Attribute VB_Name = "DbFunc"
'== 標(biāo)記數(shù)據(jù)庫是否連接 ==
Private IsConnect As Boolean
'== 標(biāo)記執(zhí)行Connect()函數(shù)后，訪問數(shù)據(jù)庫的次數(shù) ==
Private Connect_Num As Integer
Private cnn As ADODB.Connection   '連接數(shù)據(jù)庫的Connection對象
Private rs As ADODB.Recordset     '保存結(jié)果集的Recordset對象

'連接數(shù)據(jù)庫
Private Sub Connect()
  '如果連接標(biāo)記為真，則返回。否則會出錯
  If IsConnect = True Then
    Exit Sub
  End If
  
  '關(guān)鍵New用于創(chuàng)建新對象cnn
  Set cnn = New ADODB.Connection
  '設(shè)置連接字符串ConnectionString屬性
  cnn.ConnectionString = conn
  '打開到數(shù)據(jù)庫的連接
  cnn.Open
  '判斷連接的狀態(tài)
  If cnn.State <> adStateOpen Then
    '如果連接不成功，則顯示提示信息，退出程序
    MsgBox "數(shù)據(jù)庫連接失敗"
    End
  End If
  
  '設(shè)置連接標(biāo)記，表示已經(jīng)連接到數(shù)據(jù)庫
  IsConnect = True
End Sub

'斷開與數(shù)據(jù)庫的連接
Private Sub Disconnect()
  Dim Rc As Long
  '如果連接標(biāo)記為假，標(biāo)明已經(jīng)斷開連接，則直接返回
  If IsConnect = False Then
    Exit Sub
  End If
  '關(guān)閉連接
  cnn.Close
  '釋放cnn
  Set cnn = Nothing
  '設(shè)置連接標(biāo)記，表示已經(jīng)斷開與數(shù)據(jù)庫的連接
  IsConnect = False
End Sub

'使用Connect_Num控制數(shù)據(jù)庫連接
Public Sub DB_Connect()
  Connect_Num = Connect_Num + 1
  Connect
End Sub
Public Sub DB_Disconnect()
  If Connect_Num >= CONNECT_LOOP_MAX Then
    Connect_Num = 0
    Disconnect
  End If
End Sub
'強制關(guān)閉api方式訪問的數(shù)據(jù)庫，計數(shù)器復(fù)位
Public Sub DBapi_Disconnect()
  Connect_Num = 0
  Disconnect
End Sub

'執(zhí)行數(shù)據(jù)庫操作語句
Public Sub SQLExt(ByVal TmpSQLstmt As String)
  '創(chuàng)建Command對象cmd
  Dim cmd As New ADODB.Command
  
  '連接到數(shù)據(jù)庫
  DB_Connect
  '設(shè)置cmd的ActiveConnection屬性，指定與其關(guān)聯(lián)的數(shù)據(jù)庫連接
  Set cmd.ActiveConnection = cnn
  '設(shè)置要執(zhí)行的命令文本
  cmd.CommandText = TmpSQLstmt
'  MsgBox TmpSQLstmt
  '執(zhí)行命令
  cmd.Execute
  '清空cmd對象
  Set cmd = Nothing
  '斷開與數(shù)據(jù)庫的連接
  DB_Disconnect
End Sub

'執(zhí)行數(shù)據(jù)庫查詢語句
Public Function QueryExt(ByVal TmpSQLstmt As String) As ADODB.Recordset
  '創(chuàng)建Recordset對象rst
  Dim rst As New ADODB.Recordset
  
  '連接到數(shù)據(jù)庫
  DB_Connect
  '設(shè)置rst的ActiveConnection屬性，指定與其關(guān)聯(lián)的數(shù)據(jù)庫連接
  Set rst.ActiveConnection = cnn
  '設(shè)置游標(biāo)類型
  rst.CursorType = adOpenDynamic
  '設(shè)置鎖定類型
  rst.LockType = adLockOptimistic
  '打開記錄集
  rst.Open TmpSQLstmt
  '返回記錄集
  Set QueryExt = rst
End Function