Entity Framework Core的坑,Select后再对导航属性进行查询或Select前进行Skip/Take
Posted on 2019-05-21 17:29 火冰·瓶 阅读(2114) 评论(0) 收藏 举报把asp.net core的项目发布到ubuntu上了,运行的时候出现了如下警告:
warn: Microsoft.EntityFrameworkCore.Query[20500]
The LINQ expression 'where [g.ResBaseInfo].ResType.Equals(Hotel)' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
The LINQ expression 'Skip(__p_3)' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
The LINQ expression 'Take(__p_4)' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[10106]
The Include operation for navigation '[g].ResBaseInfo' is unnecessary and was ignored because the navigation is not reachable in the final query results. See https://go.microsoft.com/fwlink/?linkid=850303 for more information.
warn: Microsoft.EntityFrameworkCore.Query[20500]
The LINQ expression 'where [g.ResBaseInfo].ResType.Equals(Hotel)' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
The LINQ expression 'Count()' could not be translated and will be evaluated locally.
本来打算不理会的,但是仔细看了下,大概的意思是会把所有数据拉到本地再进行查询处理,如果数据量大了,服务器肯定遭不住,还是分析代码找到了原因。
错误在于先在一个公共方法里select出了基础数据,然后在Controller中再次根据条件进行where,如果where的是导航属性中的属性,就会报上面的警告。修改了代码,把对导航属性的where语句放到select前,问题解决。
public IQueryable<ResBaseInfoView> GetResBaseInfoViewQueryable(Lang lang, ResType resType = 0)
{
var jquery = _context.ResBaseInfoMultipleLanguage
//.Include(g => g.ResBaseInfo)
//.ThenInclude(g => g.AreaCode)
.Where(g => !g.ResBaseInfo.IsDelete && g.Language.Equals(lang));
if (resType != 0)
{
jquery = jquery.Where(g => g.ResBaseInfo.ResType == resType);
}
var result = jquery
.Select(rbml => new ResBaseInfoView
{
ID = rbml.ResBaseInfoID,
AddAccountID = rbml.ResBaseInfo.AddAccountID,
AreaCodeID = rbml.ResBaseInfo.AreaCodeID,
IsDelete = rbml.ResBaseInfo.IsDelete,
Language = rbml.Language,
MLID = rbml.MLID,
UpdateTime = rbml.ResBaseInfo.UpdateTime,
ImageName = rbml.ResBaseInfo.ImageName,
Name = rbml.Name,
ResType = rbml.ResBaseInfo.ResType,
ResTypeName = rbml.ResBaseInfo.ResType.GetDescription(lang),
AreaName = rbml.ResBaseInfo.AreaCode.GetML_Name(lang),
Address = rbml.Address,
AddTime = rbml.ResBaseInfo.AddTime,
Lng = rbml.ResBaseInfo.Lng,
Lat = rbml.ResBaseInfo.Lat,
ZoomLevel = rbml.ResBaseInfo.ZoomLevel,
IsShow = rbml.ResBaseInfo.IsShow,
MobilePhone = rbml.MobilePhone,
Telephone = rbml.Telephone,
Sequence = rbml.ResBaseInfo.Sequence
});
return result;
}
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