I have a parent table named Employees which has a foreign key in a child table EmployeePrisons as follows
public class EmployeePrisons : FullAuditedEntity<long>
{
public long EmployeeId { get; set; }
public long PrisonId { get; set; }
public Employee Employee { get; set; }
public PrisonsLkpt Prison { get; set; }
}
Now i want the user to be able to select more than one prisons, to find all the employees that work in that list of prisonsIds. So i was thinking of using intersect inside the where clause. like this
The variable prisons is also list
employees=employees.Where(x => x.Prisons.Select(c => c.PrisonId).ToList().Intersect(prisons).Count()!=0 && x.Attendance.Any(y => y.ExitTime == null));
But it always give this error:
Expression of type 'System.Collections.Generic.List1[System.Int64]' cannot be used for parameter of type 'System.Linq.IQueryable1[System.Int64]' of method
'System.Linq.IQueryable1[System.Int64] Intersect[Int64](System.Linq.IQueryable1[System.Int64],
System.Collections.Generic.IEnumerable`1[System.Int64])' (Parameter
'arg0')
Please if anyone can help me it will be very useful
Related
I am using Entity Framework and this is my view model:
public class UserDetailsModel:CityModel
{
public int Id { get; set; }
public string Fullname { get; set; }
}
public class VendorInCategoryModel
{
public int CategoryId { get; set; }
public int VendorId { get; set; }
public virtual CategoryMasterModel CategoryMaster { get; set; }
public virtual UserDetailsModel UserDetails { get; set; }
}
public class CategoryMasterModel
{
public int CategoryId { get; set; }
public string CategoryName { get; set; }
}
This is my query to fetch vendor details along with category details of particular vendor say v001:
UserDetailsModel workerDetails = context.UserDetails.
Where(d => d.Id == _vendorId).
Select(d => new UserDetailsModel
{
Id = d.Id,
Fullname = d.Fullname,
CategoryId = d.VendorInCategory.Select(v => v.CategoryId).FirstOrDefault(),
}).SingleOrDefault();
Here I have used FirstOrDefault to fetch categoryId (that is single value)
But I don't want to use FirstOrDefault as I have used in so many queries and it is giving me wrong output in some cases. So that the reason why I don't want to use FirstOrDefault.
When I have written SingleOrDefualt in place of FirstOrDefault it is throwing me error
that use FirstOrDefault.
So how to overcome this? Can anybody please help me?
It looks like maybe your outer select is capable of returning multiple results (e.g. if there are more than one UserDetailsModel with the same Id). If it returns multiple results then your call to .SingleOrDefault() will throw an exception as it expects only a single result or no results. See LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria for more details.
I am using EF6, WebApi2, AngularJS and BreezeJs.
I have the following entities:
Person
{
public string Name { get; set;}
public virtual ICollection<GenericProfileCountry> Countries { get; protected set; }
}
public class GenericProfileCountry
{
public string PersonId{ get; set; }
public virtual Person Person{ get; set; }
public string CountryIso { get; set; }
public virtual Country Country { get; set; }
}
public class Country
{
public string Iso { get; set; }
public string Name { get; set; }
}
Now I have a query that brings all Persons through breeze as follows:
return zEntityQuery.from('Contacts').expand('Profile, Countries')
.orderBy(contactOrderBy)
.toType(entityName)
.using(self.manager).execute()
.to$q(querySucceeded, self._queryFailed);
What I would like to do is perform a where statement on the above query with criteria that are on the intermediate entity. So say I want to bring only contacts that their first country (a person can have multiple countries) iso code is equal to 'GB'.
In Linq it would be something like Contacts.Where(contact => contact.Countries.First().CountryIso == 'GB')
Could something similar be expressed in the where(predicate) of breeze? I thought of going the other way (start from the intermediate table and filter from there), but not sure if that is the correct approach.
You can achieve that by creating a predicate with the keyword any or all
.where('Countries','any','CountryIso','eq','GB')
In case you want to create a predicate on grand children : BreezeJS Predicates on 2nd level expanded entities
Edit
If you want to get the first contacts whose countries Isos start with 'GB', you can achieve that by:
Jay's suggestion.
using Linq at Breeze controller:
public IQueryable<Person> ContactsWithFilteredCountryIso(string CountryIso)
{
return _contextProvider.Context.Persons.Where(p => p.Countries.First().CountryIso== CountryIso);
}
Then on the client:
return zEntityQuery.from('Contacts')
.withParameters({ CountryIso: "GB"})
.expand('Profile, Countries')
.orderBy(contactOrderBy)
.toType(entityName)
.using(self.manager).execute()
.to$q(querySucceeded, self._queryFailed);
Writing a select projection on countries with bringing up Contacts can be implemented by issuing a Breeze query on countries and expanding contact:
return zEntityQuery.from('Countries').expand('Contact')
.select('Country.name')
.where('CountryIso','eq','GB')
.orderBy(contactOrderBy)
.toType(entityName)
.using(self.manager).execute()
.to$q(querySucceeded, self._queryFailed);
I have two entities
public class Datatype
{
[Key]
public int Id { get; set; }
[StringLength(96)]
public string DataTypeName { get; set; }
}
public class Attribute
{
[Key]
public int Id { get; set; }
[StringLength(96)]
public string Attribute_Name { get; set; }
[ForeignKey("Datatype")]
public int? DatatypeId { get; set; }
public virtual Datatype Datatype { get; set; }
}
In DataBase Initialize I have this code
Datatype dt = new Datatype();
dt.DataTypeName = "text";
context.datatypes.Add(dt);
//Above code is working fine. And After execution I can see
//in records a row.. with id=1 and datatype=text
Attribute at = new Attribute();
at.Attribute_Name = "Description";
//at.DatatypeId = 1; But if I uncomment this line
context.attributes.Add(at); // Then This Gives Following Error
The INSERT statement conflicted with the FOREIGN KEY constraint
"FK_dbo.Attributes_dbo.Datatypes_DatatypeId". The conflict occurred in database
"dyescan", table "dbo.Datatypes", column 'Id'
Assuming that the above code executes before either of the two objects have been saved to the database then it will not work simply because your object 'dt' will not have an ID of 1 before it's been saved to the database and therefore you cannot associate with attribute on '1' YET!
Instead you should not set the 'DatatypeId' but simply set the 'Datatype' like so:
at.Datatype = dt;
This will leave entity framework to figure out what the actual foreign key associated should/would be when savechanges is called.
Given the following:
public class Department
{
public int DepartmentID { get; set; }
public string Name { get; set; }
public virtual ICollection<Course> Courses { get; set; }
}
public class Course
{
public int CourseID { get; set; }
public string Title { get; set; }
public int Credits { get; set; }
public int DepartmentID { get; set; }
public virtual Department Department { get; set; }
}
If I turn lazy loading off and issue the following:
var departments = _DepartmentRepository.GetAll()
.Include(c => c.courses);
Then I get the answers with a Department object inside of them.
Is there a way I can just include the courses and not get back the Department object. For example can I just include one level (courses).
You are just including one level. The department object inside the course is there because EF has done some relationship fixup so that you can navigate to the department from the course.
If you don't want departments then just get the courses directly. That is context.Courses.ToList(); or via a courses repo if you have one.
When fetching entities EF will automatically populate navigation properties where it is already tracking the target object. This means if you do say:
// Load the department with a PK of 1
_DepartmentRepository.Find(1);
and then, using the same context, for example:
// Load a course with PK of 17
_CourseRepository.Find(17);
If this courses department id is 1, then EF will have automatically populated it's Department navigation property even though you didn't specify the include. You could stop this behavior by not making the Department navigation property virtual.
Setup
Using MVC 3 + Code First
Here are my classes
public class Member
{
[Key]
public Guid ID { get; set; }
[Required]
public String Email { get; set; }
[Required]
public String FirstName { get; set; }
[Required]
public String LastName { get; set; }
public String Sex { get; set; }
public String Password { get; set; }
public String PasswordSalt { get; set; }
public DateTime RegisterDate { get; set; }
public DateTime LastOnline { get; set; }
public String SecurityQuestion { get; set; }
public String SecurityAnswer { get; set; }
public virtual ICollection<FamilyMember> Families { get; set; }
public virtual ICollection<Relationship> Relationships { get; set; }
}
public class Relationship
{
[Key]
public Guid ID { get; set; }
[ForeignKey("Member1")]
public Guid Member1ID { get; set; }
[ForeignKey("Member2")]
public Guid Member2ID { get; set; }
public Guid RelationshipTypeID { get; set; }
public virtual RelationshipType RelationshipType { get; set; }
public virtual Member Member1 { get; set; }
public virtual Member Member2 { get; set; }
}
Here is the problem
The database table "Relationship" is being created with the following columns:
ID, Member1ID, Member2ID, RelationshipTypeID, Member_ID
Why is it creating the Member_ID column?
I've seen this post in which the user has the same type of setup, but I am unsure of how to define the InverseProperty correctly. I tried using fluent API calls but from what I can tell they will not work here since I have two foreign keys referring to the same table.
Any help would be appreciated!
Member_ID is the foreign key column which EF created for the navigation property Member.Relationships. It belongs to a third association from Member.Relationships refering to an end endpoint which is not exposed in your Relationship entity. This relationship has nothing to do with the other two relationships from Relationship.Member1 and Relationship.Member2 which also both have an endpoint not exposed in Member.
I guess, this is not what you want. You need always pairs of endpoints in two entities to create an association. One endpoint is always a navigation property. The second endpoint can also be a navigation property but it is not required, you can omit the second navigation property.
Now, what is not possible, is to associate two navigation properties (Member1 and Member2) in one entity with one navigation property (Relationships) in the other entity. That is what you are trying to do apparently.
I assume that your Member.Relationships property is supposed to express that the member is either Member1 or Member2 in the relationship, or that it participates in the relationship, no matter if as Member1 or Member2.
Unfortunately you cannot express this in the model appropriately. You have to introduce something like RelationsshipsAsMember1 and RelationsshipsAsMember2 and for these two collection you can use the InverseProperty attribute as shown in the other question. In addition you can add a helper property which concats the two collections. But this is not a mapped property but readonly:
public class Member
{
// ...
[InverseProperty("Member1")]
public virtual ICollection<Relationship> RelationshipsAsMember1 { get; set; }
[InverseProperty("Member2")]
public virtual ICollection<Relationship> RelationshipsAsMember2 { get; set; }
public IEnumerable<Relationship> AllRelationships
{
get { return RelationshipsAsMember1.Concat(RelationshipsAsMember2); }
}
}
Accessing AllRelationships will cause two queries and roundtrips to the database (with lazy loading) to load both collections first before they get concatenated in memory.
With this mapping the Member_ID column will disappear and you will only get the two expected foreign key columns Member1ID, Member2ID because now you have only two associations and not three anymore.
You could also think about if you need the Relationships collection in the Member entity at all. As said, navigation properties on both sides are not required. If you rarely need to navigate from a member to its relationships you could fetch the relationships also with queries on the Relationship set, like so:
var relationships = context.Relationships
.Where(r => r.Member1ID == givenMemberID || r.Member2ID == givenMemberID)
.ToList();
...or...
var relationships = context.Relationships
.Where(r => r.Member1ID == givenMemberID)
.Concat(context.Relationships
.Where(r => r.Member2ID == givenMemberID)
.ToList();
This would give you all relationships the member with ID = givenMemberID participates in without the need of a navigation collection on the Member entity.