In my application i want to compare data of two users from database table using linq.
lets say i have ten columns in UserMaster table.
Now based on the comparision i want to display result.
Like is 10 out of 10 columns matches for those two users result will be 100,if 9 columns matches then result will be 90 and if 0 matches thn result will be 0.
i dont want to write if else for somany time.
I am new to linq.
Mmy data table has four columns. How can I get only selected columns name?
View 5 Repliesi'm writing an asp.net C# web application; i have an in-memory datatable named 'table1' having three columns 'country', 'productId' and 'productQuantity'; i want to pivot that table in order to obtain a new table (suppose 'table2') having the first column 'country' as a fixed column and a dynamic number and names of columns 'product_1', 'product_2', ..., 'product_n' according to the total number of products existing in 'table1'; the first column 'country' must contain the country name; the dynamic generated columns 'product_1', 'product_2', ..., 'product_n' must contain the productQuantity that has been selled for each specific product in the specified country
i'm using Linq query expressions to write the code; the problem is that i cannot hard-code the names neither the values of the products; i cannot predict how much products exist in the datatable;
for now, i'm testing the results using the following expression :
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i'm giving an example on how 'table1' looks like and how 'table2' must look like :
view example image of the two tables table1 and table2
I want to copy data from a table[tblExcel][No.of columns:2] to another table[ev_event] which has 5 columns, 2 columns from the another table, 3 columns from user defined value
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I am quite new to LINQ, and I am stuck with this probably basic problem, but haven't been able to find a solution, so I thought I could ask here.
So, I have this repository where I put my functions for data accessing, and now I need to write a function to get all the applicants that have applied for this particular advertisement, and their values too. Now, the values are stored in a separate M:N table, where every row consists of the applicantID,advertisementID and value. I just wanna append the value to every applicant that I show, so that it would look like a Ranking List.
However, I do not seem to know how to select just the name column from the Applicant table, and just the Value column from the ApplicantValue table.
And there's this Iqueryable interface that further confuses me...
Here's my function to get the Applicants only:
[Code]....
Now, if I try to add to the definition of the type two columns, it says that it only messes with types, i.e. one type should be passed. So I figured I would do a ViewModel and then pass it, like this
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and then in the function I have no idea how to pass the values:
how can i select a record from A table and insert into B table using linq?
View 2 RepliesI'm currectly tryin to access a specific value in my database in a specific column. I'm tryin to use the primary key of the table to access the actual value in the row of that ID.
The current code:
[Code]....
Just iterates through the table and looking for any row with the boolean 'checkin' value is True, then it takes the 'id' value of that row and stores it into an array. Is there a way that I can access a another entry, and only that entry, in the table with the 'id' stored in the array?
Like if my data base contained and int, primarykey, `id` value, a boolean, `checkedin` value, and a `time` value, is there a way to access, lets say, the row with `id` equalling 3 and and the checkIn value from that row?
How to handle this error
"An explicit value for the identity column in table 'UserActivation' can only be specified when a column list is used and IDENTITY_INSERT is ON."
i have a table which showing the food data from my Model, including Name, Amount, Storage and Expiry Date. I wish to either:
1. Let user click on the column header and sort the column they want
2. Or default showing the food which almost expired on the top of the table
I am working on a web app for an online photo album. It is the last project in Scott Mitchell's book: "ASP.Net 2.0 in 24 hours".
I am creating a page where users can enter new photo images. The functionality for uploading an image will come later. I am working on just inserting a new row into the Pictures table with an optional category, a required title and a required description.
I am getting an error when I try to insert a new row.
Here is a screenshot of the page with a shot of the dropdown list.
The Categories are user-specific. I am getting the correct values retrieved.
[URL]
There are two pretty simple database tables involved here.
NOTE: The CategoryID and PIctureID are both autoincrement integer columns.
[URL]
The page uses a DetailsView that uses a SqlDataSource that uses the Pictures table. (The DetailsView's Default Mode property is set to "Insert". The "Enable Inserting" checkbox is also checked.)
The dropdown list uses a dropdown control that uses a SqlDataSource that uses the Categories table.
When the "Insert" button is clicked the CategoryID value associated with selected (Category) Name on the dropdown list will be used along with the Title and Description values to insert a row in to the Pictures table. (If no Category value is selected, then a null value will be used for the CategoryID. This is OK because the CategoryID column in the Pictures table allows nulls.)
My problem is that I am getting this error:
Cannot insert explicit value for identity column in table 'Pictures' when IDENTITY_INSERT is set to OFF.
(FYI: I have the full version of both Visual Studio and SQL Server.)
Here is my source code for the page:
[Code]....
i have 3 tables which are Table A(a Id,b Id),
Table B(b Id,a Id,c Id),
Table C(c Id,b Id)
How can i select Table C column by using table A?
I have to find the best way to do this using LINQ. I need to summarize an amount in a iTransaction table by
Account (e.g. 12345) and add that amount to an same Account ( e.g12345) if it exists in a iAccount table . Here is the code which syntax checks ok and tested ok up to the .submitChanges statement (i.e. I stopped and didn't allow the submit.
Following is the LINQ code. (1) Is that a good way to do this. OR should I try the INTERCEPT.
(2) How is the best way to insert a new record/row in the iAccounts table if it DOES NOT exist in the iAccount Table.
[Code]....
I want to create a temporary table where the columns of that temporary table needs to be dynamic (those columns needs to come from the rows of another table)
View 6 RepliesI have a question about linq delete.
I have 2 table in database and they are joined.
First Table: UserID, UserName, UserSurname, UserPhone, CompanyId
Second Table: CompanyId, CompanyName
First Table I have many recods with related second table.
I want to delete one company in second record, But firtly I have to delete users (more than 1)
How can I delete it with using linq?
I am using this C# with linq to sql:
string currentLabel = from s2f in stream2FieldTypesTable
where s2f.s2fID == item.s2fID
&& (s2f.s2fLabel != item.s2fLabel || s2f.s2fIsRequired != item.s2fIsRequired)
select s2f.s2fLabel;
I am getting a compiler error saying i can't assign type System.Linq.IQueryable<string> to string.
I tried this code:
string currentLabel = from s2f in stream2FieldTypesTable
where s2f.s2fID == item.s2fID
&& (s2f.s2fLabel != item.s2fLabel || s2f.s2fIsRequired != item.s2fIsRequired)
select s2f.s2fLabel.ToString();
And that returns the same error. I'm sure this is a simple thing. what am I missing? I just want the first s2fLabel that matches the where clause.
I would like to select some data from multiple tables and calculate a new column IN the query.In SQL it would look like: (select A, B, ((C * D) + (C * E)) as 'calc' from tab1 join tab2 on.join tab3 on.join tab4 on ...);I've tried this in linq, but it didn't work as I believe.
[Code]...
I am trying to translate this:
SELECT IDNum, Max(Convert(varchar(20), (TimeOut - TimeIn), 108))
FROM IO_Times Group by IDNum
order by Max(Convert(varchar(20), (TimeOut - TimeIn), 108)) desc";
Into LINQ in C#. The above returns a list of the maximum value of (TimeOut-TimeIn) that corresponds to each unique IDNum (There are multiple TimeOut-TimeIn values for every IDNum).Here is what I am trying now:
from IO_Time in db.IO_Times
orderby SqlMethods.DateDiffMinute(IO_Time.TimeIn, IO_Time.TimeOut) descending
group IO_Time by IO_Time.IDNum into list
select new
{
ID = list.Key,
Time = list
});
This returns the correct IDs in the correct order, but the "list" contains everything in the database entry (which makes sense). I have also tried group by IDNum and Time, but then I get unique time entries and multiple IDs returned.I could do a foreach loop and manually sort it all out, but I would really rather not do that.
how to get column names from linq datasource?
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I got a sql table and is trying to sort the data by the column that contains the data entered in a search form.
My code is below:
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I am using Linq to read data from the database, the database has 5 coloumns.Here is the code that I am using to read from the database.
[Code]....
Now, I call this method as : var retrieved_Data = objDataMgrClass.ReadData();Now comes the problem that I am facing how to read each coloumn from this var retrived_Data??? I have tried using foreach loop but i keep getting an error : foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator'.The foreach loop i have used as:
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All I am trying to do is query the database, then get the returned values, so that I can do some calculations. But, I don't understand how to get the values from the database row that is returned, so that I can assign it for usage.
I would like to do something where the logic goes: for the index of [1] (which is just column 1), multiply it by 2. For the index of [2] (which is just column 2), multiply it by 3.
Example below:
This does NOT work:
[Code]....
I was wondering if there is easy solution to this or I'm stuck with following:When updating DB:
dti.Pass = Crypter.Encrypt(dti.Pass);
_db.SubmitChanges();
When selecting from DB:
Data.DbTableItem dti = _db.Single(a=>a.Id == id);
dti.Pass = Crypter.Decrypt(dti.Pass);
Meaning - I am not really into writing repetitive code and this seems like logical thing to be supported by LINQ; so I'm wondering if it is.
I'm using Linq to Sql to call some stored procedures for more complex work; is there any way Linq to Sql can tell me when the output columns from the stored procedure do not match the properties of my entity object? It seems that Linq to Sql tries its best to match the columns and ignores any mismatches.
View 8 RepliesI have a column called regdate datetime default getdate() , the column is notnull.I am using linq to sql.I have created instance of that table and when i try to insert record into the table, I am getting daterange exception.(range should be 1/1/1753 to 31/12/9999).In that object I am not setting any value to regdate property as that would be taken care by sql server.If i set regdate = datetime.now.date then record is inserted successfully.I dont want to set any value from front-ent.I want sql server to do that for me like we do it using stored procedure.
View 6 Repliesis there a way to update a column for all rows in a collection using linq like sql does it
eg. UPDATE myTable SET myColumn='newValue'
Also weighing options as to whether there is better performance using linq to sql for this or straight sql to DB via table adapters etc.
