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  • Best ways to format LINQ queries.

    - by Aren B
    Before you ignore / vote-to-close this question, I consider this a valid question to ask because code clarity is an important topic of discussion, it's essential to writing maintainable code and I would greatly appreciate answers from those who have come across this before. I've recently run into this problem, LINQ queries can get pretty nasty real quick because of the large amount of nesting. Below are some examples of the differences in formatting that I've come up with (for the same relatively non-complex query) No Formatting var allInventory = system.InventorySources.Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }).GroupBy(i => i.Region, i => i.Inventory); Elevated Formatting var allInventory = system.InventorySources .Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy( i => i.Region, i => i.Inventory); Block Formatting var allInventory = system.InventorySources .Select( src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy( i => i.Region, i => i.Inventory ); List Formatting var allInventory = system.InventorySources .Select(src => new { Inventory = src.Value.GetInventory(product.OriginalProductId, true), Region = src.Value.Region }) .GroupBy(i => i.Region, i => i.Inventory); I want to come up with a standard for linq formatting so that it maximizes readability & understanding and looks clean and professional. So far I can't decide so I turn the question to the professionals here.

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  • Change object on client side or on server side

    - by Polina Feterman
    I'm not sure what is the best practice. I have some big and complex objects (NOT flat). In that object I have many related objects - for example Invoice is the main class and one of it's properties is invoiceSupervisor - a big class by it's own called User. User can also be not flat and have department property - also an object called Department. For example I want create new Invoice. First way: I can present to client several fields to fill in. Some of them will be combos that I will need to fill with available values. For example available invoiceSupervisors. Then all the chosen values I can send to server and on server I can create new Invoice and assign all chosen values to that new Invoice. Then I will need to assign new supervisor I will pull the chosen User by id that user picked up on server from combobox. I might do some verification on the User such as does the user applicable to be invoice supervisor. Then I will assign the User object to invoiceSupervisor. Then after filling all properties I will save the new invoice. Second way: In the beginning I can call to server to get a new Invoice. Then on client I can fill all chosen values , for example I can call to server to get new User object and then fill it's id from combobox and assign the User as invoiceSupervisor. After filling the Invoice object on client I can send it to server and then the server will save the new invoice. Before saving server can run some validations as well. So what is the best approach - to make the object on client and send it to server or to collect all values from client and to make a new object on server using those values ?

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  • Need help setting up a truststore's chain of authority (in Tomcat)

    - by codeinfo
    Lead in ... I'm not an expert, by far, in application security via SSL, but am trying to establish a test environment that includes all possible scenarios we may encounter in production. For this I have a tree of Certificate Authorities (CAs) that are the issuers of an assortment of test client certificates, and node/server certificates (complex test environment representing the various published web services and other applications we integrate with). The structure of these CAs are as follows: Root CA, which has signed/issued Sub CA1, Sub CA2, and Sub CA3. These subs have then signed/issued all certificates of those various nodes and clients in the environment. Now for the question .... In my application's truststore I would like to trust everything signed by Sub CA1, and Sub CA2, but not Sub CA3 (untrusted). Does this mean my truststore should (1) ONLY include Sub CA1 and Sub CA2, or (2) should it include Root CA, Sub CA1, and Sub CA2? I don't know what is the proper way to represent this trust chain in a truststore. In the future I would also like to add a Sub CA4 (also signed/issued by the Root CA), but add that to a Certificate Revocation List (CRL) for testing purposes. Ahead of time, thank you for any help concerning this. It's greatly appreciated.

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  • Learning Java and logic using debugger. Did I cheat?

    - by centr0
    After a break from coding in general, my way of thinking logically faded (as if it was there to begin with...). I'm no master programmer. Intermediate at best. I decided to see if i can write an algorithm to print out the fibonacci sequence in Java. I got really frustrated because it was something so simple, and used the debugger to see what was going on with my variables. solved it in less than a minute with the help of the debugger. Is this cheating? When I read code either from a book or someone else's, I now find that it takes me a little more time to understand. If the alghorithm is complex (to me) i end up writing notes as to whats going on in the loop. A primitive debugger if you will. When you other programmers read code, do you also need to write things down as to whats the code doing? Or are you a genius and and just retain it?

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  • Python : How do you find the CPU consumption for a piece of code?

    - by Yugal Jindle
    Background: I have a django application, it works and responds pretty well on low load, but on high load like 100 users/sec, it consumes 100% CPU and then due to lack of CPU slows down. Problem : Profiling the application gives me time taken by functions. This time increases on high load. Time consumed may be due to complex calculation or for waiting for CPU. so, how to find the CPU cycles consumed by a piece of code ? Since, reducing the CPU consumption will increase the response time. I might have written extremely efficient code and need to add more CPU power OR I might have some stupid code taking the CPU and causing the slow down ? Any help is appreciated ! Update: I am using Jmeter to profile my webapp, it gives me a throughput of 2 requests/sec. [ 100 users] I get a average time of 36 seconds on 100 request vs 1.25 sec time on 1 request. More Info Configuration Nginx + Uwsgi with 4 workers No database used, using a responses from a REST API On 1st hit the response of REST API gets cached, therefore doesn't makes a difference. Using ujson for json parsing. Curious to Know: Python-Django is used by so many orgs for so many big sites, then there must be some high end Debug / Memory-CPU analysis tools. All those I found were casual snippets of code that perform profiling.

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  • Dynamic Data Extract Tools

    - by Kevin McGovern
    I've been searching around for a few weeks now for a tool that either is fully built or a direction of something I could build for dynamically extracting data via a web interface. Basically, what I'm looking for is a way to give users a list of all available data objects from our database and then let them pick ones from the list they'd like to view and set parameters then export the results to an excel file. Right now we're doing it purely with SQL statements but we have hundreds of objects so as you might imagine, those statements are really complex and prone to errors. It would be great if there was a tool available to do this or if someone had an idea of an easy way to organize this. Any help would be greatly appreciated. We've looked at BI tools like QlikView and Tableau but that is probably overkill for what we're trying to do. The open-source BI tools we've looked at seemed really primitive in their functionality. The other thing we looked at was MSAS (our DB is SQL Server) but I'd prefer something that was more database-agnostic and lived on a web server instead of on the database.

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  • Elegent methods for caching search results from RESTful service?

    - by Paul
    I have a RESTful web service which I access from the browser using JavaScript. As an example, say that this web service returns a list of all the Message resources assigned to me when I send a GET request to /messages/me. For performance reasons, I'd like to cache this response so that I don't have to re-fetch it every time I visit my Manage Messages web page. The cached response would expire after 5 minutes. If a Message resource is created "behind my back", say by the system admin, it's possible that I won't know about it for up to 5 minutes, until the cached search response expires and is re-fetched. This is acceptable, because it creates no confusion for me. However if I create a new Message resource which I know should be part of the search response, it becomes confusing when it doesn't appear on my Manage Messages page immediately. In general, when I knowingly create/delete/update a resource that invalidates a cached search response, I need that cached response to be expired/flushed immediately. The core problem which I can't figure out: I see no simple way of connecting the task of creating/deleting/updating a resource with the task of expiring the appropriate cached responses. In this example it seems simple, I could manually expire the cached search response whenever I create/delete/update a(ny) Message resource. But in a more complex system, keeping track of which search responses to expire under what circumstances will get clumsy quickly. If someone could suggest a simple solution or some clarifying thoughts, I'd appreciate it.

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  • I need help with a SQL query. Fetching an entry, it's most recent revision and it's fields.

    - by Tigger ate my dad
    Hi there, I'm building a CMS for my own needs, and finished planning my database layout. Basically I am abstracting all possible data-models into "sections" and all entries into one table. The final layout is as follows: Database diagram: I have yet to be allowed to post images, so here is a link to a diagram of my database. Entries (section_entries) are children of their section (sections). I save all edits to the entries in a new revision (section_entries_revisions), and also track revisions on the sections (section_revisions), in order to match the values of a revision, to the fields of the section that existed when the entry-revision was made. The section-revisions can have a number of fields (section_revision_fields) that define the attributes of entries in the section. There is a many-to-many relationship between the fields (section_revision_fields) and the entry-revisions (section_entry_revisions), that stores the values of the attributes defined by the section revision. Feel free to ask questions if the diagram is confusing. Now, this is the most complex SQL I've ever worked with, and the task of fetching my data is a little daunting. Basically what i want help with, is fetching an entry, when the only known variables are; section_id, section_entry_id. The query should fetch the most recent revision of that entry, and the section_revision model corresponding to section_revision_id in the section_entry_revisions table. It should also fetch the values of the fields in the section-revision. I was hoping for a query result, where there would be as many rows as fields in the section. Each row would contain the information of the entry and the section, and then information for one of the fields (e.g. each row corresponding to a field and it's value). I tried to explain the best I could. Again, feel free to ask questions if my description somehow lacking. I hope someone is up for the challenge. Best regards. :-)

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  • JQuery Control Update Not Happening

    - by Mad Halfling
    Hi, I've got a script that disables a button input control, empties a table body and then (after an AJAX call) re-populates it. It all works fine but sometimes there are a lot of rows in the table so the browser (IE) takes a while to empty and refill it. The strange thing is, while the rows are being emptied, the button still appears to be enabled, however if I put an alert between the button being disabled and the tbody being emptied, the button works properly, disabling visibly before the the alert comes up. Is there any way I can get the button to update before the resource consuming table emptying process/command commences? Thx MH Code sample, as requested (but it's not complex, so I didn't initially include it) $('#Search').attr('disabled', true); $('#StatusSpan').empty(); $('#DisplayTBody').empty(); then I perform my AJAX call, re-enable the button and repopulate the table. As I mentioned, normally this is really quick and isn't a problem, but if there are, say, 1500 rows in the table it takes a while to clear down but the 'Search' button doesn't update on the screen, however if I put an alert after the .attr('disabled' line the button visibly updates when the alert box is up, but without that the button doesn't visibly disable until after the table clears (which is about 3 or 4 seconds with 1500 rows), it just stays in it's down/"mid-press" state. I don't have a problem with the time the browser is taking to render the table changes, that's just life, but I need the users to see visible feedback so they know the search has started

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  • Can anyone give me a sample java socket programming for doing a peer to peer for 3 systems?

    - by Sadesh Kumar N
    I am doing an university project. I need some sample programs on peer to peer programs in java socket programming. Every where people are telling to add a server socket in the client program. I am in a confusion. Can a single program having server socket and client socket will do or i have to create two programs of one initiating a system and another peer program running thrice to solve the problem. or i need to create three programs for three peer systems. I am not clear on the architecture of building peer to peer programs using java sockets. Can some one help me giving a simple program on how to create a peer to peer connection between three systems. I know how to do a socket program for client server model and clear on the concept. But creating a peer to peer architecture sounds complex for me to understand. I also referred this thread. developing peer to peer in java The person commented second says" To make peer2peer app each client opens server socket too. When client A wishes to connect to client B it just connects to its socket. " Need some more sample and an explanation on how peer to peer java socket program works I dont want any external api like jxta to do this task. I need a clear picture on how it works alone with an example.

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  • Strategies for testing reactive, asynchronous code

    - by Arne
    I am developing a data-flow oriented domain-specific language. To simplify, let's just look at Operations. Operations have a number of named parameters and can be asked to compute their result using their current state. To decide when an Operation should produce a result, it gets a Decision that is sensitive to which parameter got a value from who. When this Decision decides that it is fulfilled, it emits a Signal using an Observer. An Accessor listens for this Signal and in turn calls the Result method of the Operation in order to multiplex it to the parameters of other Operations. So far, so good, nicely decoupled design, composable and reusable and, depending on the specific Observer used, as asynchronous as you want it to be. Now here's my problem: I would love to start coding actual Tests against this design. But with an asynchronous Observer... how should I know that the whole signal-and-parameters-plumbing worked? Do I need to use time outs while waiting for a Signal in order to say that it was emitted successfully or not? How can I be, formally, sure that the Signal will not be emitted if I just wait a little longer (halting problem? ;-)) And, how can I be sure that the Signal was emitted because it was me who set a parameter, and not another Operation? It might well be that my test comes to early and sees a Signal that was emitted way before my setting a parameter caused a Decision to emit it. Currently, I guess the trivial cases are easy to test, but as soon as I want to test complex many-to-many - situations between operations I must resort to hoping that the design Just Works (tm)...

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  • the possible solution to this design issue??

    - by Sachindra
    I need to know how to fix this issue in the designs of forms.. Getting this in firefox and this in IE... the color is not an issue.. juz need the alignment to be fixed... The code goes like this : <div class="content_form_box7_main"> <div class="content_form_box7_main1"> <input type="text" name="email" value="Comments" class="content_form_box7_inside"/> </div> </div> the style goes like : .content_form_box7_main{ float:left; color:#FFFFFF; padding:5px 0px 2px 0px; width:281px; } .content_form_box7_main1{ float:left; padding:0px 0px 0px 40px; } .content_form_box7_inside{ float:left; background-image:url(images/amcro_contact4.gif); width:206px; height:43px; background-repeat:no-repeat; border:none; background-color:#E0D1B4; vertical-align:top; } apologies if it looks complex ...

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  • Find Lines with N occurrences of a char

    - by Martín Marconcini
    I have a txt file that I’m trying to import as flat file into SQL2008 that looks like this: “123456”,”some text” “543210”,”some more text” “111223”,”other text” etc… The file has more than 300.000 rows and the text is large (usually 200-500 chars), so scanning the file by hand is very time consuming and prone to error. Other similar (and even more complex files) were successfully imported. The problem with this one, is that “some lines” contain quotes in the text… (this came from an export from an old SuperBase DB that didn’t let you specify a text quantifier, there’s nothing I can do with the file other than clear it and try to import it). So the “offending” lines look like this: “123456”,”this text “contains” a quote” “543210”,”And the “above” text is bad” etc… You can see the problem here. Now, 300.000 is not too much if I could perform a search using a text editor that can use regex, I’d manually remove the quotes from each line. The problem is not the number of offending lines, but the impossibility to find them with a simple search. I’m sure there are less than 500, but spread those in a 300.000 lines txt file and you know what I mean. Based upon that, what would be the best regex I could use to identify these lines? My first thought is: Tell me which lines contain more than 4 quotes (“). But I couldn’t come up with anything (I’m not good at Regex beyond the basics).

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  • Avoiding repetition with libraries that use a setup + execute model

    - by lijie
    Some libraries offer the ability to separate setup and execution, esp if the setup portion has undesirable characteristics such as unbounded latency. If the program needs to have this reflected in its structure, then it is natural to have: void setupXXX(...); // which calls the setup stuff void doXXX(...); // which calls the execute stuff The problem with this is that the structure of setupXXX and doXXX is going to be quite similar (at least textually -- control flow will prob be more complex in doXXX). Wondering if there are any ways to avoid this. Example: Let's say we're doing signal processing: filtering with a known kernel in the frequency domain. so, setupXXX and doXXX would probably be something like... void doFilter(FilterStuff *c) { for (int i = 0; i < c->N; ++i) { doFFT(c->x[i], c->fft_forward_setup, c->tmp); doMultiplyVector(c->tmp, c->filter); doFFT(c->tmp, c->fft_inverse_setup, c->x[i]); } } void setupFilter(FilterStuff *c) { setupFFT(..., &(c->fft_forward_setup)); // assign the kernel to c->filter ... setupFFT(..., &(c->fft_inverse_setup)); }

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  • Multiple collections tied to one base collection with filters and eventing

    - by damienc88
    I have a complex model served from my back end, which has a bunch of regular attributes, some nested models, and a couple of collections. My page has two tables, one for invalid items, and one for valid items. The items in question are from one of the nested collections. Let's call it baseModel.documentCollection, implementing DocumentsCollection. I don't want any filtration code in my Marionette.CompositeViews, so what I've done is the following (note, duplicated for the 'valid' case): var invalidDocsCollection = new DocumentsCollection( baseModel.documentCollection.filter(function(item) { return !item.isValidItem(); }) ); var invalidTableView = new BookIn.PendingBookInRequestItemsCollectionView({ collection: app.collections.invalidDocsCollection }); layout.invalidDocsRegion.show(invalidTableView); This is fine for actually populating two tables independently, from one base collection. But I'm not getting the whole event pipeline down to the base collection, obviously. This means when a document's validity is changed, there's no neat way of it shifting to the other collection, therefore the other view. What I'm after is a nice way of having a base collection that I can have filter collections sit on top of. Any suggestions?

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  • Correct way to initialize dynamic Array in C++

    - by mef
    Hey guys, I'm currently working on a C++ project, where dynamic arrays often appear. I was wondering, what could be the correct way to initialize a dynamic array using the new-operator? A colleague of mine told me that it's a no-no to use new within the constructor, since a constructor is a construct that shouldn't be prone to errors or shouldn't fail at all, respectively. Now let's consider the following example: We have two classes, a more or less complex class State and a class StateContainer, which should be self-explained. class State { private: unsigned smth; public: State(); State( unsigned s ); }; class StateContainer { private: unsigned long nStates; State *states; public: StateContainer(); StateContainer( unsigned long n ); virtual ~StateContainer(); }; StateContainer::StateContainer() { nStates = SOME_DEFINE_N_STATES; states = new State[nStates]; if ( !states ) { // Error handling } } StateContainer::StateContainer( unsigned long n ) { nStates = n; try { states = new State[nStates] } catch ( std::bad_alloc &e ) { // Error handling } } StateContainer::~StateContainer() { if ( states ) { delete[] states; states = 0; } } Now actually, I have two questions: 1.) Is it ok, to call new within a constructor, or is it better to create an extra init()-Method for the State-Array and why? 2.) Whats the best way to check if new succeeded: if (!ptr) std::cerr << "new failed." or try { /*new*/ } catch (std::bad_alloc) { /*handling*/ } 3.) Ok its three questions ;o) Under the hood, new does some sort of ptr = (Struct *)malloc(N*sizeof(Struct)); And then call the constructor, right?

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  • Data transformation question

    - by tkm
    I have data composed of a list of employers and a list of workers. Each has a many-to-many relationship with the other (so an employer can have many workers, and a worker can have many employers). The way the data is retrieved (and given to me) is as follows: each employer has an array of workers. In other words: employer n has: worker x, worker y etc. So I have a bunch of employer objects each containing an array of workers. I need to transform this data (and basically invert the relationship). I need to have a bunch of worker objects, each containing and array of employers. In other words: worker x has: employer n1, employer n2 etc. The context is hypothetical so please don't comment on why I need this or why I am doing it this way. I would really just like help on the algorithm to perform this transformation (there isn't that much data so I would prefer readability over complex optimizations which reduce complexity). (Oh and I am using Java, but pseudocode would be fine). Thanks!

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  • How to create a class by reading from another class (.cs) file with Powershell?

    - by Razcer
    I have this POGO ( simple putter getter) class that I am trying to read in PowerShell using System; using System.Runtime.Serialization; namespace MyApp.VM { [Serializable] public class MyClassVM { public Int64 CtrId { get; set; } public string CtrName { get; set; } public string CtrPhone { get; set; } public string CtrZip { get; set; } public DateTime AddDate { get; set; } } } Here is the ps1 code that is trying to read the class from a file. function Build-Pogo { $FileDir = "D:\YourDirectoryOfPogo" $ClassName = "MyClassVM" $FileName = $FileDir + "\" + $ClassName + ".cs" # Build the class from the file $AllLines = [string]::join([environment]::newline, (Get-Content $FileName)) Add-Type -TypeDefinition $AllLines # spin thru each property for class $ClassHandle = New-Object -typeName $ClassName $ClassHandle | ForEach-Object {Write-Host $_.name -foregroundcolor cyan} } *Note the last line is placeholder for more complex logic to come later. This breaks at the Add-Type with this error message for each get/set in the file. 'MyApp.VM.MyClassVM.CtrId.get' must declare a body because it is not marked abstract or extern Any info on what I'm doing wrong will be greatly appreciated.

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  • What guarantees are there on the run-time complexity (Big-O) of LINQ methods?

    - by tzaman
    I've recently started using LINQ quite a bit, and I haven't really seen any mention of run-time complexity for any of the LINQ methods. Obviously, there are many factors at play here, so let's restrict the discussion to the plain IEnumerable LINQ-to-Objects provider. Further, let's assume that any Func passed in as a selector / mutator / etc. is a cheap O(1) operation. It seems obvious that all the single-pass operations (Select, Where, Count, Take/Skip, Any/All, etc.) will be O(n), since they only need to walk the sequence once; although even this is subject to laziness. Things are murkier for the more complex operations; the set-like operators (Union, Distinct, Except, etc.) work using GetHashCode by default (afaik), so it seems reasonable to assume they're using a hash-table internally, making these operations O(n) as well, in general. What about the versions that use an IEqualityComparer? OrderBy would need a sort, so most likely we're looking at O(n log n). What if it's already sorted? How about if I say OrderBy().ThenBy() and provide the same key to both? I could see GroupBy (and Join) using either sorting, or hashing. Which is it? Contains would be O(n) on a List, but O(1) on a HashSet - does LINQ check the underlying container to see if it can speed things up? And the real question - so far, I've been taking it on faith that the operations are performant. However, can I bank on that? STL containers, for example, clearly specify the complexity of every operation. Are there any similar guarantees on LINQ performance in the .NET library specification?

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  • Adding an element to a multidimensional array

    - by stef
    How can I loop through the array below and an element per array, with key "url_slug" and value "foo"? I tried with array_push but that gets rid of the key names (it seems?) Doing a foreach($array as $k = $v) doesn't do it either, I think. The new array should be exactly the same only having 4 elements per array instead of 3, with the key / values above. Array ( [0] => Array ( [name_en] => Test 5 [url_name_nl] => test-5 [cat_name] => mobile ) [1] => Array ( [name_en] => Test 10 [url_name_nl] => test-10 [cat_name] => mobile ) [2] => Array ( [name_en] => Test 25 [url_name_nl] => test-25 [cat_name] => mobile ) ) EDIT: full working solution. A little more complex than originally described foreach ($prods as $key => &$value) { if($key == "cat_name") $slug = $value['cat_name']; $url_slug = $this->lang->line($slug); $value['url_slug'] = $url_slug; }

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  • Log4j Logging to the Wrong Directory

    - by John
    I have a relatively complex log4j.xml configuration file with many appenders. Some machines the application runs on need a separate log directory, which is actually a mapped network drive. To get around this, we embed a system property as part of the filename in order to specify the directory. Here is an example: The "${user.dir}" part is set as a system property on each system, and is normally set to the root directory of the application. On some systems, this location is not the root of the application. The problem is that there is always one appender where this is not set, and the file appears not to write to the mapped drive. The rest of the appenders do write to the correct location per the system property. As a unit test, I set up our QA lab to hard-code the values for the appender above, and it worked: however, a different appender will then append to the wrong file. The mis-logged file is always the same for a given configuration: it is not a random file each time. My best educated guess is that there is a HashMap somewhere containing these appenders, and for some reason, the first one retrieved from the map does not have the property set. Our application does have custom system properties loading: the main() method loads a properties file and calls into System.setProperties(). My first instinct was to check the static initialization order, and to ensure the controller class with the main method does not call into log4j (directly or indirectly) before setting the properties just in case this was interfering with log4j's own initialization. Even removing all vestiges of log4j from the initialization logic, this error condition still occurs.

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  • Patterns to deal with with functions that can have different kinds of results.

    - by KaptajnKold
    Suppose you have an method on an object that given the some input alters the objects state if the input validates according to some complex logic. Now suppose that when the input doesn't validate, it can be due to several different things, each of which we would like to be able to deal with in different ways. I'm sure many of you are thinking: That's what exceptions are for! I've thought of this also. But my reservation against using exceptions is that in some cases there is nothing exceptional about the input not validating and I really would like to avoid using exceptions to control what is really just in the expected flow of the program. If there were only one interpretation possible, I could simply choose to return a boolean value indicating whether or not the operation resulted in a state change or not and the respond appropriately when it did not. There is of course also the option to return a status code which the client can then choose to interpret or not. I don't like this much either because there is nothing semantic about status codes. The solution I have so far is to always check for each possible situation which I am able to handle before I call the method which then returns a boolean to inform the client if the object changed state. This leaves me the flexibility to handle as few or as many as the possible situations as I wish depending on the context I am in. It also has the benefit of making the method I am calling simpler to write. The drawback is that there is quite a lot of duplication in the client code wherever I call the method. Which of these solutions do you prefer and why? What other patterns do people use for providing meaningful feedback from functions? I know that some languages support multiple return values, and I if I had that option I would surely prefer it.

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  • Selecting records in SQL that have the minimum value for that record based on another field

    - by Ryan
    I have a set of data, and while the number of fields and tables it joins with is quite complex, I believe I can distill my problem down using the required fields/tables here for illustration regarding this particular problem. I have three tables: ClientData, Sources, Prices Here is what my current query looks like before selecting the minimum value: select c.RecordID, c.Description, s.Source, p.Price, p.Type, p.Weight from ClientData c inner join Sources s ON c.RecordID = s.RecordID inner join Prices p ON s.SourceID = p.SourceID This produces the following result: RecordID Description Source Price Type Weight ============================================================= 001002003 ABC Common Stock Vendor 1 104.5 Close 1 001002003 ABC Common Stock Vendor 1 103 Bid 2 001002003 ABC Common Stock Vendor 2 106 Close 1 001002003 ABC Common Stock Vendor 2 100 Unknwn 0 111222333 DEF Preferred Stk Vendor 3 80 Bid 2 111222333 DEF Preferred Stk Vendor 3 82 Mid 3 111222333 DEF Preferred Stk Vendor 2 81 Ask 4 What I am trying to do is display prices that belong to the same record which have the minimum non-zero weight for that record (so the weight must be greater than 0, but it has to be the minimum from amongst the remaining weights). So in the above example, for record 001002003 I would want to show the close prices from Vendor 1 and Vendor 2 because they both have a weight of 1 (the minimum weight for that record). But for 111222333 I would want to show just the bid price from Vendor 3 because its weight of 2 is the minimum, non-zero for that record. The result that I'm after would like like: RecordID Description Source Price Type Weight ============================================================= 001002003 ABC Common Stock Vendor 1 104.5 Close 1 001002003 ABC Common Stock Vendor 2 106 Close 1 111222333 DEF Preferred Stk Vendor 3 80 Bid 2 Any ideas on how to achieve this? EDIT: This is for SQL Compact Edition.

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  • [c++/STL] Selective iterator

    - by rubenvb
    FYI: no boost, yes it has this, I want to reinvent the wheel ;) Is there some form of a selective iterator (possible) in C++? What I want is to seperate strings like this: some:word{or other to a form like this: some : word { or other I can do that with two loops and find_first_of(":") and ("{") but this seems (very) inefficient to me. I thought that maybe there would be a way to create/define/write an iterator that would iterate over all these values with for_each. I fear this will have me writing a full-fledged custom way-too-complex iterator class for a std::string. So I thought maybe this would do: std::vector<size_t> list; size_t index = mystring.find(":"); while( index != std::string::npos ) { list.push_back(index); index = mystring.find(":", list.back()); } std::for_each(list.begin(), list.end(), addSpaces(mystring)); This looks messy to me, and I'm quite sure a more elegant way of doing this exists. But I can't think of it. Anyone have a bright idea? Thanks PS: I did not test the code posted, just a quick write-up of what I would try

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  • Infrastructure for high transactional system (language & hosting suggestion help)

    - by RPS
    Some of our friends (University students) are trying to develop a twitter type application, I want to plan for at least 1000 transactions per second (I know it's wishful thinking) for initial launch. This involves several people connecting and getting updates and posting (text + images) to site. In the back end db will server the data and also calculates rankings of what to push to user based on complex algorithm on the fly real-time. Our group is familiar with Java and Tomcat/MySQL. We can also easily learn/code in PHP/MySQL. What is the best suited platform for our purpose ? Though Java seem to be easy to implement for us I am afraid that hosting will be a bit difficult. I could find cloud based php hosting services (like rackspace cloudsites) at reasonable cost. Amazon EC2 is a bit over our heads to manage on day-to-day. Also any recommendation on hosting ? (PHP or Java) We don't have millions in seed money but about $20K to start with. Any advice on above or any thing in general approach is much appreciated.

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