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• Display another field in the referenced table for multiple columns with performance issues in mind

  - by israkir

  I have a table of edge like this: ------------------------------- | id | arg1 | relation | arg2 | ------------------------------- | 1 | 1 | 3 | 4 | ------------------------------- | 2 | 2 | 6 | 5 | ------------------------------- where arg1, relation and arg2 reference to the ids of objects in another object table: -------------------- | id | object_name | -------------------- | 1 | book | -------------------- | 2 | pen | -------------------- | 3 | on | -------------------- | 4 | table | -------------------- | 5 | bag | -------------------- | 6 | in | -------------------- What I want to do is that, considering performance issues (a very big table more than 50 million of entries) display the object_name for each edge entry rather than id such as: --------------------------- | arg1 | relation | arg2 | --------------------------- | book | on | table | --------------------------- | pen | in | bag | --------------------------- What is the best select query to do this? Also, I am open to suggestions for optimizing the query - adding more index on the tables etc... EDIT: Based on the comments below: 1) @Craig Ringer: PostgreSQL version: 8.4.13 and only index is id for both tables. 2) @andrefsp: edge is almost x2 times bigger than object.

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• Question regarding inheritance in wxWidgets.

  - by celestialorb

  Currently I'm attempting to write my own wxObject, and I would like for the class to be based off of the wxTextCtrl class. Currently this is what I have: class CommandTextCtrl : public wxTextCtrl { public: void OnKey(wxKeyEvent& event); private: DECLARE_EVENT_TABLE() }; Then later on I have this line of code, which is doesn't like: CommandTextCtrl *ctrl = new CommandTextCtrl(panel, wxID_ANY, *placeholder, *origin, *size); ...and when I attempt to compile the program I receive this error: error: no matching function for call to ‘CommandTextCtrl::CommandTextCtrl(wxPanel*&, <anonymous enum>, const wxString&, const wxPoint&, const wxSize&)’ It seems that it doesn't inherit the constructor method with wxTextCtrl. Does anyone happen to know why it doesn't inherit the constructor? Thanks in advance for any help!

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• Get data types from arbitrary sql statement in SQL Server 2008

  - by Christopherous 5000

  Given some arbitrary SQL I would like to get the data types of the returned columns. The statement might join many tables, views, TVFs, etc. I know I could create a view based on the query and get the datatypes from that, hoping there's a quicker way. Only think I've been able to think of is writing a .net utility to run the SQL and examine the results, wondering if there is a TSQL answer. i.e. Given (not real tables just an example) SELECT p.Name AS PersonName, p.Age, a.Account as AccountName FROM Person as p LEFT JOIN Account as a ON p.Id = a.OwnerId I would like to have something like PersonName: (nvarchar(255), not null) Age: (smallInt, not null) etc...

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• How can open source projects obtain license for commercial software without spending a lot of money?

  - by Ikaso

  I just joined an open source project on codeplex. The project is based on the .NET compact framework. So the development tool is Visual Studio. Currently I am using some trial version of Visual Studio which is going to end and I wondered how can I obtain a valid license to work on the project without spending a lot of money. Please pay attention that the Express edition does not help me since my application is running on Windows Mobile 6.5 which is not supported on the Express edition (and the 2010 Express edition supports only Windows Mobile Phone 7 series development). In the general sense, are there some organizations that donate software licenses for open source projects?

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• search engine crawling frequency

  - by Aditya Pratap Singh

  I want to design a search engine for news websites ie. download various article pages from these websites, index the pages, and answer search queries on the index. I want a short pseudocode to find an appropriate crawling frequency -- i do not want to crawl too often because the website may not have changed, and do not want to crawl too infrequently because index would then be out of date. Assume that crawling code looks as follows while(1) { sleep(sleep_interval); // sleep for sleep_interval crawl(website); // crawls the entire website diff = diff(currently_crawled_website, previously_crawled_website); // returns a % value of difference between the latest and previous crawls of the website sleep_interval = infer_sleep_interval(diff, sleep_interval); } looking for a pseudocode for the infer_sleep_interval method: long sleep_interval infer_sleep_interval(int diff_percentage,long previous_sleep_interval) { ... ... ... } i want to design method which adaptively alters the sleeping interval based on the update frequency of the website.

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• NoSQL and meteorological data

  - by christian studer

  So there's this new cool thing, these NoSQL-databases. And so there's my data: Rows of rows of rows of meteorological data: Values, representing certain measurements at a certain station (Identified by a WMO number, not coordinates), at a certain time. Not every station measures every parameter, not every parameter is measured all the time. I store this data (30 years worth of hourly values, resulting in ~1 billion values) currently in MySQL. The continous growth and the forseeable addition of even more data give me a little headache. Reading about the document based NoSQL systems which seem to scale rather easily, I was wondering if NoSQL is a viable data storage concept for meteorological data too. Do you have any experience with this?

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• How to access system.webserver web.config node in .NET 2

  - by JK

  Are there any .NET APis that can read/update the system.webServer node in web.config? I know I can do it via reading/parsing the web.config file as xml but that's awkward. To read/update the system.web node in .NET 2 I can use: HttpModulesSection httpModulesSection = (HttpModulesSection)configuration.GetSection("system.web/httpModules"); But is there any API based way of accessing system.web/modules using .NET 2? I have to reference the .NET 2 version of system.web.configuration because I don't know in advance if my web app will be run on a server with .NET 2 or 3.5. So it is limited to .NET 2 API calls only. Thanks

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• Whats the difference between Paxos and W+R>=N in Cassandra?

  - by user1128016

  Dynamo-like databases (e.g. Cassandra) provide ability to enforce consistency by means of quorum, i.e. a number of synchronously written replicas (W) and a number of replicas to read (R) should be chosen in such a way that W+RN where N is a replication factor. On the other hand, PAXOS-based systems like Zookeeper are also used as a consistent fault-tolerant storage. What is the difference between these two approaches? Does PAXOS provide guarantees that are not provided by W+RN schema?

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• Loading tables dynamically with NHibernate

  - by Trevor Goertzen

  I'm working on a project that requires me to load tables based on table names stored in another table. More tables will be added to the DB (and by someone else), so creating NHibernate mapping files for each table isn't an option. Does anyone know if it is possible to load tables dynamically using NHibernate? Edit: I should add that I'm on .NET 2.0, so I can't use Fluent NHibernate. Thanks for the suggestion though guys. I will use that as evidence in convincing my associates to upgrade.

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• Google Datastore low-level api query by key property

  - by Keyur

  I'm using the low-level google datastore api and I want to query by the key property and another property (let's call it category). I need to query based on a list of keys for which I'll use the IN operator. I know that the max. number of values you can provide for the IN clause is 30. I have 2 questions: Does the limit of 30 IN values apply to the key property as well? Do I need to create a composite index on {_key_ + category} or just on {category} for this query? Thanks, Keyur

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• OOoBean with RCP

  - by Haythem

  Hi, I am trying to open OpenOffice documents on a View in RCP. I used for that the OleFram but he is not giving good results and now I am trying to integrate the OOoBean on my application but I can not see how I can do that. I am using Java 1.6 and Eclipse 3.5 and based on this sample http://www.eclipsezone.com/eclipse/forums/t48966.html My application have to show OOwriter and OOCalc documents and to be able to edit and save them. Is it possible to get this application working on a ViewPart? Thanks for the help.

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• Is there a module that implements an efficient array type in Erlang?

  - by dsmith

  I have been looking for an array type with the following characteristics in Erlang. append(vector(), term()) O(1) nth(Idx, vector()) O(1) set(Idx, vector(), term()) O(1) insert(Idx, vector(), term()) O(N) remove(Idx, vector()) O(N) I normally use a tuple for this purpose, but the performance characteristics are not what I would want for large N. My testing shows the following performance characteristics... erlang:append_element/2 O(N). erlang:setelement/3 O(N). I have started on a module based on the clojure.lang.PersistentVector implementation, but if it's already been done I won't reinvent the wheel.

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• New to programming

  - by Shaun

  I have a form (Quote) with an auto-number ID, on the form at the moment are two subforms that show different items (sub 1 shows partition modules sub 2 shows partition abutments) both forms use the same parts tables to build them. Both forms are linked to the quote form using the ID. All works well until the forms is refreshed or re-loaded, subform 1 shows the module names and quantities and blank spaces for the abutment names but shows the quantiews for the abutments, the reverse of this is shown in the abutments subform 2. When the lists for the variuos types and the detailed parts lists are printed they are correct. This seems to be only a visual problem. All based on Access 2003. Subform 1 SELECT Quote_Modules.ModuleID, Quote_Modules.QuoteID, Quote_Modules.ModuleDescription, Quote_Modules.ModuleQty, Quote.Style, Quote.Trim FROM Quote INNER JOIN Quote_Modules ON Quote.QuoteID=Quote_Modules.QuoteID ORDER BY Quote_Modules.ModuleID; Subform 2 SELECT Quote_Modules.ModuleID, Quote_Modules.QuoteID, Quote_Modules.ModuleDescription, Quote_Modules.ModuleQty, Quote.Style, Quote.Trim FROM Quote INNER JOIN Quote_Modules ON Quote.QuoteID=Quote_Modules.QuoteID ORDER BY Quote_Modules.ModuleID;

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• Available message types in JMS?

  - by Caylem

  This is based on a past exam question. The question is asking to describe the four types of message available using JMS. The problem is it says the four, not just four. So it assumes their is only four, no more no less. However according to this site their seems to be five; streams maps text objects bytes *Another book states that XML is another potential type in future versions of JMS. Is XML already available? Am I missing something or is the question just wrong? Thanks.

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• SVG drawing application with vector export

  - by Bram Jetten

  I want to create a drawing application where I can place text and images on a canvas. Those elements also need to be interactively manipulated. Eventually the resulting canvas has to be exported to a vector based PDF. An excellent contender for this functionality would be SVG. However, this application also needs to be crossbrowser compatible. I've been browsing around for some time now and have seen a couple of solutions available. I found among others RaphaelJS and Google's SVGWeb for working with SVG. Now for converting those SVG files to a PDF I'm not sure if for instance Batik will offer me what I am looking for. Also, how would bitmap images be handled when converting the SVG to PDF?

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• Stop 2 identical queries from executing almost simultaneously?

  - by James Simpson

  I have developed an AJAX based game where there is a bug caused (very remote, but in volume it happens at least once per hour) where for some reason two requests get sent to the processing page almost simultaneously (the last one I tracked, the requests were a difference of .0001 ms). There is a check right before the query is executed to make sure that it doesn't get executed twice, but since the difference is so small, the check hasn't finished before the next query gets executed. I'm stumped, how can I prevent this as it is causing serious problems in the game. Just to be more clear, the query is starting a new round in the game, so when it executes twice, it starts 2 rounds at the same time which breaks the game, so I need to be able to stop the script from executing if the previous round isn't over, even if that previous round started .0001 ms ago.

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• GA written in Java

  - by EnderMB

  I am attempting to write a Genetic Algorithm based on techniques I had picked up from the book "AI Techniques for Game Programmers" that uses a binary encoding and fitness proportionate selection (also known as roulette wheel selection) on the genes of the population that are randomly generated within the program in a two-dimensional array. I recently came across a piece of pseudocode and have tried to implement it, but have come across some problems with the specifics of what I need to be doing. I've checked a number of books and some open-source code and am still struggling to progress. I understand that I have to get the sum of the total fitness of the population, pick a random number between the sum and zero, then if the number is greater than the parents to overwrite it, but I am struggling with the implementation of these ideas. Any help in the implementation of these ideas would be very much appreciated as my Java is rusty.

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• Is there a decent JSON editor around?

  - by al4nis

  I'm looking for a JSON editor that is able to do syntax checking and outline view. Browser-based editors are not an option as they are clumsy for editing lots of local files. Eclipse plug-in would be ideal, but I would be happy with anything that works. I found only two so far, those in Aptana Studio Pro and Spket IDE (both available as plug-ins for Eclipse). While they have decent outline views, their syntax checking doesn't catch most of the common errors (like missing commas or braces) which makes them almost useless.

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• c# control location precision

  - by AC

  I need more precision then integer based locations when puttng controls on a form. It seems control.location only supports Point. Is there a work around for this? Point p = new Point(100, 200); this.Location = p;// this works of course PointF pF = new PointF(100.04f, 200.08f); this.Location = pF;// this does not work of course because Location expects a Point not PointF Is there some setting on the base form, or base control I can set to have more location precision?

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• Play 2.0 RESTful request post-processing

  - by virtualeyes

  In regard to this question I am curious how one can do post-request REST processing a la (crude): def postProcessor[T](content: T) = { request match { case Accepts.Json() => asJson(content) case Accepts.Xml() => asXml(content) case _ => content } } overriding onRouteRequest in Global config does not appear to provide access to body of the response, so it would seem that Action composition is the way to go to intercept the response and do post-processing task(s). Question: is this a good idea, or is it better to do content-type casting directly within a controller (or other class) method where the type to cast is known? Currently I'm doing this kind of thing everywhere: toJson( i18n("account not found") ) toJson( Map('orderNum-> orderNum) ) while I'd like the toJson/toXml conversion to happen based on accepts header post-request.

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• How do you keep track of your programming TODOs?

  - by Simucal

  I'm one of those people who can't get anything done without a to-do list. If it isn't on the list it doesn't exist. Notepad Method: When I'm programming I've been keeping notepad open with a list of to-do's for my current project. I'll constantly re-arrange these based off priority and I cross them off and move them to the completed section when I'm finished with that particular task. Code Comments: Some programmers pepper their projects source code with: // TODO: Fix this completely atrocious code before anyone sees it Plus, I know that there are some tools that show you a list of all TODOs in your code as well. Website Task Tracker: Remember The Milk Backpack Manymoon Voo2do Gmail Tasks TeuxDeux TodoDodo Ta-da lists ... and many more What have you found to be the best method of keeping track of your to-do lists for multiple projects? Related Question: What can someone do to get organized around here? Related Question: Getting Organized; the to-do list.

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• iPhone + alternative to drop downs

  - by pratik

  Hello, I am developing native iPhone app. I have one requirement that, there are 5 drop downs in the screen, where user will select each value and based on that there will be a graph generated on screen. Also the drop downs are cascading, meaning that depending on value selected in upper drop down, the values in lower drop downs will change. If it was a web app than, I had no problem as we have drop downs available. But it is a native iPhone app and we don't have drop down in iPhone SDK. Please suggest me some other alternative to achieve the same. Regards, Pratik

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• Unique task queue task names only for active duration

  - by antony.trupe

  I want to guarantee that a task is not in a task queue more then once, so I generate a unique name based on it's payload. But, that task name is reserved for up to 7 days, which is not what I want; I only want it reserved for the duration the task is queued; it could be immediately re-queued. Once a Task with name N is written, any subsequent attempts to insert a Task named N will fail. Eventually (at least seven days after the task successfully executes), the task will be deleted and the name N can be reused. Is there a way to check if the named task is already in the queue then add it if it's not? Or a totally different approach?

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• Editing Multiple files in vi with Wildcards

  - by Alan Storm

  When using the programmers text editor vi, I'll often using a wildcard search to be lazy about the file I want to edit vi ThisIsAReallLongFi*.txt When this matches a single file it works great. However, if it matches multiple files vi does something weird. First, it opens the first file for editing Second, when I :wq out of the file, I get a message the bottom of the terminal that looks like this E173: 4 more files to edit Hit ENTER or type command to continue When I hit enter, it returns me to edit mode in the file I was just in. The behavior I'd expect here would be that vi would move on to the next file to edit. So, What's the logic behind vi's behavior here Is there a way to move on and edit the next file that's been matched? And yes, I know about tab completion, this question is based on curiosity and wanting to understand the shell better.

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• Jasmine DOM test using jasmine jquery with require module

  - by Purushoth

  I am using custom variant of jasmine 2.0 from here https://github.com/erikringsmuth/jasmine2-amd-specrunner. So that testing my require.js based application made possible. Here i have facing problem with using jasmine-jquery. The jasmine object is undefined. $ and window is fine. function (window, jasmine, $) I have reference added jasmine and jquery lib too <script type="text/javascript" src="lib/jasmine.js"></script> <script type="text/javascript" src="lib/jquery-2.1.1.min.js"></script> <script type="text/javascript" src="lib/helpers/jasmine-jquery.js"></script>

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