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  • Maths: Determining angle in 3D space

    - by 742
    I hope this is the proper location to ask this question which is the same as this one, but expressed as pure math instead of graphically (at least I hope I translated the problem to math correctly). Considering: two vectors that are orthogonal: Up (ux, uy, uz) and Look (lx, ly, lz) a plane P which is perpendicular to Look (hence including Up) Y1 which is the projection of Y (vertical axis) along Look onto P Question: what is the value of the angle between Y1 and Up? As mathematicians will agree, this is a very basic question, but I've been scratching my head on walls now for at least two weeks without being able to visualize the solution... maybe now too old for finding solutions to school exercises. I'm looking for the scalar trigonometric solution, not a solution using a matrix. Thanks.

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  • How do we, as a community, help encourage programming in public schools? (Or state Schools for the U

    - by NoMoreZealots
    PRIMARY MOTIVATION My office gets involved with the "First Robotics" competitions and one thing that lingers year to year is the students typically have no preparation for doing even simple programming as part of the public schools system. While the science classes provide some basic grasp of mechanical and electrical concepts, by in large computer programming gets no coverage from the curriculum. (This my be different in other areas of the country/world.) What makes it worse is there is only a short period of time you have to prepare the student's and help them design the robot. Talking to some professors from local colleges, it's a problem because you can't assume even the most basic understanding for freshman CS majors. Languages like Python, Lua and BASIC are simple enough for at least high school level students, if not younger. SCOPE So how do you get public schools to support a programming, at least to the level of "Try it in BASIC" examples that used to be at the end of a chapter in my Algebra book? At least enough to prepare them for event's such as the FIRST Robotic competitions. Which the primary objectives are to teach problem solving and team work, and to possible foster an interest in Math, Science and Engineering in general. (Not force feed to them, as some people her seem to be implying.) Edit: Why teach kids: (Since 2000 CS enrollment in US colleges has decreased by 70% while college enrollment has increased, this is a PROBLEM.) Saying there is no value in teaching someone programming in Jr./High school because they might think "they know programming." Is like saying there's no value in teaching High school science and physics, because they might decide they "know physics." Leading to abuse like: "I passed a high school physics class, I'm going to develop a Unified Quantum Gravitational Theory." Better Prepared students are better students. Instead it would allows college programs to raise the bar on the entry level courses, allowing students to be weeded out based on their understanding of more advanced material. Plus people who did poorly in that in topic in High school aren't as likely to say "I think there's money in computer's so I'll computer science." Plus if people take it in high school and decide THEN that it's not for them, it's better than them wasting their money to PAY a college to figure that out. The result is that people who take the degree are more likely to succeed and be there for the RIGHT reasons. (i.e. It's what they REALLY want to do. And that's REALLY the key to being good at anything.) Programming is like anything else, the more practice and genuine interest you have the better you get. If you start them later, they get less practice. The earlier give them the opportunity to start, the more practice they will get. All other things equal, the more practice the better the programmer.

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  • ASP.Net 4.0 - Response required in SiteMap building?

    - by Nick Craver
    I'm running into an issue upgrading a project to .Net 4.0...and having trouble finding any reason for the issue (or at least, the change causing it). Given the freshness of 4.0, not a lot of blogs out there for issues yet, so I'm hoping someone here has an idea. Preface: this is a Web Forms application, coming from 3.5 SP1 to 4.0. In the Application_Start event we're iterating through the SiteMap and constructing routes based off data there (prettifying URLs mostly with some utility added), that part isn't failing though...or at least isn't not getting that far. It seems that calling the SiteMap.RootNode (inside application_start) causes 4.0 to eat it, since the XmlSiteMapProvider.GetNodeFromXmlNode method has been changed, looking in reflector you can see it's hitting HttpResponse.ApplyAppPathModifier here: str2 = HttpContext.Current.Response.ApplyAppPathModifier(str2); HttpResponse wasn't used at all in this method in the 2.0 CLR, so what we had worked fine, in 4.0 though, that method is called as a result of this stack: [HttpException (0x80004005): Response is not available in this context.] System.Web.XmlSiteMapProvider.GetNodeFromXmlNode(XmlNode xmlNode, Queue queue) System.Web.XmlSiteMapProvider.ConvertFromXmlNode(Queue queue) System.Web.XmlSiteMapProvider.BuildSiteMap() System.Web.XmlSiteMapProvider.get_RootNode() System.Web.SiteMap.get_RootNode() Since Response isn't available here in 4.0, we get an error. To reproduce this, you can narrow the test case down to this in global: protected void Application_Start(object sender, EventArgs e) { var s = SiteMap.RootNode; //Kaboom! //or just var r = Context.Response; //or var r = HttpContext.Current.Response; //all result in the same "not available" error } Question: Am I missing something obvious here? Or, is there another event added in 4.0 that's recommended for anything related to SiteMap on startup? For anyone curious/willing to help, I've created a very minimal project (a default VS 2010 ASP.Net 4.0 site, all the bells & whistles removed and only a blank sitemap and the Application_Start code added). It's a small 10kb zip available here: http://www.ncraver.com/Test/SiteMapTest.zip Update: Not a great solution, but the current work-around is to do the work in Application_BeginRequest, like this: private static bool routesRegistered = false; protected void Application_BeginRequest(object sender, EventArgs e) { if (!routesRegistered) { Application.Lock(); if (!routesRegistered) RouteManager.RegisterRoutes(RouteTable.Routes); routesRegistered = true; Application.UnLock(); } } I don't like this particularly, feels like an abuse of the event to bypass the issue. Does anyone have at least a better work-around, since the .Net 4 behavior with SiteMap is not likely to change?

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  • Obfuscate strings in Python

    - by Caedis
    I have a password string that must be passed to a method. Everything works fine but I don't feel comfortable storing the password in clear text. Is there a way to obfuscate the string or to truly encrypt it? I'm aware that obfuscation can be reverse engineered, but I think I should at least try to cover up the password a bit. At the very least it wont be visible to a indexing program, or a stray eye giving a quick look at my code. I am aware of pyobfuscate but I don't want the whole program obfuscated, just one string and possibly the whole line itself where the variable is defined. Target platform is GNU Linux Generic (If that makes a difference)

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  • Is a successor for TeX/LaTeX in sight?

    - by Mnementh
    TeX/LaTeX is great, I use it in many ways. Some of it's advantages are: it uses text files, this way the input-files can be diffed and many tools exist to work with text it is very flexible it has a stable layout: if I change something at the start of the document, it doesn't affect other things at the end of the document it has many extensions to reach different goals (a successor would start without extensions, but would have a good extension-system) you can use standard build control tools to support complicated documents (thanks dmckee) you can encapsulate solutions and copy&paste them to new documents or send them to others to learn from (thanks dmckee) But on the other hand some little things are not so good: it is hard to learn at the beginning it is complicated to control position of images a few things are a little counter-intuitive sometimes you have to type too much (begin{itemize} ... \end{itemize}) So, does there exist a successor/alternative to LaTeX or at least is some hot candidate for an alternative in development. A real successor/good alternative would keep the advantages and fix the disadvantages, or at least some of them.

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  • ASP.NET plug-in architecture, settings problem

    - by Xaqron
    I want to divide business layer (BLL) of an asp.net application into multiple components. Each component is a .NET class library which is compiled as a standalone DLL. These components should have their own configuration files. For example "MyNameSpace.Users.dll" contains classes about users of the website and there's a password policy to check if password length is at least x characters. When webmaster edits the config file of this DLL and set x to y then component (DLL) should use new value (y) in the future and enforce passwords to be at least y characters. I want each component as a single project and compile them separaely (and not to put all projects in a solution in Visual Studio), and put the DLLs of these libraries into the "Bin" folder of my ASP.NET application. Is it possible ? Where should I put these config files ?

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  • What is more interesting or powerful: Curry/Mercury/Lambda-Prolog/your suggestion.

    - by Bubba88
    Hi! I would like to ask you about what formal system could be more interesting to implement from scratch/reverse engineer. I've looked through some existing and rather open (open in the sense of free/open-source) projects of logical/declarative programming systems. I've decided to make up something similar in my free time, or at least to catch the general idea of implementation. It would be great if some of these systems would provide most of the expressive power and conciseness of modern academic investigations in logic and it's relation with computational models. What would you recommend to study at least at the conceptual level? For example, Lambda-Prolog is interesting particularly because it allows for higher order relations, but AFAIK (I might really be mistaken :)) is based on intuitionist logic and therefore lack the excluded-middle principle; that's generally a disatvantage for me.. I would also welcome any suggestions about modern logical programming systems which are less popular but more expressive/powerful. I guess, this question will need refactoring, but thank you in advance! :)

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  • MVC 3 Remote Validation jQuery error on submit

    - by Richard Reddy
    I seem to have a weird issue with remote validation on my project. I am doing a simple validation check on an email field to ensure that it is unique. I've noticed that unless I put the cursor into the textbox and then remove it to trigger the validation at least once before submitting my form I will get a javascript error. e[h] is not a function jquery.min.js line 3 If I try to resubmit the form after the above error is returned everything works as expected. It's almost like the form tried to submit before waiting for the validation to return or something. Am I required to silently fire off a remote validation request on submit before submitting my form? Below is a snapshot of the code I'm using: (I've also tried GET instead of POST but I get the same result). As mentioned above, the code works fine but the form returns a jquery error unless the validation is triggered at least once. Model: public class RegisterModel { [Required] [Remote("DoesUserNameExist", "Account", HttpMethod = "POST", ErrorMessage = "User name taken.")] [Display(Name = "User name")] public string UserName { get; set; } [Required] [Display(Name = "Firstname")] public string Firstname { get; set; } [Display(Name = "Surname")] public string Surname { get; set; } [Required] [Remote("DoesEmailExist", "Account", HttpMethod = "POST", ErrorMessage = "Email taken.", AdditionalFields = "UserName")] [Display(Name = "Email address")] public string Email { get; set; } [StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 8)] [DataType(DataType.Password)] [Display(Name = "Password")] public string Password { get; set; } [StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 8)] [DataType(DataType.Password)] [Display(Name = "Confirm password")] public string ConfirmPassword { get; set; } [Display(Name = "Approved?")] public bool IsApproved { get; set; } } public class UserRoleModel { [Display(Name = "Assign Roles")] public IEnumerable<RoleViewModel> AllRoles { get; set; } public RegisterModel RegisterUser { get; set; } } Controller: // POST: /Account/DoesEmailExist // passing in username so that I can ignore the same email address for the same user on edit page [HttpPost] public JsonResult DoesEmailExist([Bind(Prefix = "RegisterUser.Email")]string Email, [Bind(Prefix = "RegisterUser.UserName")]string UserName) { var user = Membership.GetUserNameByEmail(Email); if (!String.IsNullOrEmpty(UserName)) { if (user == UserName) return Json(true); } return Json(user == null); } View: <script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script> <script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.8.17/jquery-ui.min.js" type="text/javascript"></script> <script type="text/javascript" src="/Content/web/js/jquery.unobtrusive-ajax.min.js"></script> <script type="text/javascript" src="/Content/web/js/jquery.validate.min.js"></script> <script type="text/javascript" src="/Content/web/js/jquery.validate.unobtrusive.min.js"></script> ...... @using (Html.BeginForm()) { @Html.AntiForgeryToken() <div class="titleh"> <h3>Edit a user account</h3> </div> <div class="body"> @Html.HiddenFor(model => model.RegisterUser.UserName) @Html.Partial("_CreateOrEdit", Model) <div class="st-form-line"> <span class="st-labeltext">@Html.LabelFor(model => model.RegisterUser.IsApproved)</span> @Html.RadioButtonFor(model => model.RegisterUser.IsApproved, true, new { @class = "uniform" }) Active @Html.RadioButtonFor(model => model.RegisterUser.IsApproved, false, new { @class = "uniform" }) Disabled <div class="clear"></div> </div> <div class="button-box"> <input type="submit" name="submit" value="Save" class="st-button"/> @Html.ActionLink("Back to List", "Index", null, new { @class = "st-clear" }) </div> </div> } CreateEdit Partial View @model Project.Domain.Entities.UserRoleModel <div class="st-form-line"> <span class="st-labeltext">@Html.LabelFor(m => m.RegisterUser.Firstname)</span> @Html.TextBoxFor(m => m.RegisterUser.Firstname, new { @class = "st-forminput", @style = "width:300px" }) @Html.ValidationMessageFor(m => m.RegisterUser.Firstname) <div class="clear"></div> </div> <div class="st-form-line"> <span class="st-labeltext">@Html.LabelFor(m => m.RegisterUser.Surname)</span> @Html.TextBoxFor(m => m.RegisterUser.Surname, new { @class = "st-forminput", @style = "width:300px" }) @Html.ValidationMessageFor(m => m.RegisterUser.Surname) <div class="clear"></div> </div> <div class="st-form-line"> <span class="st-labeltext">@Html.LabelFor(m => m.RegisterUser.Email)</span> @Html.TextBoxFor(m => m.RegisterUser.Email, new { @class = "st-forminput", @style = "width:300px" }) @Html.ValidationMessageFor(m => m.RegisterUser.Email) <div class="clear"></div> </div> Thanks, Rich

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  • More interactive ZODB packing

    - by Mikko Ohtamaa
    Hi, Current ZMI management "Pack database" functionality is little rough. 1) Could it be possible to have some kind of progress indicator for web UI? E.g. one telling how many minutes/hours are left giving at least some kind of estimate 2) How does ZODB packing affect the responsivity of the site? Are all transactions blocked? 3) Any command line scripts with progress indicator available so you could do this from a ZEO command line client? 4) At least some kind of log markers to logout output... [INFO] 30% done... 3:15 to go

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  • JQuery: Specify placement of error messages inline using Metadata and Validate plugins

    - by jalperin
    I'm doing form validation using JQuery with the validate and metadata plugins. I'm using the metadata plugin so I can specify the rules and messages inline in the html form instead of in the javascript in the page . I'm getting an error when I try to specify the location of the error message using errorPlacement. (If I specify it in the section it works fine, but not if I specify it inline.) Here's what my html looks like: <input name="list" id="list1" type="checkbox" validate="{required:true, minlength:1, messages:{required:'Please select at least one newsletter.', minlength:'Please select at least one newsletter.'}, errorPlacement: function(error, element) { error.appendTo('#listserror');} }"> As reported by the validate debug function, the error is: "error.appendTo is not a function." It works fine if I specify it in the section like this: $().ready(function() { $("#subscribeForm").validate({ errorPlacement: function(error, element) { if (element.attr("name") == "list" ) error.appendTo("#listserror"); else error.insertAfter(element); } }); });

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  • IIS 6 session timing out a lot quicker than expected

    - by Echiban
    I am working with an web application that has its sessions timing out a lot quicker than expected. We expected a timeout of 15 minutes but it's timing out at 3-4 minutes. Info about environment: IIS6 classic ASP / COM+ app timeout OK on current PROD, much quicker in dev / QA environments We already disabled app pool recycling, and even put IIS in isolation mode - no effect HTTP err log doesn't display any lines when session times out We've done a close comparison of PROD and DEV / QA environments, and given we use virtual machines on all of them, settings should be preserved. I tried to find IIS blog notes from David Wang but many of them now have HTTP 404 errors, and I don't know what else to do. Please help! At the very least, is there a way to get IIS to log every time a session expires? At the very least some means of logging / debugging IIS would be useful. Thanks in advance.

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  • 3D Math: Calculate Bank (Roll) angle from Look and Up orthogonal vectors

    - by 742
    I hope this is the proper location to ask this question which is the same as this one, but expressed as pure math instead of graphically (at least I hope I translated the problem to math correctly). Considering: two vectors that are orthogonal: Up (ux, uy, uz) and Look (lx, ly, lz) a plane P which is perpendicular to Look (hence including Up) Y1 which is the projection of Y (vertical axis) along Look onto P Question: what is the value of the angle between Y1 and Up? As mathematicians will agree, this is a very basic question, but I've been scratching my head for at least two weeks without being able to visualize how to project Y onto P... maybe now too old for finding solutions to school exercises. I'm looking for the trigonometric solution, not a solution using a matrix. Thanks.

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  • Articles about replication schemes/algorithms?

    - by jkff
    I'm designing an hierarchical distributed system (every node has zero or more "master" nodes to which it propagates its current data). The data gets continuously updated and I'd like to guarantee that at least N nodes have almost-current data at any given time. I do not need complete consistency, only eventual consistency (t.i. for any time instant, the current snapshot of data should eventually appear on at least N nodes. It is tricky to define the term "current" here, but still). Nodes may fail and go back up at any moment, and there is no single "central" node. O overflowers! Point me to some good papers describing replication schemes. I've so far found one: Consistency Management in Optimistic Replication Algorithms

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  • Quering distinct values throught related model

    - by matheus.emm
    Hi! I have a simple one-to-many (models.ForeignKey) relationship between two of my model classes: class TeacherAssignment(models.Model): # ... some fields year = models.CharField(max_length=4) class LessonPlan(models.Model): teacher_assignment = models.ForeignKey(TeacherAssignment) # ... other fields I'd like to query my database to get the set of distinct years of TeacherAssignments related to at least one LessonPlan. I'm able to get this set using Django query API if I ignore the relation to LessonPlan: class TeacherAssignment(models.Model): # ... model's fields def get_years(self): year_values = self.objects.all().values_list('year').distinct().order_by('-year') return [yv[0] for yv in year_values if len(yv[0]) == 4] Unfortunately I don't know how to express the condition that the TeacherAssignment must be related to at least one LessonPlan. Any ideas how I'd be able to write the query? Thanks in advance.

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  • How, exactly, does the double-stringize trick work?

    - by Peter Hosey
    At least some C preprocessors let you stringize the value of a macro, rather than its name, by passing it through one function-like macro to another that stringizes it: #define STR1(x) #x #define STR2(x) STR1(x) #define THE_ANSWER 42 #define THE_ANSWER_STR STR2(THE_ANSWER) /* "42" */ Example use cases here. This does work, at least in GCC and Clang (both with -std=c99), but I'm not sure how it works in C-standard terms. Is this behavior guaranteed by C99? If so, how does C99 guarantee it? If not, at what point does the behavior go from C-defined to GCC-defined?

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  • how to store dynamically generated pages in html?

    - by Dharmik Bhandari
    I'm working on ASP.net MVC3 Web application that is facing scalability issue. For improving performance I want to store dynamically generated pages in html and serve them from generated html directly rather then querying database for each page request. I'm sure this will dramatically increase performance. Can any one share any hint / example / tutorial on how to do it? And what are challenges? I would also like to know how others are handling performance issue for large e-commerce sites with at-least thousand categories and 200k products with at least 200-500 concurrent visitors? What are the best approaches? Thanks in advance.

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  • Other SecurityManager implementations available?

    - by mhaller
    Is there any other implementation (e.g. in an OSS project) of a Java SecurityManager available which has more features than the one in the JDK? I'm looking for features like configurable at runtime policies updateable at runtime, read from other data sources than a security.policy file Thread-aware, e.g. different policies per Thread Higher-level policies, e.g. "Disable network functions, but allow JDBC traffic" Common predefined policies, e.g. "Allow read-access to usual system properties like file.encoding or line.separator, but disallow read-access to user.home" Monitoring and audit trace logging, e.g. "Log all file access, log all network access going NOT to knownhost.example.org" Blocking jobs "requesting" a permission until an administrator grants permission, letting the thread/job continue ... I'm pretty sure that application servers (at least the commercial ones) have their own SecurityManager implementation or at least their own policy configuration. I'm wondering if there is any free project with similar requirements.

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  • Implementing simple business model in Haskell

    - by elmes
    Supose we have a very simple model: Station has at least one Train Train has at least two Stations The model has to allow to check what stations any given train visits and to check what trains visit a particular station. How to model it in Haskell? I am a Haskell newbie, so please correct me: once an object is created, you cannot modify it - you can only make a new object based on that one (~immutability). Am I right? If so, I'll have to create a lot of temporary variables with semi-initialized objects (during deserialization or even in unit tests). Basically what I need is an example of modeling domain classes in Haskell - after reading "Learn you a haskell.." I still have no idea how to use this language.

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  • Finding the best jquery plugins

    - by Lan
    Is there a resource for finding the "best" jquery plugins, or at least just the most used ones? For example, I wanted to find a menu jquery plugin but when I goto the jquery website there are so many to look through and I don't see a way to see how popular each one is. For ruby there's the http://ruby-toolbox.com/ which lists many plugins, how popular they are, info about them, etc. Is there something similar or at least some way to filter through all the jquery plugins? EDIT 1: To shed some more light on this - the "most popular" link on the jquery page is useless. I can't find a way to search through it but even worse, the ratings don't seem to mean much. Ex - the first item, in other words the most popular plugin in that list has 5 stars and TWO votes. Doesn't seem like a very reliable resource to me.

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  • How can a large number of developers write software without either a cumbersome process or poor qual

    - by Mark Robinson
    I work at a company with hundreds of people writing software for essentially the same product. The quality of the software has to be high because so many people depend on it (not least the developers themselves). Because of this every major issue has resulted in a new check - either automated or manual. As a result the process of delivering software is becoming ever more burdensome. So that requires more developers which... well you can see it is a vicious circle. We now have a problem with releasing software quickly - the lead time even to change one line of code for a very serious issue is at least one day. What techniques do you use to speed up the delivery of software in a large organization, while still maintaining software quality?

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  • Help with Oracle SQL Count function! =)

    - by user363024
    Hi guys.. The question im struggling with is this: i have a list of helicopter names in different charters and i need to find out WHICH helicopter has the least amount of charters booked. Once i find that out i need to ONLY display the one that has the least. I so far have this: SELECT Helicopter_Name COUNT (Distinct Charter_NUM) FROM Charter_Table GROUP BY Helicopter Name ^ this is where i am stuck, i realise MIN could be used to pick out the value that is the smallest but i am not sure how to integrate this into the command. Something like Where MIN = MIN Value Id really appreciate it

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  • Checking for uppercase/lowercase/numbers with Jquery

    - by user1725794
    Either I'm being really retarded here or its just the lack of sleep but why doesn't this work? If I use the "or" operator it works for each separate test but as soon as it change it to the "and" operator it stops working. I'm trying to test the password input of a form to see if its contains lowercase, uppercase and at least 1 number of symbol. I'm having a lot of trouble with this so help would be lovely, here is the code I have. var upperCase= new RegExp('[^A-Z]'); var lowerCase= new RegExp('[^a-z]'); var numbers = new RegExp('[^0-9]'); if(!$(this).val().match(upperCase) && !$(this).val().match(lowerCase) && !$(this).val().match(numbers)) { $("#passwordErrorMsg").html("Your password must be between 6 and 20 characters. It must contain a mixture of upper and lower case letters, and at least one number or symbol."); } else { $("#passwordErrorMsg").html("OK") }

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  • MySQL query : all records of one table plus count of another table

    - by Ricardo
    Hello Guys! I have 2 tables: User and Picture. The Picture table has the key of the user. So basically each user can have multiple pictures, and each picture belongs to one user. Now, I am trying to make the following query: I want to select all the user info plus the total number of pictures that he has (even if it's 0). How can I do that? Probably it sounds quite simple, but I am trying and trying and can't seem to find the right query. The only thing I could select is this info, but only for users that have at least 1 picture, meaning that the Pictures table has at least one record for that key... But I also wanna consider the users that don't have any. Any idea? Thanks!

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