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(2062) 评论(0) 编辑 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; }