如何使用存储库模式在实体框架中执行复杂的查询（例如，通过多对多关系）？

发布于 2024-10-16 11:56:11 字数 721 浏览 0 评论 0原文

我正在使用实体框架 v4 和在这个问题的答案中找到的存储库模式：

也就是说，每个存储库都继承自一个抽象基类，该基类包含添加、删除等通用方法。并且还为该存储库/实体特有的任何方法实现特定的存储库接口。

IE。

public class CompanyRepository : Repository<Company>, ICompanyRepository {
     public Company Get(int id)
     {
       return base.ObjectSet.SingleOrDefault(x => x.Id == id);
     }
}

如何执行更复杂的查询来引用不属于此存储库的实体...（例如与另一个表的多对多关系）？

public List<Company> GetAllCompaniesForUser(int userId) 
{
    return base.ObjectSet.Where(x => x.Users ?????
}

原文

I am using Entity Framework v4 and the repository pattern found in the answer to this SO question:

Advantage of creating a generic repository vs. specific repository for each object?

Namely, each repository inherits from an abstract base class that contains generic methods like add, delete, etc. and also implements a specific repository interface for any methods that are unique to that repository/entity.

ie.

public class CompanyRepository : Repository<Company>, ICompanyRepository {
     public Company Get(int id)
     {
       return base.ObjectSet.SingleOrDefault(x => x.Id == id);
     }
}

How can I perform more complex queries that reference entities that are not part of this repository... (say across a many-to-many relationship to another table)?

public List<Company> GetAllCompaniesForUser(int userId) 
{
    return base.ObjectSet.Where(x => x.Users ?????
}

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云归处 2024-10-23 11:56:11

我认为这可能是这样做的方法：

return base.ObjectSet.Where(x => x.Users.Any(u => u.Id == userId)).ToList();

或者

var companies = from c in base.ObjectSet
                from u in c.Users
                where u.Id == userId
                select c;

return companies.ToList();

I think this may be the way to do it:

return base.ObjectSet.Where(x => x.Users.Any(u => u.Id == userId)).ToList();

var companies = from c in base.ObjectSet
                from u in c.Users
                where u.Id == userId
                select c;

return companies.ToList();

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