LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

wisemx — Wed, 16 Apr 2008 22:19:40 GMT

Awesome! Really appreciate this.

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Archana — Sun, 20 Apr 2008 15:20:44 GMT

i am new to vb & using vb 2005

i want to know about list view

pl help me

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

RickHenderson — Tue, 22 Apr 2008 18:16:38 GMT

Thanks for this, I'll try and find time to work through it and finally know what the 3 tiers of a 3-tier system are!

BTW: If you visit blogs.msdn.com and search for articles by "Beth Massi" you get nothing written... not sure thats a good thing!

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Beth Massi — Tue, 22 Apr 2008 21:06:58 GMT

Hi Rick,

Re: Search

Yes it's kind of lame, you have to search on "BethMassi" (one word) for it to work.

http://blogs.msdn.com/search/SearchResults.aspx?q=user%3aBethMassi&o=DateDescending

I think it's looking at my username and not my display name. Sigh...

Thanks for the note!

-B

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Brad — Wed, 23 Apr 2008 06:31:03 GMT

BEth, I love all your tutorials. In trying to lean LINQ, I am having a problem handling the results of a query being empty. I see in this example and many other places that the check for entity.Count() = 0 is used. I cant make it work with my quiries - instead - I get an error every time. What am I missing?

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Brad — Wed, 23 Apr 2008 07:21:57 GMT

So it turns out it has something to do with my code (Duh) being in a For each loop.

I am trying to read an Access Database that I want to selectivly update an SQL Server DB. I establish my connection to both - and as I read through the access data using a for each datareader, I check my SQL databse to see if the record exists. If it does exist, I need to verify the records are the same. If the record does not exist, I need to create a new record.

I cant seem to make it work with any block (ie Try/Catch, For Each)

Somehow the variable needs to be available outside the block. Any ideas?

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Kent — Thu, 24 Apr 2008 07:49:26 GMT

Hi Beth. Its me again.

Anyway I would like to share this variant code I created which behaves like the SAVEALL method.

On the BaseBusiness class I created 3 public property

Public IsNew As Boolean

Public IsEdit As Boolean

Public IsDelete As Boolean

I added a tracking function on client code to keep track of all the Inserts, Updates and Deletes on each entities/sub-entities.

On the datalayer I just added these code to what SAVEALLORDERS implemented.

If Order.IsNew then

datacontext.Orders.InsertOnSubmit(Order)

elseIf Order.Isedit then

datacontext.orderdetails.InsertAllOnSubmit(Order.Orderdetails.Where(Function(a) a.IsNew))

datacontext.orderdetails.AttachAll(Order.Orderdetails.Where(Function(a) a.IsEdit), True)

dataconext.orderdetails.DeleteAllOnSubmit(Order.Orderdetails.Where(Function(a) a.IsDelete))

ElseIf Order.IsDelete

'...implement almost the same code as [delete] above

end if

These approach eliminates looping to each records.

I'm not sure of its speed efficiency.

Rgrds,

Kent

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Beth Massi — Thu, 24 Apr 2008 08:00:50 GMT

Hi Kent,

Thanks for the feedback. Yep, there are many ways you can do this depending on your tracking strategy.

Cheers,

-B

Beth Massi posts an N-Tier LINQ to SQL example

Hot Topics — Sat, 26 Apr 2008 18:55:27 GMT

This is a 3 part post where Beth Massi, MSDN Community Program Manager for Visual Basic, constructs an

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Archana — Sun, 27 Apr 2008 15:20:02 GMT

i am using vb 2008 and when i try to make new connection to database the message is

event log file is full

and connetion is not established

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Brian in England — Fri, 02 May 2008 11:48:58 GMT

Please can you put all this new programming in to new video, as an add on the ‘Use DataSets in an N-Tier Application’ as I find it hard to follow.

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Trooper — Sat, 03 May 2008 19:42:58 GMT

Hi massi, great series of Linq to SQL NTier. Im working in C# and have problems when inserting orders detail, the run time is trying to insert the order detail and the product

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

MOHAMMAD REZA TORABIPOUR — Thu, 08 May 2008 08:55:52 GMT

please help me about this questions?

1-how can i creat relation one-to many in vb6 with access file by 2 msflexgrid without use data form wizard?

2-why when we use biblio.mdb file for creat one to many relation by data form wizard we can creat it but when we creat other file for example student info and we use data form wizard for this file, vb6 can not creat one -to many relation?

thank you

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Beth Massi — Sat, 10 May 2008 01:35:24 GMT

Hi Trooper,

I'm not sure what the problem is for you. The sample does not edit the product objects at all nor attach them to the DataContext. Make sure this is the case in your code as well.

-B

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Beth Massi — Sat, 10 May 2008 01:38:33 GMT

Hi Mohammad,

You may want to ask your questions in VB 6 forums. Try: http://www.vbforums.com/forumdisplay.php?forumid=1

HTH,

-B

LINQ to SQL N-tier Smart Client

江南白衣 — Sun, 11 May 2008 19:02:22 GMT

This sample shows you one way to build an n-tier application using LINQ to SQL classes and a disconnected DataContext.

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Trooper — Tue, 20 May 2008 19:58:46 GMT

Thanx for your answer Beth, this is what my problem looked like: http://www.west-wind.com/weblog/posts/162336.aspx

My scenario whas different from your, i get, for example, the orderDetail loaded with the product entity, and when i send it back to the DAL the dataContext didnt know about that entity and tried to insert it, So I should attach that entity to the dataContext to tell it that it already exist, and then insert the order detail ;-)

re: LINQ to SQL N-Tier Smart Client - Part 3 Database Transactions

Cesar E — Fri, 23 May 2008 22:32:20 GMT

Hello Everyone! I need help on a project that I am working on; I am a new VB 2005 user and this is my first project. I have a search form where I have 6 comboboxes and a From date textbox and a To date textbox I have also added a datagridview.

I want to be able to create a search by selecting any value from the comboboxes and populate the data into the datagrid.

I have CmbPriority, Cbmstatus, Cmbdistrict, Cmbapplication, Cmbgroup, Cmbassignee, FromDatetxt, and ToDatetxtx

Any help will be greatly appreciated

I have the following, but some how is not working what am I missing.

Any help will be greatly appreciated

************************************

Private Sub get_searchtable_records()

Dim conn As New SqlClient.SqlConnection

Dim testsearch_connection As New SqlClient.SqlConnection("Persist Security Info=False;Integrated Security=SSPI;database=SupportDesk;server=local")

searchtable_string = "SELECT * FROM CallLog " & trimstring

'MsgBox(searchtable_string)

searchtable_command = New SqlClient.SqlCommand(searchtable_string, testsearch_connection)

'here is where you would check the boxes and add parameters

If CmbSrPriority.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Priorityid", SqlDbType.VarChar, 50)).Value = Me.CmbSrPriority.Text

End If

If CmbSrStatus.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Statusid", SqlDbType.VarChar, 50)).Value = Me.CmbSrStatus.Text

End If

If CmbSrDistrict.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Districtnumberid", SqlDbType.VarChar, 50)).Value = Me.CmbSrDistrict.Text

End If

If CmbSrApplication.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Applicationid", SqlDbType.VarChar, 50)).Value = Me.CmbSrApplication.Text

End If

If CmbSrGroup.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Groupid", SqlDbType.VarChar, 50)).Value = Me.CmbSrGroup.Text

End If

If CmbSrAssignee.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@Assigneeid", SqlDbType.VarChar, 50)).Value = Me.CmbSrAssignee.Text

End If

If TextBoxSrFromdate.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@datecreated", SqlDbType.DateTime, 50)).Value = Me.TextBoxSrFromdate.Text

End If

If TextBoxSrToDate.Text <> "" Then

searchtable_command.Parameters.Add(New SqlClient.SqlParameter("@dateend", SqlDbType.DateTime, 50)).Value = Me.TextBoxSrToDate.Text

End If

searchtable_dataadapter = New SqlClient.SqlDataAdapter(searchtable_command)

If searchtable_command.Connection.State = ConnectionState.Closed Then

searchtable_command.Connection.Open()

End If

searchtable_table.Clear() 'clear table to not show duplicates after refilling

searchtable_dataadapter.Fill(searchtable_table)

searchtable_command.Connection.Close()

Me.DataGridView1.DataSource = searchtable_table

End Sub

Building a "brand new application" - WPF, ADO.NET Data Services, LINQ to Entities with .NET Framework 3.5 SP1

Goto 100 - Development with Visual Basic — Tue, 08 Jul 2008 00:19:17 GMT

At the end of June I run workshops with 2 ISVs both looking to completely re-develop their applications.

Building a "brand new application" - WPF, ADO.NET Data Services, LINQ to Entities with .NET Framework 3.5 SP1

Eric and the .NET Framework — Tue, 08 Jul 2008 00:21:08 GMT

At the end of June I run workshops with 2 ISVs both looking to completely re-develop their applications.