linq-to-sql

When to use "LINQ to SQL",entity framework, or NHibernate?

With .NET, which data access method is better to use "LINQ to SQL",entity framework, or NHibernate? Should a different method be used depending on the situation or is it more of a personal preference? If so which method and when? ...

What problem is Microsoft trying to solve with all of these data access strategies?

There seems to be many different data access strategies coming out of Microsoft. There’s ‘classic’ ADO.NET, Linq2Sql, ADO.NET Entity Framework, ADO.NET Data Services, ADO.NET Dynamic Data. I’m sure that I’ve missed some. To me, it seems that there’s a lot of confusion surrounding where each frameworks fit into an application's architectu...

How can I add an "IsDirty" property to a Linq to Sql entity?

Okay, similar questions exist, but they are all about how to determine this from outside of the entity itself and use the DataContext the entity is attached to. I am binding my entities to an edit form in WPF. Within a DataTemplate, I want to be able to set the background color of the root container within a DataTemplate to show it has...

Linq to sql: Composite foreign key in one-many relation?

Hi, I'm trying to model a database in LINQ to SQL. I have a table JournalPosts. Each entity is associated with 1 or more senders or recipients. I have the following composite primary key in my table "JournalPosts": [Column(IsPrimaryKey = true)] public int CaseYear { get; set; } [Column(IsPrimaryKey = true)] public int ...

Linq to SQL error when doing a Lambda

The following lines of code is producing this error: "Overload resolution failes because no accessible 'Single' can be called with these arguments". I'm not too good with VB, but since the app I've inherited was in VB, I didn't want to rewrite it all: Dim a1 = From rows In db.tPDMLinkUsages _ Where (rows.ACCESSDATE >= DateTime.Today...

Why this Linq code always throws System.StackOverflowException?

//A query to a local object var deletionCommands = commands .Where(a => a.Operation != Operation.Addition) .Select(a => new { a.Prestador.cod_prestador, a.Prestador.cod_desdobramento }) ; //A Linq-To-SQL query var toDelete = db.Prestadors .Where(a => deletionCommands.Contains(new { a.cod_prestador, a.cod_desdobram...

Linq-to-SQL ignores SQL Server default value

When using Linq-to-SQL, adding a column to an existing table, and setting a default value on that new column, it seems that Linq to SQL ignores the default value. Has anyone else experienced this behaviour? Is there a way to fix it, so that Linq-to-SQL or SQL Server automatically sets the default value? The column I added was of type ...

LINQ to SQL - Left Outer Join with multiple join conditions

I have the following SQL which I am trying to translate to LINQ: SELECT f.value FROM period as p LEFT OUTER JOIN facts AS f ON p.id = f.periodid AND f.otherid = 17 WHERE p.companyid = 100 I have seen the typical implementation of the left outer join (ie. into x from y in x.DefaultIfEmpty() etc.) but am unsure how to introduce the oth...

Why is HasLoadedOrAssignedValue Property set to true?

hey guys, ok, here's the scenario: VS 2008 .NET 3.5 SP1, LINQ to SQL. I have a Product Entity, which has an ImageID field, so it has a relationship with the Image Entity. This is all defined in the schema and DBML. Now, say I create a new Product entity, without a ImageID, and save it to the DB. At this point, the _Image field of the ...

Linq to Sql vs Nhibernate vs SubSonic vs Stored Procedure (Help)

Hello, I am looking to develop a website for a news channel. So, Obviously its gonna receive a lot of hits daily and will be updated a lot on daily basis.. I have experience in ASP.Net and SQL Server.. These are the technologies i am considering to work with. Please help me choose the right method considering the amount of load it w...

LINQ To SQL - What is the most efficient way to loop through master/detail?

The only thing I can find when dealing with master/detail and LINQ is through databinding. However, I am using LINQ to query my data and will need to manually loop through results without the need for databinding. My final intent is to loop through a master result set, get a grouped list of children, and output the master/detail data as ...

LINQ to SQL - nullable types in where clause

I have a table with a column that has null values... when I try to query for records where that column IS NULL: THIS WORKS: var list = from mt in db.MY_TABLE where mt.PARENT_KEY == null select new { mt.NAME }; THIS DOES NOT: int? id = null; var list = from mt in db.M...

AttachAll exception: type arguments for method cannot be inferred from the usage. Try specifying the type arguments explicitly

Scenario: Trying to call the .AttachAll method on a table in my LinqToSql DataContext object. Here's the relevant simplified snippet: public void Update(Customer cust){ MyDataContext db = new MyDataContext(); db.CustomerInvoices.AttachAll(cust.Invoices); //exception raised here! db.Customer.Attach(cust); } ...

LinqToSQL - mapping out the DataContext with lots of tables?

I've been working on a project where I have been using LinqToSQL that involved a lot of tables. All of these where mapped in one .dbml file (i.e. only one DataContext). I did this on the pretense that (currently) you cant join across multiple data contexts. For example... DB1DataContext db1 = new DB1DataContext(); DB2DataContext db2 = n...

Silverlight application architecture

I just started learning Silverlight, and I'm wondering about the typical architecture of a Silverlight application and the workflow in the application (I'm using Silverlight 2, but will move to 3 any time soon). In my test-application I currently only have the two default projects - MyProject and MyProject.Web. I'm familiar with the MV...

ASP.net Dynamic Data - OnPropertyChanging Not Updating other columns

Here is my code: partial void OnisApprovedChanging(bool value) { this.dateApproved = DateTime.Now; } 'dateApproved' is updated in the business logic, but this change is not being applied to the database table. I've seen some examples where DateUpdated columns are updated whenever any edit to a table is made...

linq to entities vs fluent nhibernate vs linq to sql (Help)

Hello, I have to build a website for a news channel.. Please help me decide which technology to use for data operations? 1) Linq to Entities 2) Linq to SQL 3) Fluent NHibernate 4) ADO.Net Website will be based on ASP.Net MVC and C#. Main Issues: 1) Should be easy to maintain and scale. 2) Good Performance Please express your vie...

Put linq to sql results into hierarchical structure for using in a un-ordered list ( for jquery tree )

I have 5 tables in a L2S Classes dbml : Global >> Categories >> Sub-Category >> Item >> Item Data. I want to be able to navigate from the Global table down a tree like structure to get to the items - displaying the title from the Item Data table. I have an existing control that uses a IHierarchyData / IHierarchicalEnumerable extended co...

LINQ Refresh does not result in Changed Events

Is it just me or does changes produced by refreshing the LINQ DataContext not result in Changed Events? I have a multiuser Application which has an simple atomar locking system to prevent conflicts. So if an User changes something in the database I need to trigger Refresh on the Datacontext to reload the concerning objects. A breakpoin...

LINQ to SQL DuplicateKeyException problem

Guys, I am using LINQ2SQL and I have a table called Customers with three columns CustmerID, CustomerCode, CustomerName CustmerID is Primery Key(and Identity=yes) and CustomerCode is just UniqueKey. When I am updating this table using LINQ to SQL with duplicate customercode, I expect to see DuplicateKeyException but it is going into t...