I have the following data model:
public class Course
{
public int CourseId { get; set; }
public int StateId { get; set; }
}
public class CompletedCourse
{
public int CompletedCourseId { get; set; }
public int UserId { get; set; }
public Course Course { get; set; }
public string LicenseNumber { get; set; }
}
public class License
{
public int LicenseId { get; set; }
public int UserId { get; set; }
public int StateId { get; set; }
public string LicenseNumber { get; set; }
}
I'm trying to come up with an IQueryable for CompletedCourses and I would like to populate CompletedCourse.LicenseNumber with the LicenseNumber property of the FirstOrDefault() selection from my Licenses table where UserId and StateId match the completed course records.
Here is my query, but I don't think this will handle duplicate licenses correctly:
var entries =
(from course in context.CompletedCourses
join license in context.Licenses on course.UserId equals license.UserId
where license.StateId == course.Course.StateId
select course)
.Include(x => x.Agent)
.Include(x => x.Course.State);
Is this something that can be done in a single query? Thanks in advance.
Here is how you can do that:
var entries =
(from course in context.CompletedCourses
join license in context.Licenses
on new { course.UserId, course.Course.StateId }
equals new { license.UserId, license.StateId }
into licenses
let licenseNumber = licenses.Select(license => license.LicenseNumber).FirstOrDefault()
select new { course, licenseNumber });
But please note that with this type of projection you cannot have Includes in your query (you can, but they will not be in effect).
The EF generated query I'm getting from the above is:
SELECT
[Extent1].[CompletedCourseId] AS [CompletedCourseId],
[Extent1].[UserId] AS [UserId],
[Extent1].[LicenseNumber] AS [LicenseNumber],
[Extent1].[Course_CourseId] AS [Course_CourseId],
(SELECT TOP (1)
[Extent2].[LicenseNumber] AS [LicenseNumber]
FROM [dbo].[Licenses] AS [Extent2]
INNER JOIN [dbo].[Courses] AS [Extent3] ON [Extent3].[StateId] = [Extent2].[StateId]
WHERE ([Extent1].[Course_CourseId] = [Extent3].[CourseId]) AND ([Extent1].[UserId] = [Extent2].[UserId])) AS [C1]
FROM [dbo].[CompletedCourses] AS [Extent1]
It can be noticed that EF effectively ignores the join, so the same result can be obtained by simple natural query:
var entries =
(from course in db.CompletedCourses
let licenseNumber =
(from license in db.Licenses
where license.UserId == course.UserId && license.StateId == course.Course.StateId
select license.LicenseNumber).FirstOrDefault()
select new { course, licenseNumber });
#IvanStoev's answer was very helpful in joining on anonymous types, but ultimately I couldn't use it because I needed Includes. Here is the solution I went with that results in two DB queries instead of one which is fine for my situation.
var entries = context.CompletedCourses
.Include(x => x.Agent)
.Include(x => x.Course);
var courses = entries.ToList();
var courseIds = entries.Select(x => x.CompletedCourseId);
var licenses =
(from course in entries
join license in context.Licenses
on new { course.AgentId, course.Course.StateId }
equals new { AgentId = license.UserId, license.StateId }
where courseIds.Contains(course.CompletedCourseId)
select license);
foreach (var course in courses)
{
var license = agentLicenses.FirstOrDefault(x => x.UserId == course.AgentId &&
x.StateId == course.Course.StateId);
if (license != null)
{
course.LicenseNumber = license.LicenseNumber;
}
}
return courses;
Related
I have a question in regards with the below,
Left outer join of two tables who are not connected through Foreign Key.
Order by the results matched in second table.
I would like this to be done in LINQ Query method syntax as I am adding lots of conditions depending on the input provided along with skip and limit.
If we have below Product and Favorite tables
So the output that I would like to have is:
meaning with the favorites as part of first set and which are not favorites should be behind them. Below are the tries that I did.
I am able to join the tables get the output but not sure how I can make sure that in the first page I get all the favs.
This answer was very near to what I thought but it gets the result and then does the ordering which will not be possible in my case as I am doing pagination and using IQueryable to get less data.
Group Join and Orderby while maintaining previous query
Open to any solutions to achieve the same.
[Table("Product")]
public class ProductModel
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid ProductId { get; set; }
public string ProductName {get; set;}
public bool IsFavorite { get; set; }
}
[Table("UserFavorite")]
public class UserFavoriteModel
{
[Required]
public Guid UserId { get; set; }
[Required]
public Guid Identifier { get; set; }
[Required]
public FavoriteType Type { get; set; }
}
// Gets products
private async Task<List<ProductModel>> GetProductsAsync(
Guid categoryId,
Guid subCategoryId,
int from,
int limit)
{
var query = _context.Products.AsQueryable();
if (!string.IsNullOrEmpty(categoryId))
query = query.Where(product => product.CategoryId == categoryId);
if (!string.IsNullOrEmpty(subCategoryId))
query = query.Where(product => product.SubCategoryId == subCategoryId);
query = query.Skip(from).Take(limit);
var products = await query.ToListAsync();
query = query.GroupJoin(
_context.Favorites.AsNoTracking()
.Where(favorite => favorite.Type == FavoriteType.FASHION)
// This user Id will come from context just adding for overall picture.
.Where(favorite => favorite.UserId == userId),
//This orderby if I add will not make any difference.
//.OrderByDescending(favorite => favorite.Identifier),
v => v.ProductId,
f => f.Identifier,
(product, fav) => new { product, fav }).
SelectMany(x => x.Fav.DefaultIfEmpty(),
(x, y) => SetFavorite(x.Project, y));
}
private static ProductModel SetFavorite(ProductModel v, UserFavoriteModel si)
{
v.IsFavorite = (si != null);
return v;
}
I would do something like this:
var query =
_context.Products.AsQueryable().Select(p => new ProductModel {
ProductId = p.ProductId,
ProductName = p.ProductName,
IsFavorite =
_context.Favorites.Any(f =>
f.Identifier = p.ProductId &&
f.Type == FavoriteType.FASHION &&
f.UserId == userId
)
}).OrderByDescending(favorite => favorite.Identifier);
I'm trying to convert the following Join statement into LINQ TO SQL or LINQ to Entity. I know how to join tables in either implementation; but, i'm struggling with the AND clause in the Join statement.
SELECT DISTINCT
p.LastName,
p.FirstName
FROM
dbo.Patient p INNER JOIN dbo.FormPat fp ON p.PatientID = fp.PatientID
INNER JOIN dbo.TxCyclePhase tcp ON fp.TxCyclePhase = tcp.TxCyclePhaseID AND tcp.Type = 2
As far as LINQ to SQL is concerned, I have the followings:
var query = (from p in Context.Set<Patient>().AsNoTracking()
join fp in Context.Set<PatientForm>().AsNoTracking() on p.Id equals fp.PatientId
join tcp in Context.Set<TxCyclePhase>().AsNoTracking() on new { fp.TxCyclePhaseId, seconProperty = true } equals new { tcp.Id, seconProperty = tcp.Type == 2 }
select new
{
p.FirstName,
p.LastName,
}).Distinct();
However, I'm getting an ArgumentNullException on the second join statement.
For the LINQ to Entity, I have the followings, however, this is giving me a distinct IQueryable of FormPat, instead of Patient.
var patients = Context.Set<Patient>().AsNoTracking()
.SelectMany(p => p.Forms)
.Where(fp => fp.Phase.Type == 2)
.Distinct();
As far as the LINQ to Entity is concerned, I was able to figure it out. I'd still like to know how to do it in LINQ to SQL tho.
I'm using the EF fluent API. My Patient object looks like:
public Patient()
{
Programs = new HashSet<Program>();
}
public virtual ICollection<PatientForm> Forms { get; set; }
My PatientForm object looks like:
public class PatientForm
{
public int FormId { get; set; }
public Patient CurrentPatient { get; set; }
public TxCyclePhase Phase { get; set; }
}
And the CyclePhase object looks like:
public TxCyclePhase()
{
this.FormPats = new HashSet<PatientForm>();
}
public int Id { get; set; }
public virtual ICollection<PatientForm> FormPats { get; set; }
In the entity configurations, I have the relationships set. So, in the repository, all I have to do is to use the Any() function when selecting the Patient forms.
var patients = Context.Set<Patient>().AsNoTracking()
.Where(p => p.Forms.Any(f => f.Phase.Type == 2))
.Distinct();
This is just strange behavior to me.
LINQ transforming my statements creating bizarre execution plans. It's adding sub-queries when I don't ask it to and it's including or excluding joins in this sub-query based on the order of my joins, which leaves me scratching my head. At this point it's impossible for me to optimize this script based on the unpredictable nature of LINQ to Entities.
SETUP
//define global filter
Expression<Func<Contract_SeqExecution, bool>> globalFilter = r => r.ModifiedByFirstName.Contains("w");
...
//extend global filter
Expression<Func<Contract_SeqExecution, bool>> descendantFilter = x => x.client_id == 1 && x.project_status == true && x.parentId != null;
descendantFilter = descendantFilter.And(globalFilter);
//query
IQueryable<Contract_SeqExecution> geDescendantResults = c.queryGroups(this);
//execute
geDescendantResults.AsExpandable().Where(descendantFilter).Dump();
LINQ QUERY
public IQueryable<Contract_SeqExecution> queryGroups(UserQuery context)
{
var result = (from ge in context.group_execution
join aseq in context.automation_sequences on ge.automation_sequence_id equals aseq.id
join modify_u in context.users on aseq.last_modified_by_id equals modify_u.id into modify_uSub
from modify_u in modify_uSub.DefaultIfEmpty()
join p in context.project on aseq.project_id equals p.id
join asstatus in context.automation_sequence_status on ge.run_status_id equals asstatus.id
join es in context.execution_schedule on ge.schedule_id equals es.id
join exe_u in context.users on ge.executed_by_id equals exe_u.id
join create_u in context.users on aseq.created_by_id equals create_u.id
select new Contract_SeqExecution
{
client_id = p.client_id,
project_status = p.status,
ID = ge.id,
Name = aseq.name,
ModifiedByFirstName = modify_u.first_name,
ModifiedByLastName = modify_u.last_name,
FailedInd = asstatus.fail_alert_ind,
parentId = ge.parent_group_exec_id,
patriarchId = ge.patriarch_id
});
return result;
}
If I reorder the joins in the above statement my execution plan changes and LINQ-to-entities decides I want a sub-query....sigh.
Seriously all I did was change the order of the joins in the images below. Drastically different execution plans which will later on hurt performance of the query. What gives? Am I missing something obvious?
Is it picking information up from the entity framework schema? Could it be missing FK definitions or indexes that are driving this crazy behavior? At this point I'm just shooting in the dark. Hopefully someone here can shed some light on this.
Below is the class Contract_SeqExecution. I'm currently running this in a LinqPad C# Program hitting my DAL dll, linq-to-entities.
public class Contract_SeqExecution
{
public int ID { get; set; }
public string Name { get; set; }
public string DisplayName { get; set; }
public int SeqID { get; set; }
public int CaseGroupInd { get; set; }
public string CaseGroupText { get; set; }
public string ExecRatio { get; set; }
public string ModifiedByFirstName { get; set; }
public string ModifiedByLastName { get; set; }
public string Project { get; set; }
public string Uploaded { get; set; }
public string UploadRatio { get; set; }
public bool FailedInd { get; set; }
public bool HoldInd { get; set; }
public int? parentId { get; set; }
public int? patriarchId { get; set; }
public DateTime? SchedRunTime { get; set; }
//other fields
public string Machine {get;set;}
public int is_accepting_changes {get;set;}
public string holding_at_name {get;set;}
public string RunStatus {get;set;}
public string CaseGroupStatus {get; set;}
public string TCStatusColor {get; set;}
public string ExecutedBy {get;set;}
public string CreatedBy {get;set;}
public int? ScheduleID {get;set;}
public bool SeqUploaded {get;set;}
//end other fields
public int? parent_group_exec_id { get; set; }
public int client_id { get; set; }
public bool project_status { get; set; }
public IQueryable<Contract_SeqExecution> queryGroups(UserQuery context)
{
var result = (from ge in context.group_execution
join asstatus in context.automation_sequence_status on ge.run_status_id equals asstatus.id
join es in context.execution_schedule on ge.schedule_id equals es.id
join exe_u in context.users on ge.executed_by_id equals exe_u.id
join aseq in context.automation_sequences on ge.automation_sequence_id equals aseq.id
join p in context.project on aseq.project_id equals p.id
join create_u in context.users on aseq.created_by_id equals create_u.id
join modify_u in context.users on aseq.last_modified_by_id equals modify_u.id into modify_uSub
from modify_u in modify_uSub.DefaultIfEmpty()
select new Contract_SeqExecution
{
client_id = p.client_id,
project_status = p.status,
ID = ge.id,
Name = aseq.name,
ModifiedByFirstName = modify_u.first_name,
ModifiedByLastName = modify_u.last_name,
FailedInd = asstatus.fail_alert_ind,
parentId = ge.parent_group_exec_id,
patriarchId = ge.patriarch_id,
});
return result;
}
}
UPDATE
So I took Andrew's advice and looked into doing this the more "LINQ" way. I like to include FKs in my entities because I feel it's a more natural way to write SQL, habits die hard. I went ahead and rewrote my LINQ expression and the results are now consistent.
Example:
var result = (from ge in context.group_execution
//join asstatus in context.automation_sequence_status on ge.run_status_id equals asstatus.id
//join es in context.execution_schedule on ge.schedule_id equals es.id
//join exe_u in context.users on ge.executed_by_id equals exe_u.id
//join aseq in context.automation_sequences on ge.automation_sequence_id equals aseq.id
//join p in context.project on aseq.project_id equals p.id
//join create_u in context.users on aseq.created_by_id equals create_u.id
//join modify_u in context.users on aseq.last_modified_by_id equals modify_u.id into modify_uSub
//from modify_u in modify_uSub.DefaultIfEmpty()
select new Contract_SeqExecution
{
//client_id = p.client_id,
//project_status = p.status,
ID = ge.id,
Name = ge.automation_sequences.name,
ModifiedByFirstName = ge.automation_sequences.modified_by_user.first_name,
ModifiedByLastName = ge.automation_sequences.modified_by_user.last_name,
//FailedInd = asstatus.fail_alert_ind,
parentId = ge.parent_group_exec_id,
patriarchId = ge.patriarch_id,
});
return result;
I have three tables holding Users Groups and their association, UserGroups as laid out in this fiddle:
I am trying to obtain the maximum level among the users' groups as shown in the query in the fiddle using linq2sql.
However, EntityFramework obfuscates the join table, TblUserGroup and instead just gives me the navigation properties: TblGroups.Users or User.TblGroups
This is what I have put together thus far but Linqpad tells me it cannot execute:
var maxGroup = from ua in ctx.TblGroups
group ua by ua.TblUsers.Select(s=>s.UserId)
into g
select new
{
UserId= g.Key,
MaxLevel = g.Max(s => s.GroupLevel)
};
Seems you can do it like this:
var result = users.Select(u => new
{
UserId = u.Id,
MaxLevel = u.Groups.Max(g => g.GroupLevel)
});
Having:
class User
{
public int UserId { get; set; }
public string UserName { get;set; }
public List<Group> Groups { get; set; }
}
class Group
{
public int GroupId { get; set; }
public string GroupName { get; set; }
public int GroupLevel { get; set; }
public List<User> Users { get; set; }
}
Does it work for you?
var maxGroup = ctx.TblUsers
.Where(u => u.TblUserGroups != null)
.Select(u => new
{
UserId = u.UserId,
MaxGroupLevel = u.TblUserGroups.TblGroups.Max(g => g.GroupLevel)
}
);
I am having trouble figuring out how to traverse a one to many relasionship using LINQ-To-SQL in my asp.net site that uses EF 5. I have made the relationships in the class files but when I try to go from parent to child in my where clause I am not given a list of the child columns to filter on. Can anyone tell me what is wrong with my code, I am new to EF and LINQ.
Product.cs:
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public virtual Category Category { get; set; }
}
}
Category.cs:
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public virtual IList<Product> Products { get; set; }
}
Codebehind:
using (var db = new Compleate())
{
rpBooks.DataSource = (from c in db.Categories
where c.Products.Name == "Books"
select new
{
c.Name
}).ToList();
}
Do you want all products in the books category?
from p in db.Products
where p.Category.Name == "Books"
select new
{
p.Name
}
Or do you want to have all categories that contain products that are called called books?
from c in db.Categories
where c.Products.Contains( p => p.Name == "Books")
select new
{
c.Name
}
BTW, if you're only selecting the name, you can skip the anonymous type in the select part...
select p.name
Ok I had to update the codebhind to look like:
using (var db = new Compleate())
{
rpBooks.DataSource = (from c in db.Categories
join p in db.Products on c.ID equals p.id
where c.Products.Name == "Books"
select new
{
c.Name
}).ToList();
}
It should be name = c.Name it's not an issue with traversing, it's an issue with syntax, read the brief article on anonymous types here