Search Results

Search found 42453 results on 1699 pages for 'question'.

Page 130/1699 | < Previous Page | 126 127 128 129 130 131 132 133 134 135 136 137  | Next Page >

• DialogFX: A New Approach to JavaFX Dialogs

  - by HecklerMark

  How would you like a quick and easy drop-in dialog box capability for JavaFX? That's what I was thinking when a weekend presented itself. And never being one to waste a good weekend...  :-) After doing some "roll-your-own" basic dialog building for a JavaFX app, I recently stumbled across Anton Smirnov's work on GitHub. It was a good start, but it wasn't exactly what I was after, and ideas just kept popping up of things I'd do differently. I wanted something a bit more streamlined, a bit easier to just "drop in and use". And so DialogFX was born. DialogFX wasn't intended to be overly fancy, overly clever - just useful and robust. Here were my goals: Easy to use. A dialog "system" should be so simple to use a new developer can drop it in quickly with nearly no learning curve. A seasoned developer shouldn't even have to think, just tap in a few lines and go. Why should dialogs slow "actual development"?  :-) Defaults. If you don't specify something (dialog type, buttons, etc.), a good dialog system should still work. It may not be pretty, but it shouldn't throw gears. Sharable. It's all open source. Even the icons are in the commons, so they can be reused at will. Let's take a look at some screen captures and the code used to produce them.   DialogFX INFO dialog Screen captures Windows Mac  Sample code         DialogFX dialog = new DialogFX();        dialog.setTitleText("Info Dialog Box Example");        dialog.setMessage("This is an example of an INFO dialog box, created using DialogFX.");        dialog.showDialog(); DialogFX ERROR dialog Screen captures Windows Mac  Sample code         DialogFX dialog = new DialogFX(Type.ERROR);        dialog.setTitleText("Error Dialog Box Example");        dialog.setMessage("This is an example of an ERROR dialog box, created using DialogFX.");        dialog.showDialog(); DialogFX ACCEPT dialog Screen captures Windows Mac  Sample code         DialogFX dialog = new DialogFX(Type.ACCEPT);        dialog.setTitleText("Accept Dialog Box Example");        dialog.setMessage("This is an example of an ACCEPT dialog box, created using DialogFX.");        dialog.showDialog(); DialogFX Question dialog (Yes/No) Screen captures Windows Mac  Sample code         DialogFX dialog = new DialogFX(Type.QUESTION);        dialog.setTitleText("Question Dialog Box Example");        dialog.setMessage("This is an example of an QUESTION dialog box, created using DialogFX. Would you like to continue?");        dialog.showDialog(); DialogFX Question dialog (custom buttons) Screen captures Windows Mac  Sample code         List<String> buttonLabels = new ArrayList<>(2);        buttonLabels.add("Affirmative");        buttonLabels.add("Negative");         DialogFX dialog = new DialogFX(Type.QUESTION);        dialog.setTitleText("Question Dialog Box Example");        dialog.setMessage("This is an example of an QUESTION dialog box, created using DialogFX. This also demonstrates the automatic wrapping of text in DialogFX. Would you like to continue?");        dialog.addButtons(buttonLabels, 0, 1);        dialog.showDialog(); A couple of things to note You may have noticed in that last example the addButtons(buttonLabels, 0, 1) call. You can pass custom button labels in and designate the index of the default button (responding to the ENTER key) and the cancel button (for ESCAPE). Optional parameters, of course, but nice when you may want them. Also, the showDialog() method actually returns the index of the button pressed. Rather than create EventHandlers in the dialog that really have little to do with the dialog itself, you can respond to the user's choice within the calling object. Or not. Again, it's your choice.  :-) And finally, I've Javadoc'ed the code in the main places. Hopefully, this will make it easy to get up and running quickly and with a minimum of fuss. How Do I Get (Git?) It? To try out DialogFX, just point your browser here to the DialogFX GitHub repository and download away! Please take a look, try it out, and let me know what you think. All feedback welcome! All the best, Mark 

  Read the article

• SQL SERVER – Replace a Column Name in Multiple Stored Procedure all together

  - by pinaldave

  I receive a lot of emails every day. I try to answer each and every email and comments on Facebook and Twitter. I prefer communication on social media as this gives opportunities to others to read the questions and participate along with me. There is always some question which everyone likes to read and remember. Here is one of the questions which I received in email. I believe the same question will be there any many developers who are beginning with SQL Server. I decided to blog about it so everyone can read it and participate. “I am beginner in SQL Server. I have a very interesting situation and need your help. I am beginner to SQL Server and that is why I do not have access to the production server and I work entirely on the development server. The project I am working on is also in the infant stage as well. In product I had to create a multiple tables and every table had few columns. Later on I have written Stored Procedures using those tables. During a code review my manager has requested to change one of the column which I have used in the table. As per him the naming convention was not accurate. Now changing the columname in the table is not a big issue. I figured out that I can do it very quickly either using T-SQL script or SQL Server Management Studio. The real problem is that I have used this column in nearly 50+ stored procedure. This looks like a very mechanical task. I believe I can go and change it in nearly 50+ stored procedure but is there a better solution I can use. Someone suggested that I should just go ahead and find the text in system table and update it there. Is that safe solution? If not, what is your solution. In simple words, How to replace a column name in multiple stored procedure efficiently and quickly? Please help me here with keeping my experience and non-production server in mind.” Well, I found this question very interesting. Honestly I would have preferred if this question was asked on my social media handles (Facebook and Twitter) as I am very active there and quite often before I reach there other experts have already answered this question. Anyway I am now answering the same question on the blog so all of us can participate here and come up with an appropriate answer. Here is my answer - “My Friend, I do not advice to touch system table. Please do not go that route. It can be dangerous and not appropriate. The issue which you faced today is what I used to face in early career as well I still face it often. There are two sets of argument I have observed – there are people who see no value in the name of the object and name objects like obj1, obj2 etc. There are sets of people who carefully chose the name of the object where object name is self-explanatory and almost tells a story. I am not here to take any side in this blog post – so let me go to a quick solution for your problem. Note: Following should not be directly practiced on Production Server. It should be properly tested on development server and once it is validated they should be pushed to your production server with your existing deployment practice. The answer is here assuming you have regular stored procedures and you are working on the Development NON Production Server. Go to Server Note >> Databases >> DatabaseName >> Programmability >> Stored Procedure Now make sure that Object Explorer Details are open (if not open it by clicking F7). You will see the list of all the stored procedures there. Now you will see a list of all the stored procedures on the right side list. Select either all of them or the one which you believe are relevant to your query. Now… Right click on the stored procedures >> SELECT DROP and CREATE to >> Now select New Query Editor Window or Clipboard. Paste the complete script to a new window if you have selected Clipboard option. Now press Control+H which will bring up the Find and Replace Screen. In this screen insert the column to be replaced in the “Find What”box and new column name into “Replace With” box. Now execute the whole script. As we have selected DROP and CREATE to, it will created drop the old procedure and create the new one. Another method would do all the same procedure but instead of DROP and CREATE manually replace the CREATE word with ALTER world. There is a small advantage in doing this is that if due to any reason the error comes up which prevents the new stored procedure to be created you will have your old stored procedure in the system as it is. “ Well, this was my answer to the question which I have received. Do you see any other workaround or solution? Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Stored Procedure, SQL Tips and Tricks, T SQL, Technology

  Read the article

• How to mark posts as edited?

  - by user156814

  I would like to have questions marked as "Edited", but I dont know what the best way to do this would be. Users post a question, people answer/comment on the question, and if necessary the user edits/updates the question (just like SO). I would like to note that the user edited the question, but I'm not sure of the best way to do this. I was going to add a last_edited column in the table (because thats all thats really important to me), but I'm not sure if I should just split the edit times (and whatever else) into another table and record everytime the question gets edited.

  Read the article

• SQL SERVER – Weekly Series – Memory Lane – #032

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function.  2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Interviewing - convincing young interviewers that my experience matters [closed]

  - by ritu

  As requested, I split this question from a two part question I asked at http://stackoverflow.com/questions/2482071/modern-web-development-general-question My question is how do i convince the young programmers who interview me that my years of system programming experience, MFC, Win32 programming are still relevant and I should not be automatically rejected because I don't know the differences between Drupal and <pick your technology>. It seems like I can ask a dozen question that these guys won't be able to answer but somehow because I don't know the latest fad counts against me. I do read, but if you don't use what you read in your daily work, you will never have expert knowledge of it. So bottom line: is the only way for me to take a .NET or Java job is for me to start at the bottom all over?

  Read the article

• Best 3D Graphics Engine for .NET

  - by George Stocker

  I've been thinking about tinkering with 3D graphics programming in .NET. In the past, I've thought about Truevision3D, and XNA, but I've not used either of these. I scanned Stackoverflow for the exact question, but neither of the (almost) relevant question (such as this question about rendering graphics, and this question about Learning Game Programming) answer my specific question. Out of the graphics engine APIs you've used for .NET, which is the easiest to use, which has the most features, and which is the cheapest? Which would you recommend for a .NET programmer to learn first?

  Read the article

• rails nested attributes

  - by user342798

  I am using rails 3.0.0.beta3 and I am trying to implement form with nested attributes using :accepts_nested_attributes_for. My form is nested to three levels: Survey Question Answer. Survey has_many Questions, and Question has many Answers. Inside the Survey model, there is :accepts_nested_attributes_for :questions and inside the question mode, there is :accepts_nested_attributes_for :answers Everything is working fine except when I add a new answer to an existing question, it doesn't get created. However, if I make changes to the corresponding question while creating the answer, I can successfully create the answer. This example is exactly similar to a railscast: http://railscasts.com/episodes/197-nested-model-form-part-2 but doesn't work in rails3 (at least in my case). Please let me know if there is any issue with nested attributes in Rails 3. Thanks in advance.

  Read the article

• Is it a good idea to cache data from web services into a database?

  - by Thierry Lam

  Let's assume that Stackoverflow offers web services where you can retrieve all the questions asked by a specific user. A request to get all question from user A can result in the following json output: { { "question": "What is rest?", "date_created": "20/02/2010", "votes": 1, }, { "question": "Which database to use for ...", "date_created": "20/07/2009", "votes": 5, }, } If I want to manipulate and present the data in any ways that I want, will it be wise to dump it in a local database? At some point, I will also want to retrieve all answers for each question and store them in a local database. The workflow that I'm thinking is: User logs in. Web services retrieve all questions asked by the logged in user, dump them in a local database. User wants all answers for a specific question, another web service does the retrieval and dump them in a local database. After user logs out, delete from the local database all questions and answers from that user.

  Read the article

• Recursive Syntax in Oslo

  - by Kevin Lawrence

  I'm writing my first DSL with Oslo and I am having a problem with a recursive syntax definition. The input has sections which can contain questions or other sections recursively (composite pattern) like this: Section: A Question: 1 Question: 2 Section: B Question: 1 End End My definition for a Section looks like this syntax Section = "Section:" id:Text body:(SectionBody)* "End Section"; Which works (but doesn't handle recursive sections) if I define SectionBody like this syntax SectionBody = (Question); but doesn't work with a recursive definition like this syntax SectionBody = (Question | Section); What am I missing?

  Read the article

• How do I flag only one of the formsets in django admin ?

  - by azuer88

  I have these (simplified) models: class Question(models.Model): question = models.CharField(max_length=60) class Choices(models.Model): question = models.ForeignKey(Question) text = models.CharField(max_length=60) is_correct = models.BooleanField(default=False) I've made Choices as an inline of Question (in admin). Is there a way to make sure that only one Choice will have is_correct = True? Ideally, is_correct will be displayed as a radio button when it is displayed in the admin formset (TabularInline). My first solution was to override the validation of the formset but did understand how to do this. (is_correct is displayed as checkbox, and I'd display an error that only one is_correct should be selected.)

  Read the article

• In an Android TextView, is it possible to insert paragraphs?

  - by johnrock

  Below is an example of the type of problem that I have. I have data in a pojo that I need to display in a textview... the data has pseudo code that denotes each paragraph with [p] I would like to somehow parse the [p]'s into paragraphs when they are displayed in the textview. Can this be done? Is there something I can substitute for the [p] that will make a new paragraph in the textview? Question question = new Question(); question.setText("Here is the first paragraph.[p] And this should be the second."); TextView view = (TextView) findViewById(R.id.qtext); view.setText(question.getParsedText());

  Read the article

• How to structure a database with questions and answers?

  - by Andreas Johannessen

  Hi I am going to make a simple application that uses a database. I could need some guidance on how to structure it. I shall make question program. What I have in mind is. One table with questions One table with the difficulity of the question One table with the category of the question However, what do I do with the answers? Have them as seperate columns in the question-table? It sounds like a bad practice.(Also, where do I have the correct answer) Each question will have 5 answers where only one of them is correct.

  Read the article

• Model Django Poll

  - by MacPython

  I followed the django tutorial here: http://docs.djangoproject.com/en/dev/intro/tutorial01/ and now I am at creating a poll. The code below works fine until I want to create choices, where for some reason I always get this error message: line 22, in unicode return self.question AttributeError: 'Choice' object has no attribute 'question' Unfortunatley, I dont understand where I made an error. Any help would be greatly appreciated. Thanks for the time! CODE: import datetime from django.db import models class Poll(models.Model): question = models.CharField(max_length=200) pub_date = models.DateTimeField('date published') def __unicode__(self): return self.question def was_published_today(self): return self.pub_date.date() == datetime.date.today() class Choice(models.Model): poll = models.ForeignKey(Poll) choice = models.CharField(max_length=200) votes = models.IntegerField() def __unicode__(self): return self.question

  Read the article

• django: Selecting questions that was not asked

  - by Oleg Tarasenko

  Hi, I am creating small django application which holds some few questions (and answers for them) What I want to do is to show user random question, but only from those which was not solved by him yet. I wonder how to do this. For now, I defined user profile model this way: class UserProfile(models.Model): rank = models.IntegerField(default = 1) solvedQ = models.ManyToManyField(Question) user = models.ForeignKey(User, unique=True) So solved problems are added this way: if user.is_authenticated(): profile = user.get_profile() profile.rank += 1 profile.solvedQ.add(Question.objects.get(id=id)) Now if the view must show random question, but not from already solved list... Is there a good way to intersect Questions and solvedQuestions.... so question is chosen from the unsolved list?

  Read the article

• Launch Webcast Q&A: Oracle WebCenter Suite 11g - The Platform for the Modern User Experience

  - by howard.beader(at)oracle.com

  Did you have a chance to watch the Oracle WebCenter Suite 11g Launch Webcast yet? Andy MacMillan presented some great information on the webcast and answered quite a few of your questions in the Q&A session as well. For your reading pleasure we have captured a number of the questions and answers and they are summarized below: Question: Can you tell me what should our Portal strategy be for integrating and extending our Oracle enterprise applications? Answer: We recommend that you look at this in two steps, the first would be to ensure that you have a good understanding of our common user experience architecture. Internally our product teams at Oracle are already investing in this quite heavily today for Fusion Applications and this is driving natural convergence from a UX strategy standpoint. The second step would be to look at how best to componentize the back office applications so that the business users across your organization can take advantage of these -- don't make it just about putting a new skin on top of what you already have from an application standpoint, instead look at how best to embed the social computing capabilities as part of the solution for your business users. Question: We are currently using the BEA WebLogic Portal now, should we stay on WLP or should we be looking at moving to WebCenter or when should we move to WebCenter? Answer: Our strategy has been called "Continue & Converge", this theme means that you can continue to use WebLogic or Plumtree portals until your organization is ready to move to WebCenter and in the mean time you can continue to deploy what you need to in your organization of WLP or WCI Portals with the full support of Oracle. In addition WebCenter Services can be leveraged for social computing to complement what you are already doing today and enable your organization to take advantage of some of the latest and greatest social computing capabilities. We have migration scripts and conversion capabilities available as well as programs where Oracle can help you evaluate your options to decide how best to move forward. WebCenter provides the best of the best capabilities and will enable you to take advantage of new capabilities that may not exist in your current portal today. In the end though it's up to you as a customer as to when you want to make the transition to Oracle WebCenter Suite. Question: Can you tell me how is Oracle leveraging WebCenter internally and for its Application and Middleware product UX strategies? Answer: Internally, Oracle is leveraging WebCenter for our employees and thus far we are seeing significant updates with our users taking advantage of the business activity streams, team spaces and collaboration capabilities. From a product strategy standpoint, our product teams are taking advantage of the common user experience architecture and leveraging WebCenter to provide social and collaborative capabilities to the Oracle Applications and providing new types of composite applications with what is coming with Fusion Applications. WebCenter also provides a common user experience across all the products in the Oracle Fusion Middleware family as well. Question: Our organization is currently using SharePoint, but we are also an Oracle Applications customer, how should we be thinking about WebCenter as we move forward? Answer: Great question. Typically, we are seeing organizations using SharePoint for its core use cases of small team collaboration and file server replacement. WebCenter can connect to SharePoint as a content source to feed into WebCenter quite easily and it leverages the robust Oracle ECM product under WebCenter as well. In addition, SharePoint team sites can be connected to WebCenter utilizing our SharePoint connector. With Oracle WebCenter though, we are really targeting business users and enterprise applications, thus affecting positive change on the processes that drive the business to improve productivity across your organization. Question: Are organizations today using WebCenter as a Web platform for externally facing public websites? Answer: Yes, we are seeing a convergence around web content management and portal types of websites with customers converting them from just broadcasting content to making it a much richer personalized experience and also exposing back-office applications as well. Web Content Management capabilities are already embedded in WebCenter so that organizations can take advantage now of the benefits a personalized web experience provides for your customers. This is simply a short summary of a few of the questions addressed on the webcast, please tune in now to learn more about Oracle WebCenter, the user experience platform for the enterprise and the web! The Oracle WebCenter Suite 11g Launch Webcast can be found here

  Read the article

• Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

  - by Mike

  EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

  Read the article

• The IOC "child" container / Service Locator

  - by Mystagogue

  DISCLAIMER: I know there is debate between DI and service locator patterns. I have a question that is intended to avoid the debate. This question is for the service locator fans, who happen to think like Fowler "DI...is hard to understand...on the whole I prefer to avoid it unless I need it." For the purposes of my question, I must avoid DI (reasons intentionally not given), so I'm not trying to spark a debate unrelated to my question. QUESTION: The only issue I might see with keeping my IOC container in a singleton (remember my disclaimer above), is with the use of child containers. Presumably the child containers would not themselves be singletons. At first I thought that poses a real problem. But as I thought about it, I began to think that is precisely the behavior I want (the child containers are not singletons, and can be Disposed() at will). Then my thoughts went further into a philosophical realm. Because I'm a service locator fan, I'm wondering just how necessary the notion of a child container is in the first place. In a small set of cases where I've seen the usefulness, it has either been to satisfy DI (which I'm mostly avoiding anyway), or the issue was solvable without recourse to the IOC container. My thoughts were partly inspired by the IServiceLocator interface which doesn't even bother to list a "GetChildContainer" method. So my question is just that: if you are a service locator fan, have you found that child containers are usually moot? Otherwise, when have they been essential? extra credit: If there are other philosophical issues with service locator in a singleton (aside from those posed by DI advocates), what are they?

  Read the article

• Passing two variables to separate table...associations problem

  - by bgadoci

  I have developed an application and I seem to be having some problems with my associations. I have the following: class User < ActiveRecord::Base acts_as_authentic has_many :questions, :dependent => :destroy has_many :sites , :dependent => :destroy end Questions class Question < ActiveRecord::Base has_many :sites, :dependent => :destroy has_many :notes, :through => :sites belongs_to :user end Sites (think of this as answers to questions) class Site < ActiveRecord::Base acts_as_voteable :vote_counter => true belongs_to :question belongs_to :user has_many :notes, :dependent => :destroy has_many :likes, :dependent => :destroy has_attached_file :photo, :styles => { :small => "250x250>" } validates_presence_of :name, :description end When a Site (answer) is created I am successfully passing the question_id to the Sites table but I can't figure out how to also pass the user_id. Here is my SitesController#create def create @question = Question.find(params[:question_id]) @site = @question.sites.create!(params[:site]) respond_to do |format| format.html { redirect_to(@question) } format.js end end

  Read the article

• Two questions on ensuring EndInvoke() gets called on a list of IAsyncResult objects

  - by RobV

  So this question is regarding the .Net IAsyncResult design pattern and the necessity of calling EndInvoke as covered in this question Background I have some code where I'm firing off potentially many asynchronous calls to a particular function and then waiting for all these calls to finish before using EndInvoke() to get back all the results. Question 1 I don't know whether any of the calls has encountered an exception until I call EndInvoke() and in the event that an exception occurs in one of the calls the entire method should fail and the exception gets wrapped into an API specific exception and thrown upwards. So my first question is what's the best way then to ensure that the remainder of the async calls get properly terminated? Is a finally block which calls EndInvoke() on the remainder of the unterminated calls (and ignores any further exceptions) the best way to do this? Question 2 Secondly when I first fire off all my asyc calls I then call WaitHandle.WaitAll() on the array of WaitHandle instances that I've got from my IAsyncResult instances. The method which is firing all these async calls has a timeout to adhere to so I provide this to the WaitAll() method. Then I test whether all the calls have completed, if not then the timeout must have been reached so the method should also fail and throw another API specific exception. So my second question is what should I do in this case? I need to call EndInvoke() to terminate all these async calls before I throw the error but at the same time I don't want the code to get stuck since EndInvoke() is blocking. In theory at least if the WaitAll() call times out then all the async calls should themselves have timed out and thrown exceptions (thus completing the call) since they are also governed by a timeout but this timeout is potentially different from the main timeout

  Read the article

• Suggestions for a django db structure

  - by rh0dium

  Hi Say I have the unknown number of questions. For example: Is the sky blue [y/n] What date were your born on [date] What is pi [3.14] What is a large integ [100] Now each of these questions poses a different but very type specific answer (boolean, date, float, int). Natively django can happily deal with these in a model. class SkyModel(models.Model): question = models.CharField("Is the sky blue") answer = models.BooleanField(default=False) class BirthModel(models.Model): question = models.CharField("What date were your born on") answer = models.DateTimeField(default=today) class PiModel(models.Model) question = models.CharField("What is pi") answer = models.FloatField() But this has the obvious problem in that each question has a specific model - so if we need to add a question later I have to change the database. Yuck. So now I want to get fancy - How do a set up a model where by the answer type conversion happens automagically? ANSWER_TYPES = ( ('boolean', 'boolean'), ('date', 'date'), ('float', 'float'), ('int', 'int'), ('char', 'char'), ) class Questions(models.model): question = models.CharField(() answer = models.CharField() answer_type = models.CharField(choices = ANSWER_TYPES) default = models.CharField() So in theory this would do the following: When I build up my views I look at the type of answer and ensure that I only put in that value. But when I want to pull that answer back out it will return the data in the format specified by the answer_type. Example 3.14 comes back out as a float not as a str. How can I perform this sort of automagic transformation? Or can someone suggest a better way to do this? Thanks much!!

  Read the article

• How do I convert a simple ruby flashcard program into a ROR app?

  - by Mark Wilbur

  What I'm trying to do is make a basic flashcard app on rails. At this point, all I'm looking for is the functionality to iterate through a list of flashcards, quiz the user and let the user know if they were right or not. In ruby, it didn't take me long to write: class Card attr_accessor :answer, :question def initialize(answer = "", question="") @answer = answer @question = question end def quiz puts "What does #@question mean?" answer = gets.chomp if answer == @answer puts "Right" return true else puts "Wrong" return answer end end end class Cardlist attr_accessor :Cards def initialize(Cards = []) @Cards = Cards end def quiz Cards.each do |w| w.quiz end end end The problem I'm having with rails is figuring out where to put the logic to loop through all the cards in the list. I've made models specifying that Card belongs_to cardlist and that Cardlist has_many cards. I know application logic should go in the controller, but if I were to make a "quiz" action for my Cardlist controller, how would I make it iterate through all the cards? After each "quiz" page generated, I'd need to get an answer back from the user, respond (maybe flash) whether it was right or not and then continue onto the next question. Would any of that logic have to go into the view in order to make sure it's sending back the user inputted answers to the controller?

  Read the article

• Problem in mutiple :dependent=> :destroy when multiple polymorphic is true

  - by piemesons

  I have four models question, answer, comment and vote.Consider it same as stackoverflow. Question has_many comments Answers has_many comments Questions has_many votes answers has_many votes comments has_many votes Here are the models (only relevant things) class Comment < ActiveRecord::Base belongs_to :commentable, :polymorphic => true has_many :votes, :as => :votable, :dependent => :destroy end class Question < ActiveRecord::Base has_many :comments, :as => :commentable, :dependent => :destroy has_many :answers, :dependent => :destroy has_many :votes, :as => :votable, :dependent => :destroy end class Vote < ActiveRecord::Base belongs_to :votable, :polymorphic => true end class Answer < ActiveRecord::Base belongs_to :question, :counter_cache => true has_many :comments, :as => :commentable , :dependent => :destroy end Now the problem is whenever i am trying to delete any question/answer/comment its giving me an error NoMethodError in QuestionsController#destroy undefined method `each' for 0:Fixnum if i remove this line from any of the model (question/answer/comment) has_many :votes, :as => :votable, :dependent => :destroy then it works perfectly. It seems there is a problem while deleting the records active record is not able to find out the proper path because of multiple joins within the tables.

  Read the article

• Error in Android's clearCheck() for RadioGroup?

  - by Manuel R. Ciosici

  I'm having an issue with RadioGroup's clearChecked(). I'm displaying a multiple choice question to the user and after the user selects an answer I check the answer, give him some feedback and then move to the next question. In the process of moving to the next question I clearCheck on the RadioGroup. Can anyone explain to me why the onCheckedChanged method is called 3 times? Once when the change actually occurs (with the user changes), once when I clearCheck(with -1 as the selected id) and once in between (with the user changes again)? As far as I could tell the second trigger is provoked by clearCheck. Code below: private void checkAnswer(RadioGroup group, int checkedId){ // this makes sure it doesn't blow up when the check is cleared // also we don't check the answer when there is no answer if (checkedId == -1) return; if (group.getCheckedRadioButtonId() == -1) return; // check if correct answer if (checkedId == validAnswerId){ score++; this.giveFeedBack(feedBackType.GOOD); } else { this.giveFeedBack(feedBackType.BAD); } // allow for user to see feedback and move to next question h.postDelayed(this, 800); } private void changeToQuestion(int questionNumber){ if (questionNumber >= this.questionSet.size()){ // means we are past the question set // we're going to the score activity this.goToScoreActivity(); return; } //clearing the check gr.clearCheck(); // give change the feedback back to question imgFeedback.setImageResource(R.drawable.question_mark); //OTHER CODE HERE } and the run method looks like this public void run() { questionNumber++; changeToQuestion(questionNumber); }

  Read the article

• Limiting a search to records from last_request_at...

  - by bgadoci

  I am trying to figure out how to display a count for records that have been created in a table since the last_request_at of a user. In my view I am counting the notes of a question with the following code: <% unless @questions.empty? %> <% @questions.each do |question| %> <%= h(question.notes.count) %> end end This is happening in the /views/users/show.html.erb file. Instead of counting all the notes for the question, I would only like to count the notes that have been created since the users last_request_at datetime. I don't neccessarily want to scope notes to display this 'new notes' count application wide, just simply in this one instance. To accomplish I am assuming I need to create a variable in the User#show action and call it in the view but not really sure how to do that. Other information you may need: class Note < ActiveRecord::Base belongs_to :user belongs_to :question end class Question < ActiveRecord::Base has_many :notes, :dependent => :destroy belongs_to :user end

  Read the article

• What’s new in IIS8, Perf, Indexing Service-Week 49

  - by OWScott

  You can find this week’s video here. After some delays in the publishing process week 49 is finally live.  This week I'm taking Q&A from viewers, starting with what's new in IIS8, a question on enable32BitAppOnWin64, performance settings for asp.net, the ARR Helper, and Indexing Services. Starting this week for the remaining four weeks of the 52 week series I'll be taking questions and answers from the viewers. Already a number of questions have come in. This week we look at five topics. Pre-topic: We take a look at the new features in IIS8. Last week Internet Information Services (IIS) 8 Beta was released to the public. This week's video touches on the upcoming features in the next version of IIS. Here’s a link to the blog post which was mentioned in the video Question 1: In a number of places (http://learn.iis.net/page.aspx/201/32-bit-mode-worker-processes/, http://channel9.msdn.com/Events/MIX/MIX08/T06), I've saw that enable32BitAppOnWin64 is recommended for performance reasons. I'm guessing it has to do with memory usage... but I never could find detailed explanation on why this is recommended (even Microsoft books are vague on this topic - they just say - do it, but provide no reason why it should be done). Do you have any insight into this? (Predrag Tomasevic) Question 2: Do you have any recommendations on modifying aspnet.config and machine.config to deliver better performance when it comes to "high number of concurrent connections"? I've implemented recommendations for modifying machine.config from this article (http://www.codeproject.com/KB/aspnet/10ASPNetPerformance.aspx - ASP.NET Process Configuration Optimization section)... but I would gladly listen to more recommendations if you have them. (Predrag Tomasevic) Question 3: Could you share more of your experience with ARR Helper? I'm specifically interested in configuring ARR Helper (for example - how to only accept only X-Forwards-For from certain IPs (proxies you trust)). (Predrag Tomasevic) Question 4: What is the replacement for indexing service to use in coding web search pages on a Windows 2008R2 server? (Susan Williams) Here’s the link that was mentioned: http://technet.microsoft.com/en-us/library/ee692804.aspx This is now week 49 of a 52 week series for the web pro. You can view past and future weeks here: http://dotnetslackers.com/projects/LearnIIS7/ You can find this week’s video here.

  Read the article

< Previous Page | 126 127 128 129 130 131 132 133 134 135 136 137  | Next Page >