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  • 解决 EF 分层查询的一个性能问题[转]

    前两年帮朋友 做了个网吧管理软件,采用动软的三层架构 sql语句生成的。最近因功能变更 要改动,而我这段正在做asp.net mvc +ef+autofac的一个电商网站。索性 就把原来的底层全重新了套用了我现在的架构 EF6.0+autofac+三层架构,上层的asp.net没有变。改完后发现交班页面打开巨慢。

       

    跟踪EF生成的sql语句   发现生成的sql 有问题,查找的全表,而全表有近10万条的数据。

    继续跟踪数据库的耗时查询 发现确实是这条语句占时间

    为什么会这样呢,我在查询里做条件搜索了,为啥 结果不对呢?

    贴出 BaseRepository.cs 的代码

    class="code_img_closed" src="/Upload/Images/2014080923/0015B68B3C38AA5B.gif" alt="" />logs_code_hide('90546e12-ce1e-45ff-857c-4fbf39441633',event)" src="/Upload/Images/2014080923/2B1B950FA3DF188F.gif" alt="" />

     1 public class BaseRepository<T> :IDBbase<T>  where T : class
     2     {
     3         //实例化EF框架
     4        protected skdbContext db = new skdbContext();
     5 
     6         //添加
     7         public T AddEntities(T entity)
     8         {
     9             db.Entry<T>(entity).State = EntityState.Added;
    10             db.SaveChanges();
    11             return entity;
    12         }
    13 
    14         //修改
    15         public bool UpdateEntity(T entity)
    16         {
    17             db.Set<T>().Attach(entity);
    18             db.Entry<T>(entity).State = EntityState.Modified;
    19             return db.SaveChanges() > 0;
    20         }
    21 
    22         //修改
    23         public bool DeleteEntities(T entity)
    24         {
    25             db.Set<T>().Attach(entity);
    26             db.Entry<T>(entity).State = EntityState.Deleted;
    27             return db.SaveChanges() > 0;
    28         }
    29 
    30         //查询
    31         public IQueryable<T> LoadEntities(Func<T, bool> wherelambda)
    32         {
    33             return db.Set<T>().Where<T>(wherelambda).AsQueryable();
    34         }
    35         //查询单个
    36         public T LoadEntitie(Func<T, bool> wherelambda)
    37         {
    38             return db.Set<T>().FirstOrDefault<T>(wherelambda);
    39         }
    40 
    41         //分页
    42         public IQueryable<T> LoadPagerEntities<S>(int pageSize, int pageIndex, out int total,
    43             Func<T, bool> whereLambda, bool isAsc, Func<T, S> orderByLambda)
    44         {
    45             var tempData = db.Set<T>().Where<T>(whereLambda);
    46 
    47             total = tempData.Count();
    48 
    49             //排序获取当前页的数据
    50             if (isAsc)
    51             {
    52                 tempData = tempData.OrderBy<T, S>(orderByLambda).
    53                       Skip<T>(pageSize * (pageIndex - 1)).
    54                       Take<T>(pageSize).AsQueryable();
    55             }
    56             else
    57             {
    58                 tempData = tempData.OrderByDescending<T, S>(orderByLambda).
    59                      Skip<T>(pageSize * (pageIndex - 1)).
    60                      Take<T>(pageSize).AsQueryable();
    61             }
    62             return tempData.AsQueryable();
    63         }
    64     }

    View Code

    调用代码 

    return jiaobanitem.LoadEntities(t => t.JiaoBanID == jiaobanID && t.GoodsID == GoodsID).FirstOrDefault();

    参考 nopCommerce  修改baserepository

      1 public class EFRepository<T> : IRepository<T> where T : class 
      2     {
      3         //实例化EF框架
      4        //protected YaFeiNetContext db = new YaFeiNetContext();
      5        private DbContext _context;
      6        private IDbSet<T> _entities;
      7 
      8        public EFRepository(DbContext context)
      9        {
     10            this._context = context;
     11        }
     12 
     13 
     14         //添加
     15         public virtual T AddEntities(T entity)
     16         {
     17             try
     18             {
     19                 if(entity==null)
     20                     throw new ArgumentNullException("entity");
     21                 
     22                 this.Entities.Add(entity);
     23                 this._context.SaveChanges();
     24                 return entity;
     25             }
     26             catch(DbEntityValidationException dbEx)
     27             {
     28                 var msg = string.Empty;
     29                 foreach(var validationErrors in dbEx.EntityValidationErrors)
     30                     foreach (var validationError in validationErrors.ValidationErrors)
     31                         msg += string.Format("Property:{0} Error:{1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine ;
     32 
     33                 var fail = new Exception(msg,dbEx);
     34                 throw fail;
     35             }
     36         }
     37 
     38         //修改
     39         public virtual bool UpdateEntities(T entity)
     40         {
     41             try
     42             {
     43                 if (entity == null)
     44                     throw new ArgumentNullException("entity");
     45 
     46 
     47                // this.Entities.Attach(entity);
     48                // _context.Entry<T>(entity).State = EntityState.Modified;
     49                 return this._context.SaveChanges() > 0;
     50             }
     51             catch (DbEntityValidationException dbEx)
     52             {
     53                 var msg = string.Empty;
     54                 foreach (var validationErrors in dbEx.EntityValidationErrors)
     55                     foreach (var validationError in validationErrors.ValidationErrors)
     56                         msg += string.Format("Property:{0} Error:{1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;
     57 
     58                 var fail = new Exception(msg, dbEx);
     59                 throw fail;
     60             }
     61 
     62         }
     63 
     64         //修改
     65         public virtual bool DeleteEntities(T entity)
     66         {
     67             try
     68             {
     69                 if (entity == null)
     70                     throw new ArgumentNullException("entity");
     71 
     72                 //db2.Set<T>().Attach(entity);
     73                 //db2.Entry<T>(entity).State = EntityState.Deleted;
     74                 this.Entities.Remove(entity);
     75                 return this._context.SaveChanges() > 0;
     76             }
     77             catch (DbEntityValidationException dbEx)
     78             {
     79                 var msg = string.Empty;
     80                 foreach (var validationErrors in dbEx.EntityValidationErrors)
     81                     foreach (var validationError in validationErrors.ValidationErrors)
     82                         msg += string.Format("Property:{0} Error:{1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;
     83 
     84                 var fail = new Exception(msg, dbEx);
     85                 throw fail;
     86             }
     87 
     88 
     89         }
     90 
     91         //查询
     92         public virtual IQueryable<T> LoadEntities(Func<T, bool> wherelambda)
     93         {
     94             return this.Entities.Where<T>(wherelambda).AsQueryable();
     95         }
     96         //查询单个
     97         public virtual T LoadEntitie(Func<T, bool> wherelambda)
     98         {
     99             return this.Table.Where(wherelambda).FirstOrDefault();
    100         }
    101        /// <summary>
    102        /// 根据主键查找
    103        /// </summary>
    104        /// <param name="id"></param>
    105        /// <returns></returns>
    106         public virtual T GetById(object id)
    107         {
    108             return this.Entities.Find(id);
    109         }
    110 
    111 
    112 
    113 
    114         //分页
    115         public virtual IQueryable<T> LoadPagerEntities<S>(int pageSize, int pageIndex, out int total,
    116             Func<T, bool> whereLambda, bool isAsc, Func<T, S> orderByLambda)
    117         {
    118 
    119             var tempData = this.Entities.Where<T>(whereLambda);
    120 
    121                 total = tempData.Count();
    122 
    123                 //排序获取当前页的数据
    124                 if (isAsc)
    125                 {
    126                     tempData = tempData.OrderBy<T, S>(orderByLambda).
    127                           Skip<T>(pageSize * (pageIndex - 1)).
    128                           Take<T>(pageSize).AsQueryable();
    129                 }
    130                 else
    131                 {
    132                     tempData = tempData.OrderByDescending<T, S>(orderByLambda).
    133                          Skip<T>(pageSize * (pageIndex - 1)).
    134                          Take<T>(pageSize).AsQueryable();
    135                 }
    136                 return tempData.AsQueryable();
    137             
    138 
    139         
    140         }
    141 
    142         protected virtual IDbSet<T> Entities
    143         {
    144             get
    145             {
    146                 if (_entities == null)
    147                     _entities = _context.Set<T>();
    148                 return _entities;
    149             }
    150         }
    151 
    152 
    153         public virtual IQueryable<T> Table
    154         {
    155             get { return this.Entities; }
    156         }
    157 
    158 
    159     }

    View Code

    同时修改调用代码 为

    return jiaobanitem.Table.Where(t=>t.JiaoBanID ==jiaobanID && t.GoodsID ==GoodsID).FirstOrDefault();

    问题解决 页面响应不到100ms   同时调试中 生成的sql语句已经有 查询条件了

    问题出在  

    //查询
    public IQueryable<T> LoadEntities(Func<T, bool> wherelambda)
    {
      return db.Set<T>().Where<T>(wherelambda).AsQueryable();
    }

    为了验证,我在前台直接调用 

    return this.context.Set<tb_e_jiaoBanItem>().Where(t => t.JiaoBanID == jiaobanID && t.GoodsID == GoodsID).AsQueryable().FirstOrDefault();

    页面响应也是 100ms左右,性能没问题。直接调用 dbcontext的set<>方法 没问题。但跨了几层传递后 就有问题。并没有生成我想要的查询语句

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  • 原文地址:https://www.cnblogs.com/jimcsharp/p/5894218.html
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