Imports System.data.sqlclient

Public Class DAL

Private con As SqlConnection

Private dap As SqlDataAdapter

Private cmd As SqlCommand

Private str As String

Public Sub New()

str = My.Settings.Setting

End Sub

Public Sub New(ByVal _str)

str = _str

End Sub

'mo ket noi

Public Sub moketnoi()

con = New SqlConnection(str)

If con.State <> ConnectionState.Open Then

con.Open()

End If

End Sub

'dong ket noi

Public Sub dongketnoi()

con = New SqlConnection(str)

If con.State <> ConnectionState.Closed Then

con.Close()

End If

End Sub

'lay du lieu tu csdl len dataset

Public Function layDl(ByVal sql As String) As DataSet

Dim ds As New DataSet

Try

moketnoi()

dap = New SqlDataAdapter(sql, con)

dap.Fill(ds)

Catch ex As Exception

Throw New Exception(ex.Message)

Finally

dongketnoi()

End Try

Return ds

End Function

'thuc hien cau truy van den csdl

Public Sub thuchien(ByVal sql As String)

Try

moketnoi()

cmd = New SqlCommand(sql, con)

cmd.ExecuteNonQuery()

Catch ex As Exception

Throw New Exception(ex.Message)

Finally

dongketnoi()

End Try

End Sub

End Class