I have the following query:
db.ObjectTags.Where(c =>
c.TagID == tagID &&
(!db.DeletedObjects.Any(d=> d.ForObjectTypeID == c.ForObjectTypeID && d.ForObjectID == c.ForObjectID)
|| !db.DeletedObjects.SingleOrDefault(d => d.ForObjectTypeID == c.ForObjectTypeID && d.ForObjectID == c.ForObjectID).Deleted)
)
Its goal is to return objects that are not in a deleted state.
The table DeletedObjects has two states:
A record doesn't exist (not deleted)
A record exists with a deleted (bool) value
I need to query where either the record doesn't exist, or if it does the deleted value is false.
Is there any way to condense that statement eg with SingleOrDefault()?
You only need one !db.DeletedObjects.Any(...) and no SingleOrDefault
var q = db.ObjectTags
.Where(c=> c.TagID == tagID && !db.DeletedObjects
.Any(d => d.Deleted && d.ForObjectTypeID == c.ForObjectTypeID && d.ForObjectID == c.ForObjectID));
Can you please try this linq query
db.ObjectTags.Where(c =>
c.TagID == tagID &&
(db.DeletedObjects.Any(d=> d.ForObjectTypeID == c.ForObjectTypeID && d.ForObjectID == c.ForObjectID && !c.Deleted))
)
I believe you need to left join between ObjectTags and DeletedObjects. A LINQ query like this:
from objectTag in db.ObjectTags
from deletedObject in db.DeletedObjects
.Where(deletedObject => deletedObject.ForObjectTypeID == objectTag.ForObjectTypeID && deletedObject.ForObjectID == objectTag.ForObjectID)
.DefaultIfEmpty()
where deletedObject == null || !deletedObject.Deleted
Related
The following query is not returning the proper results, it will return properly for company, but not the other two parameters. For clarification this is inside a post method of a page taking the user's input for company, name, and/or state
var transporters = await _db.TransporterProfiles
.Include(x => x.TransportState)
.Where(x => x.Company == company || company == null &&
x => x.LastName == name || name == null &&
x => x.TransportState.Name == state || state == null)
.ToListAsync();
I've tried adding parentheses around each part of the query such as
.Where((x => x.Company == company || company == null) &&
(x => x.LastName == name || name == null) &&
(x => x.TransportState.Name == state || state == null))
but this produces an error
Operator '&&' cannot be applied to operands of type 'lambda expression'
There's no reason to include company == null in the query. If you don't want a search term, don't include it at all. You can build AND conditions by adding Where clauses to a query as needed, eg :
if(value1 != null)
{
query=query.Where(x=>x.Property1 == value1);
}
if(value2 != null)
{
query=query.Where(x=>x.Property2 == value2);
}
In the question's case you can write something like this:
var query=_db.TransporterProfiles.Include(x => x.TransportState).AsQueryable();
if(company!=null)
{
query=query.Where(x => x.Company == company);
}
if(name!=null)
{
query=query.Where(x => x.LastName == name);
}
if(state!=null)
{
query=query.Where(x => x.TransportState.Name == state);
}
var transporters=await query.ToListAsync();
You don't need to include TransportState to use x.TransportState.Name in the Where clause. Include is used to eagerly load related data, not tell EF to JOIN between related tables.
If you don't want Include you can start the query with :
var query=_db.TransporterProfiles.AsQueryable();
The issue with your syntax is you have multiple lambdas that should be one.
.Where(x => (x.Company == company || company == null) &&
(x.LastName == name || name == null) &&
(x.TransportState.Name == state || state == null))
That said the actual solution is to do what #PanagiotisKanavos posted as an answer, generate the query dynamically based on the input values.
I have this attempt to execute a query:
hmrSingle = dbMngr.Set<HistoryMessagesRequested>().Where(x => x.dateregistration == msgv.DtRicezione && x.val == msgv.value && x.parameter == dmf.Description && x.DeviceID == ms.IDDevice).FirstOrDefault();
dateregistration and DtRicezione are both declared as DateTime? into the database context and they're "datetime" into MSSQL tables too.
I can't figure out why this problem is continuously present.
Any time you are using a nullable value type you need to use .value to get its value. Try:
hmrSingle = dbMngr.Set<HistoryMessagesRequested>().Where(x => x.dateregistration.value == msgv.DtRicezione.value && x.val == msgv.value && x.parameter == dmf.Description && x.DeviceID == ms.IDDevice).FirstOrDefault();
That was my query with Contains:
db.NavFilters.Where(finalExpression)
.Count(x => x.Attribute1 == e.Attribute && x.Link == link && x.SubLink == subLink && db.NavItemsFilters
.Where(n=> !(n.Promo == string.Empty || n.Promo == null))
.Select(n=>n.ItemID)
.Contains(x.ItemID) )
But, as far as I know, contains is a hard operation, and I need to optimize it. Is such query will give the same result?
db.NavFilters.Where(x=> db.NavItemsFilters.Any(n=>n.Promo != string.Empty && n.ItemID == x.ItemID))
.Where(finalExpression)
.Count(x => x.Attribute1 == e.Attribute && x.Link == link && x.SubLink == subLink)
I know, that the best solution is to add navigation properties. But I can't do that for many reasons.
You can optimize you query like this:
var navFilters = db.NavFilters.Where(finalExpression);
var thereIsAny = (from x in navFilters
join n in db.NavItemsFilters on x.ItemID equals n.ItemID
where n.Promo != string.Empty && x.Attribute1 == e.Attribute && x.Link == link && x.SubLink == subLink
).Any();
IQueryable.Contains does exist, so your query should get converted to SQL.
This is an SQL query:
SELECT Website,VendorID,Name,LinkProduct,
Link,Logo,Image,NameExtra as Industry,
(SELECT [Percent] FROM Web_Promotion
WHERE Web_Promotion.VendorID=Web_Vendor.VendorID)
AS PercentOff
FROM Web_Vendor WHERE Active='1' AND
(VendorID IN (Select VendorID FROM Web_Promotion
WHERE VendorID<>'' AND Static='True' AND [Percent] <> '0' AND
((Expires>=GETDATE()) OR (Expires IS NULL))) OR
VendorID IN (SELECT TOP 1 SC1 FROM NavItems
WHERE SC1=Web_Vendor.VendorID AND Promotion<>''
AND ((PromotionStart<=GETDATE() AND PromotionEnd>=GETDATE())
OR (PromotionStart<=GETDATE() AND PromotionEnd IS NULL))))
ORDER BY NameExtra,Sequence
I need to rewrite it to LINQ. So this is my LINQ:
return await _db.Web_Vendor.
Where(x => !(x.WebPromotion.VendorID == string.Empty || x.WebPromotion.VendorID == null)
&& x.WebPromotion.Static == true && x.WebPromotion.Percent != 0 &&
(x.WebPromotion.Expires >= DateTime.Now || x.WebPromotion.Expires == null)
||
(_db.NavItems.Where(y => x.WebPromotion.VendorID == y.SC1
&& !(y.Promotion == "" || y.Promotion == null)
&& (y.PromotionStart <= DateTime.Now) && (y.PromotionEnd >= DateTime.Now || y.PromotionEnd == null))
.Select(g => g.SC1).Take(1).Contains(x.WebPromotion.VendorID)))
.Include(x => x.WebPromotion).Where(x => x.Active == true).OrderBy(x => x.NameExtra)
.ThenBy(x => x.Sequence).ToListAsync();
I spent about three ours, but can't find an error. Original SQL query returns 16 rows, but my LINQ code returns only 13 of the. Unfortunately I have only one navigation property (Web_Vendor <-> Web_Promotion). I think that an error in the second part of my query:
||
(_db.NavItems.Where(y => x.WebPromotion.VendorID == y.SC1
&& !(y.Promotion == "" || y.Promotion == null)
&& (y.PromotionStart <= DateTime.Now) && (y.PromotionEnd >= DateTime.Now || y.PromotionEnd == null))
.Select(g => g.SC1).Take(1).Contains(x.WebPromotion.VendorID)))
Can any expert check my code and help me?
Correct data:
http://prntscr.com/9a5xwu
Linq data (not correct) contains the same data as correct instead of values where PercentOff is null.
The main problem is that LINQ generate inner join instead of left join in this place: http://prntscr.com/9a6stb
since you say that your linq data miss the case when PercentOff = null, i'd focus on that
I guess your "PercentOff" in Linq is Percent property, and i see that you have in your where: "x.WebPromotion.Percent != 0"
Is that a nullable value or you convert the null to the default property type, that is 0?
couldn't be that null is converted to 0 and then the query skip it?
I have the following LINQ Query:
var contents = _contentsRepository.GetAll()
.Where(a => a.SubjectId == subjectId &&
a.ContentTypeId == contentTypeId &&
a.ContentStatusId == contentStatusId )
.ToList();
I would like this select to proceed normally unless the contentStatusId == 99. If that's
the case then I want it to retrieve a row from the database with ANY contentStatusId.
Would it be best to do a check of contentStatusId first and then break this down into
two LINQ selects or is there a way I could modify my LINQ query?
Note that I am using SQL Server 2012 and my repository:
public virtual IQueryable GetAll() { return DbSet; }
I believe you can modify your query by adding a contentStatusId == 99 component to your predicate that will short-circuit the evaluation of a.ContentStatusId == contentStatusId like so:
var contents = _contentsRepository.GetAll()
.Where(a => a.SubjectId == subjectId &&
a.ContentTypeId == contentTypeId &&
(contentStatusId == 99 ||
a.ContentStatusId == contentStatusId))
.ToList();
In the normal case everything will work just like before.
In the case when contentStatusId equals 99, there will be overhead of evaluating contentStatusId == 99 for every row, although I think depending on repository you're querying this part could be inlined as a true. You should see for yourself how this impacts performance in your setup.
Try this
var contents = _contentsRepository.GetAll()
.Where(a => contentStatusId == 99 ? (a.SubjectId == subjectId &&
a.ContentTypeId == contentTypeId &&
a.ContentStatusId == contentStatusId) : (a.SubjectId == subjectId &&
a.ContentTypeId == contentTypeId) )
.ToList();
var contents = _contentsRepository.GetAll()
.Where(a =>
{
return a.ContentTypeId == 99 ||
(a.SubjectId == subjectId &&
a.ContentTypeId == contentTypeId &&
a.ContentStatusId == contentStatusId)
}