linq-to-sql

Generated LinqtoSql Sql 5x slower than SAME EXACT hand-written sql

I have a sql statement which is hardcoded in an existing VB6 app. I'm upgrading a new version in C# and using Linq To Sql. I was able to get LinqToSql to generate the same sql (before I start refactoring), but for some reason the Sql generated by LinqToSql is 5x slower than the original sql. This is running the generated Sql Directly ...

Comparison operators not supported for type IList when Paging data in Linq to Sql

I can understand what the error is saying - it can't compare a list. Not a problem, other than the fact that I don't know how to not have it compare a list when I want to page through a model with a list as a property. My Model: Event : IEvent int Id string Title // Other stuff.. LazyList<EventDate> Dates // The "problem" prop...

asp.net mvc nerddinner question linq to entities join question

Hi experts, I am working on a website similar to nerddinner. Is it possible to perform similar join using Linq to entities what is done with linq to sql in nerddinner. I am posting the codes below. public IQueryable<Dinner> FindByLocation(float latitude, float longitude) { var dinners = from dinner in FindUpcomingDinners() ...

LINQ(2 SQL) Insert Multiple Tables Question

I have 3 tables. A primary EmploymentPlan table with PK GUID EmploymentPlanID and 2 FK's GUID PrevocServicesID & GUID JobDevelopmentServicesID. There are of course other fields, almost exclusively varchar(). Then the 2 secondary tables with the corresponding PK to the primary's FK's. I am trying to write the LINQ INSERT Method and am...

SQL Server 2005 Data Encryption And LINQ TO SQL

I have a ASP.NET MVC application and I have used Linq-to-SQL queries to get data from my SQL Server database. Now for security purposes I need to encrypt my database. How does Linq-to-SQL work with encrypted databases? ...

LINQ-to-SQL class doesn't implement INotifyPropertyChanging & INotifyPropertyChanged if pulling from local database

I modified my data source in my LINQ-to-SQL class (by the old delete and drag back in method), and was surprised to see the INotifyPropertyChanging & INotifyPropertyChanged interfaces no longer implemented in the generated classes (MyDb.designer.cs). The methods for the individual fields went from looking like this... [Column(Storage="...

How dynamic can I make my LINQ To SQL Statements?

I have the need to construct a LINQ To SQL statement at runtime based on input from a user and I can't seem to figure out how to dynamically build the WHERE clause. I have no problem with the following: string Filters = "<value>FOO</value>"; Where("FormattedMessage.Contains(@0)",Filters) But what I really need is to make the entire W...

Problem passing in Func as parameter to Where clause

I have this simple 2 lines of following code. It compiles fine but never return results in the datagridview. If I change func to p=> p.PTNT_FIRST_NAME.StartsWith(this.textBox1.Text), it works just fine. What's the problem here? Func<PATIENT, bool> func = (PATIENT p) => p.PTNT_FIRST_NAME.StartsWith(this.textBox1.Text); this.dataGridView1...

how to get cartesian products between database and local sequences in linq?

I saw this similar question here but can't figure out how to use Contains in Cartesian product desired result situation: http://stackoverflow.com/questions/1712105/linq-to-sql-exception-local-sequence-cannot-be-used-in-linq-to-sql-implementatio Let's say I have following: var a = new [] { 1, 4, 7 }; var b = new [] { 2, 5, 8 }; var te...

Ensuring Database Integrity when Adding and Deleting

As I am developing my database, I am working to ensure data integrity. So, for example, a Book should be deleted when its Author is deleted from the database (but not vice-versa), assuming one author. When I setup the foreign-key, I did set up a CASCADE, so I feel like this should happen automatically if I perform a delete from LINQ. ...

WPF & Linq To SQL binding ComboBox to foreign key

I'm having trouble binding a ComboBox to a foreign key in WPF using Linq To SQL. It works fine when displaying records, but if I change the selection on the ComboBox, that change does not seem to affect the property to which it is bound. My SQL Server Compact file has three tables: Players (PK is PlayerID), Events (PK is EventID), and ...

LINQDataSource - Query Multiple Tables?

I have a database and I've created a DBML Linq-to-SQL file to represent this database. I've created a new aspx page and dropped a linqdatasource and a formview control onto it. When I configure the linqdatasource it gives me the choice only to select * from one table...but I want to pull from multiple tables. e.g. I have tables like simp...

whats wrong in this LINQ synatx?

Hi, I am trying to convert a SQL query to LINQ. Somehow my count(distinct(x)) logic does not seem to be working correctly. The original SQL is quite efficient(or so i think), but the generated SQL is not even returning the correct result. I am trying to fix this LINQ to do what the original SQL is doing, AND in an efficient way as the o...

LINQ thinks I need an extra INNER JOIN, but why?

I have a LINQ query, which for some reason is generating an extra/duplicate INNER JOIN. This is causing the query to not return the expected output. If I manually comment that extra JOIN from the generated SQL, then I get seemingly correct output. Can you detect what I might have done in this LINQ to have caused this extra JOIN? Thanks...

LINQ query checks for null

I have a userList, some users don't have a name (null). If I run the first LINQ query, I got an error saying "object reference not set to an instance of an object" error. var temp = (from a in userList where ((a.name == "john") && (a.name != null)) select a).ToList(); However, if I switch the order by putting ...

Unit Testing, IDataContext and Stored Procedures via Linq

hey folks, I'm currently using Stephen Walther's approach to unit testing Linq to SQL and the datacontext (http://stephenwalther.com/blog/archive/2008/08/17/asp-net-mvc-tip-33-unit-test-linq-to-sql.aspx) which is working a treat for all things linq. My Dal layer takes in an IDataContext, I use DI (via Unity) to concrete that up as the ...

Use Linq to SQL to generate sales report

I currently have the following code to generate a sales report over the last 30 days. I'd like to know if it would be possible to use linq to generate this report in one step instead of the rather basic loop I have here. For my requirement, every day needs to return a value to me so if there are no sales for any day then a 0 is returned...

Is it possible to use SqlGeography with Linq to Sql?

I've been having quite a few problems trying to use Microsoft.SqlServer.Types.SqlGeography. I know full well that support for this in Ling to Sql is not great. I've tried numerous ways, beginning with what would the expected way (Database type of geography, CLR type of SqlGeography). This produces the NotSupportedException, which is wide...

Convert IEnumerable to EntitySet

Hey all, Hoping somebody can shed some light, and perhaps a possible solution to this issue I'm having... I have used LINQ to SQL to pull some data from a database into local entities. They are products from a shopping cart system. A product can contain a collection of KitGroups (which are stored in an EntitySet (System.Data.Linq.Ent...

How to return a message from my repository class to my controller and then to my view in asp.net-mvc?

I use this for checking an existing emailId in my table and inserting it...It works fine how to show message to user when he tries to register with an existing mailId.... if (!taxidb.Registrations.Where(u => u.EmailId == reg.EmailId).Any()) { taxidb.Registrations.InsertOnSubmit(reg); taxidb.SubmitChanges(); } and my control...