很少采用Access做数据库开发，前段时间，朋友接了一个小单，让我帮忙做后台开发，采用Access + Asp.Net开发，结果在开发过程使用Access碰到不少问题，所以把这些问题总结一下，希望对其它人有些帮助 1： Access分页脚本问题 使用Access作为数据库开发系统时
很少采用Access做数据库开发，前段时间，朋友接了一个小单，让我帮忙做后台开发，采用Access + Asp.Net开发，结果在开发过程使用Access碰到不少问题，所以把这些问题总结一下，希望对其它人有些帮助
1： Access 分页脚本问题
使用Access作为数据库开发系统时，页面数据分页的方案有好几种：
1.1 使用DataGridView自带的分页功能.
1.2. 使用SELECT TOP NOT IN 来实现。类似如下所示：
<p><span>SELECT</span><span>TOP</span><span>100</span><span><br><br> </span><span>[</span><span>ID</span><span>]</span><span> ,<br><br> </span><span>[</span><span>Message</span><span>]</span><span> ,<br><br> </span><span>[</span><span>CreateDate</span><span>]</span><span><br><br></span><span>FROM</span><span> ScrollMessage<br><br></span><span>WHERE</span><span> ID </span><span>NOT</span><span>IN</span><span> ( </span><span>SELECT</span><span>TOP</span><span>900</span><span><br><br> ID<br><br> </span><span>FROM</span><span> ScrollMessage<br><br> </span><span>ORDER</span><span>BY</span><span> ID )<br><br></span><span>ORDER</span><span>BY</span><span> ID</span></p>
1.3．使用嵌套的TOP结合分页控件AspNetPager来实现
1.4. 设置一个自增长字段.并且该字段为INDEX.(网上有方案，我没有研究过这种方案)
其实上面几种方案中，我觉得效率最高的应该是使用TOP嵌套方案（特别是当数据量大的时候），也是我下面将要讲解的。 如下图所示：假设有些滚动信息需要分页显示，则我们可以这样处理
1.1 解决Access 分页，首页或最后一页数据显示错误、混乱问题
<p><span>///</span><span><summary></summary></span><span><br><br> </span><span>///</span><span> 分页获取滚动消息数据<br><br> </span><span>///</span><span></span><span><br><br> </span><span>///</span><span><param name="pageSize"></span><span>一页显示数据条数</span><span></span><span><br><br> </span><span>///</span><span><param name="curPageSize"></span><span>当前页的数据在所有数据中位置（排序）</span><span></span><span><br><br> </span><span>///</span><span><param name="condition"></span><span>查询条件</span><span></span><span><br><br> </span><span>///</span><span><returns></returns></span><span>返回当前条件下的滚动消息</span><span></span><span><br></span><span><br> </span><span>public</span><span> DataTable GetScrollMessage(</span><span>int</span><span> pageSize, </span><span>int</span><span> curPageSize, </span><span>string</span><span> condition)<br><br> {<br><br> </span><span>string</span><span> cmdText </span><span>=</span><span>string</span><span>.Format(</span><span>@"</span><span>SELECT * FROM<br><br> (SELECT TOP {0} * FROM<br><br> (<br><br> SELECT TOP {1} ID, Message,CreateDate<br><br> FROM ScrollMessage<br><br> WHERE 1=1 {2}<br><br> ORDER BY ID DESC<br><br> ) T<br><br> ORDER BY T.ID ASC <br><br> ) TT ORDER BY TT.ID DESC; <br><br> </span><span>"</span><span>, pageSize, curPageSize, condition);<br><br> <br><br> <br><br> </span><span>return</span><span> DbHelper.ExecuteDataSet(cmdText).Tables[</span><span>0</span><span>];<br><br> <br><br> }</span></p>
View Code
<p><span>private</span><span>void</span><span> BindGridView()<br> {<br> </span><span>//</span><span> 当前页数据显示个数</span><span><br></span><span>int</span><span> pageSize </span><span>=</span><span> AspNetPager1.PageSize;<br><br> </span><span>//</span><span> AspNetPager 控件中当前显示的页</span><span><br></span><span>int</span><span> pageIndex </span><span>=</span><span> AspNetPager1.CurrentPageIndex;<br> </span><span>int</span><span> curPageSize </span><span>=</span><span>0</span><span>;<br> MessageMangent module </span><span>=</span><span>new</span><span> MessageMangent();<br><br> </span><span>//</span><span>设置AspNetPager 的RecordCount属性</span><span><br></span><span> AspNetPager1.RecordCount </span><span>=</span><span> module.GetScrollMessageCount(</span><span>""</span><span>);<br><br> </span><span>if</span><span> (pageIndex </span><span>==</span><span> AspNetPager1.PageCount)<br> {<br> pageSize </span><span>=</span><span> AspNetPager1.RecordCount </span><span>-</span><span> (pageIndex </span><span>-</span><span>1</span><span>) </span><span>*</span><span> pageSize;<br><br> </span><span>if</span><span> (curPageSize </span><span>==</span><span>0</span><span>)<br> curPageSize </span><span>=</span><span> AspNetPager1.RecordCount;<br><br> }<br> </span><span>else</span><span><br> {<br> curPageSize </span><span>=</span><span> pageSize </span><span>*</span><span> pageIndex;<br> }<br><br> <br><br> DataTable dtDataSource </span><span>=</span><span> module.GetScrollMessage(pageSize, curPageSize, </span><span>""</span><span>);<br><br> gvMessage.DataSource </span><span>=</span><span> dtDataSource;<br> gvMessage.DataBind();<br> }</span></p>上面代码已经能解决分页数据错乱问题，但是其实里面还有个隐藏的bug，就是当数据表没有任何记录时，它会报错：“SELECT 子句中包含一个保留字、拼写错误或丢失的参数，或标点符号不正确”。 可能有些人被这个人弄得莫名其妙，其实主要是TOP 0引起的， 你用SELECT TOP 0 * FROM A去查询设计里面执行下，就会弹出那个错误提示。所以要修改下上面的代码如下：
View Code
<p><span>private</span><span>void</span><span> BindGridView()<br> {<br> </span><span>//</span><span> 当前页数据显示个数</span><span><br></span><span>int</span><span> pageSize </span><span>=</span><span> AspNetPager1.PageSize;<br><br> </span><span>//</span><span> AspNetPager 控件中当前显示的页</span><span><br></span><span>int</span><span> pageIndex </span><span>=</span><span> AspNetPager1.CurrentPageIndex;<br> </span><span>int</span><span> curPageSize </span><span>=</span><span>0</span><span>;<br> MessageMangent module </span><span>=</span><span>new</span><span> MessageMangent();<br><br> </span><span>//</span><span>设置AspNetPager 的RecordCount属性</span><span><br></span><span> AspNetPager1.RecordCount </span><span>=</span><span> module.GetScrollMessageCount(</span><span>""</span><span>);<br><br> </span><span>if</span><span> (pageIndex </span><span>==</span><span> AspNetPager1.PageCount)<br> {<br> pageSize </span><span>=</span><span> AspNetPager1.RecordCount </span><span>-</span><span> (pageIndex </span><span>-</span><span>1</span><span>) </span><span>*</span><span> pageSize;<br><br> </span><span>if</span><span> (curPageSize </span><span>==</span><span>0</span><span>)<br> curPageSize </span><span>=</span><span> AspNetPager1.RecordCount;<br><br> }<br> </span><span>else</span><span><br> {<br> curPageSize </span><span>=</span><span> pageSize </span><span>*</span><span> pageIndex;<br> }<br><br> </span><span>if</span><span> (curPageSize </span><span>==</span><span>0</span><span>&&</span><span> pageSize </span><span>==</span><span>0</span><span>)<br> {<br> curPageSize </span><span>=</span><span>1</span><span>;<br> pageSize </span><span>=</span><span>1</span><span>;<br> }<br><br><br> DataTable dtDataSource </span><span>=</span><span> module.GetScrollMessage(pageSize, curPageSize, </span><span>""</span><span>);<br><br> gvMessage.DataSource </span><span>=</span><span> dtDataSource;<br> gvMessage.DataBind();<br> }</span></p>1.2 SELECT TOP 失效问题，比如只需前十条记录，结果它给你查出了所有记录。这主要是查询TOP语句的后面使用Order by，而且Order by字段中有重复值的话，那么这个TOP很会失效而会返回所有记录,所以Order by后面最好用主键字段。我又一次就是犯了这个错误，查询语句如下所示，本来工作好好的，但是由于客户需求，把CreateDate字段从yyyy-MM-dd HH:mm 改成yyyy-MM-dd 结果排序全部混乱了。
View Code
<p><span>string</span><span> cmdText </span><span>=</span><span>string</span><span> .Format(<br> </span><span>@"</span><span>SELECT * FROM <br> (<br> SELECT TOP {0} * <br> FROM (<br> SELECT TOP {1} * FROM Images I<br> INNER JOIN BaseImgPage P ON I.PageID = P.PageID AND I.SubType = P.SubType <br> WHERE I.PageID =@PageID AND I.SubType=@SubType</span><span>"</span><span>+</span><span> searchCondtion </span><span>+</span><span>@"</span><span><br> ORDER BY CreateDate ASC<br> ) ORDER BY CreateDate DESC<br> ) ORDER BY ImageSortNum DESC;</span><span>"</span><span>, pageSize, curpageSize);</span></p>2 关键字问题，像password等，这样网上介绍很多了，想必大家都比较了解。这里就不多说了
3 错误提示"操作必须使用一个可更新的查询",部署到服务器上，插入或更新数据时，有时会爆出这样的错误
1.Win 2000/ Win 2003 系统，在数据库文件上(*.mdb)点鼠标右键，选择属性，点安全，查看是否存在everyone用户，如果没有，添加everone用户，勾选"完全控制".
2.Win XP 系统,打开 data 文件夹，点击“工具”->“文件夹选项”->“查看”，找到“使用简单文件共享（推荐）”这项，把前面的勾去掉。然后在数据库文件上(*.mdb)点鼠标右键，选择属性，点安全，查看是否存在everyone用户，如果没有，添加everone用户，勾选"完全控制".
Datenbank drei Paradigmen
So löschen Sie eine Datenbank
So stellen Sie eine Verbindung zur Datenbank in VB her
MySQL-Datenbank wiederherstellen
So stellen Sie eine Verbindung zum Zugriff auf die Datenbank in VB her
So lösen Sie das Problem eines ungültigen Datenbankobjektnamens
So verbinden Sie VB mit dem Zugriff auf die Datenbank
So verbinden Sie ASP mit dem Zugriff auf die Datenbank
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