I have many Nations and for each Nation i have a lot of Teams.
The GetTeam endpoint in team controller retrieve a single Team and its related Nation. Via LINQ the query is this:
Context.Teams.Include(t => t.Nation).First(t => t.Id.Equals(__id))
The resulting JSON is what I want:
{"team":{"name":"Team1","nation":{"id":1,"name":"Nation1"}}
Let's say now that the property "name", both in Team and Nation model is dropped and a new model relation is created, with Translation.
What I want now is to retrieve the same JSON, but with a different query based on culture.
Gettin crazy understand how I can achieve it with include.
How can I compose this query in LINQ ?
select *
from Teams inner join
Translations TeamTr on Teams.id = TeamTr .id and TeamTr .culture = "IT" inner join
Nations on Teams.nation_id = Nations.id inner join
Translations NationTr on Nations .id = NationTr .id and NationTr .culture = "IT"
And compose the resulting data as JSON above?
for example:
(from team in Context.Teams
join teamTr in Context.Translations on team.id equals teamTr.id
join nation in Context.Nations on team.nation_id equals nations.id
join nationTr in Context.Translations on nation.id equals nationTr.id
where teamTr.culture == "IT" && nationTr.culture == "IT"
select new
{
teamName = team.name,
nationName = nation.name
}).ToList();
Nice catch tdayi.
First of all I've created a new class, that will be the container of the linq result:
public class TeamDetailLinqDto
{
public Team Team { get; set; }
public Translation TeamTranslation { get; set; }
public Nation Nation { get; set; }
public Translation NationTranslation { get; set; }
}
and this is the linq query:
public IQueryable<TeamDetailLinqDto> GetTeams()
{
var result = from team in Context.Teams
join teamTranslation in Context.Translations on
new { Id = team.Id, Locale = "IT" }
equals new { Id = teamTranslation.EntityId, Locale = teamTranslation.Locale }
join nation in Context.Nations on team.NationId equals nation.Id
join nationTranslation in Context.Translations on
new { Id = nation.Id, Locale = "IT" }
equals new { Id = nationTranslation.EntityId, Locale = nationTranslation.Locale }
select new TeamDetailLinqDto
{
Team = team,
TeamTranslation = teamTranslation,
Nation = nation,
NationTranslation = nationTranslation
};
return result;
}
Related
I have three tables, Organization, Department, and OrganizationDepartments. here is the relationship between them.
Now I would like to join these three tables and create another object for a DTO class. This DTO object has some properties and a list of other DTOs. Here is the DTO Class.
Organization DTO:
public class OrganizationDto
{
public string Id { get; set; }
public string OrganizationName { get; set; }
public string Logo { get; set; }
public bool? IsActive { get; set; }
public IList<OrganizationDepartmentDto> OrganizationDepartments { get; set; }
}
OrganizationDepartment DTO:
public class OrganizationDepartmentDto
{
public string OrganizationId { get; set; }
public string OrganizationName { get; set; }
public string DepartmentId { get; set; }
public string DepartmentName { get; set; }
}
Now I would like to write a LINQ query to get a Organization object along with all the departments related to that organization. The query is imcomplete because I don't know how can I get all the department information as list in a single query. The code is below:
var organizationInfo = (from org in _dbContext.Organizations
join orgDept in _dbContext.OrganizationDepartments on org.Id equals orgDept.OrganizationId
join dept in _dbContext.Departments on orgDept.DepartmentId equals dept.Id
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
OrganizationDepartments = //TODO:..
}
);
Can anyone help me to get the department lists of that organization's object (see the TODO:)?
If your entities are mapped correctly, and the relationships are correctly configured.
you can use .Include("OrganizationDepartment") and .ThenInclude("Department")to ensure relations are included into the generated Query.
If you insist on using Query Syntax. e.g from org in context.Organization
you can write out the query like this.
var q = (from org in _dbContext.Organizations
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
OrganizationDepartments = org.OrganizationDepartments.ToList()
}
Depending on your usecase. Sometimes you are not interested in actually showing the "many to many" table outside of the scope of your database.
so it might make more sense to actually flatten the Dto.
that query would look like
var q = (from org in _dbContext.Organizations
where org.Id.ToUpper() == id.ToUpper()
orderby org.CreatedOn ascending
select new OrganizationDto
{
Id = org.Id,
OrganizationName = org.OrganizationName,
Logo = org.Logo,
IsActive = org.IsActive,
Departments= org.OrganizationDepartments.Select(t => t.Departments).ToList()
}
In the code given below i want to join all the three table i get the data by joining the table but while displaying the data only the data of CK_Model is displayed. Please help
public List<CK_Model> GetDetails()
{
try
{
using (var entities = new MobileStore2020Entities())
{
var details = from a in entities.CK_Model
join b in entities.CK_Brand
on a.BrandID equals b.BrandID
join c in entities.CK_Stock
on a.ModelID equals c.ModelID
select new
{
ModelID = a.ModelID,
ModelName = a.ModelName
};
return details.ToList();
Thank You.
If I understand correctly you want to return data from all 3 tables by accessing them through your context. If you want to do this you have change your method's return type. For example create a new class with all 3 item types
public class DetailsItemType
{
public CK_Model Model{ get; set; }
public CK_Brand Brand { get; set; }
public CK_Stock Stock { get; set; }
}
Then change your method's return type to DetailsItemType and you'll have something like the following
public List<DetailsItemType> GetDetails()
{
using (var entities = new MobileStore2020Entities())
{
var details = from a in entities.CK_Model
join b in entities.CK_Brand
on a.BrandID equals b.BrandID
join c in entities.CK_Stock
on a.ModelID equals c.ModelID
select new DetailsItemType
{
Model= a,
Brand = b,
Stock = c
};
return details.ToList();
}
}
Now every time you call GetDetails() you can access all 3 tables. For example
var details = GetDetails();
var model = details.Model;
var brand = details.Brand;
var stock = details.Brand;
In Entity Framework, I would like to get one object which includes a list, but list gets only first record.
I have 2 objects Sale and Profile, they are different from database objects, I create these objects in query like "select new Sale { }". Profile object contains Sale type list. When query executed, list gets just first record in database.
Sale Complex Object
public class Sale
{
public int Id { get; set; }
public string Header { get; set; }
public double Price { get; set; }
}
Profile Complex Object
public class Profile
{
public int Id { get; set; }
public string Name { get; set; }
public List<Sale> SalesList { get; set; }
}
I use left join because it should insert this object to list, if next object is null.
Query Here
Profile profile = (from u in db.USER
join s in db.SALE on u.ID equals s.USER_ID into saleleft
from salej in saleleft.DefaultIfEmpty()
where u.ID == _userId
select new Profile
{
Id = u.ID,
Name = u.NAME,
SalesList= new List<Sale>()
{
salej != null ? new Sale
{
Id=postj.ID,
Header=salej.HEADER,
Price=salej.PRICE
} : null
}.ToList()
}).FirstOrDefault();
I guess this can be about FirstOrDefault() method. Hence I think it should get all records to SalesList. How can I get all records to list? Any idea?
Thanks in advance.
I think you need to use group here. Could you try this and let me know if it works?
// didn't test the code
Profile profile = (from u in db.USER
join s in db.SALE on u.ID equals s.USER_ID into saleleft
where u.ID == _userId
from salej in saleleft.DefaultIfEmpty()
group salej by new { u.ID, u.NAME } into g
select new Profile
{
Id = g.Key.ID,
Name = g.Key.NAME,
SalesList = g.Select( x => new Sale { Id = postj.ID, Header = x.HEADER, Price = x.PRICE }).ToList()
}).FirstOrDefault();
Btw, what is postj?
I have an Entity Framework model in which there is a "Customers" and a "CustomerPhones" table. A customer can have multiple phone numbers so the "Customer" entity has a collection of "Phone". I can query the model with no problem :
using (CustomerEntities context = new CustomerEntities())
{
Customer customer = context.Customers.FirstOrDefault();
CustomerPhone phone = customer.Phones.FirstOrDefault();
MessageBox.Show(customer.Name + " " + phone.Number);
}
The model is too complex for what I need to do (even though my example is basic) so I'm trying to boil it down to simpler POCOs. Here are the 2 simple classes :
public class SimplePhone
{
public int Id { get; set; }
public string Number { get; set; }
}
public class SimpleCustomer
{
public int Id { get; set; }
public string Name { get; set; }
//Phones is a list because a single Customer can have multiple phone numbers
public List<SimplePhone> Phones { get; set; }
}
I can populate the simple properties of the object using the "Select" method of "IQueryable" :
using (CustomerEntities context = new CustomerEntities())
{
IQueryable<SimpleCustomer> customers = context.Customers.Select(
c => new SimpleCustomer
{
Id = c.Id,
Name = c.Name
}
);
SimpleCustomer customer = customers.FirstOrDefault();
MessageBox.Show(customer.Name);
}
So my question is pretty simple : how can I populate the "Phones" property which is a list?
using (CustomerEntities context = new CustomerEntities())
{
IQueryable<SimpleCustomer> customers = context.Customers.Select(
c => new SimpleCustomer
{
Id = c.Id,
Name = c.Name
Phones = ///????
}
);
SimpleCustomer customer = customers.FirstOrDefault();
SimplePhone phone = customer.Phones.FirstOrDefault();
MessageBox.Show(customer.Name + " " + phone.Number);
}
Let me know if I'm unclear and/or you need more details.
Thanks!
I'm not sure if there isn't something more to your question, but as far as I understand, you can just call ToList and it will be materialized as a list:
IQueryable<SimpleCustomer> customers =
context.Customers.Select(c => new SimpleCustomer
{
Id = c.Id,
Name = c.Name,
Phones = c.Phones.Select(p => new SimplePhone
{
Id = p.Id, // Unless you want the custom Id, i.e. c.Id
Number = p.Number
}).ToList();
});
Hi I am trying to select the values of two columns which are second driver and price but I am getting error: Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Linq.IQueryable'. An explicit conversion exists (are you missing a cast?)
Below is the code:
public IQueryable<Event> GetSecondDriverOption(int eventID)
{
ApextrackdaysEntities entity = new ApextrackdaysEntities();
IQueryable<Event> SecondDriver = from p in entity.Events
where p.ID == eventID
select new{ p.SecondDriver,
p.SecondDriverPrice};
return SecondDriver;
}
Any help or suggestions will be appreciated thnx
You cannot use projection when you expect IQueryable<Event> where Event is your mapped type. You must either select Event :
IQueryable<Event> SecondDriver = from p in entity.Events
where p.ID == eventID
select p;
Or you must create new type and project data to a new type:
public class EventDto
{
public Driver SecondDriver { get; set; }
public Price SecondDriverPrice { get; set; }
}
and redefine your method:
public IQueryable<EventDto> GetSecondDriverOption(int eventID)
{
ApextrackdaysEntities entity = new ApextrackdaysEntities();
IQueryable<EventDto> SecondDriver = from p in entity.Events
where p.ID == eventID
select new EventDto
{
SecondDriver = p.SecondDriver,
SecondDriverPrice = p.SecondDriverPrice
};
return SecondDriver;
}
You cannot return anonymous objects. Try like this:
public IQueryable<Event> GetSecondDriverOption(int eventID)
{
ApextrackdaysEntities entity = new ApextrackdaysEntities();
var seconDriver =
from p in entity.Events
where p.ID == eventID;
select p;
return secondDriver;
}