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  • What methods should save/load a game state

    - by vedi
    There are a lot of articles about how to save a state of a game and they are pretty good. But I have one conceptual misunderstanding where should I save the state? My game has number of screens and pair of them are MainMenuScreen and MainSceneScreen these are inherited from Screen class. MainMenuScreen is shown at start of the game the MainSceneScreen little later. What is the problem? I navigated to MainSceneScreen, forced Android to stop the application (I change a language settings on the device to achieve it, please let me know if I'm wrong). After that I select the application again and I can see MainMenuScreen is shown. But I want MainSceneScreen to be shown. I suppose I should override resume method. But what class I should override? I have class PsGame that extends Game class of libgdx. I put breakpoints to its resume method and it turned out that method was not called. I investigated the problem and I've found little strange code in onResume method of AndroidApplication class of libgdx: if (!firstResume) graphics.resume(); else firstResume = false; My debugger said firstResume was true and didn't go to *graphics.resume()*line. Sorry for a lot of words but could you answer following question: What did I do wrong? What methods should I override? Thank you in advance.

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  • Webserver not giving the correct response on CURL and other httprequest methods [migrated]

    - by Maxim
    I am trying to make a REST request to a external webserver by using this code <?php $user = 'USER'; $pass = 'PASS'; $data = "MYDATA" $ch = curl_init('URL'); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_POSTFIELDS, $data); curl_setopt($ch, CURLOPT_HTTPHEADER, array( 'Content-Type: application/json', 'Content-Length: ' . strlen($data)) ); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($ch, CURLOPT_VERBOSE, true); if(!($res = curl_exec($ch))) { echo('[cURL Failure] ' . curl_error($ch)); } curl_close($ch); echo($res); Now this is a CURL request, however i tried different methods to test my result and they all give me a 403 forbidden error response that i get from the webserver, however i do get a 200 response when i run it on any other webserver (localhost, webserver2, ...) Therefore i think there is something wrong with my webserver and it might be disallowing/caching the post parameters that i provide because sometimes it returns a 200 response but most of the times it returns the 403. This is the response i get : HTTP/1.1 403 Forbidden Accept-Ranges: bytes Content-Type: application/json; charset=UTF-8 Date: Sat, 26 Oct 2013 13:56:37 GMT Server: Restlet-Framework/2.1.3 Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept Content-Length: 77 Connection: keep-alive {"error":"ForbiddenOperationException","errorMessage":"Invalid credentials."} It says Invalid credentials however i provide the correct credentials and i can confirm them because it is working on other servers. Since this is a crucial part of my script that i use for clients to register i assume that there is something wrong with the post parameters. I am running cpanel and uninstalled the following already: - varnish - apachebooster i also recompiled php already and enabled curl and its dependencies but nothing seems to resolve my problem. If more information is required then don't hesitate to ask me in the comments i will respond very quickly as i really need this. any help is appreciated. Kind regards Maxim

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  • What to Return with Async CRUD methods

    - by RualStorge
    While there is a similar question focused on Java, I've been in debates with utilizing Task objects. What's the best way to handle returns on CRUD methods (and similar)? Common returns we've seen over the years are: Void (no return unless there is an exception) Boolean (True on Success, False on Failure, exception on unhandled failure) Int or GUID (Return the newly created objects Id, 0 or null on failure, exception on unhandled failure) The updated Object (exception on failure) Result Object (Object that houses the manipulated object's ID, Boolean or status field to with success or failure indicated, Exception information if there was one, etc) The concern comes into play as we've started moving over to utilizing C# 5's Async functionality, and this brought the question up of how we should handle CRUD returns large-scale. In our systems we have a little of everything in regards to what we return, we want to make these returns standardized... Now the question is what is the recommended standard? Is there even a recommended standard yet? (I realize we need to decide our standard, but typically we do so by looking at best practices, see if it makes sense for us and go from there, but here we're not finding much to work with)

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  • Transform coordinates from 3d to 2d without matrix or built in methods

    - by Thomas
    Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use matrices or built in transformation methods I need another way. I've tried implementing the next explanation + pseudo code: http://freespace.virgin.net/hugo.elias/routines/3d_to_2d.htm Unfortunately no luck there. I've replace all the input variables with data from my own camera and object classes. I have the following data: An object with a rotation, position vector and an array of 4 3d coords (its just a plane) a camera with a position and rotation vector the viewport - a square 600 x 600 surface. The example uses a zoom factor which I've set as 1 Most hits on google use either matrix calculations or don't implement camera rotation. Basic transformation should be like this: screen.x = x / z * zoom screen.y = y / z * zoom Can anyone point me in the right direction or explain to me howto achieve this? edit: Thanks for all your posts, I haven't been able to apply all this to my project yet but I hope to do this soon.

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  • Avoid overwriting all the methods in the child class

    - by Heckel
    The context I am making a game in C++ using SFML. I have a class that controls what is displayed on the screen (manager on the image below). It has a list of all the things to draw like images, text, etc. To be able to store them in one list I created a Drawable class from which all the other drawable class inherit. The image below represents how I would organize each class. Drawable has a virtual method Draw that will be called by the manager. Image and Text overwrite this method. My problem is that I would like Image::draw method to work for Circle, Polygon, etc. since sf::CircleShape and sf::ConvexShape inherit from sf::Shape. I thought of two ways to do that. My first idea would be for Image to have a pointer on sf::Shape, and the subclasses would make it point onto their sf::CircleShape or sf::ConvexShape classes (Like on the image below). In the Polygon constructor I would write something like ptr_shape = &polygon_shape; This doesn't look very elegant because I have two variables that are, in fact, just one. My second idea is to store the sf::CircleShape and sf::ConvexShape inside the ptr_shape like ptr_shape = new sf::ConvexShape(...); and to use a function that is only in ConvexShape I would cast it like so ((sf::ConvexShape*)ptr_shape)->convex_method(); But that doesn't look very elegant either. I am not even sure I am allowed to do that. My question I added details about the whole thing because I thought that maybe my whole architecture was wrong. I would like to know how I could design my program to be safe without overwriting all the Image methods. I apologize if this question has already been asked; I have no idea what to google.

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  • Should we test all our methods?

    - by Zenzen
    So today I had a talk with my teammate about unit testing. The whole thing started when he asked me "hey, where are the tests for that class, I see only one?". The whole class was a manager (or a service if you prefer to call it like that) and almost all the methods were simply delegating stuff to a DAO so it was similar to: SomeClass getSomething(parameters) { return myDao.findSomethingBySomething(parameters); } A kind of boilerplate with no logic (or at least I do not consider such simple delegation as logic) but a useful boilerplate in most cases (layer separation etc.). And we had a rather lengthy discussion whether or not I should unit test it (I think that it is worth mentioning that I did fully unit test the DAO). His main arguments being that it was not TDD (obviously) and that someone might want to see the test to check what this method does (I do not know how it could be more obvious) or that in the future someone might want to change the implementation and add new (or more like "any") logic to it (in which case I guess someone should simply test that logic). This made me think, though. Should we strive for the highest test coverage %? Or is it simply an art for art's sake then? I simply do not see any reason behind testing things like: getters and setters (unless they actually have some logic in them) "boilerplate" code Obviously a test for such a method (with mocks) would take me less than a minute but I guess that is still time wasted and a millisecond longer for every CI. Are there any rational/not "flammable" reasons to why one should test every single (or as many as he can) line of code?

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  • What to Return with Async CRUD methods C#

    - by RualStorge
    While there is a similar question focused on Java, I've been in debates with utilizing Task objects. What's the best way to handle returns on CRUD methods (and similar)? Common returns we've seen over the years are: Void (no return unless there is an exception) Boolean (True on Success, False on Failure, exception on unhandled failure) Int or GUID (Return the newly created objects Id, 0 or null on failure, exception on unhandled failure) The updated Object (exception on failure) Result Object (Object that houses the manipulated object's ID, Boolean or status field to with success or failure indicated, Exception information if there was one, etc) The concern comes into play as we've started moving over to utilizing C# 5's Async functionality, and this brought the question up of how we should handle CRUD returns large-scale. In our systems we have a little of everything in regards to what we return, we want to make these returns standardized... Now the question is what is the recommended standard? Is there even a recommended standard yet? (I realize we need to decide our standard, but typically we do so by looking at best practices, see if it makes sense for us and go from there, but here we're not finding much to work with)

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  • Methods for getting static data from obj-c to Parse (database)

    - by Phil
    I'm starting out thinking out how best to code my latest game on iOS, and I want to use parse.com to store pretty much everything, so I can easily change things. What I'm not sure about is how to get static data into parse, or at least the best method. I've read about using NSMutableDictionary, pLists, JSON, XML files etc. Let's say for example in AS3 I could create a simple data object like so... static var playerData:Object = {position:{startX:200, startY:200}}; Stick it in a static class, and bingo I've got my static data to use how I see fit. Basically I'm looking for the best method to do the same thing in Obj-c, but the data is not to be stored directly in the iOS game, but to be sent to parse.com to be stored on their database there. The game (at least the distribution version) will only load data from the parse database, so however I'm getting the static data into parse I want to be able to remove it from being included in the eventual iOS file. So any ideas on the best methods to sort that? If I had longer on this project, it might be nice to use storyboards and create a simple game editor to send data to parse....actually maybe that's a good idea, it's just I'm new to obj-c and I'm looking for the most straightforward (see quickest) way to achieve things. Thanks for any advice.

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  • Static / Shared Helper Functions vs Built-In Methods

    - by Nathan
    This is a simple question but a design consideration that I often run across in my day to day development work. Lets say that you have a class that represents some kinds of collection. Public Class ModifiedCustomerOrders Public Property Orders as List(Of ModifiedOrders) End Class Within this class you do all kinds of important work, such as combining many different information sources and, eventually, build the Modified Customer Orders. Now, you have different processes that consume this class, each of which needs a slightly different slice of the ModifiedCustomerOrders items. To enable this, you want to add filtering functionality. How do you go about this? Do you: Add Filtering calls to the ModifiedCustomerOrders class so that you can say: MyOrdersClass.RemoveCanceledOrders() Create a Static / Shared "tooling" class that allows you to call: OrdersFilters.RemoveCanceledOrders(MyOrders) Create an extension method to accomplish the same feat as #2 but with less typing: MyOrders.RemoveCanceledOrders() Create a "Service" method that handles the getting of Orders as appropriate to the calling function, while using one of the previous approaches "under the hood". OrdersService.GetOrdersForProcessA() Others? I tend to prefer the tooling / extension method approaches as they make testing a little bit simpler. Although I dependency inject all my sourcing data into the ModifiedCustomerOrders, having it as part of the class makes it a little bit more complicated to test. Typically, I choose to use extension methods where I am doing parameterless transformations / filters. As they get more complex, I will move it into a static class instead. Thoughts on this approach? How would you approach it?

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  • Useful WatiN Extension Methods

    - by Steve Wilkes
    I've been doing a fair amount of UI testing using WatiN recently – here’s some extension methods I've found useful. This checks if a WatiN TextField is actually a hidden field. WatiN makes no distinction between text and hidden inputs, so this can come in handy if you render an input sometimes as hidden and sometimes as a visible text field. Note that this doesn't check if an input is visible (I've got another extension method for that in a moment), it checks if it’s hidden. public static bool IsHiddenField(this TextField textField) { if (textField == null || !textField.Exists) { return false; } var textFieldType = textField.GetAttributeValue("type"); return (textFieldType != null) && textFieldType.ToLowerInvariant() == "hidden"; } The next method quickly sets the value of a text field to a given string. By default WatiN types the text you give it into a text field one character at a time which can be necessary if you have behaviour you want to test which is triggered by individual key presses, but which most of time is just painfully slow; this method dumps the text in in one go. Note that if it's not a hidden field then it gives it focus first; this helps trigger validation once the value has been set and focus moves elsewhere. public static void SetText(this TextField textField, string value) { if ((textField == null) || !textField.Exists) { return; } if (!textField.IsHiddenField()) { textField.Focus(); } textField.Value = value; } Finally, here's a method which checks if an Element is currently visible. It does so by walking up the DOM and checking for a Style.Display of 'none' on any element between the one on which the method is invoked, and any of its ancestors. public static bool IsElementVisible(this Element element) { if ((element == null) || !element.Exists) { return false; } while ((element != null) && element.Exists) { if (element.Style.Display.ToLowerInvariant().Contains("none")) { return false; } element = element.Parent; } return true; } Hope they come in handy

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  • Override methods should call base method?

    - by Trevor Pilley
    I'm just running NDepend against some code that I have written and one of the warnings is Overrides of Method() should call base.Method(). The places this occurs are where I have a base class which has virtual properties and methods with default behaviour but which can be overridden by a class which inherits from the base class and doesn't call the overridden method. For example, in the base class I have a property defined like this: protected virtual char CloseQuote { get { return '"'; } } And then in an inheriting class which uses a different close quote: protected override char CloseQuote { get { return ']'; } } Not all classes which inherit from the base class use different quote characters hence my initial design. The alternatives I thought of were have get/set properties in the base class with the defaults set in the constructor: protected BaseClass() { this.CloseQuote = '"'; } protected char CloseQuote { get; set; } public InheritingClass() { this.CloseQuote = ']'; } Or make the base class require the values as constructor args: protected BaseClass(char closeQuote, ...) { this.CloseQuote = '"'; } protected char CloseQuote { get; private set; } public InheritingClass() base (closeQuote: ']', ...) { } Should I use virtual in a scenario where the base implementation may be replaced instead of extended or should I opt for one of the alternatives I thought of? If so, which would be preferable and why?

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  • LINQ – Skip() and Take() methods

    - by nmarun
    I had this issue recently where I have an array of integers and I’m doing some Skip(n) and then a Take(m) on the collection. Here’s an abstraction of the code: 1: int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 2: var taken = numbers.Skip(3).Take(3); 3: foreach (var i in taken) 4: { 5: Console.WriteLine(i); 6: } The output is as expected: 3, 9, 8 – skip the first three and then take the next three items. But, what happens if I do something like: 1: var taken = numbers.Skip(7).Take(5); In English – skip the first seven and the take the next 5 items from an array that contains only 10 elements. Think it’ll throw the IndexOutOfRangeException exception? Nope. These extension methods are a little smarter than that. Even though the user has requested more elements than what exists in the collection, the Take method only returns the first three thereby making the output of the program as: 7, 2, 0. The scenario is handled similarly when you do: 1: var taken = numbers.Take(5).Skip(7); This one takes the first 5 elements from the numbers array and then skips 7 of them. This is what is looks like in the debug mode: Just wanted to share this behavior.

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  • SQL SERVER – Maximize Database Performance with DB Optimizer – SQL in Sixty Seconds #054

    - by Pinal Dave
    Performance tuning is an interesting concept and everybody evaluates it differently. Every developer and DBA have different opinion about how one can do performance tuning. I personally believe performance tuning is a three step process Understanding the Query Identifying the Bottleneck Implementing the Fix While, we are working with large database application and it suddenly starts to slow down. We are all under stress about how we can get back the database back to normal speed. Most of the time we do not have enough time to do deep analysis of what is going wrong as well what will fix the problem. Our primary goal at that time is to just fix the database problem as fast as we can. However, here is one very important thing which we need to keep in our mind is that when we do quick fix, it should not create any further issue with other parts of the system. When time is essence and we want to do deep analysis of our system to give us the best solution we often tend to make mistakes. Sometimes we make mistakes as we do not have proper time to analysis the entire system. Here is what I do when I face such a situation – I take the help of DB Optimizer. It is a fantastic tool and does superlative performance tuning of the system. Everytime when I talk about performance tuning tool, the initial reaction of the people is that they do not want to try this as they believe it requires lots of the learning of the tool before they use it. It is absolutely not true with the case of the DB optimizer. It is a very easy to use and self intuitive tool. Once can get going with the product, in no time. Here is a quick video I have build where I demonstrate how we can identify what index is missing for query and how we can quickly create the index. Entire three steps of the query tuning are completed in less than 60 seconds. If you are into performance tuning and query optimization you should download DB Optimizer and give it a go. Let us see the same concept in following SQL in Sixty Seconds Video: You can Download DB Optimizer and reproduce the same Sixty Seconds experience. Related Tips in SQL in Sixty Seconds: Performance Tuning – Part 1 of 2 – Getting Started and Configuration Performance Tuning – Part 2 of 2 – Analysis, Detection, Tuning and Optimizing What would you like to see in the next SQL in Sixty Seconds video? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Interview Questions and Answers, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video Tagged: Identity

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  • SQL SERVER – Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    This blog post is written in response to the T-SQL Tuesday post of Prox ‘n’ Funx. This is a very interesting subject. By the way Brad Schulz is my favorite guy when it is about blogging. I respect him as well learn a lot from him. Everybody is writing something new his subject, I decided to start SQL Server 2012 analytic functions series. SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Let us fun following query. USE AdventureWorks GO SELECT SalesOrderID, OrderQty, CUME_DIST() OVER(ORDER BY SalesOrderID) AS CDist FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY CDist DESC GO Above query will give us following result. Now let us understand what is the formula behind CUME_DIST and why the values in SalesOrderID = 43670 are 1. Let us take more example and be clear about why the values in SalesOrderID = 43667 are 0.5. Now let us enhence the same example and use PARTITION BY into the OVER clause and see the results. Run following query in SQL Server 2012. USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, CUME_DIST() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) AS CDist FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID DESC, CDist DESC GO Now let us see the result of this query. We are have changed the ORDER BY clause as well partitioning by SalesOrderID. You can see that CUME_DIST() function provides us different results. Additionally now we see value 1 multiple times. As we are using partitioning for each group of SalesOrderID we get the CUME_DIST() value. CUME_DIST() was long awaited Analytical function and I am glad to see it in SQL Server 2012. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Validating Spatial Object with IsValidDetailed Function

    - by pinaldave
    What do you prefer – error or warning indicating error may happen with the reason for the error. While writing the previous statement I remember the movie “Minory Report”. This blog post is not about minority report but I will still cover the concept in a single statement “Let us predict the future and prevent the crime which is about to happen in future”. (Please feel free to correct me if I am wrong about the movie concept, I really do not want to hurt your sentiment if you are dedicated fan). Let us switch to the SQL Server world. Spatial data types are interesting concepts. I love writing about spatial data types because it allows me to be creative with shapes (just like toddlers). When working with Spatial Datatypes it is all good when the spatial object works fine. However, when the spatial object has issue or it is created with invalid coordinates it used to give a simple error that there is an issue with the object but did not provide much information. This made it very difficult to debug. If this spatial object was used in the big procedure and while this big procedural error out because of the invalid spatial object, it is indeed very difficult to debug it. I always wished that the more information provided regarding what is the problem with spatial datatype. SQL Server 2012 has introduced the new function IsValidDetailed(). This function has made my life very easy. In simple words this function will check if the spatial object passed is valid or not. If it is valid it will give information that it is valid. If the spatial object is not valid it will return the answer that it is not valid and the reason for the same. This makes it very easy to debug the issue and make the necessary correction. DECLARE @p GEOMETRY = 'Polygon((2 2, 6 6, 4 2, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 4 4, 4 2, 2 3, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'LINESTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO Here is the resultset of the above query. You can see any valid query and some invalid query. If the query is invalid it also demonstrates the reason along with the error message. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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  • SQL SERVER – Fix: Error: 147 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference

    - by pinaldave
    Everybody was beginner once and I always like to get involved in the questions from beginners. There is a big difference between the question from beginner and question from advanced user. I have noticed that if an advanced user gets an error, they usually need just a small hint to resolve the problem. However, when a beginner gets error he sometimes sits on the error for a long time as he/she has no idea about how to solve the problem as well have no idea regarding what is the capability of the product. I recently received a very novice level question. When I received the problem I quickly see how the user was stuck. When I replied him with the solution, he wrote a long email explaining how he was not able to solve the problem. He thanked multiple times in the email. This whole thing inspired me to write this quick blog post. I have modified the user’s question to match the code with AdventureWorks as well simplified so it contains the core content which I wanted to discuss. Problem Statement: Find all the details of SalesOrderHeaders for the latest ShipDate. He comes up with following T-SQL Query: SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = MAX(ShipDate) GO When he executed above script it gave him following error: Msg 147, Level 15, State 1, Line 3 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference. He was not able to resolve this problem, even though the solution was given in the query description itself. Due to lack of experience he came up with another version of above query based on the error message. SELECT * FROM [Sales].[SalesOrderHeader] HAVING ShipDate = MAX(ShipDate) GO When he ran above query it produced another error. Msg 8121, Level 16, State 1, Line 3 Column ‘Sales.SalesOrderHeader.ShipDate’ is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause. What he wanted actually was the SalesOrderHeader all the Sales shipped on the last day. Based on the problem statement what the right solution is as following, which does not generate error. SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = (SELECT MAX(ShipDate) FROM [Sales].[SalesOrderHeader]) Well, that’s it! Very simple. With SQL Server there are always multiple solution to a single problem. Is there any other solution available to the problem stated? Please share in the comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • "static" as a semantic clue about statelessness?

    - by leoger
    this might be a little philosophical but I hope someone can help me find a good way to think about this. I've recently undertaken a refactoring of a medium sized project in Java to go back and add unit tests. When I realized what a pain it was to mock singletons and statics, I finally "got" what I've been reading about them all this time. (I'm one of those people that needs to learn from experience. Oh well.) So, now that I'm using Spring to create the objects and wire them around, I'm getting rid of static keywords left and right. (If I could potentially want to mock it, it's not really static in the same sense that Math.abs() is, right?) The thing is, I had gotten into the habit of using static to denote that a method didn't rely on any object state. For example: //Before import com.thirdparty.ThirdPartyLibrary.Thingy; public class ThirdPartyLibraryWrapper { public static Thingy newThingy(InputType input) { new Thingy.Builder().withInput(input).alwaysFrobnicate().build(); } } //called as... ThirdPartyLibraryWrapper.newThingy(input); //After public class ThirdPartyFactory { public Thingy newThingy(InputType input) { new Thingy.Builder().withInput(input).alwaysFrobnicate().build(); } } //called as... thirdPartyFactoryInstance.newThingy(input); So, here's where it gets touchy-feely. I liked the old way because the capital letter told me that, just like Math.sin(x), ThirdPartyLibraryWrapper.newThingy(x) did the same thing the same way every time. There's no object state to change how the object does what I'm asking it to do. Here are some possible answers I'm considering. Nobody else feels this way so there's something wrong with me. Maybe I just haven't really internalized the OO way of doing things! Maybe I'm writing in Java but thinking in FORTRAN or somesuch. (Which would be impressive since I've never written FORTRAN.) Maybe I'm using staticness as a sort of proxy for immutability for the purposes of reasoning about code. That being said, what clues should I have in my code for someone coming along to maintain it to know what's stateful and what's not? Perhaps this should just come for free if I choose good object metaphors? e.g. thingyWrapper doesn't sound like it has state indepdent of the wrapped Thingy which may itself be mutable. Similarly, a thingyFactory sounds like it should be immutable but could have different strategies that are chosen among at creation. I hope I've been clear and thanks in advance for your advice!

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  • Do you prefer building your interfaces in IB or programmatically? and why?

    - by LolaRun
    I've been using Xcode and building iPhone apps for two months, but I'm finding it really hard to grasp good application design. I always face problems—like you can't put your tabbarcontroller in another custom viewcontroller, for example—that 'sometimes', of course, would work if you did the creation of the views/viewcontrollers programmatically. So I don't know if I should start writing the creation of my objects or use Interface Builder. What are your experiences?

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  • SQL SERVER – Four Posts on Removing the Bookmark Lookup – Key Lookup

    - by pinaldave
    In recent times I have observed that not many people have proper understanding of what is bookmark lookup or key lookup. Increasing numbers of the questions tells me that this is something developers are encountering every single day but have no idea how to deal with it. I have previously written three articles on this subject. I want to point all of you looking for further information on the same post. SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 2 SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 3 SQL SERVER – Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries In one of my recent class we had in depth conversation about what are the alternative of creating covering indexes to remove the bookmark lookup. I really want to this question open to all of you and see what community thinks about the same. Is there any other way then creating covering index or included index to remove his expensive keylookup? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Backup and Restore, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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  • SQL SERVER – Solution – Challenge – Puzzle – Usage of FAST Hint

    - by pinaldave
    Earlier I had posted quick puzzle and I had received wonderful response to the same from Brad Schulz. Today we will go over the solution. The puzzle was posted here: SQL SERVER – Challenge – Puzzle – Usage of FAST Hint The question was in what condition the hint FAST will be useful. In the response to this puzzle blog post here is what SQL Server Expert Brad Schulz has pointed me to his blog post where he explain how FAST hint can be useful. I strongly recommend to read his blog post over here. With the permission of the Brad, I am reproducing following queries here. He has come up with example where FAST hint improves the performance. USE AdventureWorks GO DECLARE @DesiredDateAtMidnight DATETIME = '20010709' DECLARE @NextDateAtMidnight DATETIME = DATEADD(DAY,1,@DesiredDateAtMidnight) -- Query without FAST SELECT OrderID=h.SalesOrderID ,h.OrderDate ,h.TerritoryID ,TerritoryName=t.Name ,c.CardType ,c.CardNumber ,CardExpire=RIGHT(STR(100+ExpMonth),2)+'/'+STR(ExpYear,4) ,h.TotalDue FROM Sales.SalesOrderHeader h LEFT JOIN Sales.SalesTerritory t ON h.TerritoryID=t.TerritoryID LEFT JOIN Sales.CreditCard c ON h.CreditCardID=c.CreditCardID WHERE OrderDate>=@DesiredDateAtMidnight AND OrderDate<@NextDateAtMidnight ORDER BY h.SalesOrderID; -- Query with FAST(10) SELECT OrderID=h.SalesOrderID ,h.OrderDate ,h.TerritoryID ,TerritoryName=t.Name ,c.CardType ,c.CardNumber ,CardExpire=RIGHT(STR(100+ExpMonth),2)+'/'+STR(ExpYear,4) ,h.TotalDue FROM Sales.SalesOrderHeader h LEFT JOIN Sales.SalesTerritory t ON h.TerritoryID=t.TerritoryID LEFT JOIN Sales.CreditCard c ON h.CreditCardID=c.CreditCardID WHERE OrderDate>=@DesiredDateAtMidnight AND OrderDate<@NextDateAtMidnight ORDER BY h.SalesOrderID OPTION(FAST 10) Now when you check the execution plan for the same, you will find following visible difference. You will find query with FAST returns results with much lower cost. Thank you Brad for excellent post and teaching us something. I request all of you to read original blog post written by Brad for much more information. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQLAuthority News – SQL Server Technical Article – The Data Loading Performance Guide

    - by pinaldave
    The white paper describes load strategies for achieving high-speed data modifications of a Microsoft SQL Server database. “Bulk Load Methods” and “Other Minimally Logged and Metadata Operations” provide an overview of two key and interrelated concepts for high-speed data loading: bulk loading and metadata operations. After this background knowledge, white paper describe how these methods can be [...]

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  • SQL SERVER – Weekly Series – Memory Lane – #033

    - 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 Spatial Database Definition and Research Documents Here is the definition from Wikipedia about spatial database : A spatial database is a database that is optimized to store and query data related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to process spatial data types. Select Only Date Part From DateTime – Best Practice A very common question which I receive is how to only get Date or Time part from datetime value. In this blog post I explain the same in very simple words. T-SQL Paging Query Technique Comparison (OVER and ROW_NUMBER()) – CTE vs. Derived Table I have received few emails and comments about my post SQL SERVER – T-SQL Paging Query Technique Comparison – SQL 2000 vs SQL 2005. The main question was is this can be done using CTE? Absolutely! What about Performance? It is identical! Please refer above mentioned article for the history of paging. SQL SERVER – Cannot resolve collation conflict for equal to operation One of the very first error I ever encountered in my career was to resolve this conflict. I have blogged about it and I have realized that many others like me who are facing this error. LEN and DATALENGTH of NULL Simple Example Here is the question for you what is the LEN of NULL value? Well it is very easy – just read the blog. Recovery Models and Selection Very simple and easy explanation of the Database Backup Recovery Model and how to select the best option for you. Explanation SQL SERVER Hash Join Hash join gives best performance when two more join tables are joined and at-least one of them have no index or is not sorted. It is also expected that smaller of the either of table can be read in memory completely (though not necessary). Easy Sequence of SELECT FROM JOIN WHERE GROUP BY HAVING ORDER BY SELECT yourcolumns FROM tablenames JOIN tablenames WHERE condition GROUP BY yourcolumns HAVING aggregatecolumn condition ORDER BY yourcolumns NorthWind Database or AdventureWorks Database – Samples Databases In this blog post we learn how to install Northwind database. I also shared the source where one can download this database as that is used in many examples on MSDN help files. sp_HelpText for sp_HelpText – Puzzle A simple quick puzzle – do you know the answer of it? If not, go ahead and read the blog. 2008 SQL SERVER – 2008 – Step By Step Installation Guide With Images When SQL Server 2008 was newly introduced lots of people had no clue how to install SQL Server 2008 and the amount of the question which I used to receive were so much. I wrote this blog post with the spirit that this will help all the newbies to install SQL Server 2008 with the help of images. Still today this blog post has been bible for all of the people who are confused with SQL Server installation. Inline Variable Assignment I loved this feature. I have always wanted this feature to be present in SQL Server. The last time when I met developers from Microsoft SQL Server, I had talked about this feature. I think this feature saves some time but make the code more readable. Introduction to Policy Management – Enforcing Rules on SQL Server If our company policy is to create all the Stored Procedure with prefix ‘usp’ that developers should be just prevented to create Stored Procedure with any other prefix. Let us see a small tutorial how to create conditions and policy which will prevent any future SP to be created with any other prefix. 2009 Performance Counters from System Views – By Kevin Mckenna Many of you are not aware of this fact that access to performance information is readily available in SQL Server and that too without querying performance counters using a custom application or via perfmon. Till now, this fact has remained undisclosed but through this post I would like to explain you can easily access SQL Server performance counter information. Without putting much effort you will come across the system viewsys.dm_os_performance_counters. As the name suggests, this provides you easy access to the SQL Server performance counter information that is passed on to perfmon, but you can get at it via tsql. Customize Toolbar – Remove Debug Button from Toolbar I was fond of SQL Server Debugger feature in SQL Server 2000. To my utter disappointment, this feature was withdrawn from SQL Server 2005. The button of the debugger is similar to a play button and is used to run debugging commands of Visual Studio. Because of this reason, it gets very much infuriating for developers when they are developing on both – Visual Studio and SSMS. Let us now see how we can remove debugging button from SQL Server Management Studio. Effect of Normalization on Index and Performance A very interesting conversation which started from twitter. If you want to read one link this is the link I encourage you to read it. SSMS Feature – Multi-server Queries Using SQL Server Management Studio (SSMS) DBAs can now query multiple servers from one window. It is quite common for DBAs with large amount of servers to maintain and gather information from multiple SQL Servers and create report. This feature is a blessing for the DBAs, as they can now assemble all the information instantaneously without going anywhere. Query Optimizer Hint ROBUST PLAN – Question to You “ROBUST PLAN” is a kind of query hint which works quite differently than other hints. It does not improve join or force any indexes to use; it just makes sure that a query does not crash due to over the limit size of row. Let me elaborate upon it in the blog post. 2010 Do you really know the difference between various date functions available in SQL Server 2012? Here is a three part story where we explored the same with examples: Fastest Way to Restore the Database Difference Between DATETIME and DATETIME2 Difference Between DATETIME and DATETIME2 – WITH GETDATE Shrinking NDF and MDF Files – Readers’ Opinion Shrinking Database always creates performance degradation and increases fragmentation in the database. I suggest that you keep that in mind before you start reading the following comment. If you are going to say Shrinking Database is bad and evil, here I am saying it first and loud. Now, the comment of Imran is written while keeping in mind only the process showing how the Shrinking Database Operation works. Imran has already explained his understanding and requests further explanation. I have removed the Best Practices section from Imran’s comments, as there are a few corrections. 2011 Solution – Puzzle – SELECT * vs SELECT COUNT(*) This is very interesting question and I am very confident that not every one knows the answer to this question. Let me ask you again – Which will be faster SELECT* or SELECT COUNT (*) or do you think this is apples and oranges comparison. 2012 Service Broker and CAP_CPU_PERCENT – Limiting SQL Server Instances to CPU Usage In SQL Server 2012 there are a few enhancements with regards to SQL Server Resource Governor. One of the enhancement is how the resources are allocated. Let me explain you with examples. Let us understand the entire discussion with the help of three different examples. Finding Size of a Columnstore Index Using DMVs One of the very common question I often see is need of the list of columnstore index along with their size and corresponding table name. I quickly re-wrote a script using DMVs sys.indexes and sys.dm_db_partition_stats. This script gives the size of the columnstore index on disk only. I am sure there will be advanced script to retrieve details related to components associated with the columnstore index. However, I believe following script is sufficient to start getting an idea of columnstore index size. Developer Training Resources and Summary Roundup Developer Training - Importance and Significance - Part 1 In this part we discussed the importance of training in the real world. The most important and valuable resource any company is its employee. Employees who have been well-trained will be better at their jobs and produce a better product.  An employee who is well trained obviously knows more about their job and all the technical aspects. I have a very high opinion about training employees and it is the most important task. Developer Training – Employee Morals and Ethics – Part 2 In this part we discussed the most crucial components of training. Often employees are expecting the company to pay for their training and the company expresses no interest in training the employee. Quite often training expenses are the real issue for both the employee and employer. Developer Training – Difficult Questions and Alternative Perspective - Part 3 This part was the most difficult to write as I tried to address a few difficult questions and answers. Training is such a sensitive issue that many developers when not receiving chance for training think about leaving the organization. Developer Training – Various Options for Developer Training – Part 4 In this part I tried to explore a few methods and options for training. The generic feedback I received on this blog post was short and I should have explored each of the subject of the training in details. I believe there are two big buckets of training 1) Instructor Lead Training and 2) Self Lead Training. Developer Training – A Conclusive Summary- Part 5 There is no better motivation than a personal desire to learn new technology. Honestly there is nothing more personal learning. That “change is the only constant” and “adapt & overcome” are the essential lessons of life. One cannot stop the learning and resist the change. In the IT industry “ego of knowing all” and the “resistance to change” are the most challenging issues. A Quick Look at Logging and Ideas around Logging Question: What is the first thing comes to your mind when you hear the word “Logging”? Strange enough I got a different answer every single time. Let me just list what answer I got from my friends. Let us go over them one by one. Beginning Performance Tuning with SQL Server Execution Plan Solution of Puzzle – Swap Value of Column Without Case Statement Earlier this week I asked a question where I asked how to Swap Values of the column without using CASE Statement. Read here: SQL SERVER – A Puzzle – Swap Value of Column Without Case Statement. I have proposed 3 different solutions in the blog posts itself. I had requested the help of the community to come up with alternate solutions and honestly I am stunned and amazed by the qualified entries. 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

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  • SQL SERVER – Introduction to PERCENTILE_CONT() – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    SQL Server 2012 introduces new analytical function PERCENTILE_CONT(). The book online gives following definition of this function: Computes a specific percentile for sorted values in an entire rowset or within distinct partitions of a rowset in Microsoft SQL Server 2012 Release Candidate 0 (RC 0). For a given percentile value P, PERCENTILE_DISC sorts the values of the expression in the ORDER BY clause and returns the value with the smallest CUME_DIST value (with respect to the same sort specification) that is greater than or equal to P. If you are clear with understanding of the function – no need to read further. If you got lost here is the same in simple words – it is lot like finding median with percentile value. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO The above query will give us the following result: You can see that I have used PERCENTILE_COUNT(0.5) in query, which is similar to finding median. Let me explain above diagram with little more explanation. The defination of median is as following: In case of Even Number of elements = In ordered list add the two digits from the middle and devide by 2 In case of Odd Numbers of elements = In ordered list select the digits from the middle I hope this example gives clear idea how PERCENTILE_CONT() works. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Oracle Text query parser

    - by Roger Ford
    Oracle Text provides a rich query syntax which enables powerful text searches.However, this syntax isn't intended for use by inexperienced end-users.  If you provide a simple search box in your application, you probably want users to be able to type "Google-like" searches into the box, and have your application convert that into something that Oracle Text understands.For example if your user types "windows nt networking" then you probably want to convert this into something like"windows ACCUM nt ACCUM networking".  But beware - "NT" is a reserved word, and needs to be escaped.  So let's escape all words:"{windows} ACCUM {nt} ACCUM {networking}".  That's fine - until you start introducing wild cards. Then you must escape only non-wildcarded searches:"win% ACCUM {nt} ACCUM {networking}".  There are quite a few other "gotchas" that you might encounter along the way.Then there's the issue of scoring.  Given a query for "oracle text query syntax", it would be nice if we could score a full phrase match higher than a hit where all four words are present but not in a phrase.  And then perhaps lower than that would be a document where three of the four terms are present.  Progressive relaxation helps you with this, but you need to code the "progression" yourself in most cases.To help with this, I've developed a query parser which will take queries in Google-like syntax, and convert them into Oracle Text queries. It's designed to be as flexible as possible, and will generate either simple queries or progressive relaxation queries. The input string will typically just be a string of words, such as "oracle text query syntax" but the grammar does allow for more complex expressions:  word : score will be improved if word exists  +word : word must exist  -word : word CANNOT exist  "phrase words" : words treated as phrase (may be preceded by + or -)  field:(expression) : find expression (which allows +,- and phrase as above) within "field". So for example if I searched for   +"oracle text" query +syntax -ctxcatThen the results would have to contain the phrase "oracle text" and the word syntax. Any documents mentioning ctxcat would be excluded from the results. All the instructions are in the top of the file (see "Downloads" at the bottom of this blog entry).  Please download the file, read the instructions, then try it out by running "parser.pls" in either SQL*Plus or SQL Developer.I am also uploading a test file "test.sql". You can run this and/or modify it to run your own tests or run against your own text index. test.sql is designed to be run from SQL*Plus and may not produce useful output in SQL Developer (or it may, I haven't tried it).I'm putting the code up here for testing and comments. I don't consider it "production ready" at this point, but would welcome feedback.  I'm particularly interested in comments such as "The instructions are unclear - I couldn't figure out how to do XXX" "It didn't work in my environment" (please provide as many details as possible) "We can't use it in our application" (why not?) "It needs to support XXX feature" "It produced an invalid query output when I fed in XXXX" Downloads: parser.pls test.sql

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  • SQL SERVER – A Funny Cartoon on Index

    - by pinaldave
    Performance Tuning has been my favorite subject and I have done it for many years now. Today I will list one of the most common conversation about Index I have heard in my life. Every single time, I am at consultation for performance tuning I hear following conversation among various team members. I want to ask you, does this kind of conversation happens in your organization? Any way, If you think Index solves all of your performance problem I think it is not true. There are many other reason one has to consider along with Indexes. For example I consider following various topic one need to understand for performance tuning. ?Logical Query Processing ?Efficient Join Techniques ?Query Tuning Considerations ?Avoiding Common Performance Tuning Issues Statistics and Best Practices ?TempDB Tuning ?Hardware Planning ?Understanding Query Processor ?Using SQL Server 2005 and 2008 Updated Feature Sets ?CPU, Memory, I/O Bottleneck Index Tuning (of course) ?Many more… Well, I have written this blog thinking I will keep this blog post a bit easy and not load up. I will in future discuss about other performance tuning concepts. Let me know what do you think about the cartoon I made. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Humor, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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