Question

ADO.net数据库连接方式有几种?

具体有几种,都是什么?
每种的优点和缺点都是什么?

Answer 1

看一下这个例子吧.
Public Sub ConnectionStringX()

Dim cnn1 As ADODB.Connection
Dim cnn2 As ADODB.Connection
Dim cnn3 As ADODB.Connection
Dim cnn4 As ADODB.Connection

' 不使用数据源名 (DSN) 打开连接。
Set cnn1 = New ADODB.Connection
cnn1.ConnectionString = "driver={SQL Server};" & _
"server=bigsmile;uid=sa;pwd=pwd;database=pubs"
cnn1.ConnectionTimeout = 30
cnn1.Open

' 使用 DSN 和 ODBC 标记打开连接。
Set cnn2 = New ADODB.Connection
cnn2.ConnectionString = "DSN=Pubs;UID=sa;PWD=pwd;"
cnn2.Open

' 使用 DSN 和 OLE DB 标记打开连接。
Set cnn3 = New ADODB.Connection
cnn3.ConnectionString = "Data Source=Pubs;User ID=sa;Password=pwd;"
cnn3.Open

' 使用 DSN 和单个参数而非连接字符串打开连接。
Set cnn4 = New ADODB.Connection
cnn4.Open "Pubs", "sa", "pwd"

' 显示连接的状态。
MsgBox "cnn1 state: " & GetState(cnn1.State) & vbCr & _
"cnn2 state: " & GetState(cnn2.State) & vbCr & _
"cnn3 state: " & GetState(cnn3.State) & vbCr & _
"cnn4 state: " & GetState(cnn4.State)

cnn4.Close
cnn3.Close
cnn2.Close
cnn1.Close

End Sub

Public Function GetState(intState As Integer) As String

Select Case intState
Case adStateClosed
GetState = "adStateClosed"
Case adStateOpen
GetState = "adStateOpen"
End Select

End Function