LINQ To SQL And The DBML File / Multiple Database Development
Aug 11, 2009
I have a WPF application that uses a SQL2008 database. I have a copy of the database on a laptop and on my home machine. My application is versioned using SVN and I am obviously able go from the work laptop to the home machine and update/commit as required to ensure I am using the latest code for the application.However the database is a different story in that any change I make I create a backup and then transfer the backup to the other machine etc. This way I get the data and the changes made on each system. In order to do this the database connection using a different connectionstring and I change a setting in my app to use a different connection based on my location.
I have now started to use LINQ to SQL and DBML files in my application, and finally getting to the question, I don't know how I can change the connectionstring it uses in code so it will use the correct database in the DBML.Also, is there a better way to transfer the database so I don't need to do the backups and restores? The only reason why I have not versioned the Schema is because I am not sure how that would handle my data as this is key to my development, ie various environment settings etc are stored in the DB and brought through at runtime.
I have a class that add extra information about a column for linq2sql (see code below) right now, I have to explicitly tell what column I want that info on, how would you put that code with a loop on every column in every table from a dbml file? I was doing my test on a very very small DB, now I have to implement it on a much more bigger database and I really don't want to do it manually for every tables/columns it will take hours.
how it's being used:
Partial Class Contact ''contact is a table inside a dbml file.
Private _ContactIDColumn As ExtraColumnInfo Private _ContactNameColumn As ExtraColumnInfo Private _ContactEmailColumn As ExtraColumnInfo
I am looking for a VB.net book that strings me through the entire development process of an application (Prefered: WPF ,LINQ ,ADO). I have read a few books on OOP and VB.net with small code samples demonstrating the specific idea of the chapter.I think it would be really helpful if there was a book that programmed an entire application that uses a sql database (Northwind , Adventureworks).
I have an application written in ASP.NET and using EF. I want to make a copy of the live database, have my application point to the copy, and be able to run the application against it as if it is live...but making updates to the copy.
I know I can manually copy the database and manually update the web.config files...but I'm wondering if there is a better, more automated method for achieving this with VS 2010?
Also, if there is anything I need to know about setting up a live/dev version of a database while using EF4.
Why would database drivers work in the development environment of VB.Net and not once the project is built and installed on the same pc? I've tried the MS ODBC Oracle driver. I've tried various ODBC datasources. All work when I am in the development environment but none once I build and install. No matter whether the configuration is Debug or Release. This is the only project having this problem. I have other apps (VB.Net) that access the same database (Oracle 9.2) with no problem.The environment variables are the same during both types of runs. The error messages vary depending upon the driver being used.
i'm worried about doing this since my changes will be overwritten when the dbml file is auto generated again (as they often are).i'm thinking of doing a partial class and writing out the same properties to annotate them, but worried that it will complain about duplicates, and the reason i can't even experiment brings me to the second part of my questions...
that, the expandable arrow on my dbml file listing is missing, right clicking and selecting "View Code" just displays an empty partial class as below.
when i double click my dbml file at the solution explorer, I get this error: the operation could not be completed. unspecified error I'm working on a VB.Net project, using visual studio 2008, mssql 2008.
I have created my site using ASP.NET Personal Starter Kits 3.5. I use Visual Studio 2008 only . .with its built-in SQL Server (2005 Express) ... my database in App_Data is ASPNETDB.MDF ...I have created some of my tables also ....in ASPNETDB ..In my local PC the site was running fine ...But when I publish my site on production server it doesn't work and shows the following error
I have a linq union statement that has been giving me some trouble and I can't see where the issue is.The error is....All queries combined using a UNION, INTERSECT or EXCEPT operator must have an equal number of expressions in their target lists.
I know the error means that I am selecting different amounts of elements in one of the linq statements, but I've examined this query extensively and I haven't been able to see that as the issue.
Select Distinct s.* from #ScopeIDs x Join Scopes s on s.ScopeID=x.ScopeID or x.ScopeID is null
in LINQ to SQL? (This query would return all Scopes whose ScopeID is present in #ScopeIDs, unless one of the entries in #ScopeIDs is null, in which case it returns all Scopes).
A "literal" translation doesn't work, since LINQ doesn't support joining with multiple conditions - code along these lines ...
From x in ScopeIDs Join s in Scopes on s.ScopeID equals x.ScopeID or x.ScopeID equals nothing Distinct Select s ... doesn't compile.
I have a list of attachments that I need to group by clientCLID and EmailAddress. From this grouped list I only need a list of clientCLIDs. After fiddling for a while I've managed to get it to work as follows:
I spent a lot of time on this problem. I am able to do simple Group By LINQ queries (on one property) but for multiple fields I'm a little stuck... Here is a LINQPad sample of what I want to do :
dim lFinal={new with {.Year=2010, .Month=6, .Value1=0, .Value2=0}, new with {.Year=2010, .Month=6, .Value1=2, .Value2=1}, new with {.Year=2010, .Month=7, .Value1=3, .Value2=4},
in my prev question i was suggested with LINQ solution. It was great and simple. I tried to solve next similar but a bit diff problem with similar approach but i failed.
how can i make the below code better
For Each Item As ListViewItem In RoomsListView.Items For Each Item1 As Room In myBookedRooms If Item1.UIN = Item.SubItems(1).Text Then
it is possible to do a multiple records editing by linqtosql method in one click event?What I've been trying to do is to edit all the names in the table which are having the same account number.
Private Sub Button2_Click(------------) Handles Button2.Click Dim accnt As String accnt = Textbox1.Text Dim db As New memrecDataContext()
[code]....
Why is it these codes could only edit records in one datarow?Can you debug the codes to edit all records which are having the same account number after it is being query?
I have a vb.net web application and when a particular function runs , i get data timeouts in the rest of the application..(ie..row not found errors or column does not belong to table but it does) The function is adding multiple rows in multiple tables in the database and is running in a for loop. It seems to be all SQL related but I am not seeing anything in the error logs in SQL or in the application Right now I am assuming it is memory related where to start note..the for loop will be replaced with a bulk insert but right now I jest need to resolve the issue of the timeouts
I'm using Entity Framework code first and pulling some data back from our database. In the table I'm accessing is 13 columns that store the number of a items a customer purchased per week for the last 13 weeks as a char field. I have no control over how this data is stored. I need to total the 13 weeks results together to get a combined total, so take week1 + week2 + week3.... = Total Items Purchased over 13 weeks.In SQL I'd just Cast the char to an Integer and add the values together. But I'm struggling finding a solution to do this in linq.
I tried (From c in Table Select New With {.Usage = (Convert.ToInt32(c.week1) +
I call upon the VB ninjas out there. Here's my situation. I need to eventually be able to pass multiple models to a view. Currently I have a linq to sql class that, of course, has a bunch of generated model definitions. I need to make a model that implements multiple models. I somewhat understand how to do this in C#, but this project is testing my VB skillz. Here's some snippets from my linq to sql models. I need to combine these two into one model to pass to the view.
On my view there is a datatable holding a collection of ServerRow and 4 textboxes (Hostname, OS, Location, Zone). When the user types into any of the 4 boxes I want to immediately filter this list. I have this code setup and ready to go that on the set method of each textbox property I call the filter method.
Now onto the problem: if I have 4 criteria that means I have 2 to the power of 4 different scenarios. What I would like to do is write a linq statement with all of these scenarios dealt with such that if any of the properties are NullOrEmpty they will not be used in the Where clause and on the flip side if there is a value the corresponding field will be searched with a Contains.
I have the following example datatable:[code]And now the user should be able to compare multiple periods. In this example the user chose two periods: 1.1.2010 - 31.12.2010 and 1.1.2011 - 31.12.2011. The result of the example should be:[code]
I have been searching for quite a while about joining multiple datatables via LINQ to dataset (When i say multiple, i don't mean just 2!!!), and it seems there aren't lot of examples in the net. I have seen examples of joining two datatables, done that, no problem there. Now i want to join three datatables. And there's nothing i can find out there.For example i have a 3 datatables:
myFilteredContractors = (From c In myFilteredContractors Join cc In myConClasses On c.ContractorId Equals cc.ContractorId Where inClassifications.Contains(cc.ClassificationId)[code].....
This is properly ordering this list of contractors by the number of classifications that they have.I also want to order them by whether or not they have a field set (CompanyOverview), which if is an empty string should be below those contractors who have set their CompanyOverview. Also, after the CompanyOverview is ordered I want to order by Registration Date.So it should order by:
Number of Classifications Whether Overview has been set (c.CompanyOverview) Registration Date (c.AppliedDate)
