1 Public strCnn As String  ‘数据库连接字符串
 2 Public AdoCnn As ADODB.Connection ‘数据库连接
 3 Public IsConnect As Boolean  ‘判断是否连接
 4 
 5 
 6 Private Sub Connect() ‘连接数据库
 7     On Error GoTo Err:
 8     If IsConnect = True Then  ‘如果连接标记为真，则返回。否则会出错
 9         Exit Sub
10     End If
11     
12     Set AdoCnn = New ADODB.Connection ‘关键New用于创建新对象cnn
13     With AdoCnn
14         .ConnectionString = strCnn
15         .ConnectionTimeout = 10
16         .Open
17     End With
18     IsConnect = True  ‘设置连接标记，表示已经连接到数据库
19     Exit Sub
20 Err:
21     If Err = -2147467259 Then
22         Set Cnn = Nothing
23         MsgBox Err.Description & "请检查数据库配置!", vbOKOnly + vbInformation, "Connect"
24     Else
25         MsgBox Err.Description & "请检查数据库配置!", vbExclamation, "Connect"
26     End If
27     
28 End Sub
29 
30 Public Sub Disconnect() ‘断开与数据库的连接
31     Dim rc As Long
32     If IsConnect = False Then Exit Sub ‘如果连接标记为假，标明已经断开连接，则直接返回
33     AdoCnn.Close  ‘关闭连接
34     
35     Set AdoCnn = Nothing
36     IsConnect = False
37 End Sub
38 
39 Public Sub DB_Connect() ‘使用Connect_Num控制数据库连接
40     Connect_Num = Connect_Num + 1
41     Connect
42 End Sub
43 
44 Public Sub DB_Disconnect()
45     If Connect_Num >= CONNECT_LOOP_MAX Then
46         Connect_Num = 0
47         Disconnect
48     End If
49 End Sub
50 
51 Public Sub DBapi_Disconnect() ‘强制关闭api方式访问的数据库，计数器复位
52     Connect_Num = 0
53     Disconnect
54 End Sub
55 
56 Public Sub ExecSql(ByVal TmpSql As String)   ‘执行数据库操作语句
57     On Error GoTo Err:
58     Dim cmd As New ADODB.Command  ‘创建Command对象cmd
59     DB_Connect    ‘连接到数据库
60     Set cmd.ActiveConnection = AdoCnn  ‘设置cmd的ActiveConnection属性，指定与其关联的数据库连接
61     cmd.CommandText = TmpSql  ‘设置要执行的命令文本
62     cmd.Execute
63     Set cmd = Nothing
64     DB_Disconnect
65     Exit Sub
66 Err:
67     MsgBox Err.Description, 64, "ExecSql"
68 End Sub
69 
70 Public Function QuerySql(ByVal TmpSql As String) As ADODB.Recordset ‘执行数据库查询语句
71     On Error GoTo Err:
72     Dim rst As New ADODB.Recordset
73     DB_Connect    ‘连接到数据库
74     If IsConnect = False Then Exit Function
75     Set rst.ActiveConnection = AdoCnn    ‘设置rst的ActiveConnection属性，指定与其关联的数据库连接
76     rst.CursorType = adOpenKeyset
77     rst.LockType = adLockOptimistic   ‘设置锁定类型
78     rst.Open TmpSql    ‘打开记录集
79     Set QuerySql = rst    ‘返回记录集
80     Exit Function
81 Err:
82     MsgBox Err.Description, 64, "QuerySql"
83 End Function
84 
85 Public Function GetFieldValue(FieldValue As Variant) As String
86     GetFieldValue = IIf(Not IsNull(FieldValue), FieldValue, "")
87 End Function