CODEWITHSUNDEEP
linqentity-framework
JoeBrockhaus
JoeBrockhaus

Reputation: 2793

complex EF graph linq join

entity model

So, that's my model .. nice and complex.

I'm looking to get Areas by a UserID. If I were doing this in SQL, I would do a bunch of joins all the way up to the Users table. How would you do this in LINQ query syntax or method chaining?

I can do this pretty straightforward from the other way around, but then I have to do a lot of extra work to flatten the resulting graph and it also requires pulling back all the entities in between.

If I can optionally include AreasPermissions & Permissions, that would be gravy .. but at this point I wouldn't mind an additional query to fetch those.

Another option I was floating was using a function import to a sproc and map that to an Area .. but when I start needing to include other entities it makes that option less elegant. I'm also trying to avoid using sprocs just to use sprocs because it's always a slippery slope with folks .. 'use a sproc for one thing' tends to mold into 'don't use EF (table access) for anything'. 

var userByID = new Func<User, bool>(x => x.UserId.Equals(userID, StringComparison.InvariantCultureIgnoreCase));
var user = this._context.Users
    .Include("TeamsUsers.Team.TeamsRoles.Role.RolesAreasPermissions.AreaPermission.Area")
    .Include("TeamsUsers.Team.TeamsRoles.Role.RolesAreasPermissions.AreaPermission.Permission")
    .Single(userByID);

Upvotes: 1

Views: 222

Answers (1)

david.s
david.s

Reputation: 11403

I have no way of testing this, but I think it should work:

var result = 
    from user in _context.Users
    where user.Id == userId
    from teamUser in user.TeamUsers
    from teamRole in teamUser.Team.TeamRoles
    from roleAreaPermission in teamRole.Role.RoleAreaPermissions
    select roleAreaPermission.AreaPermission.Area;

Upvotes: 4

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