I have some problems trying to query my database. The problem is that I'm not sure how to multiple join tables in my database.
tables to make it easier:
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What I'm supposed to do is to find all the teachers (predavac) who were teachers on the specific activity (aktivnost) and who had specific attendee (polaznik). The problem is I'm not sure how to do multiple joins on this one.
The gist of the problem is that we have an alumni table (one record per person) and also a couple of other tables (one to many) that have degree info and interest info. In a search screen in our app you can search for criteria that spans all three tables (there are actually more fields and tables than shown in the example below but I am trying to keep it simple).
The code below works (properly returns people without degrees for example) but still feels a little clunky or over-engineered to me. Are there easier ways to do this? NOTE: I have been through quite a few iterations/approaches to making the correct data be returned.
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I have one question regarding how to make the below mentioned type of query more optimized so that mine query perfomace can be increased.
Select a.name1,a.address1,b.field3,c.field4,d.field6,e.field7
from a
inner join b on a.id=b.id
inner join c on c.id=b.id
inner join d on d.id=c.id
iner join e on e.id=d.id
union all
Select a1.name1,a1.address1,b1.field3,c.field4,d.field6,e.field7
from a1
inner join b1 on a1.id=b1.id
inner join c on c.id=b1.id
inner join d on d.id=c.id
iner join e on e.id=d.id
union all
Select a2.name1,a2.address1,b2.field3,c.field4,d.field6,e.field7
from a2
inner join b2 on a2.id=b2.id
inner join c on c.id=b2.id
inner join d on d.id=c.id
iner join e on e.id=d.id
All the above three select query at last using the same inner join condition, means last two inner join condition are the same for all the select query.
Is there any way so that this query can be optimized?
how to give a multiple inner joins to the single table
View 1 RepliesOne of my peer wrote a query based on multiple tables using joins. One of the table is in a different database The query was taking much time
1. Create an SP
2. Create a temp table and copy all records from the external db
3. Avoid using Left Join as much as possible and use Inner Join
4. Create and use indexes
5. Remove tables/columns that are not necessary
In this scenario, I would like to suggest to use Covering Index, but how can it be created for multiple tables and a temp table?
Is it possible to have multiple conditions in an SQL select command. I have an SQL Table with the follwing filds.
Image1
Image1Approved
Image2
Image2Approved
Etc
Image1 is a varchar(50) and stroes the picture name. Image1Approved is a tinyint (0 = Pending, 1 = Declined & 2 = Approved) I am using the following to query the SQL database.
SelectCommand="SELECT Image1, Image1Approved, Image2, Image2Approved, Image3, Image3Approved FROM UserProfiles WHERE (UserId = @UserId)"
The part that I am stuck on is only returning the images that have there associated approved condition set. I know how to do this with a seperate select command for each image but can this be done for all image files in one statement.
I have a form that has a detailsview. In that detailview I have and edit button that is visible only when a condition is met. I made the edit command field a template to achive this. My Question is can I have multiple conditions that make the edit button visible. Attached is my current linkbutton with the current variable.
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i create view in sql server and execute a select query using AND operator on it using vb.net and bind data with gridview...but i am not getting result in grid
View 3 RepliesIs it possible to do an optional join as follows?:
private void OptionalJoin(string phrase)
{
from t in db.Table
// (if phrase != string.Empty then) join t2 in db.Table2 on t.Id equals t2.Id
select t
}
Although I'm aware that I can copy/paste this and move the conditional logic outside the query, the query is ~200 lines and there are 4 different optional joins I would like to incorporate, so it would get messy and be difficult to maintain. I'm looking for a clean, streamlined way to do this.
I have two tables.[Table.Game] Columns are "PK_id" "username" and "couponID" [Table.Coupons] Columns are "PK_id" "CouponID" and "Points" The two columns "CouponID" are associated with eachother. Let say i have two rows with the user "harry" in [Table.Game] this person has two different couponID. In [Table.Coupons] this user "harry" has "CouponID" 1 and 2. Column "Points" have 10 and 20. To the question how do u sum this two different point values that have different "CouponIDs". This does work if i have only one "CouponId". But not when the user has 2 different CouponIDs. Values is 0
var points = (from p in linq.Coupons
join g in linq.games on p.couponID equals g.couponID
where g.username == username && g.couponID == p.couponID
select (int)p.win).Sum();
I have a requirement where i need to combine tables from two different datacontext. Does Cross context is allowed in Linq??
i wrote a linq query but its throwing error.
Executed a linq query, and now needs to bind it to the gridview. here is code that doesn't bind anything currently:
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Tables:
WORKORDER and CUSTFIELD
Fields:
WORKORDER = WORKORDERID
CUSTFIELD = WORKORDERID, CUSTFIELDNAME, CUSTFIELDVALUE
There are multiple different type of name/value pairs. I want to specifically return the custfield value where custfield name is "INCIDENT", and the custfield value where custfield name is "NETWORK" all for the appropriate WORKORDERID
I've tried a few different ways and just can't grasp how the linq is supposed to go to get the results I want. I can get an incident value, or network value, but not both.
I have the proper association set up in the dbml so both of these work to get the single value:
var b = from i in edcwdv.WOCUSTFIELDs join p in edcwdv.WORKORDERs on i.WORKORDERID equalsp.WORKORDERID where i.CUSTFIELDNAME.Contains("INCIDENT") select new { i.CUSTFIELDNAME, i.CUSTFIELDVALUE, p.WORKORDERID };
var incident = from wo in edcwdv.WORKORDERs orderby wo.WORKORDERID where wo.WOCUSTFIELDs.CUSTFIELDNAME.Contains("INCIDENT") select new { wo.WORKORDERID, wo.WOCUSTFIELDs.CUSTFIELDVALUE}; So essentially i want to pull the value for each of the fields, INCIDENT and NETWORK
The objective is to send automated emails to which of whom come from the results of my LINQ to SQL script. As I am not sure on 'automated' stuff I was going to approach this in the aspect of having a field in the table that the results are taken from change after the emails have been sent i.e. obj.EmailSent = true; - So that everytime the admin homepage is loaded it isnt sending it out again (eliminating duplication).
From that I would have to create a method to detect a new year and upon that reset all entries of the EmailSent field in the DB table to 'false', but for now its just the initial problem thats causing confusion.
I was going to opt for a 'foreach' solution so that all the recipients, individually, get their emails and not all together. Its the 'foreach' I'm not sure on as well as setting all the results collected to the new value of 'EmailSent' to 'true'.
Here is my attempt:
C#:
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I have a partitioned db where several tables have the exact same structure. I'm able to query the tables using linq, but only by quering the individual tables 1 at a time and by using the explicit table name. For example at the moment, I have 8 tables so I have something similar to the following:
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Is there any way, that based on a certain value (stringValue), I could determine which table to query and then code the linq query just once?
I have a couple tables that are kind of unrelated - id like to search through both of them and create a type that i can sift through later
something like this doesnt work
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I basically want to create a list of "AnimalSearchResults" that contains all dogs and all cats that have that name Whats the best way to do something like this?
When I am updating a record with linq to sql my DeleteLesson() method is getting called multiple times.My controller looks like this :
public ActionResult Delete(int id)
{
deleteLesson(id);[code]....
EDIT.also if I use confirm = "Do you want to delete" in ajax options I will have to click okay three times.
I'm creating a repository and service layer in my app, and my repo has a very simple function
Public Function GetRegions() As IQueryable(Of Region) Implements IRegionRepository.GetRegions
Dim region = (From r In dc.Regions
Select r)
Return region.AsQueryable
End Function
Now in my Service layer I've got a function like this
Public Function GetRegionById(ByVal id As Integer) As Region Implements IRegionService.GetRegionById
Return _RegionRepository.GetRegions().Where(Function(r) r.ID = id).FirstOrDefault
End Function
But i can't figure out how to add And r.isActive = True
how to have multiple operators in this query?
Using Linq to Sql how do i group the following 2 tables.
Orders Table:
CustomerID | Name |Date
1 | order1 | 2010-01-01
2 | order2 | 2010-01-01
2 | order3 | 2010-04-01
Calls Table:
CustomerID | Name |Date
1 | call1 | 2010-01-01
3 | call2 | 2010-06-01
2 | call3 | 2010-05-01
I want to group the two tables by date , Result:
Date | Orders | Calls
2010-01-01 | 2 | 1
2010-04-01 | 1 | 0
2010-05-01 | 0 | 1
2010-06-01 | 0 | 1
i know how to group a single table ,from o in Orders group o by o.Date.Date into og select new {Date = og.Key,Orders= og.Count()};
How can I declare multiple groups in LINQ? I get this error "Range variable 'Group' is already declared." Error found in bold and underlined text below.
Dim SportsWear = From c in dbContext.SportsTable Group Join grp_Attire In dbContext.AttireTable On grp_Attire.AttireId Equals c.AttireId Into Group From sportsAttire In Group.DefaultIfEmpty() Group Join grp_SportType In dbContext.SportType On grp_SportType.TypeId Equals c.TypeId Into Group From sportsType In Group.DefaultIfEmpty() Select New With { _ .Attire = sportsAttire.AttireName,.Type = sportsType.TypeName}
I am trying to delete three related objects on one submit. Delete fails on one of the child objects, because of foreign key contraint with another table, It deletes one (the parent) but not the two child objects. All in one SubmitChanges(). I even used the TransactionScope, still same thing. So here is the scenario:
I have an object called Page which has a collection of objects called Webinars. There is another object Called Product which is one to one with Webinar.
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I'm using Entity Framework.
I have 3 tables:
- Products (Primary key productId)
- Categories (Primary key categoryId)
- Product_to_categories (Table with two fields, CategoryId and ProductId)
One product can be assigned to multiple categories.
How should I download the products from specific category?
Now I retrieve them in that way:
int PageNum = 1;
int PageSize = 10;
int categoryId = 5;
var categoryModel = db.Categories.FirstOrDefault(c => c.CategoryId == categoryId);
var results = (from p in categoryModel.Products select p).Skip((PageNum - 1) * PageSize).Take(PageSize).ToList();
But when there is a lot of products in category my server crushed. I want only 10 products per page.
I am selecting some products from database and would like to show them in client's grid using WCF. Problem is I don't know how to pass selected collection to the client since my method can't return that data type.
My method:
public class Service1 : IService1
{
public ProductData GetData(int value)
{
using( NorthwindEntities NWEntities = new NorthwindEntities()){
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In the code bdehind && syntax does not work, any ideas?
Entities ctx3 = new Entities();
var uniqueQuote = from quot in ctx3.Quotes.Include("aspnet_Users").Include("Enquiries")
where quot.Enquiries.EnquiryId == selectedEnquiryId && [code]...
Error 2 Delegate 'System.Func' does not take '1' arguments C:LocalGarageFinderLocalGarageFinderEnquiryDetail.aspx.cs 56 33 LocalGarageFinder
I ned to run a query with two joins, the second join does not work please help with the correct syntax.
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