Linq To SQL Transaction Insert Then Select Really Slow

May 25, 2011

I'm developing a piece of a system that basically migrates data from one set of tables to another set. Everything works fine, but I've decided to employ transactions instead of just failing on things that are partially completed. (That is, if some exception occurs, I want to rollback instead of having partial data migrated.)

I have a service (in the 3-tier architecture way, not web) which begins a transaction on the data access layer. The data context is shared in the data access class which contains many methods. Those methods use various LINQ-to-SQL techniques to update/insert/delete. All the LINQ-to-SQL "selects" are within CompiledQueries. [code]...

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Transaction Error On Call To Commit() When Select Has Been Executed Inside Transaction?

May 9, 2011

I get this error at the Commit of a transaction in a desktop application:

This OleDbTransaction has completed; it is no longer usable.

Other posts I have seen with similar error suggests this can occur if it takes a long time, or contains large amounts of data. This is not the case here.Logging tells me it takes 140 ms from Begin to Commit and about 10 commands executed inside the transaction.It is using an Oracle database.This class is a simplified version of my database class:

Class MyDatabase
Private mConnection AS OleDbConnection
Private mTransaction AS OleDbTransaction

[code]....

Is it not allowed to run a select inside a transaction like this? Or can it be done by running the transaction in a specific isolation level (I see that the BeginTransaction method has an optional parameter for doing this) ? ..Or some other sollution..? In my case, it was not a problem to move the select to run before the transaction started, but what if you need to run selects that must run inside the transaction?

Oracle Transaction - Rollback Your Transaction If You Haven't Commit The Transaction

Oct 31, 2011

I want to know that do you still need to rollback your transaction if you haven't commit the transaction that was created earlier.

[Code]...

INSERT With Transaction And Parameters?

Mar 5, 2010

I'm learning about VB.Net and need to work with an SQLite database using the open-source System.Data.SQLite ADO.Net solution.The examples I found in the HOWTO section are only in C#. Would someone have a simple example in VB.Net that I could study to understand how to use transactions when INSERTing multiple parameters?[code]

Insert SQL 2008 Parent And Child Rows In A Single Transaction?

Nov 13, 2010

First, a little background (greatly simplified): I have two classes, one called Entity and one called Item which a subclass of Entity. They each store their individual properties in seperate SQL 2008 tables using TableAdapters generated by a strongly typed DataSet. The Entity class has a Save() method that looks like this:

Public Sub Save()
entityTableAdapter.Update(entityRow)
End Sub

[Code]....

Indeed, the SQL table does not contain a row in the Entity table with the necessary ID at this point because the transaction is not complete.

My goal is to prevent the Entity record from being inserted if inserting the Item record fails. I could write code to delete the Entity record again, but this does not seem very elegant to me...

Insert Row In Excel Very Slow?

Oct 15, 2011

using System;
using System.Collections.Generic;
using System.ComponentModel;

[code].....

VS 2010 Getting Started With Linq, Code Is Very Slow?

Oct 19, 2011

I am using DataSet.ReadXml() to create a DataSet from the following XML file, so that I can quickly query it using Linq.[URL]..I then use the following object to create a DataTable which can be used as a dictionary, with a ConvertToFriendlyFormat function that takes an Emulator_Id and and a string that corresponds to a DicEntry node's StoredFormat attributed, and return the same node's FriendlyFormat attribute.

This does work BUT it is extremely slow (~11 seconds to call it ~220 times). I have been unable to figure out how create the DataSet when the object is initialised and just query the simple DataTable in the ConvertToFriendlyFormat call. I guess this is what is slowing it down?

[Code]...

Creating A Reference To An Object In An IEnumerable Linq Query Would Be Really Slow?

Jun 18, 2009

Is there any particular reason why creating a reference to an object in an IEnumerable Linq query would be really slow? I have a Linq query list consisting of my own objects (count is about 200).I was doing a time-critical task, and this line (which was used a lot in a loop) took nearly a millisecond to execute:

Dim CurObject as MyClass = QueryResult(CurIndex)

VS 2008 - Transaction SProc's In Code - Says That My Insertcommand's Transaction Object Is Null

Apr 29, 2009

I've seen plenty of examples of transactions in the actual store procedure's SQL. But I'm wanting to do the transaction and keep track of it in code. I tried this but it says that my insertcommand's transaction object is null. How can I fix this?

vb Dim conn As SqlConnection = DBConnections.SQLServerConnection
conn.Open()
Dim params(1) As SqlParameter

[CODE]....

Transaction Object - The Transaction Property Of The Command Has Not Been Initialized

Mar 5, 2009

What is this kind of exception?

Error : Execute requires the command to have a transaction object when the connection assigned to the command is in a pending local transaction. The transaction property of the command has not been initialized..

This one causes the error: Dim oOperation As COperationOutputTypeBS
oOperation = COperationOutputTypeBS.GetOperationOutputType(txtOperationCode.Text)

Asp.net - LINQ To SQL - Select SUM With A WHERE?

Aug 17, 2009

I'm having trouble getting a Linq to Sql query to work. Basically, I want the sum of a column in a table for only rows matching a certain condition. A simplified version is this:

Orders = order that contains products
OrderProducts = relational table containing products that are in an order
Products = table containing information about products

I can get the total sum of the qty of products like this:

Dim totalQty = requests.Sum(Function(p) p.OrderProducts.Sum(Function(q) CType(q.ProductQty, Nullable(Of Integer))))

(Requests is a IQueryable of Orders)But I also need to get the sum of qty where the actual product meets a certain condition. Something like...

Dim totalQty = requests.Sum(Function(p) p.OrderProducts.Sum(Function(q) CType(q.ProductQty, Nullable(Of Integer))))... WHERE p.OrderProducts.Product.ProductAttribute = true

How would I go about getting that query with the additional where clause to only get the sum of the qtys where the productAttribute = true ?

Linq To SQL Sub Select?

Oct 12, 2009

I have the following query which groups some records and then filters where the count of the grouped records is 1.

I'd like to take the returned result and perform another query to retrieve the entire record from the JobcodesWorkingRollup table where the ParentNode column equals the result of this query:

Dim query = From r In context.GetTable(Of JobcodesWorkingRollup)() _
Group r By r.ParentNode Into g = Group _
Where g.Count = 1 _
Select New With {.cnt = g.Count, .nm = g.FirstOrDefault.ParentNode}

How To Bulk Insert Using LINQ

Jun 28, 2009

I am using VB.NET with LINQ to MS SQL.I have two following tables. Now I want to insert multiple items in Tags Table using LINQ, but also wants to check that if any of tag exists in Tags table. It doesn't insert it again and bring the TagID in both cases (if inserted or if found existed)[code]What's the best way to acheive this using LINQ?

LINQ To SQL - Bulk Insert Using VB?

Aug 10, 2009

utilizing the whole LINQ to SQL method?

I've got a DB with about 7 tables I'm trying to link some .net pages to and as much as I can qry most of these tables, I'm having a heck of a time inserting into them. One complex scenerio I am finding revolves around the use of a GUID and how to get that particular GUID to propogate over into another table...

SQL - How To Insert New Record Through LINQ

Aug 1, 2011

I am trying to insert a new record though linq. I am able to update and read data with out any problem, but how to just inset a new record. Here is a start of my function.

Public Function AddAddressInfo(ByVal objdeptGUID As String, ByVal objGEOCode As String, ByVal objArressCommonName As String, ByVal objStreetAddress As String, ByVal objAddressNotes As String, ByVal objIsPublic As Boolean, ByVal objSesionToken As String)
''#Check of Token is good
If CheckToken(objSesionToken, objdeptGUID) = False Then
Return "Error"
End If
[Code] .....

"select Count()" Is Very Slow?

Jul 19, 2010

I have a database with 1,000,000 records and a query like this:

select count(code) from table1

It works well on the local system but becomes very slow on the network. Other queries like select * from table execute quickly, but select count(code) from table1 is very slow. I can't change the database's structure. My database is Foxpro and I use VB.NET.

Edit: Should I write code like this?

dim ds as new dataset
dim da as new datadapter("select count(*) from table ", connection)
da.fill(ds,"tbl1")

Then how can I get select count(code) from table1 from the dataset? Or do I have to use LINQ?

Edit 2: I mean the comparison between select count(*) and select count(code).

Asp.net - Linq Select Compound From

Apr 16, 2009

I'm experimenting with linq compount selects. I find the following query not to return any element:

Dim q = From s In d.GetChildRows("DossierSinistri") _
From i In s.GetChildRows("DossierIncarichi") _
Select s

[Code].....

Asp.net Mvc - Why Can't Get Anything Back When Use Linq To Sql Select

Feb 3, 2011

Why can't I get any values back when I use Linq to Sql? BHS_TimeSheet is my database table in which have some records. Model.TimeSheet is a class I create in the model. Private db As DataFactoryDataContext

[Code]...

C# - Linq Ambiguity On Where And Select

Nov 15, 2011

Today I ran into an issue with LINQ to objects (not SQL) that popped up due to a typo. I had a .Select one place and a .Where in another place. I was expecting same result but they are showing different numbers. Assume somelist has 10 elements with all elements having qty = 0

[Code]...

LINQ Select In .NET And C# Differences?

Mar 16, 2011

When using VB.NET I can do the following:

Public Function GetUser(ByVal ID as Integer) As User
Dim dc As New YesEntities()
Return (From u in dc.Users Where u.ID = ID).Single()
End Function

And on my .aspx/.vbhtml page I can access the user's department name like this:

Dim DepartmentName as String = new User().GetUser(12).Department.Name

[Code]...

Select Controls Using LINQ?

Jul 25, 2010

i try to select controls using LINQ but it show error

here is the code:

Dim testcontrol As VariantType
testcontrol = From cControl As Control In Me.Controls.OfType(PictureBox) Select cControl Order By Name Ascending

[Code].....

[2008] Using Select With Linq

Jan 9, 2009

I have seen different examples in Linq and one used Select and another didnt but both return the same results. Is there a reason why we should use Select ?

[Code]...

Asp.net - Insert One To Many Relationship Using Checkboxlist In LINQ To SQL?

Mar 7, 2010

I have 3 tables:

CustomerType
CusID
EventType
EventTypeID

[code]....

Then I want it to automatically insert data into CustomerEventType table based on the last EvenTypeID data that's just inserted and the checks of the CusID that is using CheckBoxList1 bounded from CustomerType (Suppose there are 2 IDs. )After I Click on Insert button the data in EventType table and CustomerEventType table should be:

EventType
EventTypeID
1
CustomerEventType

[code]....

The only question that I have is, what should be the code behind the insert button using VB.NET LINQ-to-SQL to get this result?

Insert Master Detail LINQ SQL WPF?

Mar 17, 2012

I have a SQL db with an order master and order details table. For simplicity here is the basic schema:

Header:
id int
Customer nvarchar(50)

[code].....

Structure An Insert Command In LINQ?

Dec 29, 2010

I am attempting to insert a new record into a table in a dataset using LINQ commands. The data in the record is defined by the text in some text boxes.

At the moment, I am working with the following:

[Code]...

.net - Linq To Object - Select Distinct

Mar 18, 2010

I can't quite figure out why this Linq Statement isn't working as i would expect:

[Code]....

I would assume that this would create a new collection of anonymous types, that would be distinct. Instead it creates a collection the size of the "ThisParentCollection" with duplicate "MyAnonymousType" in it (duplicate id's).

C# - Linq Select Certain Properties Into Another Object?

May 28, 2009

So say I have a collection of Bloops

Class Bloop
Public FirstName
Public LastName

[Code]....

Is it possible using Linq to select the FirstName and LastName out of all the Bloops in the collection of Bloops and return a collection of Razzies? Or am i limited to a For-Loop to do my work?

To clear up any confusion, either VB or C# will do. Also this will probably lead to me asking the question of (What about using a "Where" clause).

C# - Select` And `sub` Have Brackets Around Them In VB Linq Expressions?

Jul 12, 2011

I converted the following query from C#:

src.Select((c, i) => src.Substring(i)).Count(sub => sub.StartsWith(target))

To the VB.NET query:

src.[Select](Function(c, i) src.Substring(i)).Count(Function([sub]) [sub].StartsWith(target))

Using Developer Fusion. I was just wondering why the VB.NET version has [] throughout.

LINQ / Select Distinct From Dataset?

Aug 20, 2010

I have a single columned datatable inside a single tabled dataset.I just want to convert this dataset to distinct rows. Here is my code, it gives compile error '.' expected.

Dim query = _
From email In ds.Tables(0) _
Select email.Field<string>("Email").Distinct()

EDIT: I changed to (Of String) and it works... BUT NOW 'query' is an ienumerable collection of characters... not a datatable... so how do I convert back easily without manually doing a loop?

Linq To SQL Query To Select Maximum Value

Jun 21, 2010

Linq to SQL query to Select the maximum "MeanWindSpeed" value? The database name is "WeatherArchives" The TableName is "TblValues" The Column is "MeanWindSpeed" And Also, I would like to have a query to get me the Max "MeanWindSpeed" in each year,

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