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Read the guidelines on how to ask a question then start again,
Never underestimate the power of human stupidity
RAH
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All you need is a few loops and counters. Try think about it as you write it down on paper:
- How many initial spaces to print
- After the
1 , how many zeros to print - How many more lines to process
- etc ...
Veni, vidi, abiit domum
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how do i get opening balance from previous day closing balance.
here is the example
date 14/2/2013 closingbalance 2000
date 15/2/2013 opening balance 2000
credit 2000
debit 500
date 15/2/2013 closingbalance 3500
date 16/2/2013 opening balance 3500 and so on
here previous closing balance become opening balance.
problem is that i have to show data between date and no idea how to get opening balance of first record.
i am using sqlser 2005 and crystal report 10.
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This is not a report problem, it is a SQL issue. You must create the query that produces the results for the report to display. So one of the columns in your result set needs to be opening balance
Never underestimate the power of human stupidity
RAH
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One of the things that I have done is create a XSD for the report and pass the data to the report from your code so that you can do whatever manipulation you want prior to handing it to crystal.
report.DataSource = (object with same schema as the XSD)
Thanks
JD
http://www.seitmc.com/seitmcWP
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I'm a freelance programmer, and one of the major bugbears with working by myself is that I have no-one to bounce ideas off, so my code becomes very personal, if that's the right word, and I sometimes wonder if I'm doing things the right way. For instance, when I interrogate my database using Linq to Entities I use the following code (to return an instance of the purchase class).
internal static Purchase ReturnPurchaseItem(int PiD)
{
RegulusEntities RG = new RegulusEntities();
Purchase purchase = (from PU in RG.Purchases
where PU.PurchaseID == PiD
select PU).FirstOrDefault();
return purchase;
}
I would be very grateful if you could critique my code and maybe suggest more efficient ways of returning an instance of a class, or using the entity framework for that matter.
(If I've got this in the wrong forum, please forgive me, and transfer me to the right one!).
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There simply isn't enough code here to make any real judgment of what you're doing. I can see some smallish things but nothing about any patterns you're using.
1) Your method is called "Return..." something. Personally, I always name methods that return something "Get...". Return is a bit more vague as to what it does. Does "Return" refer to retrieving a database object, or does it refer to some business rule method. It's the concept of "self documenting code". Method names should describe exactly what they do.
2) Entities (or DbContext) classes should be Disposed when you're done with them. It should be something like this:
internal static Purchase GetPurchaseItem(int purchaseId)
{
Purchase purchase = null;
using (var context = new RegulusEntities())
{
return context.Purchases.Find(purchaseId);
}
}
3) If you have a primary key Id for an object, you don't need an entire Linq query to find it. You just need to call the Find method to retrieve it. Find() will return the object with the specified key. If it's not found, it'll throw a InvalidOperationException . You can replace it with FirstOrDefault() if you want the "Get..." method to return a null of the specified type instead of throwing.
Other than that, a couple of rules I follow:
I don't have my database code return any ViewModel objects, not does it accept any. My database layer will accept and return Entity objects only. If these objects need to be translated into ViewModel objects, I can have another layer above this that does the translation, such as in an MVC Controller class or what I call a "Services" class.
I never expose my database layer directly to UI code.
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You might want to be careful whom you reply to. Now that you replied to the wrong person, the OP will not get an email saying that someone else replied to him.
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My eyes just played a trick on me.
I've corrected the reply to the right person now...
Certainty of death, small chance of success...
What are we waiting for?
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Thanks for the reasoned and well thought out answer Dave. In showing you only a tiny patch of my code, I actually missed out the whole structure that this little method sits in.
This method, as with all my other calls to EF sits in a service class written to handle all the calls to a particular table. for example, all the calls to the purchase table are made from the clsPurchaseHandler class, thus separating it from the UI.
Your answer is exactly what I wanted. as I explained I am a freelance programmer running my own little operation, and I haven't got the luxury of being able to discuss code with anyone, and there's always the niggle at the back of my mind that 'I know it works, but is it the most efficient'. Your code detailing the disposal of entities after use and the find method is invaluable.
As for my naming of the method "ReturnPurchaseItem", that's my usual practise, as that's what the method does, I take your point that it may sound vague, but I've got a lot of code out in the wild that uses this notation, so for now, I'll stick with it.
Thanks again Dave, much appreciated.
George
George
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Sorry to be a pest Dave, but the 'find' method you suggest isn't available to my version of EF. I've read up on it and it appears to come in after EF 4.0. I appear to be running EF 6.0, but I still can't see it. What am I doing wrong?
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You have to import the System.Data.Entity namespace at the top of the code file.
If you get the red squiggly under Find , right click the word and then you should be able to pick Resolve -> System.Data.Entity.
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I've done all of that Dave, and I still get the red squiggly. It's got to be something to do with the version of the System.data.entity dll that I'm importing. EF reports that it's using version 6, but the DLL reports version 4. I'll keep trying, but until then, I'll use the version that works, but I can't help feeling that i's going to get up and bite me one day.
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If you've got a mismatch like that, something went terribly wrong.
Go to the Package Manager Console and do a Uninstall-Package EntityFramework . Then go through the References in the project and remove the EntityFramework reference if it's still there.
Once that's done, you can go back to the Package Manager Console and do a
Install-Package EntityFramework".<br />
<br />
That should take care of any mismatches.<br />
<div class="signature"><small><a href="http:
<font color="Blue">Dave Kreskowiak</font><br />
</div>
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I've been battling since Tuesday to fix this Dave. (sorry for taking so much of your time), I've done what you detailed above, but still the 'find' method isn't recognised. Funny thing though, the text I get when I try to use the method is:
"Error 1 'System.Data.Objects.ObjectSet<entityresearch.purchase>' does not contain a definition for 'find' EntityResearch...."
I thought the find method would be in System.Data.Entity?
I've gone so far as repairing my .NET 4.5 but that didn't work either.
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Repairing anything isn't going to do anything for you. Nothing is broken except your code.
There are multiple Find methods. The one that works on DbSets is in System.Data.Entity. If it's saying the you're using the System.Data.Objects namespace version, you're not using Entity Framework. Your entity sets have been defined using ObjectSet instead of DbSet.
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How can I define my entity sets using DbSet then? To all intents and purposes I am using Entity framework, it's calling it up in app.config, and in the references, so what can be going wrong?
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Using CodeFirst, in your DbContext derived class:
public DbSet<myclasstype> MyTableName { get; set; }
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Thanks Dave, But what If I'm using DB first?
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Wait, you mentioned EF 4.0 .DLL's, correct?
Is this an old EF 4.0 project you're upgrading?? If so, see Upgrading to EF6[^].
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I started a new project to test the find method, and I'm still getting the problem.
My app.config looks like this:
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
</entityFramework>
</configuration>
The System.Data.Entity DLL reports as being version 4.0. I downloaded a version 5.0 of this DLL, but even that reports as version 4.0
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I've found what I've been doing wrong Dave. When I've been adding the Entity Data model when I started the project, I've been deleting the two .tt template files and setting the code generation strategy in the edmx properties to 'default'. This hasn't been generating the (correct) code to use dBSet. I've still got a lot to learn yet about this, as it's opened a few more cans of worms for me, (For example, what happened to my 'AddObject' methods?)
This highlights my original point. I'm a freelance developer, and have been for about 10 years now. I work by myself, and I have no-one to bounce ideas off, or show me my mistakes. I learnt EF by buying Julia Lerman's book and studying enough of it to get my current project up and running, but not going any further. When I worked for a software house in England, I used to dread code review day, but I can see now how useful it was.
I know I'm still missing a lot, and I would be grateful if you could point me to a good tutorial about the correct way to deal with Entity Framework, and .tt files and all.
Thanks for all your patience Dave, it's been much appreciated.
George
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The best out there are Julia's books. I have them all and am going the CodeFirst route on my current project. I've been working on this one for the last year and will probably be doing it for another.
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