I have two model classes first one is "Ticket" and other is "ExpTicket" there is only one additional column/properties in ExpTicket and others properties are same in both lists. I extract the data from database in the form of ExpTicket list and then re-assign all column/properties to Ticket List except one additional column which does not exist in Ticket list.
But iam unable to assign data from "ExpTicket" list to "Ticket" list. If anyone can timely help I shall be very thankful. Following is the code which i need to convert From ExpTicket into "Ticket" List but failed. Please help.
var GetTicket = ticketRepository.ExpTicket(r => r.TicketId == TicketId).ToList();
List<Ticket> CTicket = GetTicket.ToList();
First you have:
var GetTicket = ticketRepository.ExpTicket(r => r.TicketId == TicketId).ToList();
Then make a query:
var CTickets = (from t in GetTicket
select new Ticket{field1=t.field1,field2=t.field2...}).ToList();
Or just readjust your model to use TPT (Table per type, Table per type code first) Good luck
var CTickets = new List<Ticket>();
var ExpTicket = ticketRepository.Where(r => r.TicketId == TicketId);
foreach (var ticket in ExpTicket)
{
CTickets.Add(new Ticket { TicketId = ticket.TicketId, ... and so on });
}
// CTickets is the new list of tickets
Related
I have a table called "UserAnswers".below screenshot contains table data
I want to get data by surveyId and group by CreatedBy column.
for an example
There is a user called "amara#gmail.com".this user contains 4 records for a SurveyId.
I want to get this like below
Answers : [
{"2"},
{"1","0","1","1"},
{"1","2","4","3"},
{"Blue"}]
But my code returns this array for every rows.I meant duplicate records returning.
Here is my code
var qstns = await (from uans in _context.UserAnswers
where uans.SurveyId == id
select new UserAnswersReturnDto
{
UserEmail = uans.CreatedBy,
Qustns = (from ans in _context.UserAnswers
where ans.CreatedBy == uans.CreatedBy
select new UserAnswersSet
{
QNo = ans.QNo,
Ansrs = JsonConvert.DeserializeObject<JArray>(string.IsNullOrEmpty(ans.Answers) ? "[]" : ans.Answers)
}).ToArray()
}).ToListAsync();
So how to solve this issue.I opened many questions for this problem,but no one answered.Please help me.Thanks in advanced
You need to actually group your data before returning:
I used LINQ Lambda notation, but it should be quite easy to translate back to query if you're so inclined:
var qstns = _context.UserAnswers.Where(uans => uans.SurveyId == id)
.GroupBy(uans => uans.CreatedBy)
.Select(grans => new UserAnswersReturnDto {
UserEmail = grans.Key,
Qustions = grans.Select(ans => new UserAnswersSet() {
QNo = ans.QNo,
Ansrs = ans.Answers
}).ToList()
} ).ToList();
I didn't have time to double-check this, but I hope it serves as a guide to help you solve your issue!
There is no group by statement in your linq query.
I am lambda querying models (I make projection with other classes-GameBankVM, GameCouponBankVM) and at the end, I would like to loop throuh query result and update the model field. But I am getting The entity or complex type 'EPINMiddleWareAPI.Models.GameBankVM' cannot be constructed in a LINQ to Entities query.
Here is my sample code:
var gameBankResult = await (context.GameBanks.Where(g => g.productCode == initiate.productCode)
.Take(initiate.quantity)
.Select(g => new GameBankVM
{
quantity = g.quantity,
currency = g.currency,
initiationResultCode = g.initiationResultCode,
productCode = g.productCode,
productDescription = g.productDescription,
referenceId = g.referenceId,
responseDateTime = g.responseDateTime,
unitPrice = g.unitPrice,
totalPrice = g.totalPrice,
coupons = g.coupons.Select(c => new GameCouponBankVM
{
Pin = c.Pin,
Serial = c.Serial,
expiryDate = c.expiryDate
}).ToList()
})).ToListAsync();
if (gameBankResult.Count() != 0)
{
foreach (var item in gameBankResult)
{
item.referenceId = initiate.referenceId;
context.Entry(item).State = System.Data.Entity.EntityState.Modified;
}
await context.SaveChangesAsync();
return Ok(gameBankResult);
}
How can I update referenceId on my GameBank model/table?
In this scenario, your data won't be updated because your query is returning a List of GameBankVM and not a List of GameBank, now technically speaking, you are breaking SRP, you should either update your data or query your data not both in the same method, you may want to refactor your method like this :
1.- Create a private method for data update, in this case, you query directly GameBank iterate thru list entries, make your changes and save them to the database, this same method can return List of GameBank to avoid another database roundtrip.
2.- In the controller after you call your new method, you can run the transformation query to convert List of GameBank to List of GameBankVM and return it to the view.
There are many other ways to do this, I'm just recommending this as a less impact way to make your controller work. But if you are willing to make things better, you can create a business layer where you resolve all your business rules, or you can use patterns like CQS or CQRS.
I am using EF Framework to retrieve the data from SQL DB.
Sub Request Table looks like below:
In this table "org_assigneddept" is foreign key to another Department Table.
I have list of Departments as Input and I want to retrieve only those rows from DB whose org_assigneddept is matching the list.
Please find my whole code:-
private List<EventRequestDetailsViewModel> GetSummaryAssignedDeptEventRequests(List<EmpRoleDeptViewModel> vmDept)
{
List<EventRequestDetailsViewModel> vmEventRequestDeptSummary = new List<EventRequestDetailsViewModel>();
RequestBLL getRequestBLL = new RequestBLL();
Guid subRequestStatusId = getRequestBLL.GetRequestStatusId("Open");
using (var ctxGetEventRequestSumm = new STREAM_EMPLOYEEDBEntities())
{
vmEventRequestDeptSummary = (from ers in ctxGetEventRequestSumm.SubRequests
where vmDept.Any(dep=>dep.DeptId == ers.org_assigneddept)
select new EventRequestDetailsViewModel
{
SubRequestId = ers.org_subreqid
}).ToList();
}
}
It is giving the following error at the LINQ Query level:-
System.NotSupportedException: 'Unable to create a constant value of
type 'Application.Business.DLL.EmpRoleDeptViewModel'. Only primitive
types or enumeration types are supported in this context.'
Please let me know as how can I achieve the result
You cannot pass the department VMs to SQL, it doesn't know what those are.
// Extract the IDs from the view models.. Now a list of primitive types..
var departmentIds = vmDept.Select(x => x.DeptId).ToList();
then in your select statement...
..
where departmentIds.Contains(id=> id == ers.org_assigneddept)
..
I have an Oracle database where I am storing information about customers.
One of the fields is user number.
My UserNumber column is type of text.
A user sends a number in various formats:
+44777XXXXXXX
777XXXXXXX
0777XXXXXXX
So far I have:
var list = context.UserDetails.Where(x => x.UserNumber == number).ToList();
I can also do this with:
var strippedNumber = ConvertNumberToBasic(number); // this will return me number as 777XXXXXXX
now
var list = context.UserDetails.Where(x => x.UserNumber.Contains(number)).ToList();
Is there a more optimal way for me to do this?
You really need to ask the customer what they need before you can write any code for this...
I am relatively new to the EF and have the following entity model above which consists of an Asset and a Country. An Asset can belong in many countries and thus has a many-to-many relationship with country (has a join table in the database with two fields both as primary keys).
I want to be able to do the following:
Firstly when I retrieve an asset (or assets) from the model I want to get the respective countries that its associated with. I would then like to be able to bind the countries list to an IEnumerable. Retrieving the countries in this way provides me with an EntityCollection of country objects which has extension method for ToList(). Therefore not sure If I am going down the right avenue with this one. Here is my GetAll method:
public IEnumerable<Asset> GetAll()
{
using (var context = CreateAssetContext())
{
var assetEntities = context.Assets.Include("Countries").ToList();
return AssetMapper.FromEntityObjects(assetEntities);
}
}
Secondly I want to be able to select a list of countries where the AssetId == some value.
Finally I want to be able to update the list of countries for a given Asset.
Many thanks.
Firstly when I retrieve an asset (or assets) from the model I want to
get the respective countries that its associated with. I would then
like to be able to bind the countries list to an IEnumerable.
Not sure if I understand that correctly, but EntityCollection<T> implements IEnumerable<T>, so you don't have to do anything special, you just can use Asset.Countries after you have loaded the assets including the countries.
Secondly I want to be able to select a list of countries where the
AssetId == some value.
using (var context = CreateAssetContext())
{
var countries = context.Countries
.Where(c => c.Assets.Any(a => a.AssetId == givenAssetId))
.ToList();
}
Or:
using (var context = CreateAssetContext())
{
var countries = context.Assets
.Where(a => a.AssetId == givenAssetId)
.Select(a => a.Countries)
.SingleOrDefault();
}
The second option is OK (not sure if it's better than the first from SQL viewpoint) because AssetId is the primary key, so there can be only one asset. For querying by other criteria - for example Asset.Name == "XYZ" - where you could expect more than one asset I would prefer the first option. For the second you had to replace Select by SelectMany and SingleOrDefault by ToList and use Distinct to filter out possible duplicated countries. The SQL would probably be more complex.
Finally I want to be able to update the list of countries for a given
Asset.
This is more tricky because you need to deal with the cases: 1) Country has been added to asset, 2) Country has been deleted from asset, 3) Country already related to asset.
Say you have a list of country Ids ( IEnumerable<int> countryIds ) and you want to relate those countries to the given asset:
using (var context = CreateAssetContext())
{
var asset = context.Assets.Include("Countries")
.Where(a => a.AssetId == givenAssetId)
.SingleOrDefault();
if (asset != null)
{
foreach (var country in asset.Countries.ToList())
{
// Check if existing country is one of the countries in id list:
if (!countryIds.Contains(country.Id))
{
// Relationship to Country has been deleted
// Remove from asset's country collection
asset.Countries.Remove(country);
}
}
foreach (var id in countryIds)
{
// Check if country with id is already assigned to asset:
if (!asset.Countries.Any(c => c.CountryId == id))
{
// No:
// Then create "stub" object with id and attach to context
var country = new Country { CountryId = id };
context.Countries.Attach(country);
// Then add to the asset's country collection
asset.Countries.Add(country);
}
// Yes: Do nothing
}
context.SaveChanges();
}
}
Edit
For the price of a second roundtrip to the database you can probably use this simpler code:
using (var context = CreateAssetContext())
{
var asset = context.Assets.Include("Countries")
.Where(a => a.AssetId == givenAssetId)
.SingleOrDefault();
if (asset != null)
{
// second DB roundtrip
var countries = context.Countries
.Where(c => countryIds.Contains(c.CountryId))
.ToList();
asset.Countries = countries;
context.SaveChanges();
}
}
EF's change detection should recognize which countries have been added or deleted from the asset's country list. I am not 100% sure though if the latter code will work correctly.
Whats the specific question here? Are you not being able to do that?
do you want to select the countries in an asset or the countries that have a certain asset?
to update its simple, just change stuff and then context.SaveChanges() will commit to the database.