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  • PHP Game weapon accuracy

    - by noko
    I'm trying to come up with a way for players to fire their weapons and only hit for a certain percentage. For example, one gun can only hit 70% of the time while another only hits 34% of the time. So far all I could come up with is weighted arrays. Attempt 1: private function weighted_random(&$weight) { $weights = array(($weight/100), (100-$weight)/100); $r = mt_rand(1,1000); $offset = 0; foreach($weights as $k => $w) { $offset += $w*1000; if($r <= $offset) return $k; } } Attempt 2: private function weapon_fired(&$weight) { $hit = array(); for($i = 0; $i < $weight; $i++) $hit[] = true; for($i = $weight; $i < 100; $i++) $hit[] = false; shuffle($hit); return $hit[mt_rand(0,100)]; } It doesn't seem that the players are hitting the correct percentages but I'm not really sure why. Any ideas or suggestions? Is anything glaringly wrong with these? Thanks

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  • C++ code parser/processor library

    - by uray
    is there any library that parse a source code of C++ to produce lets say, call graph, class inheritance tree, flow control, class member list or anything as a ready to use graph or structure in code (not in diagram image). to make it more clear, suppose to generate call graph image, there will be a process like this: ` C++ source -> parser -> intermediate structure -> renderer -> call graph image ^ | [i need this] `

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  • STL deque accessing by index is O(1)?

    - by jasonline
    I've read that accessing elements by position index can be done in constant time in a STL deque. As far as I know, elements in a deque may be stored in several non-contiguous locations, eliminating safe access through pointer arithmetic. For example: abc-defghi-jkl-mnop The elements of the deque above consists of a single character. The set of characters in one group indicate it is allocated in contiguous memory (e.g. abc is in a single block of memory, defhi is located in another block of memory, etc.). Can anyone explain how accessing by position index can be done in constant time, especially if the element to be accessed is in the second block? Or does a deque have a pointer to the group of blocks? Update: Or is there any other common implementation for a deque?

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  • Order words by number of letters, then place words neatly

    - by bmaster
    I have a list of words in javascript similar to this: var words = ["mine", "minute", "mist", "mixed", "money", "monkey", "month", "moon", "morning", "mother", "motion", "mountain", "mouth", "move", "much", "muscle", "music", "nail", "name", "narrow", "nation", "natural", "near", "necessary", "neck", "need", "needle", "nerve", "net", "new", "news", "night"]; The words can be 1-25? letters long. I have a div id="words", with a set width of 700px (but I might change it from this). Using css/javascript/jquery, how can I make it: Order the words by number of letters Place the words inside the div tag, left to right, but so that there are no gaps at the right edge of the words div, and there is even spacing between words on a line. Each word should have a border around it and a background. Like this: |reallylongwordssdf shorterwordfdf dfsdfsdfsdf sdfsdfsdf| |sdfsdfsdf sdffsdop sdfjpogs sdfsds dfsdsd dfsdsd dfsdsd| I really have no idea where to begin with this. Perhaps I could manage to write code to order the words by number of letters, but after that, I'd be stuck. Edit: I forgot to add, the words must be links.

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  • c# warn if text box is empty or contains a non-whole number

    - by Jamaul Smith
    In my specific case, I need the value in propertyPriceTextBox to be numeric only, and a whole number. A value also has to be entered, and I can just Messagebox.Show() a warning and that's all I'd need to do. This is what I have so far. private void computeButton_Click(object sender, EventArgs e) { decimal propertyPrice; if ((decimal.TryParse(propertyPriceTextBox.Text, out propertyPrice))) decimal.Parse(propertyPriceTextBox.Text); { if (residentialRadioButton.Checked == true) commisionLabel.Text = (residentialCom * propertyPrice).ToString("c"); if (commercialRadioButton.Checked == true) commisionLabel.Text = (commercialCom * propertyPrice).ToString("c"); if (hillsRadioButton.Checked == true) countySalesTaxTextBox.Text = ( hilssTax * propertyPrice).ToString("c"); if (pascoRadioButton.Checked == true) countySalesTaxTextBox.Text = (pascoTax * propertyPrice).ToString("c"); if (polkRadioButton.Checked == true) countySalesTaxTextBox.Text = (polkTax * propertyPrice).ToString("c"); decimal result; result = (countySalesTaxTextBox.Text + stateSalesTaxTextBox.Text + propertyPriceTextBox.Text + comissionTextBox.Text).ToString("c"); } else (.) MessageBox.Show("Property Price must be a whole number."); }

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  • Looking for a fast hash-function.

    - by Julian
    Hello, I'm looking for a special hash-function. Let's say I have a large list of strings, if I order them by their hash-values they should be ordered quasi randomly. The most important point is: it must be super fast. I've tried md5 and sha1 and they're using to much cpu power. Clashes are not a problem. I'm using javascript, so it shouldn't be too complicated to implement.

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  • Strange phantom header margin bug html/css

    - by MickyJimbo
    So I'm creating this website and there is a strange untraceable bug that causes the header to move down 10 or so pixels. On a refresh the header could be correct or it could be broken. I've been testing it on Adobe Browserlab and the results are different every time.There is no discernible pattern making it incredible hard to track down. http://www.freeimagehosting.net/uploads/c866bf594d.jpg Has anyone ever had this problem and been able to fix it?

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  • Combine Arbitrary number of polygons together

    - by Jakobud
    I have an arbitrary number of polygons (hexes in this case) that are arranged randomly, but they are all touching another hex. Each individual hex has 6 x,y vertices. The vertex's are known for all the hexes. Can anyone point me in the direction of an algorithm that will combine all the hexes into a single polygon? Essentially I'm just looking for a function that spits out an array of vertex locations that are ordered in a way that when drawing lines from one to the next, it forms the polygon. This is my method so far: Create array of all the vertices for all the hexes. Determine the number of times a vertex occurs in the array If vertex is in the array 3+ times, delete the vertices from the array. If vertex is in the array 2 times, delete one of them. The next step is tricky though. I'm using canvas to draw out these polygons, which essentially involves drawing a line from one vertex to the next. So the order of the vertices in the final array is important. It can't be sorted arbitrarily. Also, I'm not looking for a "convex hull" algorithm, as that would not draw the polygon correctly. Are there any functions out there that do something like this? Am I on the right track or is there a better more efficient way?

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  • PHP, MySQL - would results-array shuffle be quicker than "select... order by rand()"?

    - by sombe
    I've been reading a lot about the disadvantages of using "order by rand" so I don't need update on that. I was thinking, since I only need a limited amount of rows retrieved from the db to be randomized, maybe I should do: $r = $db->query("select * from table limit 500"); for($i;$i<500;$i++) $arr[$i]=mysqli_fetch_assoc($r); shuffle($arr); (i know this only randomizes the 500 first rows, be it). would that be faster than $r = $db->("select * from table order by rand() limit 500"); let me just mention, say the db tables were packed with more than...10,000 rows. why don't you do it yourself?!? - well, i have, but i'm looking for your experienced opinion. thanks!

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  • Validating a phone number in Android PreferenceScreen

    - by djechelon
    I have a PreferenceScreen in which the user is capable, if system can't autodetect it, to enter the device's phone number. I'm still learning this part of Android but I managed to understand a bit of PreferenceScreens by examples provided by Android SDK itself and a few tutorials. What I want is that the user can save the phone number only if null or valid, where by "valid" I mean running a generic validation logic (ie. an anonymous method that returns true or false, that can be reused in any possible situation*) or better, just to simplify things, ^(\+39)?3[0-9]{9}$ For now I have the following XML snip <EditTextPreference android:inputType="phone" android:key="@string/preference_phoneNo" android:selectAllOnFocus="true" android:singleLine="true" android:summary="@string/pref_phoneNumber_description" android:title="@string/pref_phoneNumber" /> and following code by courtesy of Eclipse New Activity wizard: private void setupSimplePreferencesScreen() { if (!isSimplePreferences(this)) { return; } addPreferencesFromResource(R.xml.pref_general); bindPreferenceSummaryToValue(findPreference(getString(R.string.preference_phoneNo))); } addPreferenceFromResource is supposed to load the XML node and add the preference to the screen, while binPreferenceSummaryToValue is supposed to make description text change when preference is updated. Just for sake of completeness for those who don't like code courtesy of the IDE, the second method is provided by Eclipse who also provides a private class in the code file that is /** * A preference value change listener that updates the preference's summary * to reflect its new value. */ In the general case, what should I do to perform validation logic before the preference gets saved when I click OK on the preference editor? Where is the validation logic to be put in a PreferenceScreen? *Aren't we all here to learn?

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  • Latest stream cipher considered reasonably secure & easy to implement?

    - by hythlodayr
    (A)RC4 used to fit the bill, since it was so simple to write. But it's also less-than-secure these days. I'm wondering if there's a successor that's: Code is small enough to write & debug within an hour or so, using pseudo code as a template. Still considered secure, as of 2010. Optimized for software. Not encumbered by licensing issues. I can't use crypto libraries, otherwise all of this would be moot. Also, I'll consider block algorithms though I think most are pretty hefty. Thanks.

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  • Adding up row number and displaying total using COUNT (PHP MySQL)

    - by Yvonne
    I'm attempting to run a query that adds up the total number of subjects in a class. A class has many subjects. There is a 'teachersclasses' table between teachers (the user table) and classes. The principles sounds pretty simple but I'm having some trouble in getting my page to display the number of subjects for each class (directly associated with the teacher) This is what I have so far, trying to make use of the COUNT with a nested SELECT: SELECT (SELECT count(*) FROM subjects WHERE subjects.classid = class.classid) AS total_subjects, class.classname, class.classid FROM class Then I am calling up 'num_subjects' to present the total within a while loop: <?php echo $row['total_subjects']?> From the above, I am receiving the total subjects for a class, but within the same table row (for one class) and my other while loop doesnt run anymore, which returns all of the classes associated with a teacher :( ... Bit of a mess now! I know to return the classes for a particular teacher, I can do an additional WHERE clause on the session of 'teacherid' but I think my query is getting too complicated for me that errors are popping up everywhere. Anyone have a quick fix for this! Thanks very much

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  • How to add precedence to LALR parser like in YACC?

    - by greenoldman
    Please note, I am asking about writing LALR parser, not writing rules for LALR parser. What I need is... ...to mimic YACC precedence definitions. I don't know how it is implemented, and below I describe what I've done and read so far. For now I have basic LALR parser written. Next step -- adding precedence, so 2+3*4 could be parsed as 2+(3*4). I've read about precedence parsers, however I don't see how to fit such model into LALR. I don't understand two points: how to compute when insert parenthesis generator how to compute how many parenthesis the generator should create I insert generators when the symbols is taken from input and put at the stack, right? So let's say I have something like this (| denotes boundary between stack and input): ID = 5 | + ..., at this point I add open, so it gives ID = < 5 | + ..., then I read more input ID = < 5 + | 5 ... and more ID = < 5 + 5 | ; ... and more ID = < 5 + 5 ; | ... At this point I should have several reduce moves in normal LALR, but the open parenthesis does not match so I continue reading more input. Which does not make sense. So this was when problem. And about count, let's say I have such data < 2 + < 3 * 4 >. As human I can see that the last generator should create 2 parenthesis, but how to compute this? After all there could be two scenarios: ( 2 + ( 3 *4 )) -- parenthesis is used to show the outcome of generator or (2 + (( 3 * 4 ) ^ 5) because there was more input Please note that in both cases before 3 was open generator, and after 4 there was close generator. However in both cases, after reading 4 I have to reduce, so I have to know what generator "creates".

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  • MVC HTML.RenderAction – Error: Duration must be a positive number

    - by BarDev
    On my website I want the user to have the ability to login/logout from any page. When the user select login button a modal dialog will be present to the user for him to enter in his credentials. Since login will be on every page, I thought I would create a partial view for the login and add it to the layout page. But when I did this I got the following error: Exception Details: System.InvalidOperationException: Duration must be a positive number. There are other ways to work around this that would not using partial views, but I believe this should work. So to test this, I decided to make everything simple with the following code: Created a layout page with the following code @{Html.RenderAction("_Login", "Account");} In the AccountController: public ActionResult _Login() { return PartialView("_Login"); } Partial View _Login <a id="signin">Login</a> But when I run this simple version this I still get this error: Exception Details: System.InvalidOperationException: Duration must be a positive number. Source of error points to "@{Html.RenderAction("_Login", "Account");}" There are some conversations on the web that are similar to my problem, which identifies this as bug with MVC (see links below). But the links pertain to Caching, and I'm not doing any caching. OuputCache Cache Profile does not work for child actions http://aspnet.codeplex.com/workitem/7923 Asp.Net MVC 3 Partial Page Output Caching Not Honoring Config Settings Asp.Net MVC 3 Partial Page Output Caching Not Honoring Config Settings Caching ChildActions using cache profiles won't work? Caching ChildActions using cache profiles won't work? I'm not sure if this makes a difference, but I'll go ahead and add it here. I'm using MVC 3 with Razor. Update Stack Trace [InvalidOperationException: Duration must be a positive number.] System.Web.Mvc.OutputCacheAttribute.ValidateChildActionConfiguration() +624394 System.Web.Mvc.OutputCacheAttribute.OnActionExecuting(ActionExecutingContext filterContext) +127 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func1 continuation) +72 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func1 continuation) +784922 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList1 filters, ActionDescriptor actionDescriptor, IDictionary2 parameters) +314 System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +784976 System.Web.Mvc.Controller.ExecuteCore() +159 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +335 System.Web.Mvc.<c_DisplayClassb.b_5() +62 System.Web.Mvc.Async.<c_DisplayClass1.b_0() +20 System.Web.Mvc.<c_DisplayClasse.b_d() +54 System.Web.Mvc.<c_DisplayClass4.b_3() +15 System.Web.Mvc.ServerExecuteHttpHandlerWrapper.Wrap(Func`1 func) +41 System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +1363 [HttpException (0x80004005): Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'.] System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +2419 System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage) +275 System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) +94 System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter) +838 System.Web.Mvc.Html.ChildActionExtensions.RenderAction(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues) +56 ASP._Page_Views_Shared_SiteLayout_cshtml.Execute() in c:\Projects\Odat Projects\Odat\Source\Presentation\Odat.PublicWebSite\Views\Shared\SiteLayout.cshtml:80 System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +280 System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +104 System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +173 System.Web.WebPages.WebPageBase.Write(HelperResult result) +89 System.Web.WebPages.WebPageBase.RenderSurrounding(String partialViewName, Action1 body) +234 System.Web.WebPages.WebPageBase.PopContext() +234 System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +384 System.Web.Mvc.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() +33 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func1 continuation) +784900 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func1 continuation) +784900 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList1 filters, ActionResult actionResult) +265 System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +784976 System.Web.Mvc.Controller.ExecuteCore() +159 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +335 System.Web.Mvc.<c_DisplayClassb.b_5() +62 System.Web.Mvc.Async.<c_DisplayClass1.b_0() +20 System.Web.Mvc.<c_DisplayClasse.b_d() +54 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +453 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +371 Update When I Break in Code, it errors at @{Html.RenderAction("_Login", "Account");} with the following exception. The inner exception Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'. at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage) at System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) at System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter) at System.Web.Mvc.Html.ChildActionExtensions.RenderAction(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues) at ASP._Page_Views_Shared_SiteLayout_cshtml.Execute() in c:\Projects\Odat Projects\Odat\Source\Presentation\Odat.PublicWebSite\Views\Shared\SiteLayout.cshtml:line 80 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.WebPages.WebPageBase.Write(HelperResult result) at System.Web.WebPages.WebPageBase.RenderSurrounding(String partialViewName, Action1 body) at System.Web.WebPages.WebPageBase.PopContext() at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func1 continuation) Answer Thanks Darin Dimitrov Come to find out, my AccountController had the following attribute [System.Web.Mvc.OutputCache(NoStore =true, Duration = 0, VaryByParam = "*")]. I don't believe this should caused a problem, but when I removed the attribute everything worked. BarDev

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  • Ruby number_to_currency displays a totally wrong number!

    - by SueP
    Greetings! I’m an old Delphi programmer making the leap to the Mac, Ruby, Rails, and web programming in general. I’m signed up for the Advanced Rails workshop at the end of the month. In the meantime, I’ve been working on porting a mission-critical (of course) app from Delphi to RAILS. It feels like I’ve spent most of the past year with my head buried in a book or podcast. Right now, I’ve hit a major issue and I’m tearing my hair out. I literally don’t know where to go with this, I desperately don’t want to deploy with this bug, and I’m feeling a bit frantic. (The company database is currently running on an ancient XP box that’s looking rustier by the day.) So, I set up a test database that shows the problem. I’m running: OS/X 10.6.3 Rails 2.3.5 ruby 1.8.7 (2009-06-08 patchlevel 173) [universal-darwin10.0] MySQL 5.1.38-log via socket MySQL Client Version 5.1.8 ActiveRecord::Schema.define(:version => 20100406222528) do create_table “money”, :force => true do |t| t.decimal “amount_due”, :precision => 10, :scale => 2, :default => 0.0 t.decimal “balance”, :precision => 10, :scale => 2, :default => 0.0 t.text “memofield” t.datetime “created_at” t.datetime “updated_at” end The index view is right out of the generator, slightly modified to add the formatting that's breaking on me. Listing money <table> <tr> <th>Amount</th> <th>Amount to_s </th> <th>Balance to $</th> <th>Balance with_precision </th> <th>Memofield</th> </tr> <% @money.each do |money| %> <tr> <td><%=h money.amount_due %></td> <td><%=h money.amount_due.to_s(‘F’) %></td> <td><%=h number_to_currency(money.balance) %></td> <td><%=h number_with_precision(money.balance, :precision => 2) %></td> <td><%=h money.memofield %></td> <td><%= link_to ‘Show’, money %></td> <td><%= link_to ‘Edit’, edit_money_path(money) %></td> <td><%= link_to ‘Destroy’, money, :confirm => ‘Are you sure?’, :method => :delete %></td> </tr> *<% end %> *</table> <%= link_to ‘New money’, new_money_path %> This seemed to work pretty well. Then I started testing with production data and hit a major problem with number_to_currency. The number in the database is: 10542.28, I verified it with the MySQL Query Browser. RAILS will display this as 10542.28 unless I call number_to_currency, then that number is displayed as: $15422.80 The error seems to happen with any number between 10,000.00 and 10,999.99 So far, I haven’t seen it outside of that range, but I obviously haven’t tested everything. I guess my workaround is to remove number_to_currency, but that leaves the views looking really sloppy and unprofessional. The formatting is messed up, things don’t line up properly and I can’t force the display to 2 decimal places. I’m seriously hoping there is an easy fix for this. I can’t imagine this being a widespread problem. It would affect so many people that someone would have fixed it! But I don’t know where to go from here. I’d desperately like some help. (Later – number_with_precision fails the same way number_to_currency does.) Sue Petersen

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  • Performance considerations for common SQL queries

    - by Jim Giercyk
    Originally posted on: http://geekswithblogs.net/NibblesAndBits/archive/2013/10/16/performance-considerations-for-common-sql-queries.aspxSQL offers many different methods to produce the same results.  There is a never-ending debate between SQL developers as to the “best way” or the “most efficient way” to render a result set.  Sometimes these disputes even come to blows….well, I am a lover, not a fighter, so I decided to collect some data that will prove which way is the best and most efficient.  For the queries below, I downloaded the test database from SQLSkills:  http://www.sqlskills.com/sql-server-resources/sql-server-demos/.  There isn’t a lot of data, but enough to prove my point: dbo.member has 10,000 records, and dbo.payment has 15,554.  Our result set contains 6,706 records. The following queries produce an identical result set; the result set contains aggregate payment information for each member who has made more than 1 payment from the dbo.payment table and the first and last name of the member from the dbo.member table.   /*************/ /* Sub Query  */ /*************/ SELECT  a.[Member Number] ,         m.lastname ,         m.firstname ,         a.[Number Of Payments] ,         a.[Average Payment] ,         a.[Total Paid] FROM    ( SELECT    member_no 'Member Number' ,                     AVG(payment_amt) 'Average Payment' ,                     SUM(payment_amt) 'Total Paid' ,                     COUNT(Payment_No) 'Number Of Payments'           FROM      dbo.payment           GROUP BY  member_no           HAVING    COUNT(Payment_No) > 1         ) a         JOIN dbo.member m ON a.[Member Number] = m.member_no         /***************/ /* Cross Apply  */ /***************/ SELECT  ca.[Member Number] ,         m.lastname ,         m.firstname ,         ca.[Number Of Payments] ,         ca.[Average Payment] ,         ca.[Total Paid] FROM    dbo.member m         CROSS APPLY ( SELECT    member_no 'Member Number' ,                                 AVG(payment_amt) 'Average Payment' ,                                 SUM(payment_amt) 'Total Paid' ,                                 COUNT(Payment_No) 'Number Of Payments'                       FROM      dbo.payment                       WHERE     member_no = m.member_no                       GROUP BY  member_no                       HAVING    COUNT(Payment_No) > 1                     ) ca /********/                    /* CTEs  */ /********/ ; WITH    Payments           AS ( SELECT   member_no 'Member Number' ,                         AVG(payment_amt) 'Average Payment' ,                         SUM(payment_amt) 'Total Paid' ,                         COUNT(Payment_No) 'Number Of Payments'                FROM     dbo.payment                GROUP BY member_no                HAVING   COUNT(Payment_No) > 1              ),         MemberInfo           AS ( SELECT   p.[Member Number] ,                         m.lastname ,                         m.firstname ,                         p.[Number Of Payments] ,                         p.[Average Payment] ,                         p.[Total Paid]                FROM     dbo.member m                         JOIN Payments p ON m.member_no = p.[Member Number]              )     SELECT  *     FROM    MemberInfo /************************/ /* SELECT with Grouping   */ /************************/ SELECT  p.member_no 'Member Number' ,         m.lastname ,         m.firstname ,         COUNT(Payment_No) 'Number Of Payments' ,         AVG(payment_amt) 'Average Payment' ,         SUM(payment_amt) 'Total Paid' FROM    dbo.payment p         JOIN dbo.member m ON m.member_no = p.member_no GROUP BY p.member_no ,         m.lastname ,         m.firstname HAVING  COUNT(Payment_No) > 1   We can see what is going on in SQL’s brain by looking at the execution plan.  The Execution Plan will demonstrate which steps and in what order SQL executes those steps, and what percentage of batch time each query takes.  SO….if I execute all 4 of these queries in a single batch, I will get an idea of the relative time SQL takes to execute them, and how it renders the Execution Plan.  We can settle this once and for all.  Here is what SQL did with these queries:   Not only did the queries take the same amount of time to execute, SQL generated the same Execution Plan for each of them.  Everybody is right…..I guess we can all finally go to lunch together!  But wait a second, I may not be a fighter, but I AM an instigator.     Let’s see how a table variable stacks up.  Here is the code I executed: /********************/ /*  Table Variable  */ /********************/ DECLARE @AggregateTable TABLE     (       member_no INT ,       AveragePayment MONEY ,       TotalPaid MONEY ,       NumberOfPayments MONEY     ) INSERT  @AggregateTable         SELECT  member_no 'Member Number' ,                 AVG(payment_amt) 'Average Payment' ,                 SUM(payment_amt) 'Total Paid' ,                 COUNT(Payment_No) 'Number Of Payments'         FROM    dbo.payment         GROUP BY member_no         HAVING  COUNT(Payment_No) > 1   SELECT  at.member_no 'Member Number' ,         m.lastname ,         m.firstname ,         at.NumberOfPayments 'Number Of Payments' ,         at.AveragePayment 'Average Payment' ,         at.TotalPaid 'Total Paid' FROM    @AggregateTable at         JOIN dbo.member m ON m.member_no = at.member_no In the interest of keeping things in groupings of 4, I removed the last query from the previous batch and added the table variable query.  Here’s what I got:     Since we first insert into the table variable, then we read from it, the Execution Plan renders 2 steps.  BUT, the combination of the 2 steps is only 22% of the batch.  It is actually faster than the other methods even though it is treated as 2 separate queries in the Execution Plan.  The argument I often hear against Table Variables is that SQL only estimates 1 row for the table size in the Execution Plan.  While this is true, the estimate does not come in to play until you read from the table variable.  In this case, the table variable had 6,706 rows, but it still outperformed the other queries.  People argue that table variables should only be used for hash or lookup tables.  The fact is, you have control of what you put IN to the variable, so as long as you keep it within reason, these results suggest that a table variable is a viable alternative to sub-queries. If anyone does volume testing on this theory, I would be interested in the results.  My suspicion is that there is a breaking point where efficiency goes down the tubes immediately, and it would be interesting to see where the threshold is. Coding SQL is a matter of style.  If you’ve been around since they introduced DB2, you were probably taught a little differently than a recent computer science graduate.  If you have a company standard, I strongly recommend you follow it.    If you do not have a standard, generally speaking, there is no right or wrong answer when talking about the efficiency of these types of queries, and certainly no hard-and-fast rule.  Volume and infrastructure will dictate a lot when it comes to performance, so your results may vary in your environment.  Download the database and try it!

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  • Regular Expressions

    - by Rocky
    Hello Everyone, I am new to Stackoverflow and I have a quick question. Let's assume we are given a large number of HTML files (large as in theoretically infinite). How can I use Regular Expressions to extract the list of Phone Numbers from all those files? Explanation/expression will be really appreciated. The Phone numbers can be any of the following formats: (123) 456 7899 (123).456.7899 (123)-456-7899 123-456-7899 123 456 7899 1234567899 Thanks a lot for all your help and have a good one!

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  • Input array is longer than the number of columns in this table

    - by Adam
    I've recently started to use SQLite and began to integrate it into a C# project I'm working on. However, randomly my project will throw the exception: Input array is longer than the number of columns in this table I'm having a hard time trying the trace the problem because it seems to be thrown on a random basis. DataTable table = new DataTable(); //exception is thrown here table = Global.db.ExecuteQuery("SELECT * FROM vm_manager"); Some of the data that gets returned from this query is as follows: http://i.imgur.com/9rlLN.png If anyone has any advice, I'd be grateful. EDIT: I'm unable to show the execute query function as it resides inside a dll from the following sql lite wrapper http://www.codeproject.com/KB/database/cs_sqlitewrapper.aspx

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  • Regular Expression for finding phone numbers

    - by Rocky
    Hello Everyone, I am new to Stackoverflow and I have a quick question. Let's assume we are given a large number of HTML files (large as in theoretically infinite). How can I use Regular Expressions to extract the list of Phone Numbers from all those files? Explanation/expression will be really appreciated. The Phone numbers can be any of the following formats: (123) 456 7899 (123).456.7899 (123)-456-7899 123-456-7899 123 456 7899 1234567899 Thanks a lot for all your help and have a good one!

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  • Using the mpz_powm functions from the GMP/MPIR libraries with negative exponents

    - by Mihai Todor
    Please consider the following code: mpz_t x, n, out; mpz_init_set_ui(x, 2UL); mpz_init_set_ui(n, 7UL); mpz_init(out); mpz_invert(out, x, n); gmp_printf ("%Zd\n", out);//prints 4. 2 * 4 (mod 7) = 1. OK mpz_powm_ui(out, x, -1UL, n);//prints 1. 2 * 1 (mod 7) = 2. How come? gmp_printf ("%Zd\n", out); mpz_clear(x); mpz_clear(n); mpz_clear(out); I am unable to understand how the mpz_powm functions handle negative exponents, although, according to the documentation, it is supposed to support them. I would expect that raising a number to -1 modulo n is equivalent to inverting it modulo n. What am I missing here?

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  • Unique serial number in a java web application.

    - by Zenzen
    I've been wondering what's the correct practice for generating unique ids? The thing is in my web app I'll have a plugin system, when a user registers a plugin I want to generate a unique serial ID for it. I've been thinking about storing all numbers in a DB or a file on the server, generating a random number and checking whether it already exists in the DB/file, but that doesn't seem that good. Are there other ways to do it? Would using the UUID be the preferred way to go?

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  • Actionscript NetStream.play drops port in relative URLs

    - by Steve Middleton
    Hi, the current page my flash application is running from is http://localhost:3000/. I'm trying to play a video using NetStream.play(relativeURL) by using a relative URL (e.g. "myVideo.flv"), but when I look at the actual request made by actionscript, it's dropping the port number. (e.g. http://localhost/myVideo.flv). Is there something I can do on the flash side to make this work? Is anyone else having this problem?

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