ADO数据访问模型(四)

六、RecordSet对象
　　写到这一篇的时候，我不禁想到了先贤的两句话，一句是孟子在曹刿论战中所说的：一鼓作气，再而衰，三而竭。这篇ADO总结报告的前五部分都是一鼓作气之作，不知这后面的再而衰部分是否能保持连续了。另外的一句是王安石在游褒禅山记中所说的：世之奇伟、瑰怪、非常之观，常在于险远，而人之所罕至焉，故非有志者不能至也。我们学习编程又何尝不是这样了，若非有志，能及于险远是不能真正掌握的。
　　好了，讲了这么多的题外话，还是让我们回到正题上来，我想，由于大家对RecordSet都有足够的认识，所以我就不象前面的几章中那样对它的每一个属性和方法都做完整的介绍，我想通过几个有代表性的编程实例来给大家讲一讲。
1、 方法
AddNew, CancelBatch, CancelUpdate, Clone, Close, Delete, GetRows, Move, MoveFirst, MoveLast, MoveNext, MovePrevious, NextRecordset, Open, Requery, Resync, Supports, Update, UpdateBatch
2、 属性
AbsolutePage,AbsolutePosition,ActiveConnection,BOF,Bookmark, CacheSize, CursorLocation, CursorType, EditMode, EOF, Filter, LockType, MarshalOptions, MaxRecords, PageCount, PageSize, RecordCount, Source, State, Status
3、 集合
Fields,Properties
实例一：分页显示及导航：
　　为什么我要再提分页的这个问题呢？因为这是一个最基本的问题，虽然有很多关于分页的文章，但我觉得他们的方法偏于复杂。其实RecordSet的 AbsolutePage就可以轻松的实现分页，当你指定了PageSize属性后，对AbsolutePage指定值就可以翻转到指定的页面。但是如果你想使用AbsolutePage的话，你必须在打开RecordSet对象之前将它的CursorLocation值设为adUseClient，这个属性是继承Connection对象的一个相同属性的。你也可以在打开Connection对象之前来设定它。下面是源代码，为了方便，我将导航栏独立成了一个子程序方便大家使用。
$#@60;%
sub navigator(PageNo,Target)
Response.Write "$#@60;table border=0$#@62;"
Response.Write "$#@60;tr$#@62;"
Response.Write "$#@60;td$#@62;"
if PageNo$#@62;1 then
Response.write "$#@60;a href="&chr(34)&Target&"?Page=1"&chr(34)&"$#@62;┃第一页$#@60;/a$#@62;"
else
Response.Write "┃第一页"
end if
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;td$#@62;"
if PageNo$#@60;rs.PageCount then
Response.write"$#@60;a href="&chr(34)&Target&"?Page="&PageNo+1&chr(34)&"$#@62;┃下一页$#@60;/a$#@62;"
else
Response.Write "┃下一页"
end if
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;td$#@62;"
if PageNo$#@62;1 then
Response.write "$#@60;a href="&chr(34)&Target&"?Page="&PageNo-1&chr(34)&"$#@62;┃前一页$#@60;/a$#@62;"
else
Response.Write "┃前一页"
end if
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;td$#@62;"
if PageNo$#@60;rs.PageCount then
Response.write "$#@60;a href="&chr(34)&Target&"?Page="&rs.PageCount&chr(34)&"$#@62;┃最后一页$#@60;/a$#@62;"
else
Response.Write "┃最后一页"
end if
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;td$#@62;"
Response.Write "┃页次:"&PageNo&"/"&rs.PageCount&"页┃"&rs.PageSize&"条记录/页┃"
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;td valign="middle"$#@62;"
Response.Write "$#@60;form action="&chr(34)&Target&chr(34)&" method="&chr(34)&"POST"&chr(34)&"$#@62;"
Response.Write "$#@60;input type="text"size=3 maxlength=4 name="Page"$#@62;"
Response.Write " $#@60;input type="submit"value="转到"$#@62;"
Response.Write "$#@60;/form$#@62;"
Response.Write "$#@60;/td$#@62;"
Response.Write "$#@60;/tr$#@62;"
Response.Write "$#@60;/table$#@62;"
end sub
%$#@62;

$#@60;%
const adCmdText=&H0001
const adVarChar=200
const adInteger=3
const adParamInput=&H0001
const adCmdTable=&H0002
const adUseClient=3
const adDate=7
const adLongVarChar=201
set conn=Server.CreateObject("ADODB.Connection")
conn.ConnectionString="Driver={Microsoft Access Driver (*.mdb)};DBQ="& _
Server.Mappath("/source_ASP")&"/process/process.mdb;"
conn.Open
%$#@62;
$#@60;%
const MaxPageSize=5
%$#@62;
$#@60;HTML$#@62;
$#@60;head$#@62;
$#@60;title$#@62; See Book $#@60;/title$#@62;
$#@60;/head$#@62;
$#@60;body$#@62;
$#@60;%
dim i,j,PageNo
set rs=Server.CreateObject("ADODB.RecordSet")
rs.ActiveConnection=conn
rs.CursorLocation=adUseClient
rs.Open "Select * From books",,,adCmdText
if rs.BOF then
Response.Write "欢迎使用图书,资料管理程序!"
else
rs.PageSize=MaxPageSize
if isempty(Request.QueryString("Page")) then
PageNo=1
elseif cInt(Request.QueryString("Page"))$#@60;1 then
PageNo=1
elseif cInt(Request.QueryString("Page"))$#@62;rs.PageCount then
PageNo=rs.PageCount
else
PageNo=cInt(Request.QueryString("Page"))
end if
if Request.ServerVariables("Request_Method")="POST" and not Isempty(Request.Form("Page")) then
PageNo=cInt(Request.Form("Page"))
end if
rs.AbsolutePage=PageNo
Response.Write "$#@60;table border="0" width="100%"$#@62;"
Response.Write "$#@60;tr$#@62;$#@60;td colspan="&rs.fields.count&"$#@62;"
Target="books.ASP"
call navigator(PageNo,Target) "调用导航栏
Response.Write "$#@60;/td$#@62;$#@60;/tr$#@62;"
Response.Write "$#@60;tr$#@62;"
for i=0 to rs.fields.count-1
Response.Write "$#@60;td$#@62;"&rs.fields.item(i).name&"$#@60;/td$#@62;"
next
Response.Write "$#@60;/tr$#@62;"
j=0
while (not rs.EOF) and j$#@60;rs.PageSize
Response.Write "$#@60;tr$#@62;"
for i=0 to rs.fields.count-1
if i=1 then
Response.Write "$#@60;td$#@62;"&"$#@60;a href="&chr(34)&"status.ASP?BookName="& _
rs.fields.item(i).value&chr(34)&"$#@62;"&rs.fields.item(i).value&"$#@60;/a$#@62;$#@60;/td$#@62;"
"这里这样写是为了级联式查询而做的。
else
Response.Write "$#@60;td$#@62;"&rs.fields.item(i).value&"$#@60;/td$#@62;"
end if
next
Response.Write "$#@60;/tr$#@62;"
rs.MoveNext
j=j+1
wend
Response.Write "$#@60;/table$#@62;"
end if
%$#@62;