看到本文的标题,相信你会忍不住进来看看!
没错,本文要讲的就是这个重量级的东西,这个不仅仅支持单表查询,更能支持连接查询,
加入一个表10W数据,另一个表也是10万数据,当你用linq建立一个连接查询然后利用take,skip读取第N页数据的时候,
你的程序就挂了,因为,你很可能读取需要几十秒甚至几分钟以上。
下面来讲解一下,ASP.NET MVC + EF 利用存储过程读取大数据的详细过程。
1.首先,我们创建一个实体类PageinationInfo,主要用于分页,如下
1 public class PageinationInfo
2 {
3 /// <summary>
4 /// 要显示的表或多个表的连接
5 /// </summary>
6 public string strTable { get; set; }
7
8 /// <summary>
9 /// 要查询的字段
10 /// </summary>
11 public string strField { get; set; }
12
13 /// <summary>
14 /// 每页多少条记录
15 /// </summary>
16 public int pageSize { get; set; }
17
18 /// <summary>
19 /// 当前页
20 /// </summary>
21 public int pageIndex { get; set; }
22
23 /// <summary>
24 /// 查询条件,不需where
25 /// </summary>
26 public string strWhere { get; set; }
27
28 /// <summary>
29 /// 用于排序的主键
30 /// </summary>
31 public string strSortKey { get; set; }
32
33 /// <summary>
34 /// 用于排序,如:id desc (多个id desc,dt asc)
35 /// </summary>
36 public string strSortField { get; set; }
37
38 /// <summary>
39 /// 排序,0-顺序,1-倒序
40 /// </summary>
41 public bool strOrderBy { get; set; }
42
43 /// <summary>
44 /// 总记录数
45 /// </summary>
46 public int RecordCount { get; set; }
47
48 /// <summary>
49 /// 总页数
50 /// </summary>
51 public int PageCount { get; set; }
52
53 /// <summary>
54 /// 查询耗时,毫秒为单位
55 /// </summary>
56 public int UsedTime { get; set; }
57
58 }
2.然后我们再DAL层新建一个类 PageinationInfoService 主要用于实现分页读取数据,如下:
1 public class PageinationInfoService
2 {
3 /// <summary>
4 /// 获取分页列表
5 /// </summary>
6 /// <param name="pageinationInfo"></param>
7 /// <returns></returns>
8 public IList<Entity> GetPageinationInfoList<Entity>(PageinationInfo pageinationInfo) where Entity : class
9 {
10 dynamic result = null;
11 using (SnsLearningLogManagerDB db = new SnsLearningLogManagerDB())
12 {
13 #region SqlParameter参数
14 SqlParameter[] paras = new SqlParameter[10];
15 paras[0] = new SqlParameter("strTable", DbType.String);
16 paras[0].Value = pageinationInfo.strTable;
17
18 paras[1] = new SqlParameter("strField", DbType.String);
19 paras[1].Value = pageinationInfo.strField;
20
21 paras[2] = new SqlParameter("pageSize", DbType.Int16);
22 paras[2].Value = pageinationInfo.pageSize;
23
24 paras[3] = new SqlParameter("pageIndex", DbType.Int16);
25 paras[3].Value = pageinationInfo.pageIndex;
26
27 paras[4] = new SqlParameter("strWhere", DbType.String);
28 paras[4].Value = pageinationInfo.strWhere;
29
30 paras[5] = new SqlParameter("strSortKey", DbType.String);
31 paras[5].Value = pageinationInfo.strSortKey;
32
33 paras[6] = new SqlParameter("strSortField", DbType.String);
34 paras[6].Value = pageinationInfo.strSortField;
35
36 paras[7] = new SqlParameter("strOrderBy", DbType.Boolean);
37 paras[7].Value = pageinationInfo.strOrderBy;
38
39 paras[8] = new SqlParameter("RecordCount", DbType.Int16);
40 paras[8].Value = pageinationInfo.RecordCount;
41 paras[8].Direction = ParameterDirection.Output;
42
43 paras[9] = new SqlParameter("UsedTime", DbType.Int16);
44 paras[9].Value = pageinationInfo.UsedTime;
45 paras[9].Direction = ParameterDirection.Output;
46 #endregion
47
48 try
49 {
50 result = db.Database.SqlQuery<Entity>("exec LYBPager @strTable,@strField,@pageSize,@pageIndex,@strWhere,@strSortKey,@strSortField,@strOrderBy,@RecordCount output,@UsedTime output", paras).ToList();
51 pageinationInfo.RecordCount = (int)paras[8].Value;
52 pageinationInfo.UsedTime = (int)paras[9].Value;
53 }
54 catch (Exception ex)
55 {
56 throw;
57 }
58 }
59 return result;
60 }
61 }
PageinationInfoService类中我们传入的参数是实体和PageinationInfo,实体主要是用于接收数据并封装到实体中,LYBPager 这个是数据库中存储过程的名称,而UsedTime 就是存储过程读取数据所用的时间
BLL层的东西,我就不贴出来了,你们或者用工厂模式或者用简单3层,这个都无关紧要。
3.接下来,我们在Controller里来处理我们的业务需求,贴一段自己项目的代码作为分析,如下
1 public ActionResult Index(string LabelName,string _Title,string _Content, int pageNumber = 1, int pageSize = 10)
2 {
3 #region 分页
4 SnsModels.PageinationInfo pageinationInfo = new SnsModels.PageinationInfo();
5 pageinationInfo.pageIndex = pageNumber;
6 pageinationInfo.pageSize = pageSize;
7 pageinationInfo.RecordCount = 0;
8 pageinationInfo.strField = "*";
9 pageinationInfo.strOrderBy = true;
10 pageinationInfo.strSortField = "ArticleID desc";
11 pageinationInfo.strSortKey = "ArticleID";
12 pageinationInfo.strTable = "ArticleInfo";
13 pageinationInfo.strWhere = " 1=1";
14 pageinationInfo.UsedTime = 0;
15 pageinationInfo.PageCount = 0;
16 #endregion
17
18 IList<SnsModels.LabelInfo> LabelInfoList = Repository.GetList<SnsModels.LabelInfo>();
19 ViewBag.LabelInfoList = new SelectList(LabelInfoList,"LabelName","LabelName");
20
21 #region 参数处理
22 if (LabelName != null)
23 {
24 if (!string.IsNullOrEmpty(LabelName))
25 {
26 pageinationInfo.strWhere += " and LabelName like '%" + HttpUtility.UrlDecode(LabelName.Trim()) + "%'";
27 ViewBag.LabelInfoList = new SelectList(LabelInfoList, "LabelName", "LabelName",LabelName.Trim());
28 }
29 }
30 if (_Title != null)
31 {
32 if (!string.IsNullOrEmpty(_Title))
33 {
34 pageinationInfo.strWhere += " and Title like '%" + _Title.Trim() + "%'";
35 }
36 }
37 if (_Content != null)
38 {
39 if (!string.IsNullOrEmpty(_Content))
40 {
41 pageinationInfo.strWhere += " and Content like '%" + _Content.Trim() + "%'";
42 }
43 }
44 #endregion
45
46
47 IList<SnsModels.ArticleInfo> List = PageinationInfoManager.GetPageinationInfoList<SnsModels.ArticleInfo>(pageinationInfo);
48
49 #region 传值
50 ViewBag.List = List;
51 ViewBag.pageNumber = pageNumber;
52 ViewBag.pageSize = pageSize;
53 ViewBag.RecordCount = pageinationInfo.RecordCount;
54 ViewBag.LabelName =HttpUtility.UrlDecode(LabelName);
55 ViewBag._Title = _Title;
56 ViewBag._Content = _Content;
57 #endregion
58
59 return View();
60 }
上面我们通过把参数传递到PageinationInfo,然后根据传递的参数拼凑pageinationInfo.strWhere现实了多条件查询,
pageNumber,pageSize 我们已经传递到View,你可以通过Jquery插件展示你的分页,点击一下一页的时候,跳转回控制器就行了。
4,接下来,我给出存储过程,代码如下:
USE [LearningLogManagerDB2]
GO
/****** Object: StoredProcedure [dbo].[LYBPager] Script Date: 07/30/2014 11:51:44 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
--参数说明-------------------------------------------------------------
/**//*
@strTable --要显示的表或多个表的连接
@strField --要查询出的字段列表,*表示全部字段
@pageSize --每页显示的记录个数
@pageIndex --要显示那一页的记录
@strWhere --查询条件,不需where
@strSortKey --用于排序的主键
@strSortField --用于排序,如:id desc (多个id desc,dt asc)
@strOrderBy --排序,0-顺序,1-倒序
@RecordCount --查询到的总记录数
@UsedTime --耗时测试时间差
*/
ALTER PROCEDURE [dbo].[LYBPager]
@strTable varchar(1000) = '[dbo].[ttable]',--表名
@strField varchar(1000) = '*', --查询字段
@pageSize int = 10, --每页多少条记录
@pageIndex int = 1, --当前页
@strWhere varchar(1000) = '1=1', --查询条件
@strSortKey varchar(1000) = 'id', --主键
@strSortField varchar(500) = 'id DESC', --排序
@strOrderBy bit = 1, --是否排序 1表示排序
@RecordCount int OUTPUT, --总记录数
@UsedTime int OUTPUT --查询耗时,毫秒为单位
AS
SET NOCOUNT ON
Declare @sqlcount INT
Declare @timediff DATETIME
select @timediff=getdate()
Begin Tran
DECLARE @sql nvarchar(500),@where1 varchar(200),@where2 varchar(200)
IF @strWhere is null or rtrim(@strWhere)=''
BEGIN--没有查询条件
SET @where1=' WHERE '
SET @where2=' '
END
ELSE
BEGIN--有查询条件
SET @where1=' WHERE ('+@strWhere+') AND ' --本来有条件再加上此条件
SET @where2=' WHERE ('+@strWhere+') ' --原本没有条件而加上此条件
END
--SET @sql='SELECT @intResult=COUNT(*) FROM '+@strTable+@where2
BEGIN
SET @sql='SELECT @sqlcount=COUNT(*) FROM (select '+@strSortKey+' from '+ @strTable + @where2 +') As tmptab'
END
--print @sql
EXEC sp_executesql @sql,N'@sqlcount int OUTPUT',@sqlcount OUTPUT --计算总记录数
SELECT @RecordCount = @sqlcount --设置总记录数
IF @pageIndex=1 --第一页
BEGIN
SET @sql='SELECT TOP '+CAST(@pageSize AS varchar(200))+' '+@strField+' FROM '+@strTable+@where2+'ORDER BY '+ @strSortField
END
Else
BEGIN
IF @strOrderBy=0
SET @sql='SELECT TOP '+CAST(@pageSize AS varchar(200))+' '+@strField+ ' FROM '+
@strTable+@where1+@strSortKey+'>(SELECT MAX('+case when charindex('.',@strSortKey)>0 then right(@strSortKey,len(@strSortKey)-charindex('.',@strSortKey)) else @strSortKey end+') '+ ' FROM (SELECT TOP '+
CAST(@pageSize*(@pageIndex-1) AS varchar(200))+' '+@strSortKey+' FROM '+@strTable+@where2+
'ORDER BY '+@strSortField+') t) ORDER BY '+@strSortField
ELSE
SET @sql='SELECT TOP '+CAST(@pageSize AS varchar(200))+' '+@strField+' FROM '+@strTable+@where1+
@strSortKey+'<(SELECT MIN('+case when charindex('.',@strSortKey)>0 then right(@strSortKey,len(@strSortKey)-charindex('.',@strSortKey)) else @strSortKey end+') '+ ' FROM (SELECT TOP '+CAST(@pageSize*(@pageIndex-1) AS varchar(200))+' '+
@strSortKey+' FROM '+@strTable+@where2+'ORDER BY '+@strSortField+') t) ORDER BY '+@strSortField+''
END
print @sql
--select @RecordCount
EXEC(@sql)
print @sql
If @@Error <> 0
Begin
RollBack Tran
Return -1
End
Else
Begin
Commit TRAN
set @UsedTime = datediff(ms,@timediff,getdate())
--select @UsedTime
--select datediff(ms,@timediff,getdate()) as 耗时
Return @sqlcount
End
当然存储过程不是本人写的,我只是利用而已,也用了很久了,感觉还可以,有兴趣的可以分析分析。
在此非常感谢很多博友加入本人ASP.NET MVC QQ群,并且都很踊跃提问。
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来源:oschina
链接:https://my.oschina.net/u/4366862/blog/4403552