data from DB & fill ur mentioned DatSet, ofter that what ever u do on ur DataSet will need [u]DataAdapter.Update(DataSet)</u> if u have deleted 3 Record of ur DataSet & Updated 2 Record & Inserted 5 Row in DataSet they all will Updated with DB with a SINGLE Update Method. fo rmor read ur MSDN & find out what a great gift is! but in other hand has some disadvantaged. Like working Client side as a traditional ADO obj.

Always:),
Hovik Melkomian.