让所有的SQL表使用的foreach的值 [英] get all the values in Sql table using foreach

问题描述

我需要从表StaffSectionInCharge让所有的入侵检测系统，它只有两列和STAFFID SectionId，我和STAFFID的StudentId值.....问题是我不能直接获取这些记录此表.....我使用实体框架，此表的设计

  [EdmRelationshipNavigationPropertyAttribute（模型，StaffSectionInCharge，科）]
    公共EntityCollection＆lt;节＆GT;第
    {
        得到
        {
            返回((IEntityWithRelationships)this).RelationshipManager.GetRelatedCollection<Section>(\"Model.StaffSectionInCharge\", 部分）;
        }
        组
        {
            如果（（价值！= NULL））
            {
                ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedCollection<Section>(\"Model.StaffSectionInCharge\", 节，值）;
            }
        }
    }
 

我可以像

通过对员工表访问此表

 员工员工= buDataEntities.Staffs.First（S = GT; s.StaffId STAFFID ==）;
第节= buDataEntities.Sections.First（S = GT; s.SectionId == SectionId）;staff.Sections.Add（部分）;
buDataEntities.savechanges（）;
 

这样我可以记录添加到该StaffSectionInCharge表....

在这里我要得到相应的SectionId所有StaffIds

我试图让像

  DataAccess.Staff人员=新DataAccess.Staff（）;的foreach（在staffs.Sections.Select INT人员（S = GT; s.SectionId））
            {            }
 

但它没有工作，任何人都可以帮助我在这里

解决方案

  VAR staffIds = buDataEntities.Staffs
    。凡（ST = GT; st.Sections.Any（SE = GT; se.SectionId == SectionId））
    。选择（ST = GT; st.StaffId）
    .ToList（）;
 

或

  VAR staffIds = buDataEntities.Sections
    。凡（SE = GT; se.SectionId == SectionId）
    .SelectMany（SE = GT; se.Staffs.Select（ST = GT; st.StaffId））
    。不同（）
    .ToList（）;
 

这两个选项应该工作。如果 SectionId 是部分的主键可以smplify第二code为：

  VAR staffIds = buDataEntities.Sections
    。凡（SE = GT; se.SectionId == SectionId）
    。选择（SE = GT; se.Staffs.Select（ST = GT; st.StaffId））
    .SingleOrDefault（）;
 

I need to get all the Ids' from the table "StaffSectionInCharge", it has only two columns StaffId and SectionId, I have values of StaffId and StudentId.....the problem is I can't get the records directly to this table.....am using entity framework and the design of this table is

[EdmRelationshipNavigationPropertyAttribute("Model", "StaffSectionInCharge", "Section")]
    public EntityCollection<Section> Sections
    {
        get
        {
            return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedCollection<Section>("Model.StaffSectionInCharge", "Section");
        }
        set
        {
            if ((value != null))
            {
                ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedCollection<Section>("Model.StaffSectionInCharge", "Section", value);
            }
        }
    }

I can access this table through staff table like

Staff staff = buDataEntities.Staffs.First(s => s.StaffId == StaffId);
Section section = buDataEntities.Sections.First(s => s.SectionId == SectionId);

staff.Sections.Add(section);
buDataEntities.savechanges();

like this I can add the records to this StaffSectionInCharge table....

here I want to get all the StaffIds for the corresponding SectionId

I tried getting like

DataAccess.Staff staffs = new DataAccess.Staff();

foreach (int staff in staffs.Sections.Select(s=>s.SectionId))
            { 

            }

but its not working, can anyone help me here

解决方案

var staffIds = buDataEntities.Staffs
    .Where(st => st.Sections.Any(se => se.SectionId == SectionId))
    .Select(st => st.StaffId)
    .ToList();

or

var staffIds = buDataEntities.Sections
    .Where(se => se.SectionId == SectionId)
    .SelectMany(se => se.Staffs.Select(st => st.StaffId))
    .Distinct()
    .ToList();

Both options should work. If SectionId is the primary key of Section you can smplify the second code to:

var staffIds = buDataEntities.Sections
    .Where(se => se.SectionId == SectionId)
    .Select(se => se.Staffs.Select(st => st.StaffId))
    .SingleOrDefault();

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