查询关联表,一级用Include二级以后用ThenInclude。 usingConsoleApp1.Data;//上下文的文件夹usingMicrosoft.EntityFrameworkCore;//ef框架using(vardb =newOAContext()) {varstu = db.Student.AsNoTracking().Include(s=>s.users).ToList();//二级三级以上往后加ThenInclude(c=>c.关联名)即可foreach(varsinstu)...
正如其他人在comments中所说的那样，您可以使用EF6 code来解析表达式并应用相关的Include/ThenInclude调用...
var blogs = context.Blogs.Include(blog => blog.Posts) .ThenInclude(post => post.Author).ToList(); 1. 2. 但是,任何技术都有两面性,优势不可能让你占完了,使用N+1 模式的优点是可以单独缓存部分数据。 跟踪与非跟踪查询 跟踪行为决定了 EF Core 是否将有关实体实例的快照信息保留在其更改跟踪器中。
varblogs = context.Blogs.Include(blog => blog.Posts) .ThenInclude(post => post.Author).ToList(); 但是,任何技术都有两面性,优势不可能让你占完了,使用N+1 模式的优点是可以单独缓存部分数据。 跟踪与非跟踪查询 跟踪行为决定了EF Core是否将有关实体实例的快照信息保留在其更改跟踪器中。如果已跟踪某...
生成的 store 命令将包含每个 Include 的外部联接或联合,具体取决于映射。 类似这样的查询将在单个有效负载中从数据库中引入大型连接图表,这会加剧所有带宽问题,尤其是当有效负载中有大量冗余时(例如,使用多个级别的 Include 来遍历一对多方向中的关联时)。
Docker 容器化应用中的 EF Core(第 3 部分) 通过Julie Lerman 在过去的两篇文章,我介绍了在生成较小的 ASP.NET Core API 使用实体框架封装在 Docker 容器中。在第一篇文章,我包含在容器内的一个 SQLite 数据库。在第二个,我针对 Azure SQL 数据库可从任何位置访问。更大的难题在这...
In EFCore3 Preview 7 onwards, there is a significant slow down when I have a query with many .ThenInclude()s, e.g. new WhyYouSoSlowDb(options) .Blog .Include(x => x.Posts) .ThenInclude(x => x.PostInstances) .ThenInclude(x => x.Comments) ...
In EF Core 6.0, this support has been expanded to include cases where non-navigation collections are contained in the query projection.The following are example queries showing the translation on SQL Server into either a single query or multiple queries....
Alternative (not MS based) Language Integrated Query (LINQ) technology for relational databases. It allows you to use C# to write strongly typed SQL queries. For EF Core: 3-8. Full C# support for query creation: multiple statements inside lambda, variables, functions, etc. ...
Overall, EF8 RC 2 contains all the major feature features we intend to ship in EF8, although further tweaks and bug fixes are coming for GA. These features include: Allow Multi-region or Application Preferred Regions in EF Core Cosmos ...