Question

Am using Entity framework to connect database with my asp.net application. Here I’ve a Foreign key table which has two columns, StaffId and SectionId. Here StaffId is the Primary key of Staff table and SectionId is the Primary key of Sections table. I have values in this table like

StaffId     SectionId
-------     ---------
  1            1
  2            5
  5            8
  1            5
  1            8

here I know the StaffId and I need to get all the SectionIds for this corresponding staffid(eg. 1,5 and 8 for staff 1 here).

If I want to know the details with First method, with the known StaffId I can do like,

DataObject.Entities dataEntities=new DataObject.Entities();

DataObject.Section section = dataEntities.Sections.First(s=>s.Staffs
                                  .Select(ss=>ss.StaffId).Contains(staffId));

with this I can get the information about the first section that matches with the StaffId.(ex:info about sectionid=1 here)

In the same way I tried to get all the sectionIds for a particular staffId like,

List<int> sectionIds = dataEntities.Sections.Where(s => s.Staffs.Where
                       (ss => ss.StaffId == staffId)).Select(sec=>sec.SectionId);

but its not working, can anyone help me here

Answer 1

here I know the StaffId and I need to get all the SectionIds for this
corresponding staffid

List<int> sectionIds = dataEntities.Sections
    .Where(se => se.Staffs.Any(st => st.StaffId == staffId))
    .Select(se => se.SectionId)
    .ToList();