When setting up my database, I forgot to set the delete rule to cascade on foreign keys. Now, I can't delete a user from the ASP.net control panel due to the FK constraints. So, I need to go through all my tables and allow cascade delete on all keys.Once I do this, will I need to redo my Linq .dbml? (ie: delete each table on it and drag it back on) or does it not matter?
View 5 RepliesI am using VS 2010 I've created LiNQ .dbml file via .. Model>Add New Item>Data>LINQ to SQL Clases I've put table on designer surface using drag & drop. I've done all this from one tutorial. There Is Mapping with arrows between tables in tutorial. How can i do this?
View 2 RepliesI have created a page with a gridview in asp.net that displays the records of a database table and allows users to delete checked records by clicking on a delete button. After I delete a record and I try to refresh the page from the browser (I am using mozilla)I get the follow message:
"To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier."
and if I click resend another record is deleted automatically. Even though I am reloading the gridview after the deletion the application executes again the onclick event of the delete button is executed and the gridview things that there is a checkedbox selected so the code executes my delete function again.
Is there any way to get rid of these behavior. I have been trying quit a few things but nothing works for me.
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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Is there a quick and easy way to update my LINQ dbml files?Right now, if I update a Stored Procedure, I need to open the dbml designer file, delete the old SP, save, drag and drop the new SP, and save again. Dont' get me wrong, this isn't "hard"... just with all the fancy new technology out there, it would be nice to be able to just right-click and hit "update".
View 2 Repliesi have some confusion using compund from in linq.I know the concept of compound from but in database table how can we use.can anyone give me example of it.
View 3 RepliesHow do add read-only computed column in LinqToSql designer (dbml)? My existing table structure:
Name: ID, Type: int, AutoGenerate: true, AutoSync: OnInsert, PrimaryKey:
true, ServerDataType: int not null identity, Source: IDName: Name, Type: string, ServerDataType: nvarchar(100) not null, Source:
NameName: Value, Type: byte[], ServerDataType: VarBinary(max), Source:
Value, UpdateCheck: Never
I want add the 4th colum name: Name: HasValue, Type: bool --> [Value] != null
I am using two Updatepanels in ASP.NET AJAX and as soon as there is some event in first updatepanel, it will get refreshed at that time I want my second Updatepanel getting refreshed too. How can I do that ?
View 2 RepliesI need to make a category filter. For this purpose I have two tables "Ingredient" and "Category"
My Category Table looks like this:
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And my ingredient table:
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I want to join the two tables so when the KategoriID match it should then return all from that category.
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I was trying to find out how I can join more than 2 tables using the LINQ-to-SQL syntax. For instance, joining 2 tables in SQL:
SELECT * FROM Table1 AS T1 INNER JOIN Table2 AS T2 ON T1.Key=T2.Column1WHERE T2.Key='17';
can be expressed as:
var Result = from T1 in DbContext.Table1 join T2 in DbContext.Table2 on T1.Key equals T2.ForeignKey where T2.Key=17 select new { T1, T2 };
But how would I join 3 or more tables using LINQ? For example:
SELECT * FROM (Table1 AS T1 INNER JOIN Table2 AS T2 ON T1.Key=T2.Column1) INNER JOIN Table3 AS T3 ON T3.Key=T2.Column2 WHERE T2.Key='37';
I've been searching and experimenting and I cannot seem to find any informraiton on this. One example I found involves putting the result for the frist join into a temp object, and then performing the second join. I'm not sure performance-wise if that's the same as doing a 3-table join directly using a single SQL statement.
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:
[Code]....
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 two tables:
Entity
ID (PK), int
Name
Descrip
Users
ID (PK)
EntityID, int (this is not connected to Entity table)
Now I am using LINQ to pull the records which has a Entity.ID = something. Which will show me couple of records in my GridView. Here is my LINQ statement:
protected void Page_Load(object sender, EventArgs e)
{
string getEntity = Request.QueryString["EntityID"];
int getIntEntity = Int32.Parse(getEntity);
OISEntityTestingDataContext db = new OISEntityTestingDataContext();
//OISLinqtoSQLDataContext db = new OISLinqtoSQLDataContext();
var tr =
from r in db.Users
join s in db.Entities on r.UserID equals s.ID
where s.ID == getIntEntity
select new
{
//To Show Items in GridView!
};
GridView1.DataSource = tr;
GridView1.DataBind();
}
Now here I am getting an error mesg on 'join' The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'Join What does that mean?
I have T_articles to save the articles.
each article has authorCode , and categoryCode.
each article can be modified by the author several times.
and I save every modification in the T_articles in a difference row.
now I want to dislpay for each autor:
author name, article name , article category's name, last modified date
In SQL I should to it like that:
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I try to write it in Linq so:
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so I got error:
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and again I got an error:
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I am very new to Linq , i want to check if the PrintingAdminSetting table has rows in it and then if it has then i want to get the value and assign it to txtMaxJobs textbox
below is teh code
, please let me know teh syntax to check .
var DC = new ServiceDataContext();
var rec = DC.PrintingAdminSetting.Where("").First();
txtMaxJobs.Text = rec.ParaName.ToString();
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?
Here's my DB structure:
I have three tables.
User, Details, Optional
User has fields: ID, FirstName, LastName
Details has fields: ID, MyDetails1, MyDetails2, User_ID
Optional has fields: ID, MyOptions1, MyOptions2, User_ID
There is a 1 to many relationship with User & Detail (User ID & Detail User_ID)
There is a 1 to many relationship with User & Optional (User ID & Optional User_ID)
With that said, one user can have many details and/or many optionals
Now I'm trying to build a linq query that will say:
"where user id = x, select FirstName, LastName, all MyDetails1 from every record where User_ID == x, all MyOptions1 from every record where User_ID == x"
After the merge I should have one string that lists the distict user & all of their many fields:
FirstName + LastName + (MyDetails1 + MyDetails1 + MyDetails1..etc) + (MyOptions1 + MyOptions1)
Anyone try this before?
I tried this with JOIN but this doesn't do the trick for what I'm looking for.
So if I had 3 MyDetails records associated with ID == 2, I would get three results like:
John Doe MyDetails_X
John Doe MyDetails_Y
John Doe MyDetails_Z
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()};
The main problem is that I recieve the following message:
"base {System.SystemException} = {"Unable to create a constant value of type 'BokButik1.Models.Book-Author'. Only primitive types ('such as Int32, String, and Guid') are supported in this context."}"
based on this LinQ code:
[Code]....
How shall I solve this problem to get a class instance that contain with property title and Book-AuthorID?I also have tried making some dummy by using "allbooks" relation with Code Samples from the address
http://www.hookedonlinq.com/JoinOperator.ashx. Unfortunately, still same problem.
I also have taken account to Int32 due to entity framework http://msdn.microsoft.com/en-us/library/bb896317.aspx. Unfortunatley, still same problem.
Using database with 3 tables and one of them is a many to many relationship. This database is used in relation with entity framework
Book-Author
Book-Author (int)
BookID (int)[code]....
I was wondering how Linq to Sql determines which tables to write to when given primary/foreign Key relationships. I can (hopefully) better explain using an example. I have the following tables:
Customer CustomerStatus CustomerType CustomerAddresses
Therefore I have a Customer Entity, a CustomerStatus entity, a CustomerType Entity and a List of CustomerAddresses. In my code, I load up the Customer Entity and the List of CustomerAddresses because that's all I need. For some reason Linq to Sql is trying to insert a new Customer Status record. I have no idea why its doing this.
Can anyone please explain to me how linq to sql determines which table(s) will be written to based on the entities above?
How to get data from two tables through linq .1 ) productsDetails 2) productsImages to bind further listview.
View 1 RepliesDoes anyone have some really great tutorials on how to use link with datasets that contain multiple tables that utilise primary key and foreign key relations? For eample
Table1
- id (PK)
- language
Table2
-id (PK)
-programmingword
Table3
-id (PK)
-languages_ID (FK)
-pgrammingword_ID (FK)
-translatedword
Linq search for: Table3.translatedword where Table1.Language ='french' and Table2.programmingword = "yes" does this make sense? im looking for exampes/ tutorials for how to do this? or can anyone recommend any good books on linq?
I'm working with asp.net 3.5 WebForms and LINQ to Entities.
I created the database with their relationships, but when I go to import the data with LinqToEntities, some reports and have not seen any reports 1 to 1.
I can create them after the reports have imported the tables LinqToEntities?
I'm a newbie to this so bear with me. From what I've read online LINQ to Entity should see the relationships without having to specify the joins between multiple tables. I have a relationship that goes across 4 tables Employee, EmployeeDepartmentLink, EmployeeProjectLink, and Project. The idea is an employee can be in multiple departments and work on multiple projects with it being specified which department the employee is in for that project.
This is a C# MVC3 program connecting to a SQL database using VS 2010 Express.
I have no problem with running this query to find employees on a project:
[Code]....
Tring to do the reverse, finding projects that an employee worked on results in an error:
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Error message: The specified type member 'EmployeeDepartmentLinks' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. So I have 2 questions,
1) Why would it work in one direction and not the other? I've played around with it for a couple days with the same results.
2) Does it matter that my primary key and foreign keys are not named the same since all the relationships are connected in SQL? Ex: in Employee (EmployeePK)--(EmployeeFK) in EmployeeDepartmentLink Trying different stuff in LINQPad I was able to get the 2nd query to work if I specified all the joins which I thought was not neccesary with LINQ to Entity. I converted an SQL query that I made on the server into a LINQ query below which works.
As the title sugests, I am missing a (basic?) concept as I teach myself asp.net, linq, and C#. It has been awhile since I've done anything object oriented, so I don't know how much that is impacting this gap in my understanding. Anyhow, here is what I am trying to do. I have three SQL Server tables: PERSON, POSITION, AREA. There is a 1 to many relationship between PERSON and POSITION, and a 1 to 1 relationship between POSITION and AREA. Given the following code I verify who the person is who has logged into the browser:
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I want to be able to return all of the AREAs the person is able to access, based on the position they currently hold. I am able to easily do this in a SQL Server query, and I am sure I can do this with a SQL stored procedure once I pass the EMPLOYEE_ID to the procedure. However, I would rather do this in the page_load event, and load the returned results into gridview1 for the viewer. The issue I am running into is in building the LINQ query. When I try to build it, I can only get access to two of the three tables, depending on which table I select with db. Is it possible to access all three tables in the same query?
I want to do execute a LINQ query, and I have the name of the table to query stored in a variable:
string tableName = "SomeTable";
DataContext db = new DataContext();
var vResult = from t in db.tableName where t.Id = ....