‘DbFunc.bas
‘== 標記數據庫是否連接 ==
Private IsConnect As Boolean
‘== 標記執行Connect()函數後，訪問數據庫的次數 ==
Private Connect_Num As Integer
Private cnn As ADODB.Connection   ‘連接數據庫的Connection對象
Private rs As ADODB.Recordset     ‘保存結果集的Recordset對象

‘連接數據庫
Private Sub Connect()
  ‘如果連接標記為真，則返回。否則會出錯
  If IsConnect = True
 
 Then
    Exit Sub
  End If
  
  ‘關鍵New用於創建新對象cnn
  Set cnn = New ADODB.Connection
  ‘設置連接字符串ConnectionString屬性
  cnn.ConnectionString = Conn
  ‘打開到數據庫的連接
  cnn.Open
  ‘判斷連接的狀態
  If cnn.State <> adStateOpen Then
    ‘如果連接不成功，則顯示提示信息，退出程序
    MsgBox "數據庫連接失敗"
    End
  End If
  
  ‘
 
設置連接標記，表示已經連接到數據庫
  IsConnect = True
End Sub

‘斷開與數據庫的連接
Private Sub Disconnect()
  Dim Rc As Long
  ‘如果連接標記為假，標明已經斷開連接，則直接返回
  If IsConnect = False Then
    Exit Sub
  End If
  ‘關閉連接
  cnn.Close
  ‘釋放cnn
  Set cnn = Nothing
  ‘設置連接標記，表示已經斷開與數據庫的連接
  IsConnect = False
End Sub

‘使用Connect_Num控制數據庫連接
 

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
‘強制關閉api方式訪問的數據庫，計數器復位
Public Sub DBapi_Disconnect()
  Connect_Num = 0
  Disconnect
End Sub

‘執行數據庫操作語句
Public Sub SQLExt(ByVal TmpSQLstmt As String)
  ‘創建Command對象cmd
  Dim cmd As New ADODB.Command
  
  ‘連接到數據庫
  DB_Connect
  ‘設置cmd的ActiveConnection屬性，指定與其關聯的數據庫連接
  Set cmd.ActiveConnection = cnn
  ‘設置要執行的命令文本
  cmd.CommandText = TmpSQLstmt
 ‘MsgBox TmpSQLstmt
  ‘執行命令
   cmd.Execute
  ‘清空cmd對象
  Set cmd = Nothing
  ‘斷開與數據庫的連接
  DB_Disconnect
End Sub

‘執行數據庫查詢語句
Public Function QueryExt(ByVal TmpSQLstmt As String) As ADODB.Recordset
  ‘創建Recordset對象rst
  Dim rst As New ADODB.Recordset
  
  ‘連接到數據庫
  DB_Connect
  ‘設置rst的ActiveConnection屬性，指定與其關聯的數據庫連接
  Set rst.ActiveConnection = cnn
  ‘設置遊標類型
  rst.CursorType = adOpenDynamic
  ‘設置鎖定類型
  rst.LockType = adLockOptimistic
  ‘打開記錄集
  rst.Open TmpSQLstmt
  ‘返回記錄集
  Set QueryExt = rst
End Function

‘Variable.bas
‘保存執行SQL語句的字符串
Public SqlStmt As String
‘
‘聲明類模塊變量
Public MyType As New Types     ‘類型對象
Public MyDep As New Department    ‘部門對象
Public MyDraw As New Draw      ‘領用對象
Public MyList As New DrawList  ‘明細對象
Public MyStore As New Store    ‘庫存對象
Public MyIn As New StoreIn    ‘入庫對象
Public MySupplier As New Supplier     ‘供應商對象
Public MyUser As New Users
Public CurUser As New Users

‘Const.bas
‘版本號
Public Const VerNum As String = "版本 1.5"
‘生成日期
Public Const GenDate As String = "日期 2018-08-29"
‘定義數據庫連接字符串
Public Const Conn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Office.mdb;"
 ‘一次執行connect操作可以訪問數據庫的次數
Public Const CONNECT_LOOP_MAX = 10

辦公用品管理系統VB——模塊