asp.net具体分页原理是怎么实现的,尤其是百万数据量时候还有个问题
举个例子,
假如,我只想读取第56页数据,那肯定是只读出第56页数据,就OK了,这样多好,减轻数据库压力
访问数据页快,请问大家,这个怎么实现呢?最最优化的方法
举个例子,
假如,我只想读取第56页数据,那肯定是只读出第56页数据,就OK了,这样多好,减轻数据库压力
访问数据页快,请问大家,这个怎么实现呢?最最优化的方法
解决方案 »
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怎么写,大哥,可以告诉我吗?
@tablefield varchar(20),
@where varchar(5000),
@orderby varchar(500),
@fieldlist varchar(1000),
@curpage int,
@page_record int,
@sort varchar(8) AS DECLARE @cmd varchar(8000)
DECLARE @uprecord int
DECLARE @Op varchar(2) -- 操作符
DECLARE @max_min varchar(4) -- 最大/最小计算 SET @op = '<'
SET @max_min = 'MIN' IF @sort = 'asc'
BEGIN
SET @Op = '>'
SET @max_min = 'MAX'
SET @uprecord=@curpage * @page_record
SET @where = '('+@where+')' IF @curpage = 0
SET @cmd = 'SELECT TOP '+cast(@page_record AS NVARCHAR)+' '+@fieldlist+' FROM '+@tablename+' WHERE '+@where+' '+@orderby
ELSE
SET @cmd = 'SELECT TOP '+cast(@page_record AS NVARCHAR)+' '+@fieldlist+' FROM '+@tablename+' WHERE '+@where+' AND '+@tablefield+'
'+@op+' (SELECT '+@max_min+'('+@tablefield+') FROM (SELECT TOP '+cast(@uprecord AS NVARCHAR)+' '+@tablefield+' FROM '+@tablename+' WHERE
'+@where+' '+@orderby+') AS TmpTbl ) AND '+@where+' '+@orderby EXEC(@cmd)
PRINT(@cmd)
GO
[/code]
@tablefield varchar(20),
@where varchar(5000),
@orderby varchar(500),
@fieldlist varchar(1000),
@curpage int,
@page_record int,
@sort varchar(8) AS BEGIN DECLARE @cmd varchar(8000)
DECLARE @uprecord int
DECLARE @Op varchar(2) -- 操作符
DECLARE @max_min varchar(4) -- 最大/最小计算 SET @op = '<'
SET @max_min = 'MIN' IF @sort = 'asc'
BEGIN
SET @Op = '>'
SET @max_min = 'MAX'
END SET @uprecord=@curpage * @page_record
SET @where = '('+@where+')' IF @curpage = 0
SET @cmd = 'SELECT TOP '+cast(@page_record AS NVARCHAR)+' '+@fieldlist+' FROM '+@tablename+' WHERE '+@where+' '+@orderby
ELSE
SET @cmd = 'SELECT TOP '+cast(@page_record AS NVARCHAR)+' '+@fieldlist+' FROM '+@tablename+' WHERE '+@where+' AND '+@tablefield+'
'+@op+' (SELECT '+@max_min+'('+@tablefield+') FROM (SELECT TOP '+cast(@uprecord AS NVARCHAR)+' '+@tablefield+' FROM '+@tablename+' WHERE
'+@where+' '+@orderby+') AS TmpTbl ) AND '+@where+' '+@orderby EXEC(@cmd)
PRINT(@cmd) END
GO
http://blog.csdn.net/46539492/archive/2008/04/02/2244627.aspx
CREATE procedure main_table_pwqzc
(@pagesize int,
@pageindex int,
@docount bit,
@this_id)
as
if(@docount=1)
begin
select count(id) from luntan where this_id=@this_id
end
else
begin
declare @indextable table(id int identity(1,1),nid int)
declare @PageLowerBound int
declare @PageUpperBound int
set @PageLowerBound=(@pageindex-1)*@pagesize
set @PageUpperBound=@PageLowerBound+@pagesize
set rowcount @PageUpperBound
insert into @indextable(nid) select id from luntan where this_id=@this_id order by reply_time desc
select a.* from luntan a,@indextable t where a.id=t.nid
and t.id>@PageLowerBound and t.id<=@PageUpperBound order by t.id
end
GO存储过程会根据传入的参数@docount来确定是不是要返回所有要分页的记录总数
特别是这两行
set rowcount @PageUpperBound
insert into @indextable(nid) select id from luntan where this_id=@this_id order by reply_time desc真的是妙不可言!!set rowcount @PageUpperBound当记录数达到@PageUpperBound时就会停止处理查询
,select id 只把id列取出放到临时表里,select a.* from luntan a,@indextable t where a.id=t.nid
and t.id>@PageLowerBound and t.id<=@PageUpperBound order by t.id
而这句也只从表中取出所需要的记录,而不是所有的记录,结合起来,极大的提高了效率!!
妙啊,真的妙!!!!
CREATE PROCEDURE Paging_RowCount
(
@Tables varchar(1000),
@PK varchar(100),
@Sort varchar(200) = NULL,
@PageNumber int = 1,
@PageSize int = 10,
@Fields varchar(1000) = '*',
@Filter varchar(1000) = NULL,
@Group varchar(1000) = NULL)
AS/*Default Sorting*/
IF @Sort IS NULL OR @Sort = ''
SET @Sort = @PK/*Find the @PK type*/
DECLARE @SortTable varchar(100)
DECLARE @SortName varchar(100)
DECLARE @strSortColumn varchar(200)
DECLARE @operator char(2)
DECLARE @type varchar(100)
DECLARE @prec int/*Set sorting variables.*/
IF CHARINDEX('DESC',@Sort)>0
BEGIN
SET @strSortColumn = REPLACE(@Sort, 'DESC', '')
SET @operator = '<='
END
ELSE
BEGIN
IF CHARINDEX('ASC', @Sort) = 0
SET @strSortColumn = REPLACE(@Sort, 'ASC', '')
SET @operator = '>='
END
IF CHARINDEX('.', @strSortColumn) > 0
BEGIN
SET @SortTable = SUBSTRING(@strSortColumn, 0, CHARINDEX('.',@strSortColumn))
SET @SortName = SUBSTRING(@strSortColumn, CHARINDEX('.',@strSortColumn) + 1, LEN(@strSortColumn))
END
ELSE
BEGIN
SET @SortTable = @Tables
SET @SortName = @strSortColumn
ENDSELECT @type=t.name, @prec=c.prec
FROM sysobjects o
JOIN syscolumns c on o.id=c.id
JOIN systypes t on c.xusertype=t.xusertype
WHERE o.name = @SortTable AND c.name = @SortNameIF CHARINDEX('char', @type) > 0
SET @type = @type + '(' + CAST(@prec AS varchar) + ')'DECLARE @strPageSize varchar(50)
DECLARE @strStartRow varchar(50)
DECLARE @strFilter varchar(1000)
DECLARE @strSimpleFilter varchar(1000)
DECLARE @strGroup varchar(1000)/*Default Page Number*/
IF @PageNumber < 1
SET @PageNumber = 1/*Set paging variables.*/
SET @strPageSize = CAST(@PageSize AS varchar(50))
SET @strStartRow = CAST(((@PageNumber - 1)*@PageSize + 1) AS varchar(50))/*Set filter & group variables.*/
IF @Filter IS NOT NULL AND @Filter != ''
BEGIN
SET @strFilter = ' WHERE ' + @Filter + ' '
SET @strSimpleFilter = ' AND ' + @Filter + ' '
END
ELSE
BEGIN
SET @strSimpleFilter = ''
SET @strFilter = ''
END
IF @Group IS NOT NULL AND @Group != ''
SET @strGroup = ' GROUP BY ' + @Group + ' '
ELSE
SET @strGroup = ''
/*Execute dynamic query*/
EXEC(
'
DECLARE @SortColumn ' + @type + '
SET ROWCOUNT ' + @strStartRow + '
SELECT @SortColumn=' + @strSortColumn + ' FROM ' + @Tables + @strFilter + ' ' + @strGroup + ' ORDER BY ' + @Sort + '
SET ROWCOUNT ' + @strPageSize + '
SELECT ' + @Fields + ' FROM ' + @Tables + ' WHERE ' + @strSortColumn + @operator + ' @SortColumn ' + @strSimpleFilter + ' ' + @strGroup + ' ORDER BY ' + @Sort + '
'
)
GO
2.页面上加button控制,button显示为当前页码,选择某一具体页码是,读取该页码对应的数据库记录.
Button如这种效果,每组显示10个或者多个|<< << < 1 2 3 4 5 6 7 8 9 10 > >> >>|
...
|<< << < 51 52 53 54 55 56 57 58 59 60 > >> >>|
题外话:经不住一些朋友的一再要求,一气写了这么几篇Ajax方面的文章,这其中大部分代码都是从我的项目中摘取出来的,不过为了演示整个程序的框架结构,所以在演示程序代码里不会有大量与实际相关的业务逻辑处理,但是这并不妨碍你利用这些理论做出复杂的、完善的应用。一、数据库分页理论在实际项目中经常会遇到一个表里有几K、几M以上的数据,而呈现给用户时并不会一下子都显示出来,所以都是分批展示给用户,这样一来可以减小网络传输量,二来也减轻服务器压力。本文展示了在数据库中如何实现分页,如何利用AjaxPro实现无刷新分页。
http://blog.csdn.net/zhoufoxcn/archive/2008/03/12/2174234.aspx
我写的效率较高
ALTER PROCEDURE PageSplit
(
@PageCurrent int, --当前页
@PageCount int, --每页的数量
@PageTotal int output --总共有多少记录
)
AS
declare @Start int --当前页的第一行是总记录的第几行
declare @Last int --当前页的最后一行是总记录的第几行
set @Start=(@PageCurrent-1)*@PageCount+1
set @Last=@PageCurrent*@PageCount
--得到总记录数
set @PageTotal=(select count(*) from NewsInfo)
--查询的信息
select NewsTitle,NewsDate from NewsInfo where NewsID between @Start and @Last order by NewsDate desc
RETURN
public partial class News_PageSplit : System.Web.UI.Page
{
int PageCount = 5;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
int PageCurrent =1;
ShowMes(PageCurrent, PageCount);
}
}
public void ShowMes(int pagecurrent,int pagecount)
{
SqlConnection Conn = new SqlConnection(System.Configuration.ConfigurationManager.AppSettings["PhotoConn"]);
Conn.Open();
SqlDataAdapter da =new SqlDataAdapter ("PageSplit",Conn);
da.SelectCommand.CommandType=CommandType.StoredProcedure;
//SqlParameter[] myparam ={ new SqlParameter("@PageCurrent",pagecurrent),
// new SqlParameter("@PageCount",pagecount)
// };
da.SelectCommand.Parameters.Add("@PageCurrent", pagecurrent);
da.SelectCommand.Parameters.Add("@pageCount",pagecount);
da.SelectCommand.Parameters.Add("@PageTotal",SqlDbType.Int);
da.SelectCommand.Parameters["@PageTotal"].Direction = ParameterDirection.Output; //绑定数据源 DataSet ds = new DataSet();
da.Fill(ds);
//总记录数
double total = Convert.ToDouble(da.SelectCommand.Parameters["@PageTotal"].Value);
//总页数
double page = Math.Ceiling(total / PageCount);
//当前页
LabCurrent.Text = pagecurrent.ToString();
//总共有多少页
LabCount.Text = page.ToString(); GridView1.DataSource = ds;
GridView1.DataBind(); BindButton();
}
protected void LinkButton2_Click(object sender, EventArgs e)
{
int current = int.Parse(LabCurrent.Text) - 1;
LabCurrent.Text = current.ToString();
ShowMes(current, PageCount);
}
protected void LinkButton1_Click(object sender, EventArgs e)
{
int current = int.Parse(LabCurrent.Text) + 1;
LabCurrent.Text = current.ToString();
ShowMes(current, PageCount);
}
public void BindButton()
{
if (LabCurrent.Text == "1")
{
LbPrev.Enabled = false;
}
else
{
LbPrev.Enabled = true;
} if (LabCurrent.Text == LabCount.Text)
{
LBnext.Enabled = false;
}
else
{
LBnext.Enabled = true;
}
}
}
他的记录有个编号
可以指定到多少条记录之后查询