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  • Testing performance of queries in mysl

    - by Unreason
    I am trying to setup a script that would test performance of queries on a development mysql server. Here are more details: I have root access I am the only user accessing the server Mostly interested in InnoDB performance The queries I am optimizing are mostly search queries (SELECT ... LIKE '%xy%') What I want to do is to create reliable testing environment for measuring the speed of a single query, free from dependencies on other variables. Till now I have been using SQL_NO_CACHE, but sometimes the results of such tests also show caching behaviour - taking much longer to execute on the first run and taking less time on subsequent runs. If someone can explain this behaviour in full detail I might stick to using SQL_NO_CACHE; I do believe that it might be due to file system cache and/or caching of indexes used to execute the query, as this post explains. It is not clear to me when Buffer Pool and Key Buffer get invalidated or how they might interfere with testing. So, short of restarting mysql server, how would you recommend to setup an environment that would be reliable in determining if one query performs better then the other?

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  • MySQL: order by and limit gives wrong result

    - by Larry K
    MySQL ver 5.1.26 I'm getting the wrong result with a select that has where, order by and limit clauses. It's only a problem when the order by uses the id column. I saw the MySQL manual for LIMIT Optimization My guess from reading the manual is that there is some problem with the index on the primary key, id. But I don't know where I should go from here... Question: what should I do to best solve the problem? Works correctly: mysql> SELECT id, created_at FROM billing_invoices WHERE (billing_invoices.account_id = 5) ORDER BY id DESC ; +------+---------------------+ | id | created_at | +------+---------------------+ | 1336 | 2010-05-14 08:05:25 | | 1334 | 2010-05-06 08:05:25 | | 1331 | 2010-05-05 23:18:11 | +------+---------------------+ 3 rows in set (0.00 sec) WRONG result when limit added! Should be the first row, id - 1336 mysql> SELECT id, created_at FROM billing_invoices WHERE (billing_invoices.account_id = 5) ORDER BY id DESC limit 1; +------+---------------------+ | id | created_at | +------+---------------------+ | 1331 | 2010-05-05 23:18:11 | +------+---------------------+ 1 row in set (0.00 sec) Works correctly: mysql> SELECT id, created_at FROM billing_invoices WHERE (billing_invoices.account_id = 5) ORDER BY created_at DESC ; +------+---------------------+ | id | created_at | +------+---------------------+ | 1336 | 2010-05-14 08:05:25 | | 1334 | 2010-05-06 08:05:25 | | 1331 | 2010-05-05 23:18:11 | +------+---------------------+ 3 rows in set (0.01 sec) Works correctly with limit: mysql> SELECT id, created_at FROM billing_invoices WHERE (billing_invoices.account_id = 5) ORDER BY created_at DESC limit 1; +------+---------------------+ | id | created_at | +------+---------------------+ | 1336 | 2010-05-14 08:05:25 | +------+---------------------+ 1 row in set (0.01 sec) Additional info: explain SELECT id, created_at FROM billing_invoices WHERE (billing_invoices.account_id = 5) ORDER BY id DESC limit 1; +----+-------------+------------------+-------+--------------------------------------+--------------------------------------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------------+-------+--------------------------------------+--------------------------------------+---------+------+------+-------------+ | 1 | SIMPLE | billing_invoices | range | index_billing_invoices_on_account_id | index_billing_invoices_on_account_id | 4 | NULL | 3 | Using where | +----+-------------+------------------+-------+--------------------------------------+--------------------------------------+---------+------+------+-------------+

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  • Compilation Error: "The modifier 'public' is not valid for this item" while creating public method o

    - by Lalit
    I am getting this error while creating public method on a class for explicitly implementing the interface. I have the workaround: by removing the explicit implementation of PrintName Method, But surprised why i am getting this error. Can anyone explain the error. Code for Library: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Test.Lib1 { public class Customer : i1 { public string i1.PrintName() //Error Here... { return this.GetType().Name + " called from interface i1"; } } public interface i1 { string PrintName(); } interface i2 { string PrintName(); } } Code for Console Test Application: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Test.Lib1; namespace ca1.Test { class Program { static void Main(string[] args) { Customer customer = new Customer(); Console.WriteLine(customer.PrintName()); //i1 i1o = new Customer(); //Console.WriteLine(i1o.printname()); //i2 i2o = new Customer(); //Console.WriteLine(i2o.printname()); } } }

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  • mysql subselect alternative

    - by Arnold
    Hi, Lets say I am analyzing how high school sports records affect school attendance. So I have a table in which each row corresponds to a high school basketball game. Each game has an away team id and a home team id (FK to another "team table") and a home score and an away score and a date. I am writing a query that matches attendance with this seasons basketball games. My sample output will be (#_students_missed_class, day_of_game, home_team, away_team, home_team_wins_this_season, away_team_wins_this_season) I now want to add how each team did the previous season to my analysis. Well, I have their previous season stored in the game table but i should be able to accomplish that with a subselect. So in my main select statement I add the subselect: SELECT COUNT(*) FROM game_table WHERE game_table.date BETWEEN 'start of previous season' AND 'end of previous season' AND ( (game_table.home_team = team_table.id AND game_table.home_score > game_table.away_score) OR (game_table.away_team = team_table.id AND game_table.away_score > game_table.home_score)) In this case team-table.id refers to the id of the home_team so I now have all their wins calculated from the previous year. This method of calculation is neither time nor resource intensive. The Explain SQL shows that I have ALL in the Type field and I am not using a Key and the query times out. I'm not sure how I can accomplish a more efficient query with a subselect. It seems proposterously inefficient to have to write 4 of these queries (for home wins, home losses, away wins, away losses). I am sure this could be more lucid. I'll absolutely add color tomorrow if anyone has questions

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  • WHMCS - Mapping of a Manually Created Invoice with its Corresponding Domain

    - by Knowledge Craving
    I am using WHMCS version 4.2.1 for maintaining domain registration & website hosting services, in one of my websites. Currently, the automatic domain registration process is working great for both the existing & new clients. The main way to register domains automatically is to mark the respective invoices as paid, and automatically the domains get registered through my selected registrar. Recently, I am facing a major problem in domain renewals, where the domain has been already registered by us in the past. The problem is that some of the corresponding invoices are not already generated for the domains & so I have to manually create invoice for each of those domain renewals. However, I am unable to map that invoice with the corresponding domain. This is required because unless the domain knows that for its renewal, an invoice has been created, the marking of the invoice as paid will not instantiate the automatic renewal process through my registrar. Can anybody please tell me the probable way of mapping the invoice with its corresponding domain? I've tried to explain the problem as it is occurring in the best way possible. Still, if any more information regarding this is required, please ask. Any help is greatly appreciated.

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  • Properties vs. Fields: Need help grasping the uses of Properties over Fields.

    - by pghtech
    First off, I have read through a list of postings on this topic and I don't feel I have grasped properties because of what I had come to understand about encapsulation and field modifiers (private, public..ect). One of the main aspects of C# that I have come to learn is the importance of data protection within your code by the use of encapsulation. I 'thought' I understood that to be because of the ability of the use of the modifiers (private, public, internal, protected). However, after learning about properties I am sort of torn in understanding not only properties uses, but the overall importance/ability of data protection (what I understood as encapsulation) within C#. To be more specific, everything I have read when I got to properties in C# is that you should try to use them in place of fields when you can because of: 1) they allow you to change the data type when you can't when directly accessing the field directly. 2) they add a level of protection to data access However, from what I 'thought' I had come to know about the use of field modifiers did #2, it seemed to me that properties just generated additional code unless you had some reason to change the type (#1) - because you are (more or less) creating hidden methods to access fields as opposed to directly. Then there is the whole modifiers being able to be added to Properties which further complicates my understanding for the need of properties to access data. I have read a number of chapters from different writers on "properties" and none have really explained a good understanding of properties vs. fields vs. encapsulation (and good programming methods). Can someone explain: 1) why I would want to use properties instead of fields (especially when it appears I am just adding additional code 2) any tips on recognizing the use of properties and not seeing them as simply methods (with the exception of the get;set being apparent) when tracing other peoples code? 3) Any general rules of thumb when it comes to good programming methods in relation to when to use what? Thanks and sorry for the long post - I didn't want to just ask a question that has been asked 100x without explaining why I am asking it again.

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  • ASP.NET MVC Map String Url To A Route Value Object

    - by mwgriffiths
    I am creating a modular ASP.NET MVC application using areas. In short, I have created a greedy route that captures all routes beginning with {application}/{*catchAll}. Here is the action: // get /application/index public ActionResult Index(string application, object catchAll) { // forward to partial request to return partial view ViewData["partialRequest"] = new PartialRequest(catchAll); // this gets called in the view page and uses a partial request class to return a partial view } Example: The Url "/Application/Accounts/LogOn" will then cause the Index action to pass "/Accounts/LogOn" into the PartialRequest, but as a string value. // partial request constructor public PartialRequest(object routeValues) { RouteValueDictionary = new RouteValueDictionary(routeValues); } In this case, the route value dictionary will not return any values for the routeData, whereas if I specify a route in the Index Action: ViewData["partialRequest"] = new PartialRequest(new { controller = "accounts", action = "logon" }); It works, and the routeData values contains a "controller" key and an "action" key; whereas before, the keys are empty, and therefore the rest of the class wont work. So my question is, how can I convert the "/Accounts/LogOn" in the catchAll to "new { controller = "accounts", action = "logon" }"?? If this is not clear, I will explain more! :) Matt This is the "closest" I have got, but it obviously wont work for complex routes: // split values into array var routeParts = catchAll.ToString().Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries); // feels like a hack catchAll = new { controller = routeParts[0], action = routeParts[1] };

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  • Using Sub-Types And Return Types in Scala to Process a Generic Object Into a Specific One

    - by pr1001
    I think this is about covariance but I'm weak on the topic... I have a generic Event class used for things like database persistance, let's say like this: class Event( subject: Long, verb: String, directobject: Option[Long], indirectobject: Option[Long], timestamp: Long) { def getSubject = subject def getVerb = verb def getDirectObject = directobject def getIndirectObject = indirectobject def getTimestamp = timestamp } However, I have lots of different event verbs and I want to use pattern matching and such with these different event types, so I will create some corresponding case classes: trait EventCC case class Login(user: Long, timestamp: Long) extends EventCC case class Follow( follower: Long, followee: Long, timestamp: Long ) extends EventCC Now, the question is, how can I easily convert generic Events to the specific case classes. This is my first stab at it: def event2CC[T <: EventCC](event: Event): T = event.getVerb match { case "login" => Login(event.getSubject, event.getTimestamp) case "follow" => Follow( event.getSubject, event.getDirectObject.getOrElse(0), event.getTimestamp ) // ... } Unfortunately, this is wrong. <console>:11: error: type mismatch; found : Login required: T case "login" => Login(event.getSubject, event.getTimestamp) ^ <console>:12: error: type mismatch; found : Follow required: T case "follow" => Follow(event.getSubject, event.getDirectObject.getOrElse(0), event.getTimestamp) Could someone with greater type-fu than me explain if, 1) if what I want to do is possible (or reasonable, for that matter), and 2) if so, how to fix event2CC. Thanks!

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  • jQuery XML loading and then innerfade effect

    - by Ryan Max
    Hello, I think I can explain myself without code, so for brevity's sake here we go: I am using jquery to pull data from an xml and put it into a ul on the page with each xml entry as a li. This is working great! However, what I am trying to do afterwards is use the innerfade plugin to make a simple animation between each of the li's. It's not working though, as it is still just loading the static list with each item visible (whereas if innerfade was working it would only display the first....then fade into the second, etc) It's not an innerfade problem however, because if I add the list in manually to the page (not injecting it with jquery) then the innerfade works fine. I'm relatively new to DOM scripting, so I think I am missing something here. I'm not quite sure how jQuery sequences everything, and I'm having trouble phrasing my question in a search engine friendly manner so here I am. Is it possible to have jquery pull the data from xml, then inject it into the page, then have innerfade work it's magic? Or am I thinking about this the wrong way? xml code: $.ajax({ type: "GET", url: "xml/playlist.xml", dataType: "xml", success: function(xml) { $(xml).find('song').each(function(){ var name = $(this).attr('title'); var date = $(this).attr('artist'); var message = $(this).attr('path'); $('<li></li>').html('<span id="an_name">'+name+'</span><span id="an_date">'+date+'</span><span id="an_message">'+message+'</span>').appendTo('#anniversary'); }); } }); innerfade code: <script type="text/javascript"> jQuery.noConflict(); jQuery(document).ready( function(){ jQuery('#anniversary').innerfade({ speed: 1000, timeout: 5000, type: 'sequence', }); });

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  • Could Python's logging SMTP Handler be freezing my thread for 2 minutes?

    - by Oddthinking
    A rather confusing sequence of events happened, according to my log-file, and I am about to put a lot of the blame on the Python logger, which is a bold claim. I thought I should get some second opinions about whether what I am saying could be true. I am trying to explain why there is are several large gaps in my log file (around two minutes at a time) during stressful periods for my application when it is missing deadlines. I am using Python's logging module on a remote server, and have set-up, with a configuration file, for all logs of severity of ERROR or higher to be emailed to me. Typically, only one error will be sent at a time, but during periods of sustained problems, I might get a dozen in a minute - annoying, but nothing that should stress SMTP. I believe that, after a short spurt of such messages, the Python logging system (or perhaps the SMTP system it is sitting on) is encountering errors or congestion. The call to Python's log is then BLOCKING for two minutes, causing my thread to miss its deadlines. (I was smart enough to move the logging until after the critical path of the application - so I don't care if logging takes me a few seconds, but two minutes is far too long.) This seems like a rather awkward architecture (for both a logging system that can freeze up, and for an SMTP system (Ubuntu, sendmail) that cannot handle dozens of emails in a minute**), so this surprises me, but it exactly fits the symptoms. Has anyone had any experience with this? Can anyone describe how to stop it from blocking? ** EDIT: I actually counted. A little under 4000 short emails in two hours. So far more than I suggested, sorry. But enough to over-fill a Sendmail's buffers?

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  • Getting the highlighted text inside selected element only.

    - by ashays
    My goal is to be able to get the highlighted text within a document, but only if that text is within a given section, and then apply a certain style to that selected text after clicking a div tag. I'll explain what I mean: So, having looked at window.getSelection() and document.selection.createRange().text, I attempted to use elmnt.getSelection() or elmnt.selection.createRange().text for some HTML element, elmnt. However, it doesn't seem to work, so that idea seems pretty null. This means I can't use this idea to determine the text that is highlighted within a given location. In case this doesn't make sense, essentially, I want html code that looks like this: <body> <div id="content">Stuff here will not be effected</div> <div id="highlightable">Stuff here can be effected when highlighted</div> <div id="morecontent">Stuff here will also not be effected</div> </body> So that whenever I've highlighted text, clicking on a specified div will apply the proper CSS. Now, on to the div tags. Basically, here's what I've got on that: $('.colorpicker').click( function(e) { console.log(getSelectedText()); } Eventually, all I want this to highlight the selected text and have the div tag change the color of the selected text to that of the respective div tag that I've selected. Neither of these seems to be working right now, and my only guess for the reason of the div tag is that it unhighlights whatever I've got selected whenever I click on the div tag. Fallbacks: If there is more than one time that 'abc' is found on the page and I highlight to color 'abc', I would like that only that copy of 'abc' be highlighted. I know this is a lot in one question, but even if I could get a little head start on this idea, my next personal project would be going a lot more smoothly. Thanks. :)

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  • Why Illegal cookies are send by Browser and received by web servers (rfc 2109, 2965)?

    - by Artyom
    Hello, According to RFC 2109, 2965 cookie's value can be either HTTP token or quoted string, and token can't include non-ASCII characters. Cookie's RFC 2109 and RFC2965 HTTP's RFC 2068 token definition: http://tools.ietf.org/html/rfc2068#page-16 However I had found that Firefox browser (3.0.6) sends cookies with utf-8 string as-is and three web servers I tested (apache2, lighttpd, nginx) pass this string as-is to the application. For example, raw request from browser: $ nc -l -p 8080 GET /hello HTTP/1.1 Host: localhost:8080 User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.9) Gecko/2009050519 Firefox/2.0.0.13 (Debian-3.0.6-1) Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: windows-1255,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive Cookie: wikipp=1234; wikipp_username=?????? Cache-Control: max-age=0 And raw response of apache, nginx and lighttpd HTTP_COOKIE CGI variable: wikipp=1234; wikipp_username=?????? What do I miss? Can somebody explain me?

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  • python VTE Terminal weirdness

    - by mykhal
    i'm trying to use the terminal from python VTE binding (python-vte from debian squeeze) as a virtual terminal emulator (just for ANSI/control chars text processing) in interactive python console, everything looks (almost) all right: >>> import vte >>> term = vte.Terminal() >>> term.feed("a\nb") >>> print repr(term.get_text(lambda *a: True).rstrip()) 'a\n b' however, launching this code (little modified) as python script, different result is yielded: $ python vte_wiredness_1.py '' strangely enough, pasting the code back into the (new) interactive python session also yields empty string: >>> import vte >>> term = vte.Terminal() >>> term.feed("a\nb") >>> print repr(term.get_text(lambda *a: True).rstrip()) '' >>> first thing caming on my mind was that the only difference between the two cases is the timing - there had to be some delay before get_text. unfortunately, preluding get_text with some seconds sleep did not help then i thought it has something to do with X window environment. but the results are the same pure linux console (with some warning on missing graphics). i wonder what causes such an unpredictable behavior (interactive console - pasted vs typed, and it's not the delay.. ant the interactive console has nothing to do with the vte terminal object.. i guess) can someone explain what is happening? is it possible to use the VTE Term such way? that the "b" letter in the output is preceded by the space, is another strangeness (all consecutive lines are preceded by more spaces.. looks like I have to send carriage return before the string.) (the lambda *a: True get_text method argument i'm using is a dummy callback, it's is some SlotSelectedCallback.. for its explanation i'd be grateful as well :) )

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  • Unit test complex classes with many private methods

    - by Simon G
    Hi, I've got a class with one public method and many private methods which are run depending on what parameter are passed to the public method so my code looks something like: public class SomeComplexClass { IRepository _repository; public SomeComplexClass() this(new Repository()) { } public SomeComplexClass(IRepository repository) { _repository = repository; } public List<int> SomeComplexCalcualation(int option) { var list = new List<int>(); if (option == 1) list = CalculateOptionOne(); else if (option == 2) list = CalculateOptionTwo(); else if (option == 3) list = CalculateOptionThree(); else if (option == 4) list = CalculateOptionFour(); else if (option == 5) list = CalculateOptionFive(); return list; } private List<int> CalculateOptionOne() { // Some calculation } private List<int> CalculateOptionTwo() { // Some calculation } private List<int> CalculateOptionThree() { // Some calculation } private List<int> CalculateOptionFour() { // Some calculation } private List<int> CalculateOptionFive() { // Some calculation } } I've thought of a few ways to test this class but all of them seem overly complex or expose the methods more than I would like. The options so far are: Set all the private methods to internal and use [assembly: InternalsVisibleTo()] Separate out all the private methods into a separate class and create an interface. Make all the methods virtual and in my tests create a new class that inherits from this class and override the methods. Are there any other options for testing the above class that would be better that what I've listed? If you would pick one of the ones I've listed can you explain why? Thanks

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  • In WMI, can I use a join (or something similar) to acquire the IisWebServer object for a site, given

    - by Precipitous
    Given a server name and a physical path, I'd like to be able to hunt down the IISWebServer object and ApplicationPool. Website url is also an acceptable input. Our technologies are IIS 6, WMI, and access via C# or Powershell 2. I'm certain this would be easier with IIS 7 its managed API. We don't have that yet. Here's what I can do: Get a list of IIS virtual directories from IISWebVirtualDirSetting and filter (offline) for the matching physical path. $theVirtualDir = gwmi -Namespace "root/MicrosoftIISv2" ` -ComputerName $servername -authentication PacketPrivacy ` -class "IISWebVirtualDirSetting" ` | where-object {$_.Path -like $deployLocation} From the virtual directory object, I can get a name (like W3SVC/40565456/root). Given this name, I can get to other goodies, such as the IIS web server object. gwmi -Namespace "root/MicrosoftIISv2" ` -ComputerName $servername ` -authentication PacketPrivacy ` -Query "SELECT * FROM IisWebServer WHERE Name='W3SVC/40589473'" The questions, restated: 1) This is a query language. Can I join or subquery so that 1 WMI query statement gets web servers based on IISWebVirtualDir.Path? How? 2) In solving 1, you'll have to explain how to query on the Path property. Why is this an invalid query? "SELECT * FROM IISWebVirtualDirSetting WHERE Path='D:\sites\globaldominator'"

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  • NHibernate.QueryException with dynamic-component

    - by Ken
    OK, this is going to be kind of a long shot, since it's a big system (which I don't claim to fully understand, yet), and the problem might not be with NHibernate itself, and I'm even having trouble reproducing it, but... I've got a class with a <dynamic-component section, and when I run a query on it (through my ASP.NET MVC app), it fails, but only sometimes. (Yeah, the worst kind!) The exception I'm seeing is: NHibernate.QueryException: could not resolve property: Attributes.MyAttributeName of: MyClassName at NHibernate.Persister.Entity.AbstractPropertyMapping.GetColumns(String propertyName) at NHibernate.Persister.Entity.AbstractPropertyMapping.ToColumns(String alias, String propertyName) at NHibernate.Persister.Entity.BasicEntityPropertyMapping.ToColumns(String alias, String propertyName) at NHibernate.Persister.Entity.AbstractEntityPersister.ToColumns(String alias, String propertyName) at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetColumns(String propertyName, ICriteria subcriteria) at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetColumnsUsingProjection(ICriteria subcriteria, String propertyName) at NHibernate.Criterion.CriterionUtil.GetColumnNamesUsingPropertyName(ICriteriaQuery criteriaQuery, ICriteria criteria, String propertyName, Object value, ICriterion critertion) at NHibernate.Criterion.CriterionUtil.GetColumnNamesForSimpleExpression(String propertyName, IProjection projection, ICriteriaQuery criteriaQuery, ICriteria criteria, IDictionary`2 enabledFilters, ICriterion criterion, Object value) at NHibernate.Criterion.SimpleExpression.ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery, IDictionary`2 enabledFilters) at NHibernate.Loader.Criteria.CriteriaQueryTranslator.GetWhereCondition(IDictionary`2 enabledFilters) at NHibernate.Loader.Criteria.CriteriaJoinWalker..ctor(IOuterJoinLoadable persister, CriteriaQueryTranslator translator, ISessionFactoryImplementor factory, CriteriaImpl criteria, String rootEntityName, IDictionary`2 enabledFilters) at NHibernate.Loader.Criteria.CriteriaLoader..ctor(IOuterJoinLoadable persister, ISessionFactoryImplementor factory, CriteriaImpl rootCriteria, String rootEntityName, IDictionary`2 enabledFilters) at NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) at NHibernate.Impl.CriteriaImpl.List(IList results) at NHibernate.Impl.CriteriaImpl.UniqueResult[T]() ...my code below here... Can anybody explain exactly what this QueryException means, i.e., so I can have an idea of what exactly it thinks is going wrong? Thanks!

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  • Add a new element to a SortedSet

    - by arjacsoh
    Can someone explain me why this code compiles and runs fine, despite the fact that SortedSet is an interface and not a concrete class: public static void main(String[] args) { Integer[] nums = {4, 7, 8, 14, 45, 33}; List<Integer> numList = Arrays.asList(nums); TreeSet<Integer> numSet = new TreeSet<Integer>(); numSet.addAll(numList); SortedSet<Integer> sSet = numSet.subSet(5, 20); sSet.add(17); System.out.println(sSet); } It prints normally the result: [7, 8, 14, 17] Furthermore, my wonder is heightened by the fact that the SortedSet cannot be instansiated (expectedly). This line does not compile: SortedSet<Integer> sSet = new SortedSet<Integer>(); However, if I try the code: public static void main(String[] args) { Integer[] nums = {4, 7, 8, 14, 45, 33}; List<Integer> numList = Arrays.asList(nums); numList.add(56); System.out.println(numList); } it throws an UnsupportedOperationException. I reckon, this comes from the fact that List is an interface and cannot be handled as a concrete class. What is true about SortedSet?

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  • i386 assembly question: why do I need to meddle with the stack pointer?

    - by zneak
    Hello everyone, I decided it would be fun to learn x86 assembly during the summer break. So I started with a very simple hello world program, borrowing on free examples gcc -S could give me. I ended up with this: HELLO: .ascii "Hello, world!\12\0" .text .globl _main _main: pushl %ebp # 1. puts the base stack address on the stack movl %esp, %ebp # 2. puts the base stack address in the stack address register subl $20, %esp # 3. ??? pushl $HELLO # 4. push HELLO's address on the stack call _puts # 5. call puts xorl %eax, %eax # 6. zero %eax, probably not necessary since we didn't do anything with it leave # 7. clean up ret # 8. return # PROFIT! It compiles and even works! And I think I understand most of it. Though, magic happens at step 3. Would I remove this line, my program would die between the call to puts and the xor from a misaligned stack error. And would I change $20 to another value, it'd crash too. So I came to the conclusion that this value is very important. Problem is, I don't know what it does and why it's needed. Can anyone explain me? (I'm on Mac OS, would it ever matter.)

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  • ruby comma operator and step question

    - by ryan_m
    so, i'm trying to learn ruby by doing some project euler questions, and i've run into a couple things i can't explain, and the comma ?operator? is in the middle of both. i haven't been able to find good documentation for this, maybe i'm just not using the google as I should, but good ruby documentation seems a little sparse . . . 1: how do you describe how this is working? the first snippet is the ruby code i don't understand, the second is the code i wrote that does the same thing only after painstakingly tracing the first: #what is this doing? cur, nxt = nxt, cur + nxt #this, apparently, but how to describe the above? nxt = cur + nxt cur = nxt - cur 2: in the following example, how do you describe what the line with 'step' is doing? from what i can gather, the step command works like (range).step(step_size), but this seems to be doing (starting_point).step(ending_point, step_size). Am i right with this assumption? where do i find good doc of this? #/usr/share/doc/ruby1.9.1-examples/examples/sieve.rb # sieve of Eratosthenes max = Integer(ARGV.shift || 100) sieve = [] for i in 2 .. max sieve[i] = i end for i in 2 .. Math.sqrt(max) next unless sieve[i] (i*i).step(max, i) do |j| sieve[j] = nil end end puts sieve.compact.join(", ")

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  • Custom Calculations in a Matrix - Reporting Services 2005

    - by bfrancis
    I am writing a report to show gas usage (in gallons) used by each department. The request is to view each month and the gallons used by each department. A column is required to display what each departments target goal is, based on the gallons of gas they have used in a past time frame. Each departments target goal is x percent less than the total gallons used for said time frame. I currently have a matrix in Reporting Services with departments making up rows, months making up columns, and gallons filling the details. The matrix is being filled by dataset1. I have the data grouping as is requested for each month by each department. My problem is calculating the target goal. My thought was to create a second dataset (dataset2) that returns the gallons used based on the time frame requested. I grouped this data by department. I was hoping I could use the department field in each dataset to make sure the appropriate numbers were used. I added a new column which shows up next to the gallons field. As I attempted to build the Expression I found out that I could only grab the gallons used from dataset2 if I was summing the gallons field. This gives me the total gallons used by every department combined. I have tried to find resources with similar examples of what I am trying to accomplish but I cannot seem to come across one. I am trying to keep this as detailed as possible without making it too wordy. I would be more than happy to clarify or explain into further detail what I have written above if it is needed. If anyone has links, comments, or suggestions they would be greatly appreciated. A very simple visual or what I am hoping to accomplish is below. The months and departments would expand based on the data returned. months ------------------------------ departments| gallons/month | target goal

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  • iPhone: Creating a hierarchy-based table navigation.

    - by Jack Griffiths
    Hi there, I've tried to ask this before, but nothing got answered. Basically, I would like someone to explain to me how to create a table, which when a cell is tapped, pushes the user to the next view for that cell. I have this so far: Click here to view what I have. I would further like to, say when CSS is tapped, it goes to a new view which has another table in it. This table would then take the user to a detail view, which is scrollable and you can switch pages through it. I would appreciate longer, more structured tutorials on how to do each and every bit to get it to work. Here's my array in my implementation file: - (void)viewDidLoad { arryClientSide = [[NSArray alloc] initWithObjects:@"CSS", @"HTML", @"JavaScript", @"XML", nil]; arryServerSide = [[NSArray alloc] initWithObjects:@"Apache", @"PHP", @"SQL", nil]; self.title = @"Select a Language"; [super viewDidLoad]; } and my .h: @interface RootViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource> { IBOutlet UITableView *tblSimpleTable; NSArray *arryClientSide; NSArray *arryServerSide; } My current code crashes the script, and this error is returned in the console: Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UITableViewController loadView] loaded the "NextView" nib but didn't get a UITableView.' If that error is the source of why it's not pushing, then an explanation of how to remedy that would also be appreciated Many thanks, Jack

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  • Can this code be further optimized??

    - by kaki
    i understand that the code given below will not be compltely understood unless i explain my whole of previous and next lines of code. But this is part of the code which is causing so much of delay in my project and want to optimize this. i want to know which code part is faulty and how could this be replaced. i guess,few can say that use of this function is heavy compared and other ligher method are available to do this work please help, thanks in advance for i in range(len(lists)): save=database_index[lists[i]] #print save #if save[1]!='text0194'and save[1]!='text0526': using_data[save[0]]=save p=os.path.join("c:/begpython/wavnk/",str(str(str(save[1]).replace('phone','text'))+'.pm')) x1=open(p , 'r') x2=open(p ,'r') for i in range(6): x1.readline() x2.readline() gen = (float(line.partition(' ')[0]) for line in x1) r= min(enumerate(gen), key=lambda x: abs(x[1] - float(save[4]))) #print r[0] a1=linecache.getline(str(str(p).replace('.pm','.mcep')), (r[0]+1)) #print a1 p1=str(str(a1).rstrip('\n')).split(' ') #print p1 join_cost_index_end[save[0]]=p1 #print join_cost_index_end gen = (float(line.partition(' ')[0]) for line in x2) r= min(enumerate(gen), key=lambda x: abs(x[1] - float(save[3]))) #print r[0] a2=linecache.getline(str(str(p).replace('.pm','.mcep')), (r[0]+1)) #print a2 p2=str(str(a2).rstrip('\n')).split(' ') #print p2 join_cost_index_strt[save[0]]=p2 #print join_cost_index_strt j=j+1 #print j #print join_cost_index_end #print join_cost_index_strt enter code here here my database_index has about 2,50,000 entries`

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  • JSF 2 f:ajax lifecycle problem

    - by gerry
    The problem is, that if a property is changed during an f:ajax request and a binded panelGroup should be newly created depending on that changed value, the old value is used. This code will explain the problem. Here is the backingbean TestBean: public String getFirst() { return first; } public void setFirst(String first) { this.first = first; } public String getLast() { return last; } public void setLast(String last) { this.last = last; } public String getName(){ return first+" "+last; } public void setDynamicPanel(HtmlPanelGroup panel){ } public HtmlPanelGroup getDynamicPanel(){ Application app = FacesContext.getCurrentInstance().getApplication(); HtmlPanelGroup component = (HtmlPanelGroup)app.createComponent(HtmlPanelGroup.COMPONENT_TYPE); HtmlOutputLabel label1 = (HtmlOutputLabel)app.createComponent(HtmlOutputLabel.COMPONENT_TYPE); label1.setValue(" --> "+getFirst()+" "+getLast()); component.getChildren().add(label1); return component; } and now the jsf/facelet code: <h:form id="form"> <h:panelGrid columns="1"> <h:inputText id="first" value="#{testBean.first}" /> <h:inputText id="last" value="#{testBean.last}" /> <h:commandButton value="Show"> <f:ajax execute="first last" render="name dyn" /> </h:commandButton> </h:panelGrid> <h:outputText id="name" value="#{testBean.name}" /> <h:panelGroup id="dyn" binding="#{testBean.dynamicPanel}" /> </h:form> After the page was initially loaded the outputText and panelGroup shows both "null" as first and last. But after the button is pressed, the outputText is updated well, but the the panelgroup shows again only "null". This is due to the problem, that the "binded method" dynamicPanel is executed before the update of the first and last properties. how can workaround this behaviour or what is wrong with my code?

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  • Beginner's guide for rails

    - by piemesons
    Hello friends i need a book/ tutorials for rails without using scoffold. All the books mentioned in the other questions are creating some depot application or etc using scaffold and then explaining things. I believe in the thing that creating big depot is worthless when you are not getting anything. All of my frnds are suggesting me to go for this pragmatic book. look i understand the book is good but i m not getting the proper things. I got the logic cause i m good in php doctrine. asp.net c c++ so i m getting the things but i m not feeling confident. I want to have a another book. Can anybody suggest me some other books. I m saying this cause it really feels good when u create a simple form and insert the values in db and u can retreive those values and MOST IMP you can explain the whole logic of the that small form application instaed of that colorfull Depot application in which things are done with scaffold and u r not getting the thing and u are confused abt the real picture.

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  • Need some help understanding this problem about maximizing graph connectivity

    - by Legend
    I was wondering if someone could help me understand this problem. I prepared a small diagram because it is much easier to explain it visually. Problem I am trying to solve: 1. Constructing the dependency graph Given the connectivity of the graph and a metric that determines how well a node depends on the other, order the dependencies. For instance, I could put in a few rules saying that node 3 depends on node 4 node 2 depends on node 3 node 3 depends on node 5 But because the final rule is not "valuable" (again based on the same metric), I will not add the rule to my system. 2. Execute the request order Once I built a dependency graph, execute the list in an order that maximizes the final connectivity. I am not sure if this is a really a problem but I somehow have a feeling that there might exist more than one order in which case, it is required to choose the best order. First and foremost, I am wondering if I constructed the problem correctly and if I should be aware of any corner cases. Secondly, is there a closely related algorithm that I can look at? Currently, I am thinking of something like Feedback Arc Set or the Secretary Problem but I am a little confused at the moment. Any suggestions? PS: I am a little confused about the problem myself so please don't flame on me for that. If any clarifications are needed, I will try to update the question.

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