vb怎样与数据库进行连接?

'SQL版

Private Con As String = "<连接字符串>"'<连接字符串>可以自动生成
Private connection As SqlClient.SqlConnection
Private command As SqlClient.SqlCommand
Public Function DBopen() As Boolean '打开数据库
Try
connection = New SqlClient.SqlConnection
connection.ConnectionString = Con
connection.Open()
Return True
Catch ex As Exception
MsgBox(ex.ToString)
Return False
End Try
End Function
Public Function DBclose() As Boolean '关闭数据库
Try
connection = New SqlClient.SqlConnection
connection.ConnectionString = Con
connection.Close()
Return True
Catch ex As Exception
MsgBox(ex.ToString)
Return False
End Try
End Function

'Access版
Private Con As String = "<连接字符串>"'<连接字符串>可以自动生成
Private connconnection As OleDb.OleDbConnection
Private conncommand As OleDb.OleDbComman