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• Replacing repetitively occuring loops with eval in Javascript - good or bad?

  - by Herc

  Hello stackoverflow! I have a certain loop occurring several times in various functions in my code. To illustrate with an example, it's pretty much along the lines of the following: for (var i=0;i<= 5; i++) { function1(function2(arr[i],i),$('div'+i)); $('span'+i).value = function3(arr[i]); } Where i is the loop counter of course. For the sake of reducing my code size and avoid repeating the loop declaration, I thought I should replace it with the following: function loop(s) { for (var i=0;i<= 5; i++) { eval(s); } } [...] loop("function1(function2(arr[i],i),$('div'+i));$('span'+i).value = function3(arr[i]);"); Or should I? I've heard a lot about eval() slowing code execution and I'd like it to work as fast as a proper loop even in the Nintendo DSi browser, but I'd also like to cut down on code. What would you suggest? Thank you in advance!

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• EventHandlers saved to databases.

  - by Stacey

  In a database application (using Sql Server right now, in C#, with Entity Framework 4.0) I have a situation where I need to trigger events when some values change. For instance assume a class "Trackable". class Trackable { string Name { get; set; } int Positive { get; set; } int Negative { get; set; } int Total { get; set; } // event OnChanged } Trackable is represented in the database as follows; table Trackables Id | guid name | varchar(32) positive | int negative | int Total is of course, calculated at runtime. When a trackable event changes, I want to inspect its previous value, and then see what it is changing to, and be capable of reacting accordingly. However different trackables need to trigger different events (to avoid a huge, massive cascading switch/if block). If this were just only C# code it would be easy - but they have to be saved to the database. I can't divide up each different trackable into a different table/class, that would be silly - they are all identical, but the event raised is different based on how they are made. So I guess my question is, is there any way to store an event handler in a database such that.. Trackable t1 = new Trackable() { Name = "Trackable1" OnChange += TrackableChangedEventHandler(OnTrackable1Change) } Trackable t2 = new Trackable() { Name = "Trackable2", OnChange += TrackableChangedEventHandler(OnTrackable2Change) }

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• Clarification on ZVals

  - by Beachhouse

  I was reading this: http://www.dereleased.com/2011/04/27/the-importance-of-zvals-and-circular-references/ And there's an example that lost me a bit. $foo = &$bar; $bar = &$foo; $baz = 'baz'; $foo = &$baz; var_dump($foo, $bar); /* string(3) "baz" NULL */ If you’ve been following along, this should make perfect sense. $foo is created, and pointed at a ZVal location identified by $bar; when $bar is created, it points at the same place $foo was pointed. That location, of course, is null. When $foo is reassigned, the only thing that changes is to which ZVal $foo points; if we had assigned a different value to $foo first, then $bar would still retain that value. I learned to program in C. I understand that PHP is different and it uses ZVals instead of memory locations as references. But when you run this code: $foo = &$bar; $bar = &$foo; It seems to me that there would be two ZVals. In C there would be two memory locations (and the values would be of the opposite memory location). Can someone explain?

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• C++: getting the address of the start of an std::vector ?

  - by shoosh

  Sometimes it is useful to use the starting address of an std::vector and temporarily treat that address as the address of a regularly allocated buffer. For instance replace this: char* buf = new char[size]; fillTheBuffer(buf, size); useTheBuffer(buf, size); delete[] buf; With This: vector<char> buf(size); fillTheBuffer(&buf[0], size); useTheBuffer(&buf[0], size); The advantage of this is of course that the buffer is deallocated automatically and I don't have to worry about the delete[]. The problem I'm having with this is when size == 0. In that case the first version works ok. An empty buffer is "allocated" and the subsequent functions do nothing size they get size == 0. The second version however fails if size == 0 since calling buf[0] may rightly contain an assertion that 0 < size. So is there an alternative to the idiom &buf[0] that returns the address of the start of the vector even if the vector is empty? I've also considered using buf.begin() but according to the standard it isn't even guaranteed to return a pointer.

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• (Java) Is there a type of object that can handle anything from primitives to arrays?

  - by Michael

  I'm pretty new to Java, so I'm hoping one of you guys knows how to do this. I'm having the user specify both the type and value of arguments, in any XML-like way, to be passed to methods that are external to my application. Example: javac myAppsName externalJavaClass methodofExternalClass [parameters] Of course, to find the proper method, we have to have the proper parameter types as the method may be overloaded and that's the only way to tell the difference between the different versions. Parameters are currently formatted in this manner: (type)value(/type), e.g. (int)71(/int) (string)This is my string that I'm passing as a parameter!(/string) I parse them, getting the constructor for whatever type is indicated, then execute that constructor by running its method, newInstance(<String value>), loading the new instance into an Object. This works fine and dandy, but as we all know, some methods take arrays, or even multi-dimensional arrays. I could handle the argument formatting like so: (array)(array)(int)0(/int)(int)1(/int)(/array)(array)(int)2(/int)(int)3(/int)(/array)(/array)... or perhaps even better... {{(int)0(/int)(int)1(/int)}{(int)2(/int)(int)3(/int)}}. The question is, how can this be implemented? Do I have to start wrapping everything in an Object[] array so I can handle primitives, etc. as argObj[0], but load an array as I normally would? (Unfortunately, I would have to make it an Object[][] array if I wanted to support two-dimensional arrays. This implementation wouldn't be very pretty.)

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• determining the starting speed for an accelerated animation (in flash/actionscript but it's a math question)

  - by vulkanino

  This question burns my brain. I have an object on a plane, but for the sake of simplicity let's work just on a single dimension, thus the object has a starting position xs. I know the ending position xe. The object has to move from starting to ending position with an accelerated (acceleration=a) movement. I know the velocity the object has to have at the ending position (=ve). In my special case the ending speed is zero, but of course I need a general formula. The only unknown is the starting velocity vs. The objects starts with vs in xs and ends with ve in xe, moving along a space x with an acceleration a in a time t. Since I'm working with flash, space is expressed in pixels, time is expressed in frames (but you can reason in terms of seconds, it's easy to convert knowing the frames-per-second). In the animation loop (think onEnterFrame) I compute the new velocity and the new position with (a=0.4 for example): vx *= a (same for vy) x += vx (same for y) I want the entire animation to last, say, 2 seconds, which at 30 fps is 60 frames. Now you know that in 60 frames my object has to move from xs to xe with a constant deceleration so that the ending speed is 0. How do I compute the starting speed vs? Maybe there's a simpler way to do this in Flash, but I am now interested in the math/physics behind this.

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• "The breakpoint will not currently be hit" error while debugging a mixed mode application (c# and unmanaged c++)

  - by user1678403

  While debugging a mixed mode application in VS2010, the breakpoint set on a line of code contained in an unmanaged c++ dll source file (called from a managed c# wrapper class) shows the infamous "The breakpoint will not currently be hit. No symbols have been loaded for this document" info message when hovering the mouse over the breakpoint on the line in question. The breakpoint itself is a red circle with a yellow info triangle instead of the usual solid red orb. Of course, the breakpoint isn't hit when the debugger is executed. Most answers I've found for this warning indicate the breakpoint hasn't been set properly, or that the expected dll is not being loaded, or that the associated pdb file is not located in the correct location, etc. etc. This is not the problem. The application does load and execute the referenced dll correctly. I've verified that the correct pdb file, with the same file date as its dll, is located in the executable's working directory along with the target dll itself. The debugger simply doesn't load the symbols for the dll, and the dll doesn't show in the Modules list. None of the solutions I've found online work for this problem. The dll doesn't show in the modules list available from 'Debug-Windows-Modules' menu selection... even though it is, in fact, loaded. Breakpoints set in the wrapper class work correctly. Deleting the bin and obj directories, cleaning and rebuilding the solution also doesn't help.

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• Using Moq to Validate Separate Invocations with Distinct Arguments

  - by Thermite

  I'm trying to validate the values of arguments passed to subsequent mocked method invocations (of the same method), but cannot figure out a valid approach. A generic example follows: public class Foo { [Dependency] public Bar SomeBar { get; set; } public void SomeMethod() { this.SomeBar.SomeOtherMethod("baz"); this.SomeBar.SomeOtherMethod("bag"); } } public class Bar { public void SomeOtherMethod(string input) { } } public class MoqTest { [TestMethod] public void RunTest() { Mock<Bar> mock = new Mock<Bar>(); Foo f = new Foo(); mock.Setup(m => m.SomeOtherMethod(It.Is<string>("baz"))); mock.Setup(m => m.SomeOtherMethod(It.Is<string>("bag"))); // this of course overrides the first call f.SomeMethod(); mock.VerifyAll(); } } Using a Function in the Setup might be an option, but then it seems I'd be reduced to some sort of global variable to know which argument/iteration I'm verifying. Maybe I'm overlooking the obvious within the Moq framework?

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• Prevent cached objects to end up in the database with Entity Framework

  - by Dirk Boer

  We have an ASP.NET project with Entity Framework and SQL Azure. A big part of our data only needs to be updated a few times a day, other data is very volatile. The data that barely changes we cache in memory at startup, detach from the context and than use it mainly for reading, drastically lowering the amount of database requests we have to do. The volatile data is requested everytime by a DbContext per Http request. When we do an update to the cached data, we send a message to all instances to catch a fresh version of all the data from the SQL server. So far, so good. Until we introduced a bug that linked one of these 'cached' objects to the 'volatile' data, and did a SaveChanges. Well, that was quite a mess. The whole data tree was added again and again by every update, corrupting the whole database with a whole lot of duplicated data. As a complete hack I added a completely arbitrary column with a UniqueConstraint and some gibberish data on one of the root tables; hopefully failing the SaveChanges() next time we introduce such a bug because it will violate the Unique Constraint. But it is of course hacky, and I'm still pretty scared ;P Are there any better ways to prevent whole tree's of cached objects ending up in the database? More information Project is ASP.NET MVC I cache this data, because it is mainly read only, and this saves a tons of extra database calls per http request

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• Patterns to deal with with functions that can have different kinds of results.

  - by KaptajnKold

  Suppose you have an method on an object that given the some input alters the objects state if the input validates according to some complex logic. Now suppose that when the input doesn't validate, it can be due to several different things, each of which we would like to be able to deal with in different ways. I'm sure many of you are thinking: That's what exceptions are for! I've thought of this also. But my reservation against using exceptions is that in some cases there is nothing exceptional about the input not validating and I really would like to avoid using exceptions to control what is really just in the expected flow of the program. If there were only one interpretation possible, I could simply choose to return a boolean value indicating whether or not the operation resulted in a state change or not and the respond appropriately when it did not. There is of course also the option to return a status code which the client can then choose to interpret or not. I don't like this much either because there is nothing semantic about status codes. The solution I have so far is to always check for each possible situation which I am able to handle before I call the method which then returns a boolean to inform the client if the object changed state. This leaves me the flexibility to handle as few or as many as the possible situations as I wish depending on the context I am in. It also has the benefit of making the method I am calling simpler to write. The drawback is that there is quite a lot of duplication in the client code wherever I call the method. Which of these solutions do you prefer and why? What other patterns do people use for providing meaningful feedback from functions? I know that some languages support multiple return values, and I if I had that option I would surely prefer it.

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• Why doesn't my processor have built-in BigInt support?

  - by ol

  As far as I understood it, BigInts are usually implemented in most programming languages as strings containing numbers, where, eg.: when adding two of them, each digit is added one after another like we know it from school, e.g.: 246 816 * * ---- 1062 Where * marks that there was an overflow. I learned it this way at school and all BigInt adding functions I've implemented work similar to the example above. So we all know that our processors can only natively manage ints from 0 to 2^32 / 2^64. That means that most scripting languages in order to be high-level and offer arithmetics with big integers, have to implement/use BigInt libraries that work with integers as strings like above. But of course this means that they'll be far slower than the processor. So what I've asked myself is: Why doesn't my processor have a built-in BigInt function? It would work like any other BigInt library, only (a lot) faster and at a lower level: Processor fetches one digit from the cache/RAM, adds it, and writes the result back again. Seems like a fine idea to me, so why isn't there something like that?

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• determine week when pick a day

  - by derikluv

  I'm trying to accomplish the following task. I'm developing a custom calendar with three views (day,week and month), there may be something out there already but I'm rewriting this as part of learning tool for me as well. So user will face with Day view when they first visit, with arrows to go back and forth to next day or previous day of course. If they click on Week View, it will give them a 7 days overview with today date as default, and once again they can go back and forth to next week or previous week. The last view is the full month calendar, once they click on the day, it will give them the detail of the day and at the same time reset the default as the day they pick. So if they go back to week view, they will see the detail for the week contain the day that they picked. This is where I have trouble wrapping my head around with, I know there are PHP functions that determine the day of the week but I can't seem to think about how to pass in the date and get the full week starting from Sunday for the day that passed in. For example, if I passed in 10/12/2012, I'd like to start the week at 10/07/12 - 10/13/12. Thank you kindly for your help or pointing to the right direction. Please excuse my grammar/spelling mistakes as well.

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• Sort MySQL query result by a alphanumeric field

  - by Jason Shultz

  I'm querying a table in a db using php. one of the fields is a column called "rank" and has data like the following: none 1-bronze 2-silver 3-gold ... 10-ambassador 11-president I want to be able to sort the results based on that "rank" column. any results where the field is "none" get excluded, so those don't factor in. As you can already guess, right now the results are coming back like this: 1-bronze 10-ambassador 11-president 2-silver 3-gold Of course, I would like for it to be sorted so it is like the following: 1-bronze 2-silver 3-gold ... 10-ambassador 11-president Right now the query is being returned as an object. I've tried different sort options like natsort, sort, array_multisort but haven't got it to work the way I'm sure it can. I would prefer keeping the results in an object form if possible. I'm passing the data on to a view in the next step. although, it's perfectly acceptable to pass the object to the view and then do the work there. so it's not an issue after all. :) thank you for your help. i'm hoping I'm making sense.

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• Is this the best way to grab common elements from a Hash of arrays?

  - by Hulihan Applications

  I'm trying to get a common element from a group of arrays in Ruby. Normally, you can use the & operator to compare two arrays, which returns elements that are present or common in both arrays. This is all good, except when you're trying to get common elements from more than two arrays. However, I want to get common elements from an unknown, dynamic number of arrays, which are stored in a hash. I had to resort to using the eval() method in ruby, which executes a string as actual code. Here's the function I wrote: def get_common_elements_for_hash_of_arrays(hash) # get an array of common elements contained in a hash of arrays, for every array in the hash. # ["1","2","3"] & ["2","4","5"] & ["2","5","6"] # => ["2"] # eval("[\"1\",\"2\",\"3\"] & [\"2\",\"4\",\"5\"] & [\"2\",\"5\",\"6\"]") # => ["2"] eval_string_array = Array.new # an array to store strings of Arrays, ie: "[\"2\",\"5\",\"6\"]", which we will join with & to get all common elements hash.each do |key, array| eval_string_array << array.inspect end eval_string = eval_string_array.join(" & ") # create eval string delimited with a & so we can get common values return eval(eval_string) end example_hash = {:item_0 => ["1","2","3"], :item_1 => ["2","4","5"], :item_2 => ["2","5","6"] } puts get_common_elements_for_hash_of_arrays(example_hash) # => 2 This works and is great, but I'm wondering...eval, really? Is this the best way to do it? Are there even any other ways to accomplish this(besides a recursive function, of course). If anyone has any suggestions, I'm all ears. Otherwise, Feel free to use this code if you need to grab a common item or element from a group or hash of arrays, this code can also easily be adapted to search an array of arrays.

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• Dealing with large directories in a checkout

  - by Eric

  I am trying to come up with a version control process for a web app that I work on. Currently, my major stumbling blocks are two directories that are huge (both over 4GB). Only a few people need to work on things within the huge directories; most people don't even need to see what's in them. Our directory structure looks something like: / --file.aspx --anotherFile.aspx --/coolThings ----coolThing.aspx --/bigFolder ----someHugeMovie.mov ----someHugeSound.mp3 --/anotherBigFolder ----... I'm sure you get the picture. It's hard to justify a checkout that has to pull down 8GB of data that's likely useless to a developer. I know, it's only once, but even once could be really frustrating for someone (and will make it harder for me to convince everyone to use source control). (Plus, clean checkouts will be painfully slow.) These folders do have to be available in the web application. What can I do? I've thought about separate repositories for the big folders. That way, you only download if you need it; but then how do I manage checking these out onto our development server? I've also thought about not trying to version control those folders: just update them directly on the web server... but I am not enamored of this idea. Is there some magic way to simply exclude directories from a checkout that I haven't found? (Pretty sure there is not.) Of course, there's always the option to just give up, bite the bullet, and accept downloading 8 useless GB. What say you? Have you encountered this problem before? How did you solve it?

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• Objective-measures of the expressiveness of programming languages [closed]

  - by Casebash

  I am very interested in the expressiveness of different languages. Everyone who has programmed in multiple languages knows that sometimes a language allows you to express concepts which you can't express in other languages. You can have all kinds of subjective discussion about this, but naturally it would be better to have an objective measure. There do actually exist objective measures. One is Turing-Completeness, which means that a language is capable of generating any output that could be generated by following a sequential set of steps. There are also other lesser levels of expressiveness such as Finite State Automata. Now, except for domain specific languages, pretty much all modern languages are Turing complete. It is therefore natural to ask the following question: Can we can define any other formal measures of expressiveness which are greater than Turing completeness? Now of course we can't define this by considering the output that a program can generate, as Turing machines can already produce the same output that any other program can. But there are definitely different levels in what concepts can be expressed - surely no-one would argue that assembly language is as powerful as a modern object oriented language like Python. You could use your assembly to write a Python interpreter, so clearly any accurate objective measure would have to exclude this possibility. This also causes a problem with trying to define the expressiveness using the minimum number of symbols. How exactly to do so is not clear and indeed appears extremely difficult, but we can't assume that just because we don't know how to solve a problem, that nobody know how to. It is also doesn't really make sense to demand a definition of expressiveness before answering the question - after all the whole point of this question is to obtain such a definition. I think that my explanation will be clear enough for anyone with a strong theoretical background in computer science to understand what I am looking for. If you do have such a background and you disagree, please comment why, but if you don't thats probably why you don't understand the question.

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• Why does java.util.concurrent.ArrayBlockingQueue use 'while' loops instead of 'if' around calls to

  - by theFunkyEngineer

  I have been playing with my own version of this, using 'if', and all seems to be working fine. Of course this will break down horribly if signalAll() is used instead of signal(), but if only one thread at a time is notified, how can this go wrong? Their code here - check out the put() and take() methods; a simpler and more-to-the-point implementation can be seen at the top of the JavaDoc for Condition. Relevant portion of my implementation below. public Object get() { lock.lock(); try { if( items.size() < 1 ) hasItems.await(); Object poppedValue = items.getLast(); items.removeLast(); hasSpace.signal(); return poppedValue; } catch (InterruptedException e) { e.printStackTrace(); return null; } finally { lock.unlock(); } } public void put(Object item) { lock.lock(); try { if( items.size() >= capacity ) hasSpace.await(); items.addFirst(item); hasItems.signal(); return; } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } P.S. I know that generally, particularly in lib classes like this, one should let the exceptions percolate up.

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• What is the most challenging part of a project like MyLifeBits

  - by kennyzx

  I have made a small utility to keep track of my daily expenses, and my coffee consumption (I always want to quit coffee but never succeed), and of course, this kind of utility is quite simple, just involving an xml file and a few hundred lines of code to manipulate the file. Then I find this project MyLifeBits, it is very intesting, but I think it should require a lot of effort to achieve its goal- that is, to record everything about a person that can be digitally record. So I wonder, it is possible to write an advanced version of my own utility - but a tiny version of MyLifeBits, that can capture: Every webpage I've read, no matter what browser I am using, just download its contents for offline reading, Auto archive emails/documents/notes that I edited, Auto archive Codes that I run/written. Well, these are basically what I do on my PC. And the captured records can be searched easily. My question is, What do you think is the most challenging part? Interoperating with Visual Studio/Office/Lotes Notes/Web browsers is one thing, Database is another thing given that "everything" is record, Advanced programming patterns since it is not a "toy project"? And others that I have overlooked but can be very difficult to handle?

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• Is this the best way to grab Common element from a Hash of arrays?

  - by Hulihan Applications

  I'm trying to get a common element from a group of arrays in Ruby. Normally, you can use the & operator to compare two arrays, which returns elements that are present or common in both arrays. This is all good, except when you're trying to get common elements from more than two arrays. However, I want to get common elements from an unknown, dynamic number of arrays, which are stored in a hash. I had to resort to using the eval() method in ruby, which executes a string as actual code. Here's the function I wrote: def get_common_elements_for_hash_of_arrays(hash) # get an array of common elements contained in a hash of arrays, for every array in the hash. # ["1","2","3"] & ["2","4","5"] & ["2","5","6"] # => ["2"] # eval("[\"1\",\"2\",\"3\"] & [\"2\",\"4\",\"5\"] & [\"2\",\"5\",\"6\"]") # => ["2"] eval_string_array = Array.new # an array to store strings of Arrays, ie: "[\"2\",\"5\",\"6\"]", which we will join with & to get all common elements hash.each do |key, array| eval_string_array << array.inspect end eval_string = eval_string_array.join(" & ") # create eval string delimited with a & so we can get common values return eval(eval_string) end example_hash = {:item_0 => ["1","2","3"], :item_1 => ["2","4","5"], :item_2 => ["2","5","6"] } puts get_common_elements_for_hash_of_arrays(example_hash) # => 2 This works and is great, but I'm wondering...eval, really? Is this the best way to do it? Are there even any other ways to accomplish this(besides a recursive function, of course). If anyone has any suggestions, I'm all ears. Otherwise, Feel free to use this code if you need to grab a common item or element from a group or hash of arrays, this code can also easily be adapted to search an array of arrays.

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• Mutate an object into an instance of one its subclasses

  - by Gohu

  Hi, Is it possible to mutate an object into an instance of a derived class of the initial's object class? Something like: class Base(): def __init__(self): self.a = 1 def mutate(self): self = Derived() class Derived(Base): def __init__(self): self.b = 2 But that doesn't work. >>> obj = Base() >>> obj.mutate() >>> obj.a 1 >>> obj.b AttributeError... If this isn't possible, how should I do otherwise? My problem is the following: My Base class is like a "summary", and the Derived class is the "whole thing". Of course getting the "whole thing" is a bit expensive so working on summaries as long as it is possible is the point of having these two classes. But you should be able to get it if you want, and then there's no point in having the summary anymore, so every reference to the summary should now be (or contain, at least) the whole thing. I guess I would have to create a class that can hold both, right? class Thing(): def __init__(self): self.summary = Summary() self.whole = None def get_whole_thing(self): self.whole = Whole()

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• Ruby On Rails -

  - by Adam S

  I am trying to create a collection_select that is dependent on another collection_select, following the railscasts episode #88.. The database includes a schedule of all cruise ships arrival dates. See attached schema diagram,... (The arrow side of the lines indicate has_many, the non-pointy side indicates belongs_to) In the "booking/new" view I have a collection_select for choosing a cruiseline, then another collection_select will appear for selecting a ship, then another for selecting the date that ship is in. If I ONLY put a collection_select for shipshedule it works fine(because of the direct association with the bookings model). However, if I try to add a collection_select for cruiselines....it breaks(Im assuming because their isnt a direct association). The collection_select for cruiselines returns an undefined method error for "cruiseline_id".....if I simply use "id" the collection_select works, but of course isnt fully functional due to incorrect naming of the form field. I have tried "has_many :shipschedules, :through = :cruiseships" in the cruiseline model and "has_many :bookings, :through = :shipschedules" in the cruiseships model... As you can see in the diagram, I need to access the cruiseships and cruiselines model through the bookings model. I have the models set up so a cruiseline has_many cruiseships, a cruiseship has_many shipschedules, and a shipschedule has_many bookings. But, the bookings model cant directly access the cruiseline model. How do I accomplish this? THANKS!!! http://www.adamstockland.com/common/images/RoRf/PastedGraphic-2.png http://www.adamstockland.com/common/images/RoRf/PastedGraphic-1.png

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• OOP beginner: classB extends classA. classA already object. method in classB needed.. etc.

  - by Yvo

  Hey guys, I'm learning myself to go from function based PHP coding to OOP. And this is the situation: ClassA holds many basic tool methods (functions). it's __construct makes a DB connection. ClassB holds specific methods based on a certain activity (extract widgets). ClassB extends ClassA because it uses some of the basic tools in there e.g. a database call. In a php file I create a $a_class = new ClassA object (thus a new DB connection). Now I need a method in ClassB. I do $b_class = new ClassB; and call a method, which uses a method from it's parent:: ClassA. In this example, i'm having ClassA 'used' twice. Onces as object, and onces via a parent:: call, so ClassA creates another DB connection (or not?). So what is the best setup for this basic classes parent, child (extend) situation? I only want to make one connection of course? I don't like to forward the object to ClassB like this $b_class = new ClassB($a_object); or is that the best way? Thanks for thinking with me, and helping :d

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• Remove .img css from prepended div

  - by Ivan Schrecklich

  OK as the title says I've got a div which is prepended and dynamically loaded. The problem I have is that I can't split the css on this one as it parses also whole strings. The usage is like that: I've got a @username somewhere in the string. If the user hovers it a div with informations will get prepended to the current username. Now there is the problem that I've allowed users to post images in this text also. As the autolinker is flexible it doesn't know the image sizes and restrictions and I want to leave it like that! So I define css classes which look like that: .minpost img{ max-height: 30px; max-width: 30px; } Of course I don't need to mention that this attribute is also inherited by the prepended div. And that I don't want to! nifty little tricks like !important won't work for me. So I am asking you guys. If you need further informations just ask?!

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• How do I size a second div to be 100% height underneath a fixed image?

  - by mk

  I'm using semi-transparent PNGs (due to the designer's overlapping of elements) and trying to achieve a layout that represents the design while still working well on the web. Thus I have simple HTML: <div id="right"> <div id="welcome"></div> <div id="welcomeRepeatingBottom"></div> </div> And I'm trying to use CSS as follows: #right { height: 100%; position: absolute; right: 0px; top: 0px; width: 430px; } #welcome { background-image: url("welcome.png"); height: 614px; width: 430px; position: absolute; top: 0px; left: 0px; } #welcomeRepeatingBottom { background: url("welcomeBottom.png") repeat-y; height: 100%; left: 0px; position: absolute; top: 614px; width: 430px; } The problem is...the #welcomeRepeatingBottom div can't overlap the #welcome div because of the transparency. What I really want is the #welcomeRepeatingBottom div to be height: 100% - 614px, but of course you can't do that. Am I missing something here or do I need to manipulate these values with JavaScript/JQuery?

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• SQL SERVER – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28

  - by pinaldave

  I have been working a lot on Wait Stats and Wait Types recently. Last Year, I requested blog readers to send me their respective server’s wait stats. I appreciate their kind response as I have received  Wait stats from my readers. I took each of the results and carefully analyzed them. I provided necessary feedback to the person who sent me his wait stats and wait types. Based on the feedbacks I got, many of the readers have tuned their server. After a while I got further feedbacks on my recommendations and again, I collected wait stats. I recorded the wait stats and my recommendations and did further research. At some point at time, there were more than 10 different round trips of the recommendations and suggestions. Finally, after six month of working my hands on performance tuning, I have collected some real world wisdom because of this. Now I plan to share my findings with all of you over here. Before anything else, please note that all of these are based on my personal observations and opinions. They may or may not match the theory available at other places. Some of the suggestions may not match your situation. Remember, every server is different and consequently, there is more than one solution to a particular problem. However, this series is written with kept wait stats in mind. While I was working on various performance tuning consultations, I did many more things than just tuning wait stats. Today we will discuss how to capture the wait stats. I use the script diagnostic script created by my friend and SQL Server Expert Glenn Berry to collect wait stats. Here is the script to collect the wait stats: -- Isolate top waits for server instance since last restart or statistics clear WITH Waits AS (SELECT wait_type, wait_time_ms / 1000. AS wait_time_s, 100. * wait_time_ms / SUM(wait_time_ms) OVER() AS pct, ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS rn FROM sys.dm_os_wait_stats WHERE wait_type NOT IN ('CLR_SEMAPHORE','LAZYWRITER_SLEEP','RESOURCE_QUEUE','SLEEP_TASK' ,'SLEEP_SYSTEMTASK','SQLTRACE_BUFFER_FLUSH','WAITFOR', 'LOGMGR_QUEUE','CHECKPOINT_QUEUE' ,'REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT','BROKER_TO_FLUSH','BROKER_TASK_STOP','CLR_MANUAL_EVENT' ,'CLR_AUTO_EVENT','DISPATCHER_QUEUE_SEMAPHORE', 'FT_IFTS_SCHEDULER_IDLE_WAIT' ,'XE_DISPATCHER_WAIT', 'XE_DISPATCHER_JOIN', 'SQLTRACE_INCREMENTAL_FLUSH_SLEEP')) SELECT W1.wait_type, CAST(W1.wait_time_s AS DECIMAL(12, 2)) AS wait_time_s, CAST(W1.pct AS DECIMAL(12, 2)) AS pct, CAST(SUM(W2.pct) AS DECIMAL(12, 2)) AS running_pct FROM Waits AS W1 INNER JOIN Waits AS W2 ON W2.rn <= W1.rn GROUP BY W1.rn, W1.wait_type, W1.wait_time_s, W1.pct HAVING SUM(W2.pct) - W1.pct < 99 OPTION (RECOMPILE); -- percentage threshold GO This script uses Dynamic Management View sys.dm_os_wait_stats to collect the wait stats. It omits the system-related wait stats which are not useful to diagnose performance-related bottleneck. Additionally, not OPTION (RECOMPILE) at the end of the DMV will ensure that every time the query runs, it retrieves new data and not the cached data. This dynamic management view collects all the information since the time when the SQL Server services have been restarted. You can also manually clear the wait stats using the following command: DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR); Once the wait stats are collected, we can start analysis them and try to see what is causing any particular wait stats to achieve higher percentages than the others. Many waits stats are related to one another. When the CPU pressure is high, all the CPU-related wait stats show up on top. But when that is fixed, all the wait stats related to the CPU start showing reasonable percentages. It is difficult to have a sure solution, but there are good indications and good suggestions on how to solve this. I will keep this blog post updated as I will post more details about wait stats and how I reduce them. The reference to Book On Line is over here. Of course, I have selected February to run this Wait Stats series. I am already cheating by having the smallest month to run this series. :) Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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