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• Display a jQuery Dialog/Popup, then set a hidden field using the result of the dialog

  - by Dan Harris

  The Problem I have a page with a form on. It has a hidden field called: generic_portrait I want the user to click a link "select portrait" This will open a Dialog/Popup using jQuery, based on a dropdown completed earlier in the form. If the value of the dropdown called "gender" is "male" then show male options, if "gender" is set to "female" show female options. Each portrait has a radio button, each with a name assigned "male1", "male2" etc Depending on the radio button selected in the popup, I want the hidden field to be set to match this. The Questions What is the best way to show a dialog/popup using jQuery, different depending on a dropdown box on the page. Use Javascript to see what is selected, then show a corresponding Div? I can do the check to see what the dropdown is set to using jQuery, but how can I then shown a specific popup based on that? Once i've popped it up, how do I take the value assigned to the selected radio box, and set the hidden field called "generic_portrait" to this value. Why i'm asking Normally I would figure this out myself, as i'm sure it's not that difficult, but I don't use Javascript and/or PHP very often, and this is due for a client urgently. So I would really, really appreciate some help on this one. Thanks for all replies in advance.

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• Looking forward to a programming future but confused where to start.

  - by Kraivyne

  Hi there, I am very new to this site and to programming. I started doing some basic programming with python a few weeks ago and recently, messing around with Java basics. My main problem is that I am completely overwhelmed and haven't got the slightest clue where I should be starting. I want to learn programming because I really enjoy doing it, the simple applications that I have managed to conjure up put a smile on my face. My plan is to eventually (by eventually I'm talking about 6 years+) go into games programming. I have been informed that C++ is the best way to go about this but haven't got the slightest clue what book/sight is optimal for someone who is still learning the very basics. These are my questions: I have been to the Definitive C++ Book Guide but am still unsure which book is best to start of with. Should I stick with Python or Java instead of moving on to C++? Is there any advice you would give to a beginner programmer? Thanks again for all your help.

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• how do i call methods from another class in android?

  - by Phani Gargey

  I have two classes in question. Both extend Activity. Class A public void displayinfo() { setContentView(R.layout.dynamicinfo); //Add some buttons dynamically here //do some processing // move on to Class B } In Class B: I want to go back to Class A state in UI if BACK button is pressed. Class B //Register a listener for this button Backbutton.setOnClickListener(new OnClickListener() { public void onClick(View arg0) { Log.i("setOnClickListener", "Pressed Back Button "); Toast.makeText(mycontext, "Pressed Back Button", Toast.LENGTH_SHORT).show(); //HERE I want to go back class's function in UI as well as restoring the sttae for that screen. } how do I do that? I looked around some questions. they did not answer clearly what I am looking for.hence the posting. thanks.I think I was adding my own Back button on the Layout I created in the Class B's UI Screen --not using the regular "Back" button on the key board. May be that was the problem.

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• SVN Version Rollback Question

  - by phimuemue

  Hello, I'm using SVN (TortoiseSVN) and often came into the following situation: I wanted to discard any changes since a specific (old) revision and turn all files back to this specific (old) version. Then I wanted to work further as if this specific (old) revision was the newest one, i.e. I wanted to be able to commit the specific old revision as a new revision. I found several solutions for this problem (for example stackoverflow.com/questions/402159/roll-back-or-revert-entire-svn-repository-to-an-older-revision or rustyrazorblade.com/2007/04/how-to-roll-back-commits-to-an-earlier-version-of-a-repository-in-svn/). However, I wonder if there is a simple way to roll back to a specific revision. I thought version control is just good for such things (or am I misunderstanding something?). Is there a simple command/button/etc. that takes an updates my local repository to an old revision and declares it to be the newest one? Since I suppose that there is no "built-in" function to do this, I wanted to know what reason lead the developers to the decision not to integrate this feature. Does anybody know this?

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• How to access parents' members from a inner class in WPF?

  - by black sensei

  Hello Experts! I'm trying to do scheduled operation let's say to check for user's credit left via web service call and update the user interface. i've tried with quartz.net to implement the scheduling bit.i created an inner class in the window class i need to update.That inner class has the method that calls the webservice and the result needs to be displayed back to the UI. here is an example of what i did. public partial class Window2 : Window { private int i; public Window2() { InitializeComponent(); } public class Myclass :IJob { public void Execute(JobExecutionContext context) { string result = doMyOperation(); //i'll like to call parent label member of name lblNotif //is something like parent.lblNotif.Content = result; //possible? } public string doMyOperation() { //calling the wermethod to retreive user's balance return result = service.GetUsersBalace(user); } } } Well the quartz bit is working and this post is not about quartz. here are my questions Question 1 : How is it possible to access Window2 controls, for instace lable lblNotif? Question 2 : If my thinking about this is wrong, what is done as best practice to solve my kind of problem, where an application need to do an operation let's say every 5mn and update the the UI. Question 3 : i at first tried to use the backgroundworker and i felt like i can't do the scheduling bit with it.Is that correct or i'm wrong. thanks for those who commented already and sorry for those who didn't get the meaning of my post.I hope this will be a bit clearer.Thanks for reading

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• SQL: Limit rows linked to each joined row

  - by SolidSnakeGTI

  Hello, I've certain situation that requires certain result set from MySQL query, let's see the current query first & then ask my question: SELECT thread.dateline AS tdateline, post.dateline AS pdateline, MIN(post.dateline) FROM thread AS thread LEFT JOIN post AS post ON(thread.threadid = post.threadid) LEFT JOIN forum AS forum ON(thread.forumid = forum.forumid) WHERE post.postid != thread.firstpostid AND thread.open = 1 AND thread.visible = 1 AND thread.replycount >= 1 AND post.visible = 1 AND (forum.options & 1) AND (forum.options & 2) AND (forum.options & 4) AND forum.forumid IN(1,2,3) GROUP BY post.threadid ORDER BY tdateline DESC, pdateline ASC As you can see, mainly I need to select dateline of threads from 'thread' table, in addition to dateline of the second post of each thread, that's all under the conditions you see in the WHERE CLAUSE. Since each thread has many posts, and I need only one result per thread, I've used GROUP BY CLAUSE for that purpose. This query will return only one post's dateline with it's related unique thread. My questions are: How to limit returned threads per each forum!? Suppose I need only 5 threads -as a maximum- to be returned for each forum declared in the WHERE CLAUSE 'forum.forumid IN(1,2,3)', how can this be achieved. Is there any recommendations for optimizing this query (of course after solving the first point)? Notes: I prefer not to use sub-queries, but if it's the only solution available I'll accept it. Double queries not recommended. I'm sure there's a smart solution for this situation. I'm using MySQL 4.1+, but if you know the answer for another engine, just share. Appreciated advice in advance :)

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• Python, web log data mining for frequent patterns

  - by descent

  Hello! I need to develop a tool for web log data mining. Having many sequences of urls, requested in a particular user session (retrieved from web-application logs), I need to figure out the patterns of usage and groups (clusters) of users of the website. I am new to Data Mining, and now examining Google a lot. Found some useful info, i.e. querying Frequent Pattern Mining in Web Log Data seems to point to almost exactly similar studies. So my questions are: Are there any python-based tools that do what I need or at least smth similar? Can Orange toolkit be of any help? Can reading the book Programming Collective Intelligence be of any help? What to Google for, what to read, which relatively simple algorithms to use best? I am very limited in time (to around a week), so any help would be extremely precious. What I need is to point me into the right direction and the advice of how to accomplish the task in the shortest time. Thanks in advance!

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• CSS to Make 2 Column Content Areas

  - by Joe Majewski

  I'm trying to stray away from using tables to form the layout of my content, and I can think of two alternatives that I'd like to better learn: (1) styling list items to be side-by-side, and (2) using div blocks that float onto the same line. Both of these would have their own uses for what I'm working on. I'm already using div tags to form the entire layout of my three-column template, but what I need to do now is a bit different. In case it helps, my project can be found here. In short, here's my question; how would I style a div so that the width of it is 50% of the width of the area it occupies, rather than 50% of the width of the page? As for my other question, what would be the best approach to styling list items so that they are side-by-side? I'm working on a registration script now, and instead of using a table with "Username" on the left and the input text on the right, I can use two list items. It's late and I've been working on this project of mine for about 8 hours straight now, so I apologize if I'm asking anything confusing. Feel free to ask me any questions about what I'm trying to do. Thanks, friends. :)

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• Velocity CTP: can we 'search' for objects?

  - by Stato Machino

  It appears that 'tags' allow us to associate a 'search term' with the objects placed into the Velocity cache space. However, these can only be queried within a 'region'. Further, regions somehow limit the locality of objects in the cache to a single server (or maybe something kinda like that). So this appears to make it hard to perform any operation for which the unique Id of the cached item is not persisted or continuously available to the application that stores and retrieves objects to and from the cache. In any case, I can't see an easy way to 'cleanse' the cache of objects or to find objects across the entire cache that may share some prefix, postfix or infix values in the cache key so that i can clear out the cache of object repeatedly created in unit tests, for example. And I am unsure about the consequences of regions being associated with single server cache locations. So I would appreciate any help with the following questions: What is the difference between a 'distributed cache' (called a 'partitioned' cache??) when using regions, and a 'local cache'? 1.a. In particular, are the region-oriented values in a distributed cache visible through a cache factory that is configured to 'see' the entire cache space? Are the operations of creating and removing 'regions' efficient enough that it would be reasonable to create a region and a group of tags for each bundle of objects that need to be cached? 2.a. Or does this just push the problem of scoping the 'search for objects' up the chain because the ability of the DataCache object to query down through regions and tags as limited as querying for the cache keys of objects themselves. Thanks, Stato

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• How to handle product ratings in a database

  - by Mel

  Hello, I would like to know what is the best approach to storing product ratings in a database. I have in mind the following two (simplified, and assuming a MySQL db) scenarios: Scenario 1: Create two columns in the product table to store number of votes and the sum of all votes. Use columns to get an average on the product display page: products(productedID, productName, voteCount, voteSum) Pros: I will only need to access one table, and thus execute one query to display product data and ratings. Cons: Write operations will be executed in a table whose original purpose is only to furnish product data. Scenario 2: Create an additional table to store ratings. products(productID, productName) ratings(productID, voteCount, voteSum) Pros: Isolate ratings into a separate table, leaving the products table to furnish data on available products. Cons: I will have to execute two separate queries on product page requests (one for data and another for ratings). In terms of performance, which of the following two approaches is best: Allow users to execute an occasional write query to a table that will handle hundreds of read requests? Execute two queries at every product page, but isolate the write query into a separate table. I'm a novice to database development, and often find myself struggling with simple questions such as these. Many thanks,

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• understanding and implementing Boids

  - by alphablender

  So I'm working on porting Boids to Brightscript, based on the pseudocode here: http://www.kfish.org/boids/pseudocode.html I'm trying to understand the data structures involved, for example is Velocity a single value, or is it a 3D value, ie velocity={x,y,z} It seems as if the pseudocode seems to mix this up where sometimes it has an equation that incudes both vectors and single-value items: v1 = rule1(b) v2 = rule2(b) v3 = rule3(b) b.velocity = b.velocity + v1 + v2 + v3 If Velocity is a tripartite value then this would make sense, but I'm not sure. So my first question here is, is this the correct datastructure for a single boid based on the Pseudocode on that page: boid={position:{px:0,py:0,pz:0},velocity:{x:0,y:0,z:0},vector:{x:0,y:0,z:0},pc:{x:0,y:0,z:0},pv:{x:0,y:0,z:0}) where pc=perceived center, pv= perceived velocity I"ve implemented a vector_add, vector_sub, vector_div, and vector boolean functions. The reason I'm starting from this pseudocode is I've not been able to find anything else that is as readable, but it still leaves me with lots of questions as the data structures are not explicitly defined for each variable. (edit) here's a good example of what i'm talking about: IF |b.position - bJ.position| < 100 THEN if b.position - b[j].position are both 3D coordinates, how can they be considered "less than 100" unless they are < {100,100,100} ? Maybe that is what I need to do here, use a vector comparison function?

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• Which of CouchDB or MongoDB suits my needs?

  - by vonconrad

  Where I work, we use Ruby on Rails to create both backend and frontend applications. Usually, these applications interact with the same MySQL database. It works great for a majority of our data, but we have one situation which I would like to move to a NoSQL environment. We have clients, and our clients have what we call "inventories"--one or more of them. An inventory can have many thousands of items. This is currently done through two relational database tables, inventories and inventory_items. The problems start when two different inventories have different parameters: # Inventory item from inventory 1, televisions { inventory_id: 1 sku: 12345 name: Samsung LCD 40 inches model: 582903-4 brand: Samsung screen_size: 40 type: LCD price: 999.95 } # Inventory item from inventory 2, accomodation { inventory_id: 2 sku: 48cab23fa name: New York Hilton accomodation_type: hotel star_rating: 5 price_per_night: 395 } Since we obviously can't use brand or star_rating as the column name in inventory_items, our solution so far has been to use generic column names such as text_a, text_b, float_a, int_a, etc, and introduce a third table, inventory_schemas. The tables now look like this: # Inventory schema for inventory 1, televisions { inventory_id: 1 int_a: sku text_a: name text_b: model text_c: brand int_b: screen_size text_d: type float_a: price } # Inventory item from inventory 1, televisions { inventory_id: 1 int_a: 12345 text_a: Samsung LCD 40 inches text_b: 582903-4 text_c: Samsung int_a: 40 text_d: LCD float_a: 999.95 } This has worked well... up to a point. It's clunky, it's unintuitive and it lacks scalability. We have to devote resources to set up inventory schemas. Using separate tables is not an option. Enter NoSQL. With it, we could let each and every item have their own parameters and still store them together. From the research I've done, it certainly seems like a great alterative for this situation. Specifically, I've looked at CouchDB and MongoDB. Both look great. However, there are a few other bits and pieces we need to be able to do with our inventory: We need to be able to select items from only one (or several) inventories. We need to be able to filter items based on its parameters (eg. get all items from inventory 2 where type is 'hotel'). We need to be able to group items based on parameters (eg. get the lowest price from items in inventory 1 where brand is 'Samsung'). We need to (potentially) be able to retrieve thousands of items at a time. We need to be able to access the data from multiple applications; both backend (to process data) and frontend (to display data). Rapid bulk insertion is desired, though not required. Based on the structure, and the requirements, are either CouchDB or MongoDB suitable for us? If so, which one will be the best fit? Thanks for reading, and thanks in advance for answers. EDIT: One of the reasons I like CouchDB is that it would be possible for us in the frontend application to request data via JavaScript directly from the server after page load, and display the results without having to use any backend code whatsoever. This would lead to better page load and less server strain, as the fetching/processing of the data would be done client-side.

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• Can I use my objects without fully populating them?

  - by LuckySlevin

  I have situation. I have to create a Sports Club system in JAVA. There should be a class your for keeping track of club name, president name and braches the club has. For each sports branch also there should be a class for keeping track of a list of players. Also each player should have a name, number, position and salary. So, I come up with this. Three seperate classes: public class Team { String clubName; String preName; Branch []branches; } public class Branch { Player[] players; } public class Player { String name; String pos; int salary; int number; } The problems are creating Branch[] in another class and same for the Player[]. Is there any simplier thing to do this? For example, I want to add info for only the club name, president name and branches of the club, in this situation, won't i have to enter players,names,salaries etc. since they are nested in each other. I hope i could be clear. For further questions you can ask.

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• Image resizing efficiency in C# and .NET 3.5

  - by Matthew Nichols

  I have written a web service to resize user uploaded images and all works correctly from a functional point of view, but it causes CPU usage to spike every time it is used. It is running on Windows Server 2008 64 bit. I have tried compiling to 32 and 64 bit and get about the same results. The heart of the service is this function: private Image CreateReducedImage(Image imgOrig, Size NewSize) { var newBM = new Bitmap(NewSize.Width, NewSize.Height); using (var newGrapics = Graphics.FromImage(newBM)) { newGrapics.CompositingQuality = CompositingQuality.HighSpeed; newGrapics.SmoothingMode = SmoothingMode.HighSpeed; newGrapics.InterpolationMode = InterpolationMode.HighQualityBicubic; newGrapics.DrawImage(imgOrig, new Rectangle(0, 0, NewSize.Width, NewSize.Height)); } return newBM; } I put a profiler on the service and it seemed to indicate the vast majority of the time is spent in the GDI+ library itself and there is not much to be gained in my code. Questions: Am I doing something glaringly inefficient in my code here? It seems to conform to the example I have seen. Are there gains to be had in using libraries other than GDI+? The benchmarks I have seen seem to indicate that GDI+ does well compare to other libraries but I didn't find enough of these to be confident. Are there gains to be had by using "unsafe code" blocks? Please let me know if I have not included enough of the code...I am happy to put as much up as requested but don't want to be obnoxious in the post.

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• Recommendation for using equals in Entities and avoiding LazyInitializationExceptions?

  - by huxendupsel

  In the beginning there is a problem that wants to be solved. In my case i got an LazyInitializationException while using indexof in a Collection to retrieve an Object for manipulation. Here i start to think about using equals in EntityBeans (OR-Mapper at all). I know there are some discussions about overriding equals in association with OR-Mapper as hibernate like [1] Entities equals(), hashCode() and toString(). How to correctly implement them? [2] To equals and hashcode or not on entity classes, that is the question. [3] Overriding equals and hashCode in Java I currently have some entities which implements the equals but inside the code i could not use equals several times because of the LazyInitializationExceptions. So i had to workaround and use eg. the name property of the object to identify it's equality. From my point of view the whole 'LazyInitializationException-thing' is not really mentioned in this questions. I'd like to know have you got some good patterns or real live recommendations how to avoid such exception in an equal-Method. Shall i use some helper Methodes to distinguish if a Object of a class is already initialized (4) or should i apdicate the use of equals and use helper classes instead (2)? And what is about catching LazyInitializationExceptions in the equals? [Edit]: If you put equals in context with the initialization of the Object then it will gain importance. Sometimes it is nessesary to have the Object fully initialized but sometimes you don't want to. Because you just need the Object itself (name, id, ...) not its Collection-Properties. So just for equalization you have to reattach the Object and load the whole bunch you don't realy need? Are there any other solutions for such a problem?

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• Problem understanding Inheritance

  - by dhruvbird

  I've been racking my brains over inheritance for a while now, but am still not completely able to get around it. For example, the other day I was thinking about relating an Infallible Human and a Fallible Human. Let's first define the two: Infallible Human: A human that can never make a mistake. It's do_task() method will never throw an exception Fallible Human: A human that will occasionally make a mistakes. It's do_task() method may occasionally throw a ErrorProcessingRequest Exception The question was: IS an infallible human A fallible human OR IS a fallible human AN infallible human? The very nice answer I received was in the form of a question (I love these since it gives me rules to answer future questions I may have). "Can you pass an infallible human where a fallible human is expected OR can you pass a fallible human where an infallible human is expected?" It seems apparent that you can pass an infallible human where a fallible human is expected, but not the other way around. I guess that answered my question. However, it still feels funny saying "An infallible human is a fallible human". Does anyone else feel queasy when they say it? It almost feels as if speaking out inheritance trees is like reading out statements from propositional calculus in plain English (the if/then implication connectives don't mean the same as that in spoken English). Does anyone else feel the same?

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• Serialport List Read problem and NullReferenceException?

  - by Plumbum7

  Hello everybody, Using Microsoft VC# 2008 Express (little fact about me : non experience in c#, programskills further very beginnerlevel. This peace op program is to communicate with Zigbee switching walloutlets (switching, status info). and is downloaded from http://plugwiselib.codeplex.com/SourceControl/list/changesets The problem: NullRefferenceException was UnHandled private void port_DataReceived(object sender, SerialDataReceivedEventArgs e) {// Event for receiving data string txt = port.ReadExisting(); Console.WriteLine(txt); List<PlugwiseMessage> msg = reader.Read (Regex.Split (txt, "\r\n" )); //Console.WriteLine( msg ); DataReceived(sender, new System.EventArgs(), msg); VC# Marks the last line and says msg is empty. so i looked further. Msg come's from txt text is filled with "000002D200C133E1\r\nPutFifoUnicast 40 : Handle 722 :"< so it goes wrong in or reader.Read or in the List so i looked further: public List<PlugwiseMessage> Read(string[] serialData) { Console.WriteLine(serialData); List<PlugwiseMessage> output = new List<PlugwiseMessage>(); Console.WriteLine(output); Both (serialData) as (output); are empty. So can i assume that the problem is in: Read(string[] serialData) But now the questions, Is Read(string[] serialData) something which is a Windows.Refence or is is from a Method ? and IF this is so is this then reader.READ (how can i find this)? (answered my own question proberly)(method reader)(private PlugwiseReader reader) So why isn't is working trough the serialData ? or is it the List<PlugwiseMessage> part, but i have no idea how it is filled can sombody help me ?

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• Which DVCS would work best on Windows for my scenario?

  - by PoorLuzer

  At work I use ClearCase and SourceSafe, but have found some time to do some time to code for myself enroute thanks to a disposable laptop. However, I wish I had a lightweight VCS on my system using which I would be able to make changes to my code during the commute and then push/grab them from my Linux systems. I use git on my home system, but I can't really get it working on Windows. I don't want all that cygwin hack. If it does not run natively on Windows, it just won't do. What have you guys tried on your Windows system? Something that YOU use. The big player at the moment seems to be Mercurial? What would be best for a one (or maybe two) man team? I just need to maintain : Versioned copies of source code. Checking in and out should be as less obtrusive as possible. I am looking forward to a multiple Undo kind of feature (like that in an EMacs buffer) but persistent. I really like the way git keeps track of lines moving between files in a source code set I should be able to move part(s)/sub tree(s) of the source tree (each sub tree implies a module/plugin to my the main software I am building) to an archival system either completly or partially and restore them back from the archive as and when required and the system should track any changes to this tree as well. I actually want to experiment with my code as much as possible without me manually keeping track of what I modified and what I need to undo once I try out some idea, so that I am back to where I want to continue from. Notes : A similar topic came up a year ago : http://stackoverflow.com/questions/4670/dvcs-choices-whats-good-for-windows I hope things have changed, and I really want people to share their own, real life experiences. Not something they recommend without using it or they think will work.

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• How to disable Rails submit buttons alongside Prototype helpers & RJS?

  - by Jesse

  I'm trying to follow this post http://stackoverflow.com/questions/576240/how-can-i-unobtrusively-disable-submit-buttons-with-javascript-and-prototype but I can't get it to work. The form triggers an RJS function, so I need to keep the helpers' onclick events intact. The RJS returns/reloads the same forms along with two new texts. I'm really confused. Here is my rails code for the forms: .span-20#comparison / new comparison . . . / voting forms (also reloaded) .span-4.prepend-3.append-6 - form_remote_tag :action => url_for(:controller => :comparisons), :method => :post do = hidden_field_tag :poem1_id, poems[:a].id = hidden_field_tag :poem2_id, poems[:b].id = hidden_field_tag :response, 1 = submit_tag "Vote for me", :disabled => false, :disable_with => 'Vote for me', :class => "compare" .span-4.append-3.last - form_remote_tag :action => url_for(:controller => :comparisons), :method => :post do = hidden_field_tag :poem1_id, poems[:a].id = hidden_field_tag :poem2_id, poems[:b].id = hidden_field_tag :response, 2 = submit_tag "Vote for me", :disable_with => 'Vote for me', :class => "compare" .span-4.prepend-8.append-8.prepend-top.last - form_remote_tag :action => url_for(:controller => :comparisons), :method => :post do = hidden_field_tag :poem1_id, poems[:a].id = hidden_field_tag :poem2_id, poems[:b].id = hidden_field_tag :response, 'draw' = submit_tag "Declare Draw", :disable_with => 'Declare Draw', :class => "compare" RJS page.replace_html :comparison, :partial => 'poems', :object => @poems page.insert_html :top, :previous, :partial => 'comparison', :object => @comparison page << "Effect.ScrollTo($('top'));"

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• Why is it possible to enumerate a LinqToSql query after calling Dispose() on the DataContext?

  - by DanM

  I'm using the Repository Pattern with some LinqToSql objects. My repository objects all implement IDisposable, and the Dispose() method does only thing--calls Dispose() on the DataContext. Whenever I use a repository, I wrap it in a using person, like this: public IEnumerable<Person> SelectPersons() { using (var repository = _repositorySource.GetNew<Person>(dc => dc.Person)) { return repository.GetAll(); } } This method returns an IEnumerable<Person>, so if my understanding is correct, no querying of the database actually takes place until Enumerable<Person> is traversed (e.g., by converting it to a list or array or by using it in a foreach loop), as in this example: var persons = gateway.SelectPersons(); // Dispose() is fired here var personViewModels = ( from b in persons select new PersonViewModel { Id = b.Id, Name = b.Name, Age = b.Age, OrdersCount = b.Order.Count() }).ToList(); // executes queries In this example, Dispose() gets called immediately after setting persons, which is an IEnumerable<Person>, and that's the only time it gets called. So, a couple questions: How does this work? How can a disposed DataContext still query the database for results when I walk the IEnumerable<Person>? What does Dispose() actually do? I've heard that it is not necessary (e.g., see this question) to dispose of a DataContext, but my impression was that it's not a bad idea. Is there any reason not to dispose of it?

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• CSS - background-size: cover; not working in Firefox

  - by Jayant Bhawal

  body{ background-image: url("./content/site_data/bg.jpg"); background-size: cover; background-repeat: no-repeat; font-family: 'Lobster', cursive; } Check: http://demo.jayantbhawal.in on firefox browsers, NOT in widescreen mode. The code works on Chrome(Android + PC) and even the stock Android browser, but NOT Firefox(Android + PC). Is there any good alternative to it? Why is it not working anyways? Googled this issue a lot of times, but no one else seems to have this problem. Is it just me? In any case, how do I fix it? There are quite some questions on SO about it too, but none of them provide a legitimate solution, so can someone just tell me if they have background-size: cover; issues on firefox too? So basically tell me 3 things: 1. Why is it happening? 2. What is a good alternative to it? 3. Is this happening to you too? On Firefox browsers of course. Chrome Version 35.0.1916.114 m Firefox Version 29.0.1 Note: I may already be trying to fix it so at times you may see a totally weird page. Wait a bit and reload.

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• Oracle Query Optimization: Why is My Second Query Faster?

  - by Patrick Cuff

  I was having some performance issues with an Oracle query, so I downloaded a trial of the Quest SQL Optimizer for Oracle, which made some changes that dramatically improved the query's performance. I'm not exactly sure why the recommended query had such an improvement; can anyone provide an explanation? Before: SELECT t1.version_id, t1.id, t2.field1, t3.person_id, t2.id FROM table1 t1, table2 t2, table3 t3 WHERE t1.id = t2.id AND t1.version_id = t2.version_id AND t2.id = 123 AND t1.version_id = t3.version_id AND t1.VERSION_NAME <> 'AA' order by t1.id Plan Cost: 831 Elapsed Time: 00:00:21.40 Number of Records: 40,717 After: SELECT /*+ USE_NL_WITH_INDEX(t1) */ t1.version_id, t1.id, t2.field1, t3.person_id, t2.id FROM table2 t2, table3 t3, table1 t1 WHERE t1.id = t2.id + 0 AND t1.version_id = t2.version_id + 0 AND t2.id = 123 AND t1.version_id = t3.version_id + 0 AND t1.VERSION_NAME || '' <> 'AA' AND t3.version_id = t2.version_id + 0 order by t1.id Plan Cost: 686 Elapsed Time: 00:00:00.95 Number of Records: 40,717 Questions: Why does re-arranging the order of the tables in the FROM clause help? Why does adding + 0 to the WHERE clause comparisons help? Why does || '' <> 'AA' in the WHERE clause VERSION_NAME comparison help? Is this a more efficient way of handling possible nulls on this column?

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• When to use CTEs to encapsulate sub-results, and when to let the RDBMS worry about massive joins.

  - by IanC

  This is a SQL theory question. I can provide an example, but I don't think it's needed to make my point. Anyone experienced with SQL will immediately know what I'm talking about. Usually we use joins to minimize the number of records due to matching the left and right rows. However, under certain conditions, joining tables cause a multiplication of results where the result is all permutations of the left and right records. I have a database which has 3 or 4 such joins. This turns what would be a few records into a multitude. My concern is that the tables will be large in production, so the number of these joined rows will be immense. Further, heavy math is performed on each row, and the idea of performing math on duplicate rows is enough to make anyone shudder. I have two questions. The first is, is this something I should care about, or will SQL Server intelligently realize these rows are all duplicates and optimize all processing accordingly? The second is, is there any advantage to grouping each part of the query so as to get only the distinct values going into the next part of the query, using something like: WITH t1 AS ( SELECT DISTINCT... [or GROUP BY] ), t2 AS ( SELECT DISTINCT... ), t3 AS ( SELECT DISTINCT... ) SELECT... I have often seen the use of DISTINCT applied to subqueries. There is obviously a reason for doing this. However, I'm talking about something a little different and perhaps more subtle and tricky.

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• What's the steps for SQL optimization and changes without reflect live system ?

  - by Space Cracker

  we have a big portal that build using SharePoint 2007 , asp.net 3.5 , SQL Server 2005 .. many developers work in it since 01/2008 and we are now doing huge analysis for current SQL Databases [not share-point DB ] to optimize and enhance it. The main db have about 330 table and 1720 stored procedure (SP) created from 01/2008 till now Many table names / Columns is very long and we want to short it we found SP names is written in 25 format :( , some of them are very complex and also we want to rename many SP parameters need to be renamed one of the biggest table is Registered user table, that will be spitted in more than one table for some optimization, many columns name will be changed I searched for the way that i can rename table names ,columns and i found SQL refactor tool but i still trying it .. my questions : Is SQl Refactor is the best tool for renaming ? or is there any other one ? if i want to make it manually, is there any references or best practice for that ? How can i do such changes in fast and stable way .. i search for recommendations and case studies if exist ?

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• Windows Phone 7.1.1 Ping

  - by Matt

  I am writing an app to connect to a third party application using REST web services. I have a configuration page that asks for an IP, Port, User Name & Password, currently it just blindly assumes you enter the correct details and attempts a connection. I want to create a test routine that goes through and checks off the following steps when setting up the config information Is the IP/Hostname correct (using ping or something) Is the Port correct Is the Username & Password correct then displays the results on screen as it's going so that if it can't connect to the service it's easier to identify where the issue is. To achieve step 1 I would like to use Ping or some equivalent that does not rely on a particular port being open. So I can eliminate dodgy DNS or a typo in the IP/Hostname. I understand from previous questions asked that ping wasn't possible in 7.0 but with Mango the sockets classes have been added in, is it possible now, if so how? If it still isn't possible is there a different way I can achieve step 1?

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