I am facing this linq query for entity framework core (2.0).
var result = await dbContext.Table1DbSet
.Where(t1e => t1e.Id == id && t1e.Id2 == id2)
.Select
(
t1e =>
t1e.Table2NavPropICollection.Select
(
t2e => new
{
singleObject = t2e.Table3NavPropObject.TargetObject,
enumerable1 = t2e.Table3NavPropObject.Table4NavPropObject.Table5NavPropICollection.Select(t5e => t5e.TargetObject),
enumerable2 = t2e.Table3NavPropObject.Table6NavPropObject.Table7NavPropICollection.Select(t7e => t7e.TargetObject),
enumerable3 = t2e.Table3NavPropObject.Table8NavPropICollection.SelectMany(t8e => t8e.Table9NavPropICollection.Select(t9e => t9e.TargetObject))
}
)
)
.ToListAsync();
The goal is to query all the referenced instances of TargetObject which is referenced accros ~ 10 different tables.
Currently it returns an IEnumerable where the anonymous object contains the properties singleObject, enumerable1, enumerable2, enumerable3. All those properties are of type TargetObject or IEnumerable.
Can I, and how, rewrite the query to not return anonymous objects but just an IEnumerable containing all the values?
For some reason the compiler won't let me iterate over the anonymous collection and flatten it manually.
This should do the trick if you want one array per t1e row.
var result = await dbContext.Table1DbSet
.Where(t1e => t1e.Id == id && t1e.Id2 == id2)
.Select
(
t1e =>
t1e.Table2NavPropICollection.Select
(
t2e => new[] {t2e.Table3NavPropObject.TargetObject}.Concat(
t2e.Table3NavPropObject.Table4NavPropObject.Table5NavPropICollection.Select(t5e => t5e.TargetObject)).Concat(
t2e.Table3NavPropObject.Table6NavPropObject.Table7NavPropICollection.Select(t7e => t7e.TargetObject)).Concat(
t2e.Table3NavPropObject.Table8NavPropICollection.SelectMany(t8e => t8e.Table9NavPropICollection.Select(t9e => t9e.TargetObject)))
)
)
.ToListAsync();
If you want it completely flat, you'll want to switch that Select to a SelectMany().
var result = await dbContext.Table1DbSet
.Where(t1e => t1e.Id == id && t1e.Id2 == id2)
.SelectMany
(
t1e =>
t1e.Table2NavPropICollection.Select
(
t2e => new[] {t2e.Table3NavPropObject.TargetObject}.Concat(
t2e.Table3NavPropObject.Table4NavPropObject.Table5NavPropICollection.Select(t5e => t5e.TargetObject)).Concat(
t2e.Table3NavPropObject.Table6NavPropObject.Table7NavPropICollection.Select(t7e => t7e.TargetObject)).Concat(
t2e.Table3NavPropObject.Table8NavPropICollection.SelectMany(t8e => t8e.Table9NavPropICollection.Select(t9e => t9e.TargetObject)))
)
)
.ToListAsync();
Is Add and/or Concat a possible solution?
PoC:
var a = new [] { 1,2,3 };
var result = new {
firstA = a.First(),
otherAs = a,
backwards = a.Reverse()
};
var final = new List<int>();
final.Add(result.firstA);
final.Concat(result.otherAs.Concat(result.backwards))
.Dump();
Related
I would like to generate this SQL query in entity framework
SELECT FunctionalAssets.Name, FunctionalAssetStructurePath.Path
FROM FunctionalAssets
LEFT JOIN FunctionalAssetStructurePath ON FunctionalAssets.Id =
FunctionalAssetStructurePath.FunctionalAssetId AND
FunctionalAssetStructurePath.StructureConfigurationId = 'A8A41B14-0A35-45D3-2A2B-08D904A3CD0B'
ORDER BY FunctionalAssetStructurePath.Path, FunctionalAssets.Name
OFFSET 0 ROWS FETCH NEXT 100 ROWS ONLY
I try with this code (but I know that it won't work)
var result = context.FunctionalAssets
.Include(x => x.FunctionalAssetsStructurePaths.Any(y => y.StructureConfigurationId == configurationId))
.OrderBy(x => x.FunctionalAssetsStructurePaths.Select(y => y.Path))
.ThenBy(x => x.Name)
.Skip(0)
.Take(100)
.AsNoTracking()
.Select(x => x.Name)
.ToList();
Have you an idea how to do this ?
Thank you
I found a solution.
var result = context.FunctionalAssets
.GroupJoin(context.FunctionalAssetStructurePathModel.Where(y => y.StructureConfigurationId == 'A8A41B14-0A35-45D3-2A2B-08D904A3CD0B'),
fa => fa.Id,
fasp => fasp.FunctionalAssetId,
(fa, fasp) => new { fa, fasp })
.SelectMany(x => x.fasp.DefaultIfEmpty(), (x, p) => new { x.fa, p.Path })
.OrderBy(x => x.Path)
.Skip(0)
.Take(100)
.ToList();
And the generated SQL query is :
SELECT [f].[Id], [f].[Name], [t].[Path]
FROM [FunctionalAssets] AS [f]
LEFT JOIN (
SELECT [f0].[FunctionalAssetId], [f0].[Path]
FROM [FunctionalAssetStructurePath] AS [f0]
WHERE [f0].[StructureConfigurationId] = 'A8A41B14-0A35-45D3-2A2B-08D904A3CD0B'
) AS [t] ON [f].[Id] = [t].[FunctionalAssetId]
ORDER BY [t].[Path]
OFFSET 0 ROWS FETCH NEXT 100 ROWS ONLY
I have a problem: I have this table
ID
Title
GenreID
Genre
Duration
1
Movie1
1,2
Cartoon, Family
80
2
Movie2
3,4
Horror, Drama
76
3
Movie3
4
Drama
110
4
Movie4
1,2
Cartoon, Family
200
I need to filter by Genre, I make my query in this way, For example if I want all movies with Genre Cartoon (2), I make:
request.genre = 2
var query1 = from q in Movies
select new Response.MovieResponse
{
MovieId = q.MovieId,
Name = q.Title,
Genres = q.Genre,
GenreIds = q.GenreID
};
if (request != null)
{
if (!string.IsNullOrEmpty(request.Title))
query1 = query1.Where(co => co.Name.StartsWith(request.name));
if (!string.IsNullOrEmpty(request.genre))
if (int.Parse(request.genre) > 0)
{
query1.AsEnumerable().Where(ca =>
request.genre .Any(x => ca.GenreIds.Contains(x)));
}
}
List<Response.StoreResponse> stores = new List<Response.StoreResponse>();
stores = await query1.ToListAsync();
I expected 2 records inside but the filter on genre does not work. I always have back all movies. The filter by title run
I tried
if (!string.IsNullOrEmpty(request.category))
if (int.Parse(request.category) > 0)
{
string[] cat = { request.category };
var q1 = query1.Where(ca => ca.CategoriesIds.Contains(cat.ToString()));
l = q1.ToList();
}
but I have error:
The LINQ expression 'DbSet<Store>()
.Join(
inner: DbSet<Country>(),
outerKeySelector: s => s.CountryId,
innerKeySelector: c => (Nullable<int>)c.CountryId,
resultSelector: (s, c) => new TransparentIdentifier<Store, Country>(
Outer = s,
Inner = c
))
.Join(
inner: DbSet<City>(),
outerKeySelector: ti => ti.Outer.CityId,
innerKeySelector: c0 => (Nullable<long>)c0.CityId,
resultSelector: (ti, c0) => new TransparentIdentifier<TransparentIdentifier<Store, Country>, City>(
Outer = ti,
Inner = c0
))
.Where(ti0 => ti0.Outer.Outer.StatusId == (Nullable<int>)2)
.Where(ti0 => DbSet<Operator>()
.Where(o => EF.Property<Nullable<Guid>>(ti0.Outer.Outer, "StoreId") != null && object.Equals(
objA: (object)EF.Property<Nullable<Guid>>(ti0.Outer.Outer, "StoreId"),
objB: (object)EF.Property<Nullable<Guid>>(o, "StoreId")))
.Count() > 0)
.Where(ti0 => string.Join<long>(
separator: ",",
values: DbSet<StoresCategory>()
.Where(s0 => EF.Property<Nullable<Guid>>(ti0.Outer.Outer, "StoreId") != null && object.Equals(
objA: (object)EF.Property<Nullable<Guid>>(ti0.Outer.Outer, "StoreId"),
objB: (object)EF.Property<Nullable<Guid>>(s0, "StoreId")))
.Select(s0 => s0.CategoryId)
.ToList()).Contains(__ToString_0))' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'. See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.
This is my query
public async Task<IEnumerable<Menu>> GetMenuByRolesAsync(string[] roles)
{
var result= await _context.Menus//.Include(o => o.Parent)
.Include(m => m.Childrens)
.ThenInclude(m => m.Childrens)
.Include(m => m.Roles.Where(r => roles.Contains(r.Name))) --it is not filtering basd on roles
.Where(m => m.ParentId == null)
.ToListAsync();
}
It is generating below query
-- #__roles_0='System.String[]' (DbType = Object)
SELECT m.id, m.icon, m.name, m.parent_id, m.url, t.role_id, t.menu_id, t.id, t.concurrency_stamp, t.name, t.normalized_name
FROM security.menu AS m
LEFT JOIN (
SELECT r.role_id, r.menu_id, r0.id, r0.concurrency_stamp, r0.name, r0.normalized_name
FROM security.role_menu AS r
INNER JOIN security.role AS r0 ON r.role_id = r0.id
WHERE r0.name = ANY (#__roles_0) OR ((r0.name IS NULL) AND (array_position(#__roles_0, NULL) IS NOT NULL))
) AS t ON m.id = t.menu_id
WHERE (m.parent_id IS NULL)
ORDER BY m.id, t.role_id, t.menu_id, t.id
This is Many to many configuration
// many to many
builder.HasMany(r => r.Menus)
.WithMany(r => r.Roles)
.UsingEntity<RoleMenu>(
j => j
.HasOne(rm => rm.Menu)
.WithMany(m => m.RoleMenus)
.HasForeignKey(rm => rm.MenuId),
j => j
.HasOne(rm => rm.Role)
.WithMany(r => r.RoleMenus)
.HasForeignKey(rm => rm.RoleId),
j =>
{
j.ToTable("role_menu", schema: "security");
j.HasKey(rm => new { rm.RoleId, rm.MenuId });
});
i need to filter menus based on roles..But it is not filtering based on roles..Am getting all the roles..I checked generated query..Please let me know what is the issue..
You are mixing filtered include with entity filtering.
Filtered include
.Include(m => m.Roles.Where(r => roles.Contains(r.Name)))
just filters the items in the related collection (menu roles in this case).
In order to filter the entity set (menus in this case), you need to replace it with the usual Where oparator, which for the desired filtering will be
.Where(m => m.Roles.Any(r => roles.Contains(r.Name)))
I need to get top 10 rows for each group in a table with entity framework.
Based on other solution on SO, I tried 2 things:
var sendDocuments = await context.Set<DbDocument>
.Where(t => partnerIds.Contains(t.SenderId))
.GroupBy(t => t.SenderId)
.Select(t => new
{
t.Key,
Documents = t.OrderByDescending(t2 => t2.InsertedDateTime).Take(10)
})
.ToArrayAsync();
error:
System.InvalidOperationException: 'The LINQ expression
'(GroupByShaperExpression: KeySelector: (d.SenderId),
ElementSelector:(EntityShaperExpression:
EntityType: DbDocument
ValueBufferExpression:
(ProjectionBindingExpression: EmptyProjectionMember)
IsNullable: False ) )
.OrderByDescending(t2 => t2.InsertedDateTime)' could not be translated. Either rewrite the query in a form that can be translated,
> or switch to client evaluation explicitly by inserting a call to
> either AsEnumerable(), AsAsyncEnumerable(), ToList(), or
> ToListAsync().
and
var sendDocuments2 = await context.Set<DbDocument>
.Where(t => partnerIds.Contains(t.SenderId))
.GroupBy(t => t.SenderId)
.SelectMany(t => t.OrderByDescending(t2 => t2.InsertedDateTime).Take(10))
.ToArrayAsync();
error:
System.InvalidOperationException: 'Processing of the LINQ expression
't => t
.OrderByDescending(t2 => t2.InsertedDateTime)
.AsQueryable()
.Take(10)' by 'NavigationExpandingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core.
Any other idea?
Update (EF Core 6.0):
EF Core 6.0 added support for translating GroupBy result set projection, so the original code for taking (key, items) now works as it should, i.e.
var query = context.Set<DbDocument>()
.Where(e => partnerIds.Contains(e.SenderId))
.GroupBy(e => e.SenderId)
.Select(g => new
{
g.Key,
Documents = g.OrderByDescending(e => e.InsertedDateTime).Take(10)
});
However flattening (via SelectMany) is still unsupported, so you have to use the below workaround if you need such query shape.
Original (EF Core 3.0/3.1/5.0):
This is a common problem, unfortunately not supported by EF Core 3.0/3.1/5.0 query translator specifically for GroupBy.
The workaround is to do the groping manually by correlating 2 subqueries - one for keys and one for corresponding data.
Applying it to your examples would be something like this.
If you need (key, items) pairs:
var query = context.Set<DbDocument>()
.Where(t => partnerIds.Contains(t.SenderId))
.Select(t => t.SenderId).Distinct() // <--
.Select(key => new
{
Key = key,
Documents =
context.Set<DbDocument>().Where(t => t.SenderId == key) // <--
.OrderByDescending(t => t.InsertedDateTime).Take(10)
.ToList() // <--
});
If you need just flat result set containing top N items per key:
var query = context.Set<DbDocument>()
.Where(t => partnerIds.Contains(t.SenderId))
.Select(t => t.SenderId).Distinct() // <--
.SelectMany(key => context.Set<DbDocument>().Where(t => t.SenderId == key) // <--
.OrderByDescending(t => t.InsertedDateTime).Take(10)
);
If possible, please guide me how to convert my SQL command to lambda expression
select d.* from takcontractdet d where d.contractid=pubcontractid and d.personid in
(
select p.id from personel p where p.parentid=pubparentid)
)
Two query
var personelIds = Personels.Where(p => p.ParentId == pubparentid)
.Select(e => e.Id).ToList();
var result = Takcontractdets.Where(d => d.contractid == pubcontractid &&
personelIds.Contains(d.PersonId)).ToList();
One query
var result = Takcontractdets.Where(d => d.contractid == pubcontractid &&
Personels.Where(p => p.ParentId == pubparentid)
.Select(e => e.Id).ToList().Contains(d.PersonId))
.ToList();