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Update issue on SQL using C#

C#Coudou22-Aug-07 22:18

22-Aug-07 22:18

dudes,

This is not the code problem. analyze problem only.
Can you help me to analyze.
Heres the scenario:

I have an application with search button and a textbox, etc.etc.
When I input the ID on the textbox and click search button. It will show the data and it can be editable and update. I have no problem on that. The issue is that when the application is distributed on different pc and it will access on the same database. What if the user will search the same ID. Who will be the one can edit and update the data. Think about excel file. If you access both file, there is a pop up window that says READ ONLY.
"How the Microsoft do that?"

Problem: How? What?

******************************
I just want to
know everything

Re: Update issue on SQL using C#

Christian Graus22-Aug-07 22:23

Christian Graus

22-Aug-07 22:23

Easy. Open the folder that the xls file is in, then open it. Notice that when it's open, a temporary file, based on the filename of the XLS, is created. They delete that to remove the lock. If you turn your computer off while it exists, on older versions, you had to delete it yourself ( perhaps not now ).

This isn't going to help you, tho. You want to mark a row as locked to a user when they start to edit it, and impliment a timeout, in case they turn THEIR PC off.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Update issue on SQL using C#

C#Coudou22-Aug-07 22:34

22-Aug-07 22:34

Christian Graus wrote:
Open the folder that the xls file is in, then open it.

I don`t have a folder, its just a form. or did you mean I will create a temp. folder.

What function should I implement on this? or what class? I don`t have any idea how to do. A concept could help.

Thanks a lot

******************************
I just want to
know everything

Re: Update issue on SQL using C#

Christian Graus22-Aug-07 23:30

Christian Graus

22-Aug-07 23:30

*sigh* Let me try again.

Excel ( which you asked about ) does it with a file. Your database is going to do it by having a column that takes the Id of the person who locked a row for editing.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

multiple inheritance

kalyan_241622-Aug-07 21:18

22-Aug-07 21:18

hi all
i have searched in google few times i am not getting rather i am not understanding y it is not there in c# and there in vb

how is the same possible in the case of interface

i go to an interview get in to problems with this question..

thanking u

Re: multiple inheritance

Michael Sync22-Aug-07 21:39

22-Aug-07 21:39

Check the answer from Microsoft C# Team ~
http://blogs.msdn.com/csharpfaq/archive/2004/03/07/85562.aspx[^]

I even posted about this in my blog..

even thought C# doesn't support multiple inheritance, it does support multiple implementation for interfaces.

Thanks and Regards,
Michael Sync ( Blog: http://michaelsync.net)

If you want to thank me for my help, please vote my message by clicking one of numbers beside "Rate this message". Why vote? Plz Read it here. Thank you.

Re: multiple inheritance

kalyan_241622-Aug-07 22:43

22-Aug-07 22:43

i read this before and now either
i not getting what author is trying to say ...
any other topics which can tell me about the difference

Re: multiple inheritance

seeitsharper22-Aug-07 23:10

22-Aug-07 23:10

The fundermental problem is there is a chance that a class can alter the behaviour (override) of a method in a base class. Now if 2 classes do this (override the same base class) and you inherit both these classes then you can have a situation where you dont know which implementation of that method you are calling.

There are other issues, but that is the one I can explain in the shortest amount of text.

-- oh and as far as interfaces go; as the interface does not define the implementation of the method, it is fine to implement multiple interfaces.

Keep your eyes open, you might spot alternatives.

Re: multiple inheritance

Christian Graus22-Aug-07 23:28

Christian Graus

22-Aug-07 23:28

That's just plain retarded, IMO. But the big question is, does VB really allow it ?

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: multiple inheritance

seeitsharper23-Aug-07 1:08

23-Aug-07 1:08

Christian Graus wrote:
That's just plain retarded

Really, I hope you are not refering to my example. I was trying to raise a point about it.

Keep your eyes open, you might spot alternatives.

Re: multiple inheritance

kalyan_241622-Aug-07 23:36

22-Aug-07 23:36

thanx a lot
i got it by a small exp. from ur explanations
thax bye

Re: multiple inheritance

Martin#22-Aug-07 23:50

22-Aug-07 23:50

Hello,

seeitsharper wrote:
Now if 2 classes do this (override the same base class) and you inherit both these classes then you can have a situation where you dont know which implementation of that method you are calling.

If you are using Interfaces in a bad designed project (like seen here[^]), you could have simmilar problems.

All the best,

Martin

Re: multiple inheritance

Christian Graus22-Aug-07 23:58

Christian Graus

22-Aug-07 23:58

Yes, the core problem is bad design, which is why C# should support MI, because it can be very useful in good designs.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: multiple inheritance

Martin#23-Aug-07 0:51

23-Aug-07 0:51

Christian Graus wrote:
which is why C# should support MI, because it can be very useful in good designs

Can be said loud and proud!!

All the best,

Martin

Re: multiple inheritance

PIEBALDconsult23-Aug-07 4:32

23-Aug-07 4:32

Perhaps in an unsafe context? Big Grin | :-D

Big Grin | :-D

Meaning only that unsafe indicates to the compiler, "I know what I'm doing, let me through."

Hmmm... maybe unsafe could also be used to allow fall-through in switches...

Re: multiple inheritance

Martin#23-Aug-07 4:36

23-Aug-07 4:36

Smile | :)

I realy enjoy reading, when you are talking to yourself.
Like this one[^]!

All the best,

Martin

Re: multiple inheritance

PIEBALDconsult23-Aug-07 6:06

23-Aug-07 6:06

Glad to be of service. Big Grin | :-D

Big Grin | :-D

Re: multiple inheritance

kalyan_241623-Aug-07 0:52

23-Aug-07 0:52

class c
{
void i1.function_some()
{
// body
}

void i2.function_some()
{
// body
}
}
class c1:c
{
c dd =new c();
i1 i=(i1)dd;
i.funcion_some();-----gets the function of interface i1 in class c
i2 i_d=new c();

i_d.function_some();---gets the function of interface i2 in class c
with the help of type casting i can get the individual definition of the functions
}
i think this will lead to some ambguity...!

Re: multiple inheritance

seeitsharper23-Aug-07 1:16

23-Aug-07 1:16

No, the point I was making was that you are inheriting behaviour. Interfaces have no behviour thus the problem is different. I agree on the what constitutes Good and bad design and perhaps Microsoft could have came up with a MI solution that worked.

Keep your eyes open, you might spot alternatives.

Re: multiple inheritance

Christian Graus22-Aug-07 23:28

Christian Graus

22-Aug-07 23:28

You're kidding - VB.NET has multiple inheritance ?

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: multiple inheritance

Colin Angus Mackay22-Aug-07 23:40

Colin Angus Mackay

22-Aug-07 23:40

kalyan_2416 wrote:
i am not understanding y it is not there in c# and there in vb

I doubt that VB.NET has multiple inheritance because it is a limitation of the CLR rather than the language.

-- Always write code as if the maintenance programmer were an axe murderer who knows where you live.

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Re: multiple inheritance

Christian Graus22-Aug-07 23:59

Christian Graus

22-Aug-07 23:59

That's what I thought, too.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: multiple inheritance

kalyan_241623-Aug-07 0:44

23-Aug-07 0:44

my mistake sorry...!

Re: multiple inheritance

Christian Graus23-Aug-07 0:51

Christian Graus

23-Aug-07 0:51

That's cool, I was just interested, because if you were right, it meant I was learning something for the night Smile | :)

Smile | :)

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: multiple inheritance

Martin#23-Aug-07 0:57

23-Aug-07 0:57

Again, a stupid downvoter on your side!
What are you doing to people here?
Are you sending spam mails over your account, or is it rude for somebody that you try to help?

Got my 5

All the best,

Martin

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