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Yes, this is for internal use to maintain state information about the objects necessary for comparision in determining changes. It isn't a data cache that can be used for storing query results and can be disabled by setting MergeOption.NoTracking.
No comment
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Hi all,
I'm trying to understanda which are the major pros and cons of ADO.NET entity framework compared to the JPA (java persistence API).
Looking and comparing manual is not easy as I'm not a developer (neither java nor .NET) so any help and feedback is appreciated.
I've google out of course for this question but there're not interesting docs or blogs related to this and of course it's difficult to find someone know both language. So any hints is appreciated.
Thanks
Ste
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There's no 1-1 comparison, just like there's no comparison between the seats of a Porsche and a Jaguar. Both are seats for their specific cars and both do their job well in their own environment.
Usually we look at the language that our devs' are most familiar with, and go with the frameworks that come with that particular language. The choice between Java/.NET is more based on resources, like your devs, and the environment it's going to work under.
Bastard Programmer from Hell 
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Yep I know. I'm doing this kind of compare as an academic work focussing my attention to some specific topic as: transparent mapping, encapsulated persistence, multi object retrieval, caching, transactions, data sources...
Now I've found that (for .NET EF):
- it does not provide any cache feature by defaults
- transparent mapping is more complicated than jpa
- if u load an object linked with FK to others, all dependents object are loaded and there's no way to limit this
- transactions are enforce inside datasource layer...but have to find other infos
Any hints is appreciated. I can state that there're definitely more infos on JPA than .NET and also MSDN is not so clear ...
Ste
Ste
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oraclepilot wrote: <layer>Any hints is appreciated. I can state that there're definitely more infos on JPA than .NET and also MSDN is not so clear ...
MSDN is aiming at developers; it's easy to find syntax, how-to's and even video's. You probably already found the portal[^] that links to the EF-forum. The overview[^]-page contains links to most of the stuff on MSDN relating the EF.
There's very little in terms of feature-lists. You'll find more on Wikipedia[^], like the ormeter[^].
oraclepilot wrote: I'm doing this kind of compare as an academic work
Good luck 
Bastard Programmer from Hell
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oraclepilot wrote: I'm trying to understanda which are the major pros and cons of ADO.NET entity
framework compared to the JPA (java persistence API).
I don't see that that is a reasonable comparison.
Some reasons why...
- You can't arbitrarily pick one or the other without consideration for what it will be used in (not features but technology.)
- JPA by itself is a specification, not an implementation.
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Interesting...I've never thought in this way.
To be specific, I have to compare the approach to persistence of objects between JPA and ADO.NET (not specifically ADO.NET EF) but AFAIK ADO.NET permits to persists object with LINQ to Entities and today with EF...right?
Ste
Ste
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I don't understand the question.
In this situation the requirements/architecture/design is going to have far more impact on any attribute in terms of comparison. That true for applications in general but it specifically true of database APIs.
And that has nothing to do with your implementation choice.
But your implementation choice is going to have a big impact on the entire application and even potentially the company as well. For example it would seem foolhardy for a business that has experienced C# developers to commit to a java platform even with some small gain.
To truly demonstrate a real benefit (something measurable that is a real attribute of the API) then all of the following must be true.
1. Such a need must exist in the first place. So for example if you must need to actually push 10,000 txns a second and you CAN'T use any other solutions (such as direct data load.)
2. One must be very experienced in ADO.Net.
3. One must be very experienced with a Java library that implements JPA.
If 2 and 3 are not both true then one runs the risk of measuring ignorance rather than API.
If 1 isn't true then other factors, like what language the company normally uses and how the API will be used are much more significant.
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Hi,
I have a few textfields in my WPF-Page.
When the array in the property is filled I see the values in the textboxes. But when the user fill the textboxes the binding doesn't work for me. Is there a solution for this problem?
Private m_AN_H As Single()
Public Property AN_H() As Single()
Get
Return m_AN_H
End Get
Set(ByVal value As Single())
m_AN_H = value
End Set
End Property
<StackPanel Grid.Column="1" Name="stp_H_0080">
<Label FontSize="10" FontWeight="Bold" HorizontalAlignment="Center">H<Label>
<TextBox Name="txt_H_00" Margin="2" Text="{Binding Path= AN_H[0],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_10" Margin="2" Text="{Binding Path= AN_H[1],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_20" Margin="2" Text="{Binding Path= AN_H[2],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_30" Margin="2" Text="{Binding Path= AN_H[3],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_40" Margin="2" Text="{Binding Path= AN_H[4],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_50" Margin="2" Text="{Binding Path= AN_H[5],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_60" Margin="2" Text="{Binding Path= AN_H[6],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_70" Margin="2" Text="{Binding Path= AN_H[7],Mode=TwoWay}"></TextBox>
<TextBox Name="txt_H_80" Margin="2" Text="{Binding Path= AN_H[8],Mode=TwoWay}"></TextBox>
</StackPanel>
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I don't think this is the best approach for this problem.
Instead of an array, use an ObservableCollection. Make a public property that exposes this collection.
Then try this,
Change your xaml to look something like this -
<StackPanel>
<ItemsControl ItemsSource={Binding MyObservableCollection} >
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" /> </ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</StackPanel>
Too much of heaven can bring you underground
Heaven can always turn around
Too much of heaven, our life is all hell bound
Heaven, the kill that makes no sound
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Setting the SelectionBackColor and SelectionForeColor of a DataGridViewLinkColumn from the design IDE doesn't take effect. The cell texts still hold the default color blue. Why is this happening? Thanks.
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hi there,
I like to write a program which will help a general person to create a new exe file.
The first exe will add some files as resources and then creates an exe. The resulting exe will basically create the files initially added.
It's something like creating a setup file but here we don't have to do anything other than reproducing the files which are embedded into an exe (like self extracting file). I can't use sfx file as i have to check certain thing in the target machine before extracting....
In short, a program that will create a very stripped down version of setup file something similar to SFX file.
Thanks for sharing idea or point to right directions.
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Maybe a BAT file? 
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hmmmm,a BAT file...
Is there a way to store file(s) inside a BAT, which we can extract during execution? Plus I have to check conditions on a local machine which will be much difficult in from a BAT file from my understanding.
If possible, i would like to use .NET applications...
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Perhaps Powershell then, if supported on the target machines, to check the local machine and invoke a net app.
I know the language. I've read a book. - _Madmatt
modified on Monday, August 22, 2011 8:39 AM
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A BAT file is just a text file with DOS commands in it. There is no way to store anything else in it.
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Create an SFX that contains two files: An exe and a zip file (which contains all your files). The exe does the system checking and decides which files to extract and uses a zip utility to extract specific files from the zip archive.
"Don't confuse experts with facts" - Eric_V
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If you can accept two files to send to the target machine your requirements could be met by
1) An application that allows the user to select files and store them into a resource only assembly (dll)
2) An application to do the checks on the target machine, read the resources and write them out as files.
The resource only assembly is created by invoking the C# compiler, csc.exe, and the following command line will create resourcelib.dll containing two files FileInfo.txt and Help-Aug2011.chm
<br />
csc /out:resourcelib.dll /target:library /resource:FileInfo.txt /resource:Help-Aug2011.chm<br />
The code needed to read the resources from the assembly and convert them back into files is fairly simple
private void CreateFilesFromResources() {
Assembly a = Assembly.LoadFile(@"E:\VC\Projects\CodingTests\BinaryResource\bin\Debug\resourcelib.dll");
foreach (String filename in a.GetManifestResourceNames()) {
Console.WriteLine("Resource name {0}", filename);
using (Stream rs = a.GetManifestResourceStream(filename)) {
using (FileStream fs = File.Create(filename)) {
Byte[] buff = new Byte[8192];
Int32 read;
while ((read = rs.Read(buff, 0, buff.Length)) > 0) {
fs.Write(buff, 0, read);
}
}
}
}
}
Hope that helps and has given you a few ideas.
Alan.
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Don't you think embedding all files in a dll will bloat it? I would say a zip file is a better alternative.
"Don't confuse experts with facts" - Eric_V
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You're right, it is uncompressed and the dll size will be the sum of the individual files plus a small overhead. I have found a limit of the technique when attempting to create a dll with some large files as somewhere between 400 and 600MB when the compiler gave up.
Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.3053
for Microsoft (R) Windows (R) 2005 Framework version 2.0.50727
Copyright (C) Microsoft Corporation 2001-2005. All rights reserved.error CS0016: Could not write to output file 'e:\VC\Projects\CodingTests\BinaryResource\resourcelib.dll' -- 'Not enough storage is available to complete this operation. '
Alan.
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To me it sounds like your best bet is to manually create an installer. You'll have to use the resource API, and file management functions, such as CreateFile. Those two sets of libraries should help you accomplish your goal.
This isn't for the purpose of executable security (File integrity) or Intellectual Property protection, is it? If so, I would recommend looking into obfuscation, using techniques such as code virtualization and runtime integrity checks.
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We all know that DataTables can't be passed through a webservice because it is not serializable.
Then how typeof(DataTable).IsSerializable is true?
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typeof(DataTable).IsSerializable is true because it's marked with the SerializableAttribute[^]
The SerializableAttribute tells the serializer to use default serialization, but the serializer will throw an exception if it encounters a type which isn't marked with the SerializableAttribute. The DataTable Columns property is of the type DataColumnCollection[^] which is not marked with the attribute and thus DataTable cannot be serialized.
But DataSet can be serialized and it contains DataTable's!
The reason DataSet can be serialized is because it implements the ISerializable interface[^] and thus custom serialization logic.
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