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ASP的数据库类[编程手札]

［作者：不详转贴自：不详点击数：更新时间：2006-3-14 9:15:13］

ASP的数据库类

一、前言
　　提到ASP操作数据库，大多数人会想到：共用的连接字串ConStr、Conn.Open ConStr建立数据库连接、Conn.Execute SqlCmd方式执行命令、RecordSet.Open Sql,Conn,1,1取得记录集，的确这种方法被99%的人或公司采用。对于操作数据库过程中产生的错误，恐怕99%的人不会进行处理，要么在程序的开头加入on error resume next“轻松”跳过去、要么让错误信息连同错误代码一同“暴尸”在浏览者面前。对于前一种情况可能会产生让人莫明其妙的怪异结果，后一种情况，可能会在某个时间（比如连接数据库时）暴露您的敏感信息，影响网站安全。当然，还是有个别负责的程序员同志会在容易产生错误的操作后面加入if err.xxxx来处理可能的错误，但这似乎不是一个好办法，一不小心就可能漏掉了。
　　我至今也没有想明白，为什么在VB和ASP.NET中都存在的On Error Goto，偏偏在ASP中被取消了。
　　另外不得不提的是，当您在前面使用on error resume next而在后面不想resume next了，对不起，没办法，您只能把它“贯彻到底”。看看其它语言的异常机制，try..catch..finally随心所欲，真是爽酷了！

　　说了这么多，并不要为ASP引入诸如异常机制等新的内容，毕竟ASP语言本身也决定这是不可能实现的（ASP.NET中实现了），只是想在ASP中最普遍的也是最容易出现错误的数据库操作中，找到一种有效的错误处理方式，并把conn、RecordSet等封装起来，达到最大限度的精简。于是便有了下面的数据库类。

二、数据库类
1、功能
　　正如前面所说，这个类的目的是把ADODB.Connection、Adodb.Recordset等烦琐的操作封装起来并在类里实现错误处理。现在看看类的成员、属性和方法：
　　1）成员：（没有公有或保护成员）
　　2）属性：
　　　　ClassName－返回类名
　　　　Version－返回版本
　　　　LastError－返回最后的错误
　　　　IgnoreError－设置/返回是否忽略数据库错误
　　　　Connection－返回连接对象（ADODB.Connection）
　　　　ConnectionString－设置/返回连接字串（本示例为SQL Server，如为其它请根据实际设定）
　　　　FieldCount、PageSize、PageCount、AbsolutePage、AbsolutePosition、Bof、Eof－请参考Adodb.Recordset相应内容
　　3）方法：
　　　　Setup－设置连接数据服务器的帐号、密码、数据库名、主机/IP
　　　　Connect－连接数据库
　　　　Close－关闭数据库连接并释放资源
　　　　Query－执行数据库查询命令并返回数据集
　　　　ExeSQL－执行SQL命令（不返回数据库）
　　　　FieldName－返回指定序号的字段名
　　　　Fields－返回指定的（序号或字段名）字段的值
　　　　Data－同上
　　　　MoveNext、MovePrevious、MoveFirst、MoveLast－请参考Adodb.Recordset相应内容

2、实现代码（DBSql.inc.asp）

内容太长，点击此处打开/折叠...

<%
'========================================================================
' CLASS NAME: clsDB
' DESIGN BY :    彭国辉
' DATE:            2003-12-18
' SITE:             http://kacarton.yeah.net/
' Blog:               http://blog.csdn.net/conch
' EMAIL:            kacarton@sohu.com
' MODIFY:
'   2004-6-25: 升级后的数据引擎，返回错误代号小于0（也可以是ASP对数值的
'              定义有变），修改错误检测err.number>0 ==> err.number<>0
'   2004-6-30：修改错误处理，忽略如游标类型改变等非错误性质的提示
'
'文章为作者原创，转载前请先与本人联系，转载请注明文章出处、保留作者信息，谢谢支持！
'========================================================================

Class clsDB

' name of this class
' var string
' @access    Private
' @see       property: Name
Private m_strName

' version of this class
' var string
' @access    Private
' @see       property: Version
Private m_strVersion

' Error Object
' @var ADODB.Connection.Errors
' @access    private
' @see       property: LastError
Private m_LastError

' Ingore all Connection.Errors
' var Boolean
' @access    private
' @see       property: IgnoreError
Private m_IgnoreError

' Connection Object
' var ADODB.Connection
' @access    Private
' @see       property: Connection
Private m_Connection

' Is connection to database?
' var boolean
' @Private
Private m_bIsConnect

' RecordSet
' var RecordSet
' @access    Private
Private m_RecordSet

' Connection string
' var string
' @access    Private
' @see       property: ConnectionString
Private m_ConneStr

' Database server host name or IP
' var string
' @access    Private
' @see       property: Host
Private m_strHost

' Database name
' var string
' @access    Private
' @see       property: Database
Private m_strDatabase

' Account to connection database
' var string
' @access    Private
' @see       property: UserName
Private m_UserName

' Password to connection database
' var string
' @access    Private
' @see       property: Password
Private m_Password

' get class name attribute.
' usage: oTemplate.Name
' access    public
Public Property Get ClassName()
    ClassName = m_strName
End Property

' get class version attribute.
' usage: oTemplate.Version
' access    public
Public Property Get Version()
    Version = m_strVersion
End Property

' Get class last error messages.
' usage: oTemplate.LastError
' @access    public
Public Property Get LastError()
    LastError = m_LastError
End Property

' Get or Set Ignore connection.errors
Public Property Get IgnoreError()
    IgnoreError = m_IgnoreError
End Property

Public Property Let IgnoreError(ByVal Value)
    m_IgnoreError = Value
End Property

' Get Connection
Public Property Get Connection()
    Connection = m_Connection
End Property

' Get connection string
Public Property Get ConnectionString()
    ConnectionString = m_ConneStr
End Property

' Set connection string
Public Property Let ConnectionString(ByVal Value)
    m_ConneStr = Value
End Property

' Get data fields count
Public Property Get FieldCount()
    FieldCount = m_RecordSet.Fields.Count
End Property

' Get RecordSet PageSize
Public Property Get PageSize()
    on error resume next
    PageSize = m_RecordSet.PageSize
    if err.number<>0 then ShowError("Can not get PageSize!")
End Property

' Set RecordSet Page Size
Public Property Let PageSize(ByVal Value)
    on error resume next
    m_RecordSet.PageSize = Value
    if err.number<>0 then ShowError("Can not set PageSize to " & Value)
End Property

' Get RecordSet page count
Public Property Get PageCount()
    PageCount = m_RecordSet.PageCount
End Property

' Get RecordSet record count
Public Property Get RecordCount()
on error resume next
    RecordCount = m_RecordSet.RecordCount
    if err.number<>0 then ShowError("Get RecordCount error.")
End Property

' Get RecordSet Absolute Page
Public Property Get AbsolutePage()
    on error resume next
    AbsolutePage = m_RecordSet.AbsolutePage
    if err.number<>0 then ShowError("Can not get AbsolutePage!")
End Property

' Set RecordSet Absolute Page
Public Property Let AbsolutePage(ByVal Value)
    on error resume next
    m_RecordSet.AbsolutePage = Value
    if err.number<>0 then ShowError("Can not set AbsolutePage to " & Value)
End Property

' Get RecordSet Absolute Position
Public Property Get AbsolutePosition()
    on error resume next
    AbsolutePosition = m_RecordSet.AbsolutePosition
    if err.number<>0 then ShowError("Can not get AbsolutePosition!")
End Property

' Set RecordSet Absolute Position
Public Property Let AbsolutePosition(ByVal Value)
    on error resume next
    m_RecordSet.AbsolutePosition = Value
    if err.number<>0 then ShowError("Can not set AbsolutePosition to " & Value)
End Property

' Bof
Public Property Get Bof()
    Bof = m_RecordSet.Bof
end Property

' Eof
Public Property Get Eof()
    Eof = m_RecordSet.EOF
end Property

'Setup the databease host name, database name, User name(account), password
Public Sub Setup(Account, Password, Database, Host)
    m_UserName = Account
    m_Password = Password
    if Database<>"" then m_strDatabase = Database
    if Host<>"" then m_strHost = Host
    m_ConneStr = "Driver={SQL Server};Server=" & m_strHost & ";Database=" &_
                 m_strDatabase & ";Uid=" & m_UserName & ";Pwd=" & m_Password & ";"
End Sub

' Connect to database
Public Function Connect()
    on error resume next
    m_Connection.Open m_ConneStr
    if err.number<>0 Then ShowError("数据库连接错误:(Server:" & m_strHost & ", Database:" & m_strDatabase & ")")
    m_bIsConnect = true
    Connect = true 'todo://
end Function

' Diconnect database
Public Function Close()
    on error resume next
    Set m_RecordSet = Nothing
    Set m_Connection = Nothing
    m_bIsConnect = false
    Close = true
    if err.number<>0 then ShowError("切断数据库连接时出错")
end Function

' Query
Public Sub Query(SQLCommand)
    on error resume Next
    if not m_bIsConnect then Connect
    Set m_RecordSet = Server.CreateObject("Adodb.Recordset")
    'Set m_RecordSet = m_Connection.Execute(SQLCommand)
    m_RecordSet.Open SQLCommand, m_Connection, 1, 1
    if err.number<>0 then ShowError(SQLCommand):exit sub
    if m_Connection.Errors.Count>0 And m_IgnoreError=false then ProcessError(SQLCommand)
End Sub

' ExeSQL Command
Public Sub ExeSQL(SQLCommand)
    on error resume Next
    if not m_bIsConnect then Connect
    m_Connection.Execute SQLCommand
    if err.number<>0 then ShowError(SQLCommand):exit sub
    if m_Connection.Errors.Count>0 And m_IgnoreError=false then ProcessError(SQLCommand)
End Sub

' Get Fields Name
Public Function FieldName(ByVal FieldId)
    on error resume next
    FieldName = m_RecordSet.Fields(FieldId).Name
    if err.number<>0 then ShowError("不能读取字段" & FieldID & "名称!")
End Function

' Get fields data
Public Function Fields(ByVal FieldId)
    on error resume next
    Fields = m_RecordSet.Fields(FieldId)
    if err.number<>0 then ShowError("不能读取字段" & FieldID & "数据!")
End Function

' Get fields data
Public Function Data(ByVal FieldId)
    on error resume next
    Data = m_RecordSet.Fields(FieldId)
    if err.number<>0 then ShowError("不能读取" & FieldID & "数据!")
    'if m_Connection.Errors.Count>0 then ShowError("不能读取" & FieldID & "数据!")
End Function

' Move to next record
Public Sub MoveNext()
    on error resume next
    if m_bIsConnect then m_RecordSet.MoveNext
    if err.number<>0 then ShowError("MoveNext error")
End Sub

' Move to Previous record
Public Sub MovePrevious()
    on error resume next
    if m_bIsConnect then m_RecordSet.MovePrevious
    if err.number<>0 then ShowError("MovePrevious error")
End Sub

' Move to First record
Public Sub MoveFirst()
    on error resume next
    if m_bIsConnect then m_RecordSet.MoveFirst
    if err.number<>0 then ShowError("MoveFirst error")
End Sub

' Move to Last record
Public Sub MoveLast()
    on error resume next
    if m_bIsConnect then m_RecordSet.MoveLast
    if err.number<>0 then ShowError("MoveLast error")
End Sub

' 2004-6-30
Private Sub ProcessError(ByVal sqltxt)
    for i=0 to m_Connection.Errors.Count-1
      If m_Connection.Errors.Item(i).Number<>0 Then ShowError(sqltxt)
    Next
End Sub

' This function is called whenever an error occurs and will handle the error
' Additionally the error message will be saved in m_strLastError.
' @param     $msg         a string containing an error message
' @access    private
' @return    void
Private Sub ShowError(ByVal sqltxt)
    for i=0 to m_Connection.Errors.Count-1
      Response.Write m_Connection.Errors.Item(i) & "(" & m_Connection.Errors.Item(i).Number & ")<br>"
    Next
    m_LastError = Err.Description

    m_Connection.Errors.Clear
    Response.Write "<br>------------------------------------------------------<br>" &_
                   "<font color=red size=4>" & sqltxt & "</font>"
'     Response.Write "<br>------------------------------------------------------<br>" &_
'                    "<font color=red size=4>" & Left(sqltxt, 10) & "...(错误信息已被屏蔽)，请与网站管理员联系！</font>"
'     Response.End
End Sub

' Class constructor, set class default attributes, you can change it
Private Sub class_Initialize
    m_strName = "clsDB"
    m_strVersion = "1.0"
    Set m_Connection = Server.CreateObject("ADODB.Connection")
    '请修改此处为你连接数据库的默认值
    Setup "sa", "password", "Northwind", "(local)"
    m_bIsConnect = False
    m_IgnoreError = False
End Sub

' Class destructor, free memory.
Private Sub class_Terminate
    Set m_RecordSet = Nothing
    Set m_Connection = Nothing
End Sub

End Class

%>

3、使用示例

<%
Function HTMLEncode(str)
If IsNull(str) Then HTMLEncode = "(NULL)" _
Else HTMLEncode = Server.HTMLEncode(str)
End Function

Dim sql, i
Set sql = New clsDB
sql.Connect
sql.ExeSQL("update Customers set Address='中华人民共和国' where ID=1")
sql.Query("select * from Customers")
Response.Write "<table border=1><tr>"
For i=0 To sql.FieldCount-1
    Response.Write "<td>" & Server.HTMLEncode(sql.FieldName(i)) & "</td>"
Next
Response.Write "</tr>"
While Not sql.Eof
    For i=0 To sql.FieldCount-1
        Response.Write "<td>" & HTMLEncode(sql.Data(i)) & "</td>" '此处可直接用字段名代替i
    Next
    Response.Write "</tr>"
    sql.MoveNext
Wend
Response.Write "</table>"
sql.Close
Set sql = Nothing
%>

三、小结
　　这还只是一个比较粗糙的数据库类，还有很多ADODB的特性没有添加在内，而且灵活性也不够。本文旨在为大家提供另一种思路，各位在看完本文后觉得还是有一点收获的话，我就很满足了。
　　此外，我的下一篇文章《将ASP查询分页封装起来》中将用到这个类。

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