I have a rather simple scenario where I have two tables in which I want to add data. They are managed with primary key/foreign key. I want to add new data into TABLE A and then retrieve the Id and insert into TABLE B.
I can certainly do it with a stored procedure, but I'm looking at trying to do it using Linq.
What is the best approach ?
I can certainly get the ID and do two separate inserts but that doesn't certainly seem to be a very good way of doing things.
db.Table.InsertOnSubmit(dbObject);
db.SubmitChanges();
Int32 id = dbOject.Id;
//Rest of the code
Any way to elegantly do this?
Do you have the relationship defined between the 2 tables in the object relational designed? If so, you can have linq take care of assigning the ID property of the second table automatically.
Example...
Table A – Order
OrderId
OrderDate
Table B – Order Item
OrderItemId
OrderId
ItemId
Code (Using LINQ-to-SQL):
Order order = new Order();
Order.OrderDate = DateTime.Now();
dataContext.InsertOnSubmit(order);
OrderItem item1 = new OrderItem();
Item1.ItemId = 123;
//Note: We set the Order property, which is an Order object
// We do not set the OrderId property
// LINQ will know to use the Id that is assigned from the order above
Item1.Order = order;
dataContext.InsertOnSubmit(item1);
dataContext.SubmitChanges();
hi i insert data into three table using this code
Product_Table AddProducttbl = new Product_Table();
Product_Company Companytbl = new Product_Company();
Product_Category Categorytbl = new Product_Category();
// genrate product id's
long Productid = (from p in Accountdc.Product_Tables
select p.Product_ID ).FirstOrDefault();
if (Productid == 0)
Productid++;
else
Productid = (from lng in Accountdc.Product_Tables
select lng.Product_ID ).Max() + 1;
try
{
AddProducttbl.Product_ID = Productid;
AddProducttbl.Product_Name = Request.Form["ProductName"];
AddProducttbl.Reorder_Label = Request.Form["ReorderLevel"];
AddProducttbl.Unit = Convert.ToDecimal(Request.Form["Unit"]);
AddProducttbl.Selling_Price = Convert.ToDecimal(Request.Form["Selling_Price"]);
AddProducttbl.MRP = Convert.ToDecimal(Request.Form["MRP"]);
// Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl );
// genrate category id's
long Companyid = (from c in Accountdc.Product_Companies
select c.Product_Company_ID).FirstOrDefault();
if (Companyid == 0)
Companyid++;
else
Companyid = (from Ct in Accountdc.Product_Companies
select Ct.Product_Company_ID).Max() + 1;
Companytbl.Product_Company_ID = Companyid;
Companytbl.Product_Company_Name = Request.Form["Company"];
AddProducttbl.Product_Company = Companytbl;
//Genrate Category id's
long Categoryid = (from ct in Accountdc.Product_Categories
select ct.Product_Category_ID).FirstOrDefault();
if (Categoryid == 0)
Categoryid++;
else
Categoryid = (from Ct in Accountdc.Product_Categories
select Ct.Product_Category_ID).Max() + 1;
Categorytbl.Product_Category_ID = Categoryid;
Categorytbl.Product_Category_Name = Request.Form["Category"];
AddProducttbl.Product_Category = Categorytbl;
Accountdc.Product_Tables.InsertOnSubmit(AddProducttbl);
Accountdc.SubmitChanges();
}
catch
{
ViewData["submit Error"] = "No Product Submit";
}
Related
I have a controller that accepts a list of strings. THese strings essentially are IDs that a user selects on the view. I need to build the model based upon fields from to tables, hence the need for the join. The bellow code will not build as it claims the properties from the joined table do not exist. It only accepts table 1 values. Item.Well_No and Item.Well_Name throw the error. These are included in the "y" table that i joined to "x"..
[HttpPost]
public ActionResult buildSelectionTable(List<string> dta)
{
var a = from x in db._AGREEMENTS
join y in db.WELL_AGMT_XREF on x.AGMT_NUM equals y.AGMT_NUM
where dta.Contains(x.AGMT_NUM)
select x;
List<AgmtModel> model = new List<AgmtModel>();
foreach (var item in a)
{
model.Add(new AgmtModel { Agmt_Name = item.AGMT_NAME, Agmt_Num = item.AGMT_NUM, Agmt_Type = item.AGMT_TYPE_DESCR, Amnt_Status = item.AGMT_STAT_DESCR, Company = item.CO_NAME, DaysToExp = item.DaysToExp, Drs_Url = item.DRS_URL, Effective_Date = item.EFF_DT, Orig_Lessee = item.ORIG_LESSEE, Prop_Status = item.AGMT_PROP_STAT_DESCR, Expiration_Date = item.EXPR_DATE, Acreage = item.LGL_AREA, Extention_Expiration = item.EXTN_EXPR_DT, WellNo = item.WELL_NO, Well_Name = item.WELL_NAME });
}
return PartialView("_SelectionTable", model);
}
You are only selecting x in your query you need to also select y and reference it.
change select x to be select new { x, y}
and then
foreach (var item in a)
{
model.Add(new AgmtModel { Agmt_Name = item.y.AGMT_NAME, Agmt_Num = item.x.AGMT_NUM ... });
}
you need to insert .x or .y before you the field to determine the field names
alternatively you could actually put the constructor directly in the query
so instead of select x
select new AgmtModel { Agmt_Name = y.AGMT_NAME, etc...}
then you can just return PartialView("_SelectionTable", a.ToList())
Some background
I'm wanting to bind a list of objects (my model-view) to a grid. The model-view contains fields for both an specific entity and fields from a joined entity.
I was getting an error when I would try to bind due to the dbContext being out of scope. I realized I needed to use the .Include() method in order to eager load my navigation property. However, I suspect that since I'm using Linq to Entities, that I'm now generating another error:
"Unable to cast the type 'System.Linq.IQueryable1' to type 'System.Data.Objects.ObjectQuery1'. LINQ to Entities only supports casting EDM primitive or enumeration types."
My code is shown below, any ideas of what I need to do here?
Thanks in advance!
public static List<PlanViewModel> GetPlans()
{
using (var context = new RepEntities())
{
var query = (from p in context.Plans
join r in context.RealEstateDetails on p.ReId equals r.ReId
select new PlanViewModel
{
PlanName = p.PlanName,
TargetCompletionDate = p.TargetCompletionDate,
ActualCompletionDate = p.ActualCompletionDate,
Provision = p.Provision,
StatusTypeId = p.StatusTypeId,
StatusCommon = p.StatusCommon,
Building = r.BuildingName,
City = r.City,
Country = r.Country
}).Include("StatusCommon");
return query.ToList();
}
}
You are almost there, just put Include("StatusCommon") right after context.Plans. Because you need to include StatusCommon before the iteration, this way you can set StatusCommon value for every iteration.
public static List<PlanViewModel> GetPlans()
{
using (var context = new RepEntities())
{
var query = (from p in context.Plans.Include("StatusCommon")
join r in context.RealEstateDetails on p.ReId equals r.ReId
select new PlanViewModel
{
PlanName = p.PlanName,
TargetCompletionDate = p.TargetCompletionDate,
ActualCompletionDate = p.ActualCompletionDate,
Provision = p.Provision,
StatusTypeId = p.StatusTypeId,
StatusCommon = p.StatusCommon,
Building = r.BuildingName,
City = r.City,
Country = r.Country
}).toList();
return query;
}
}
Based on user design I have to union together four queries and put them in a repeater.
var qryIssuer = from l in dbRRSP.LOA
join lrb in dbRRSP.LOAOrReferredBy on l.LOAOrReferredById equals lrb.LoaOrReferredById
join lat in dbRRSP.LOAAccessType on l.LOAAccessTypeId equals lat.LOAAccessTypeId
join iss in dbRRSP.Issuer on l.IssuerId equals iss.IssuerId
where
l.PersonId == personId
select new
{
LOAOrReferredByDescription = lrb.LoaOrReferredByDescription,
lat.LOAAccessTypeDescription,
PersonType = "Issuer",
LOAName = iss.CompanyName,
l.DateAdded
};
var qryEMD = from l in dbRRSP.LOA
join lrb in dbRRSP.LOAOrReferredBy on l.LOAOrReferredById equals lrb.LoaOrReferredById
join lat in dbRRSP.LOAAccessType on l.LOAAccessTypeId equals lat.LOAAccessTypeId
join emd in dbRRSP.Agent on l.AgentId equals emd.AgentId
where
l.PersonId == personId
select new
{
LOAOrReferredByDescription = lrb.LoaOrReferredByDescription,
lat.LOAAccessTypeDescription,
PersonType = "EMD",
LOAName = emd.CompanyName,
l.DateAdded
};
var qryEmdRep = from l in dbRRSP.LOA
join lrb in dbRRSP.LOAOrReferredBy on l.LOAOrReferredById equals lrb.LoaOrReferredById
join lat in dbRRSP.LOAAccessType on l.LOAAccessTypeId equals lat.LOAAccessTypeId
join ar in dbRRSP.AgentRepresentative on l.EMDRepresentativeId equals ar.AgentRepresentativeId
join arp in dbRRSP.Person on ar.PersonId equals arp.PersonId
where
l.PersonId == personId
select new
{
LOAOrReferredByDescription = lrb.LoaOrReferredByDescription,
lat.LOAAccessTypeDescription,
PersonType = "EMD Rep",
LOAName = arp.FirstName + ' ' + arp.LastName, l.DateAdded
};
var qryLOAPerson = from l in dbRRSP.LOA
join lrb in dbRRSP.LOAOrReferredBy on l.LOAOrReferredById equals lrb.LoaOrReferredById
join lat in dbRRSP.LOAAccessType on l.LOAAccessTypeId equals lat.LOAAccessTypeId
join lp in dbRRSP.LOAPerson on l.LOAPersonId equals lp.LOAPersonId
where
l.PersonId == personId
select new
{
LOAOrReferredByDescription = lrb.LoaOrReferredByDescription, lat.LOAAccessTypeDescription,
PersonType = "Person",
LOAName = lp.LOAPersonName,
l.DateAdded
};
This is the four queries. And the trickiest part is that the last field is a datetime, which is causing me some issues. I know how to union two of them together like this:
var qryMultipleLOA = qryIssuer.Union(qryEMD).ToList().Select(loa => new ExtendedLOA
{
LOAOrReferredByDescription = loa.LOAOrReferredByDescription,
LOAAccessTypeDescription = loa.LOAAccessTypeDescription,
PersonType = loa.PersonType,
LOAName = loa.LOAName,
DateAdded = DateTime.Parse(loa.DateAdded.ToString()).ToString("MM/dd/yyyy")
});
But I'm at a loss on how to add the last two queries - first I tried wrapping it in brackets and adding a .Union which didn't work, and then when I tried to nest them with appropriate .ToLists, that didn't work either.
Below is the code to bind it to the repeater.
rptLOA.DataSource = qryMultipleLOA;
rptLOA.DataBind();
Suggestions would be greatly appreciated.
Did you try something like?
var qryMultipleLOA = qryIssuer.Union(qryEMD).Union(qryEmdRep).Union(qryLOAPerson).ToList();
Provided your queries' footprints are the same, this shouldn't be an issue to chain them upon each other.
Edit:
I would also recommend the following:
Create a class to hold an instance of the resultant data.
Instead of creating lists of dynamic variables generated from Linq and hoping they all match, funnel the linq results into a List. That way you can tell immediately if you have a type mismatch.
Once you have four lists of the same List, Unions as per my syntax above will be a snap.
Dynamic Linq lists can be a pain, unwieldy and a single property type change can throw of your code at runtime rather than design time. If you follow the steps above, your code will be much more maintainable and clear to you and others.
I hope this helps in some way.
I have created a set of search results, and I wish to create a filter of available cats, with the number of results within that filter. however I get the most strangest error when trying to do this.
Unable to create a constant value of type 'NAMESPACE.Models.Products'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.
this is the code i have tried:
var cats = (from p in ctx1.SubCategories
where myCats.Contains(p.subCategoryId) && p.enabled
select new
AvailableSubCats
{
CategoryName = p.subCategoryName,
Id = p.subCategoryId,
TotalItems = model.Count(x => x.subCategoryId == p.subCategoryId)
}).Distinct();
Products is the object that is called model on the line of totalItems.
I have also tried this:
var cats = from c in ctx1.SubCategories
join p in model on c.subCategoryId equals p.subCategorySubId
group p by c.subCategoryName
into g
select new
AvailableSubCats
{
CategoryName = g.Key,
Id = 0,
TotalItems = g.Count()
};
with the same error, and dont like this because i dont know how to get the name of the category and its ID.
help much appreciated.
thanks
p.s I am using Entity framework 4.1, .net 4 and MVC 3, mysql
in short i am trying to run this in linq, but were the the products side is already a result
select c.*, (select count(productId) from Products where Products.subCategoryId = c.subCategoryId) as counter from SubCategories c
You could try turning your list of products into a list of subCategoryId's so EF can understand it. Something like:
var subCategoryIds = model.Select(m => m.subCategoryId);
var cats = (from p in ctx1.SubCategories
ctx1.SubCategories
where myCats.Contains(p.subCategoryId) && p.enabled
select new
AvailableSubCats
{
CategoryName = p.subCategoryName,
Id = p.subCategoryId,
TotalItems = subCategoryIds.Count(x => x == p.subCategoryId)
}).Distinct();
I have the following code which adapts linq entities to my Domain objects:
return from g in DBContext.Gigs
select new DO.Gig
{
ID = g.ID,
Name = g.Name,
Description = g.Description,
StartDate = g.Date,
EndDate = g.EndDate,
IsDeleted = g.IsDeleted,
Created = g.Created,
TicketPrice = g.TicketPrice
};
This works very nicely.
However I now want to populate a domain object Venue object and add it to the gig in the same statement. Heres my attempt....
return from g in DBContext.Gigs
join venue in DBContext.Venues on g.VenueID equals venue.ID
select new DO.Gig
{
ID = g.ID,
Name = g.Name,
Description = g.Description,
StartDate = g.Date,
EndDate = g.EndDate,
IsDeleted = g.IsDeleted,
Created = g.Created,
TicketPrice = g.TicketPrice,
Venue = from v in DBContext.Venues
where v.ID == g.VenueID
select new DO.Venue
{
ID = v.ID,
Name = v.Name,
Address = v.Address,
Telephone = v.Telephone,
URL = v.Website
}
};
However this doesnt compile!!!
Is it possible to adapt children objects using the "select new" approach?
What am I doing so very very wrong?
Your inner LINQ query returns several objects, not just one. You want to wrap it with a call like:
Venue = (from v in DBContext.Venues
where v.ID == g.VenueID
select new DO.Venue
{
ID = v.ID,
Name = v.Name,
Address = v.Address,
Telephone = v.Telephone,
URL = v.Website
}).SingleOrDefault()
Your choice of Single() vs. SingleOrDefault() vs. First() vs. FirstOrDefault() depends on what kind of query it is, but I'm guessing you want one of the first two. (The "OrDefault" variants return null if the query has no data; the others throw.)
I also agree with Mike that a join might be more in line with what you wanted, if there's a singular relationship involved.
Why are you doing a join and a sub select? You can just use the results of your join in the creation of a new Venue. Be aware that if there is not a one to one relationship between gigs and venues you could run into trouble.
Try this:
return from g in DBContext.Gigs
join venue in DBContext.Venues on g.VenueID equals venue.ID
select new DO.Gig { ID = g.ID, Name = g.Name, Description = g.Description,
StartDate = g.Date, EndDate = g.EndDate, IsDeleted = g.IsDeleted,
Created = g.Created, TicketPrice = g.TicketPrice,
Venue = new DO.Venue { ID = venue.ID, Name = venue.Name,
Address = venue.Address, Telephone = v.Telephone,
URL = v.Website }