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• Best practices for (over)using Azure queues

  - by John

  Hi, I'm in the early phases of designing an Azure-based application. One of the things that attracts me to Azure is the scalability, given the variability of the demand I'm likely to expect. As such I'm trying to keep things loosely coupled so I can add instances when I need to. The recommendations I've seen for architecting an application for Azure include keeping web role logic to a minimum, and having processing done in worker roles, using queues to communicate and some sort of back-end store like SQL Azure or Azure Tables. This seems like a good idea to me as I can scale up either or both parts of the application without any issue. However I'm curious if there are any best practices (or if anyone has any experiences) for when it's best to just have the web role talk directly to the data store vs. sending data by the queue? I'm thinking of the case where I have a simple insert to do from the web role - while I could set this up as a message, send it on the queue, and have a worker role pick it up and do the insert, it seems like a lot of double-handling. However I also appreciate that it may be the case that this is better in the long run, in case the web role gets overwhelmed or more complex logic ends up being required for the insert. I realise this might be a case where the answer is "it depends entirely on the situation, check your perf metrics" - but if anyone has any thoughts I'd be very appreciative! Thanks John

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• Getting hover text with selenium in java

  - by BinaryEmpire

  I am trying to figure out how to get the product availability text from a page like http://www.walmart.com/browse/TV-Video/TVs/_/N-96v3? (once a store has been selected) I selected 76574 as my zipcode and went to the "In My Store" tab The code I have now is WebElement hoverElement = driver.findElement(By.xpath(".//*[@id='Body_15992428']/span")); WebElement hidden = driver.findElement(By.xpath(".//*[@id='slapInfo_NoVariant_15992428']/div")); Actions builder = new Actions(driver); builder.clickAndHold(hoverElement).build().perform(); System.out.println(hidden.getText()); **Edit: I tried profile.setEnableNativeEvents(false); and the text is now displayed in the automated browser window. I still cannot get to the text I want though. It does not throw an exception, only displays nothing because the driver thinks its still hidden. Any one know how to fix this? I keep getting Exception in thread "main" org.openqa.selenium.InvalidElementStateException: Cannot perform native interaction: Could not load native events component. Even after I do profile.setEnableNativeEvents(true); Are there any other ways I can get the hidden text, or what am I doing wrong here? Additionally while I was inspecting the code with firebug, I saw that there is this code <script type="text/javascript"> WALMART.$(document).ready(function(){ WALMART.$('#Body_15992428').hover(function(){ WALMART.$('#SeeStoreAvailBubble').wmBubble('update',WALMART.$('#bubbleMsgUpdate_15992428').html()); }); }); </script> I dont really know how to do things directly with javascript but is there is any way of getting the message text directly from that with a javascript executor?

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• How to map a 0..1 to 1 relationship in Entity Framework 3

  - by sako73

  I have two tables, Users, and Address. A the user table has a field that maps to the primary key of the address table. This field can be null. In plain english, Address exist independent of other objects. A user may be associated with one address. In the database, I have this set up as a foreign key relationship. I am attempting to map this relationship in the Entity Framework. I am getting errors on the following code: <Association Name="fk_UserAddress"> <End Role="User" Type="GenesisEntityModel.Store.User" Multiplicity="1"/> <End Role="Address" Type="GenesisEntityModel.Store.Address" Multiplicity="0..1" /> <ReferentialConstraint> <Principal Role="Address"> <PropertyRef Name="addressId"/> </Principal> <Dependent Role="User"> <PropertyRef Name="addressId"/> </Dependent> </ReferentialConstraint> </Association> It is giving a "The Lower Bound of the multiplicity must be 0" error. I would appreciate it if anyone could explain the error, and the best way to solve it. Thanks for any help.

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• Serialization of Entity Framework Models with .NET WCF Rest Service

  - by Chris Phillips

  I'm trying to put together a very simple REST-style interface for communicating with our partners. An example object in the API is a partner, which we'd like to have serialized like this: <partner> <id>ID</id> <name>NAME</name> </partner> This is fairly simply to achieve using the .NET 4.0 WCF REST template if we simply declare a partner class as: public class Partner { public int Id {get; set;} public string Name {get; set;} } But when I use the Entity Framework to define and store Partner objects, the resulting serialization looks something like this: <Partner p1:Id="NCNameString" p1:Ref="NCNameString" xmlns:p1="http://schemas.microsoft.com/2003/10/Serialization/" xmlns="http://schemas.datacontract.org/2004/07/TheTradeDesk.AdPlatform.Provisioning"> <EntityKey p1:Id="NCNameString" p1:Ref="NCNameString" xmlns="http://schemas.datacontract.org/2004/07/System.Data.Objects.DataClasses"> <EntityContainerName xmlns="http://schemas.datacontract.org/2004/07/System.Data">String content</EntityContainerName> <EntityKeyValues xmlns="http://schemas.datacontract.org/2004/07/System.Data"> ... This XML is obviously unacceptable for use as an external API. What are suggested mechanisms for using EF for the data store but maintaining a simple XML serialization interface?

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• What is the correct high level schema.org microdata itemtype for a retail brand/company homepage?

  - by kpowz

  I'd like to hear which schema.org itemtype others would recommend using or have used in the case of completing a retail brand's company homepage microdata. Take for example TOMS's shoes: Example #1 - Using /Corporation as the high-level itemtype one can include a lot of great /Organization microdata, but nothing about the retail store. <html itemscope='itemscope' itemtype="http://schema.org/Website> <head></head> <body itemscope='itemscope' itemtype="http://schema.org/Corporation> various microdata here probably including Product microdata </body> </html> NOTE: the only schema.org property specific to /Corporation is tickerSymbol & TOMS doesn't have one. Example #2 - This code would work if TOMS started their own channel of physical retail stores & each location had it's own homepage. However, for TOMS's.com, although accurate schematically & more descriptive at the face, this is incorrect microdata markup for TOMS.com, because /ShoeStore derives from /LocalBusiness - which must represent a physical place. <html itemscope='itemscope' itemtype='http://schema.org/Website'> <head></head> <body itemscope='itemscope' itemtype='http://schema.org/ShoeStore'> a whole bunch of jabber here </body> </html> NOTE: Since TOMS is virtual & thus can't be a /Store this means you lose really cool properties like 'currenciesAccepted', 'paymentAccepted' & 'priceRange'. Is this just a 'sit and wait' situation until more schemas are approved for 'virtual places' or is there a validation-passing way to get the best of both worlds?

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• Cassandra instead of MySQL for social networking app

  - by Christopher McCann

  I am in the middle of building a new app which will have very similar features to Facebook and although obviously it wont ever have to deal with the likes of 400,000,000 million users it will still be used by a substantial user base and most of them will demand it run very very quickly. I have extensive experience with MySQL but a social app offers complexities which MySQL is not well suited too. I know Facebook, Twitter etc have moved towards Cassandra for a lot of their data but I am not sure how far to go with it. For example would you store such things as user data - username, passwords, addresses etc in Cassandra? Would you store e-mails, comments, status updates etc in Cassandra? I have also read alot that something like neo4j is much better for representing the friend relationships used by social apps as it is a graph database. I am only just starting down the NoSQL route so any guidance is greatly appreciated. Would anyone be able to advise me on this? I hope I am not being too general!

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• [Ruby] Modifying object inside a loop doesn't change object outside of the loop?

  - by Jergason

  I am having problems with modifying objects inside blocks and not getting the expected values outside the blocks. This chunk of code is supposed to transform a bunch of points in 3d space, calculate a score (the rmsd or root mean squared deviation), and store both the score and the set of points that produced that score if it is lower than the current lowest score. At the end, I want to print out the best bunch of points. first = get_transformed_points(ARGV[0]) second = get_transformed_points(ARGV[1]) best_rmsd = first.rmsd(second) best_points = second #transform the points around x, y, and z and get the rmsd. If the new points # have a smaller rmsd, store them. ROTATION = 30 #rotate by ROTATION degrees num_rotations = 360/ROTATION radians = ROTATION * (Math::PI/180) num_rotations.times do |i| second = second * x_rotate num_rotations.times do |j| second = second * y_rotate num_rotations.times do |k| second = second * z_rotate rmsd = first.rmsd(second) if rmsd < best_rmsd then best_points = second best_rmsd = rmsd end end end end File.open("#{ARGV[1]}.out", "w") {|f| f.write(best_points.to_s)} I can print out the points that are getting stored inside the block, and they are getting transformed and stored correctly. However, when I write out the points to a file at the end, they are the same as the initial set of points. Somehow the best_points = second chunk doesn't seem to be doing anything outside of the block. It seems like there are some scoping rules that I don't understand here. I had thought that since I declared and defined best_points above, outside of the blocks, that it would be updated inside the blocks. However, it seems that when the blocks end, it somehow reverts back to the original value. Any ideas how to fix this? Is this a problem with blocks specifically?

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• Modifying bundled properties from visitor

  - by ravenspoint

  How should I modify the bundled properties of a vertex from inside a visitor? I would like to use the simple method of sub-scripting the graph, but the graph parameter passed into the visitor is const, so compiler disallows changes. I can store a reference to the graph in the visitor, but this seems weird. /** A visitor which identifies vertices as leafs or trees */ class bfs_vis_leaf_finder:public default_bfs_visitor { public: /** Constructor @param[in] total reference to int variable to store total number of leaves @param[in] g reference to graph ( used to modify bundled properties ) */ bfs_vis_leaf_finder( int& total, graph_t& g ) : myTotal( total ), myGraph( g ) { myTotal = 0; } /** Called when the search finds a new vertex If the vertex has no children, it is a leaf and the total leaf count is incremented */ template <typename Vertex, typename Graph> void discover_vertex( Vertex u, Graph& g) { if( out_edges( u, g ).first == out_edges( u, g ).second ) { myTotal++; //g[u].myLevel = s3d::cV::leaf; myGraph[u].myLevel = s3d::cV::leaf; } else { //g[u].myLevel = s3d::cV::tree; myGraph[u].myLevel = s3d::cV::tree; } } int& myTotal; graph_t& myGraph; };

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• The most efficient way to calculate an integral in a dataset range

  - by Annalisa

  I have an array of 10 rows by 20 columns. Each columns corresponds to a data set that cannot be fitted with any sort of continuous mathematical function (it's a series of numbers derived experimentally). I would like to calculate the integral of each column between row 4 and row 8, then store the obtained result in a new array (20 rows x 1 column). I have tried using different scipy.integrate modules (e.g. quad, trpz,...). The problem is that, from what I understand, scipy.integrate must be applied to functions, and I am not sure how to convert each column of my initial array into a function. As an alternative, I thought of calculating the average of each column between row 4 and row 8, then multiply this number by 4 (i.e. 8-4=4, the x-interval) and then store this into my final 20x1 array. The problem is...ehm...that I don't know how to calculate the average over a given range. The question I am asking are: Which method is more efficient/straightforward? Can integrals be calculated over a data set like the one that I have described? How do I calculate the average over a range of rows?

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• Rationale in selecting Hash Key type

  - by Amrish

  Guys, I have a data structure which has 25 distinct keys (integer) and a value. I have a list of these objects (say 50000) and I intend to use a hash table to store/retrieve them. I am planning to take one of these approaches. Create a integer hash from these 25 integer keys and store it on a hash table. (Yeah! I have some means to handle collisions) Make a string concatenation on the individual keys and use it as a hash key for the hash table. For example, if the key values are 1,2,4,6,7 then the hash key would be "12467". Assuming that I have a total of 50000 records each with 25 distinct keys and a value, then will my second approach be a overkill when it comes to the cost of string comparisons it needs to do to retrieve and insert a record? Some more information! Each bucket in the hash table is a balanced binary tree. I am using the boost library's hash_combine method to create the hash from the 25 keys.

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• Storing data in a MySQL database using MySQL & PHP

  - by comma

  I'm new to PHP and MySQL and I'm trying to store a users entered data from the following fields $skill, $experience, $years which a user can also add additional fields of $skill, $experience, $years if needed so in instead of 1 of each field there might be multiples of each field. I was wondering how can I store the fields in my MySQL database using PHP and MySQL? I have the following script but I know its wrong. can some one help me fix the script listed below? Here is the PHP and MySQL code. $skill = serialize($_POST['skill']); $experience = serialize($_POST['experience']); $years = serialize($_POST['years']); for (($s = 0; $s < count($skill); $s++) && ($x = 0; $x < count($experience); $x++) && ($g = 0; $g < count($years); $g++)){ $mysqli = mysqli_connect("localhost", "root", "", "sitename"); $query1 = "INSERT INTO learned_skills (skill, experience, years) VALUES ('" . $skill[$s] . "', '" . $experience[$x] . "', '" . $years[$g] . "')"; if (!mysqli_query($mysqli, $query1)) { print mysqli_error($mysqli); return; } } Here is my MySQL table. CREATE TABLE learned_skills ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, skill TEXT NOT NULL, experience TEXT NOT NULL, years INT NOT NULL, PRIMARY KEY (id) ); CREATE TABLE u_skills ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, skill_id INT UNSIGNED NOT NULL, users_id INT UNSIGNED NOT NULL, PRIMARY KEY (id) );

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• Random number generation in MVC applications

  - by SlimShaggy

  What is the correct way of generating random numbers in an ASP.NET MVC application if I need exactly one number per request? According to MSDN, in order to get randomness of sufficient quality, it is necessary to generate multiple numbers using a single System.Random object, created once. Since a new instance of a controller class is created for each request in MVC, I cannot use a private field initialized in the controller's constructor for the Random object. So in what part of the MVC app should I create and store the Random object? Currently I store it in a static field of the controller class and lazily initialize it in the action method that uses it: public class HomeController : Controller { ... private static Random random; ... public ActionResult Download() { ... if (random == null) random = new Random(); ... } } Since the "random" field can be accessed by multiple instances of the controller class, is it possible for its value to become corrupted if two instances attempt to initialize it simultaneously? And one more question: I know that the lifetime of statics is the lifetime of the application, but in case of an MVC app what is it? Is it from IIS startup till IIS shutdown?

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• Trying to get codeblocks working on Mac, running Lion. Can't get the compiler set up properly

  - by tjtoml

  First off, sorry if this is a stupid question. I installed code::blocks to try and get to know the program and start working on teaching myself c++. I have a MacBook Pro with OS 10.7.3. I ave code::blocks 10.05. When I try to build a "Hello world" nothing happens. Based on some googling I've figured out that it's because code::blocks doesn't know where to find the debugger/compiler. Further googling yielded me this page which tells me to install Xcode and to fix some things in the code::blocks settings. However, this wiki obviously has not been updated since Apple went to the App store, because the file paths it gives for the compiler do not exist (there is no /Developer/* even after installing Xcode). Xcode 4.3.2 was already installed when I installed code::blocks and code::blocks "auto-detected" several compilers. They did not work. If anyone knows where Xcode hides its compilers now that Apple has moved to the app store, I would be much obliged.

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• Domain Authentication from .NET Client over VPN

  - by Holy Christ

  I am writing a ClickOnce WPF app that will sometimes be used over VPN. The app uses resources available only to domain authenticated users. Some of the things include accessing SSRS Reports, accessing LDAP to lookup user information, hitting web services, etc. When a user logs in from a machine that is not authenticated on the domain, I need to somehow get his credentials, authenticate him on the domain, and store his credentials. What is the recommended approach for authenticating domain users over VPN? How can I securely store the credentials? I've found several articles but, not much posted recently and a lot of the solutions seem kinda hacky, or aren't very secure (ie - storing strings clear text in memory). It would be cool if I could use the ActiveDicrtoryMembershipProvider, but that seems to be geared for use in web apps. EDIT: The above is kind of a workaround. The user must enter their domain credentials to authenticate on the VPN. It would be ideal to access the credentials the user has already entered to login to the VPN instead of the WindowsIdentity.GetCurrent() (which returns the user logged into the computer). Any ideas on how that could work? We use Juniper Networks to connect to the VPN. Thanks!

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• Regularly update database without browser/user

  - by Chris M

  I currently have a MySQL database which I was hoping to use to store regularly updated data from a temperature sensor connected to the internet. I currently have a page that, when opened, will grab the current temperature and the current timestamp and add it as an entry to the database, but I was looking for a way to do that without me refreshing the page every 5 seconds. Detail: The data comes from an Arduino Ethernet, posted to an IP address. Currently, I'm using cURL to grab the data from the IP, add a timestamp and save it to the DB. Obviously only updates when the page is refreshed (it uses PHP). Here is a live feed of the data - http://wetdreams.org.uk/ChrisProject/UI/live_graph_two.html TL;DR - Basically I need a middle man to grab the data from the IP and post it to a MySQL Edit: Thanks for all the advice. There might be a little bit of confusion, I'm looking for a solution that (ideally) doesn't require a computer to be on at all (other than the Server containing Database). Since I'm looking to store data over long periods of time (weeks), I'd like to set it up and leave a script running on the server (or Arduino) that gets the temp and posts it to the Database. In my head I would like to have a page on the server that automatically (without any browser open, or any other prompting other than a timer) calls a PHP script. Hope that clears things up!

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• Schema for storing "binary" values, such as Male/Female, in a database

  - by latentflip

  Intro I am trying to decide how best to set up my database schema for a (Rails) model. I have a model related to money which indicates whether the value is an income (positive cash value) or an expense (negative cash value). I would like separate column(s) to indicate whether it is an income or an expense, rather than relying on whether the value stored is positive or negative. Question: How would you store these values, and why? Have a single column, say Income, and store 1 if it's an income, 0 if it's an expense, null if not known. Have two columns, Income and Expense, setting their values to 1 or 0 as appropriate. Something else? I figure the question is similar to storing a person's gender in a database (ignoring aliens/transgender/etc) hence my title. My thoughts so far Lookup might be easier with a single column, but there is a risk of mistaking 0 (false, expense) for null (unknown). Having seperate columns might be more difficult to maintain (what happens if we end up with a 1 in both columns? Maybe it's not that big a deal which way I go, but it would be great to have any concerns/thoughts raised before I get too far down the line and have to change my code-base because I missed something that should have been obvious! Thanks, Philip

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• best practices question: How to save a collection of images and a java object in a single file? File

  - by Richard

  Hi all, I am making a java program that has a collection of flash-card like objects. I store the objects in a jtree composed of defaultmutabletreenodes. Each node has a user object attached to it with has a few string/native data type parameters. However, i also want each of these objects to have an image (typical formats, jpg, png etc). I would like to be able to store all of this information, including the images and the tree data to the disk in a single file so the file can be transferred between users and the entire tree, including the images and parameters for each object, can be reconstructed. I had not approached a problem like this before so I was not sure what the best practices were. I found XLMEncoder (http://java.sun.com/j2se/1.4.2/docs/api/java/beans/XMLEncoder.html) to be a very effective way of storing my tree and the native data type information. However I couldn't figure out how to save the image data itself inside of the XML file, and I'm not sure it is possible since the data is binary (so restricted characters would be invalid). My next thought was to associate a hash string instead of an image within each user object, and then gzip together all of the images, with the hash strings as the names and the XMLencoded tree in the same compmressed file. That seemed really contrived though. Does anyone know a good approach for this type of issue? THanks! Thanks!

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• Calling NSFetchedResultsController & CoreData experts

  - by JK

  I am having a few nagging issues with NSFetchedResultsController and CoreData, any of which I would be very grateful to get help on. Issue 1 - Updates: I update my store on a background thread which results in certain rows being delete, inserted or updated. The changes are merged into the context on the main thread using the "mergeChangesFromContextDidSaveNotification:" method. Inserts and deletes are updated properly, but updates are not (e.g. the cell label is not updated with the change) although I have confirmed the updates to come through the contextDidSaveNotifcation, exactly like the inserts and deleted. My current workaround is to temporarily change the staleness interval of the context to 0, but this does not seem like the ideal solution. Issue 2 - Deleting objects: My fetch batch size is 20. If an object is deleted by the background thread which is in the first 20 rows, everything works fine. But if the object is after the first 20 rows and the table is scrolled down, a "CoreData could not fulfill a fault" error is raised. I have tried resaving the context and reperforming the frc fetch - all to no avail. Note: In this scenario, the frc delegate method "didChangeObject...." is not called for the delete - I assume this is because the object in question had not been faulted at that time (as it is was outside the initial fetch range). But for some reason, the context still thinks the object is around, although is has been deleted from the store. Issue 3 - Deleting sections : When the deletion of a row leads to the deletion of a section, I have gotten the "invalid number of rows in section???" error. I have worked around this by removing the "reloadSection" line from the NSFetchedResultsChangeMove: section and replacing it with "[tableView insertRowsAtIndexPaths...." This seems to work, but once again, I am not sure if this is the best solution. Any help would be greatly appreciated. Thank you!

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• Creating an adjacency List for DFS

  - by user200081

  I'm having trouble creating a Depth First Search for my program. So far I have a class of edges and a class of regions. I want to store all the connected edges inside one node of my region. I can tell if something is connected by the getKey() function I have already implemented. If two edges have the same key, then they are connected. For the next region, I want to store another set of connected edges inside that region, etc etc. However, I am not fully understanding DFS and I'm having some trouble implementing it. I'm not sure when/where to call DFS again. Any help would be appreciated! class edge { private: int source, destination, length; int key; edge *next; public: getKey(){ return key; } } class region { edge *data; edge *next; region() { data = new edge(); next = NULL; } }; void runDFS(int i, edge **edge, int a) { region *head = new region(); aa[i]->visited == true;//mark the first vertex as true for(int v = 0; v < a; v++) { if(tem->edge[i].getKey() == tem->edge[v].getKey()) //if the edges of the vertex have the same root { if(head->data == NULL) { head->data = aa[i]; head->data->next == NULL; } //create an edge if(head->data) { head->data->next = aa[i]; head->data->next->next == NULL; }//if there is already a node connected to ti } if(aa[v]->visited == false) runDFS(v, edge, a); //call the DFS again } //for loop }

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• What's the best way to send user-inputted text via AJAX to Google App Engine?

  - by Cuga

  I'm developing in Google App Engine (python sdk) and I want to use jQuery to send an Ajax request to store an answer to a question. What is the best way to send this data to the server? Currently I have: function storeItem(question_id) { var answerInputControl = ".input_answer_"+question_id; var answer_text = $(answerInputControl).text(); $.ajax({ type: "POST", url: "store_answer.html", data: "question="+question_id, success: function(responseText){ alert("Retrieved: " + responseText); } }); } This takes a question Id and provides it to the server via the query string. But on the server-side, I'm unable to access the content of the answer control which I want to store. Without Ajax, I'm able to perform this operation with the following: class StoreAnswers(webapp.RequestHandler): def post(self): question_id = self.request.get("question_id") answer_text = self.request.get("input_answer" + question_id) But when doing this call through Ajax, my answer_text is empty. Do I need to send the contents of this control as part of the data with the Ajax request? Do I add the control itself to the query string? Its contents? Does it matter that the content might be a few hundred characters long? Is this the most-recommended practice? If sending it as a query string, what's the best way to escape the content so that a malicious user doesn't harm the system?

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• Caching queries in Django

  - by dolma33

  In a django project I only need to cache a few queries, using, because of server limitations, a cache table instead of memcached. One of those queries looks like this: Let's say I have a Parent object, which has a lot of Child objects. I need to store the result of the simple query parent.childs.all(). I have no problem with that, and everything works as expected with some code like key = "%s_children" %(parent.name) value = cache.get(key) if value is None: cache.set(key, parent.children.all(), CACHE_TIMEOUT) value = cache.get(key) But sometimes, just sometimes, the cache.set does nothing, and, after executing cache.set, cache.get(key) keeps returning None. After some test, I've noticed that cache.set is not working when parent.children.all().count() has higher values. That means that if I'm storing inside of key (for example) 600 children objects, it works fine, but it wont work with 1200 children. So my question is: is there a limit to the data that a key could store? How can I override it? Second question: which way is "better", the above code, or the following one? key = "%s_children" %(parent.name) value = cache.get(key) if value is None: value = parent.children.all() cache.set(key, value, CACHE_TIMEOUT) The second version won't cause errors if cache.set doesn't work, so it could be a workaround to my issue, but obviously not a solution. In general, let's forget about my issue, which version would you consider "better"?

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• Strange results about C++11 memory model (Relaxed ordering)

  - by Dancing_bunny

  I was testing the example in the memory model of the Anthony Williams's book "C++ Concurrency" #include<atomic> #include<thread> #include<cassert> std::atomic_bool x,y; std::atomic_int z; void write_x_then_y() { x.store(true, std::memory_order_relaxed); y.store(true, std::memory_order_relaxed); } void read_y_then_x() { while(!y.load(std::memory_order_relaxed)); if(x.load(std::memory_order_relaxed)) { ++z; } } int main() { x = false; y = false; z = 0; std::thread a(write_x_then_y); std::thread b(read_y_then_x); a.join(); b.join(); assert(z.load()!=0); } According to the explanation, relaxed operations on difference variables (here x and y) can be freely reordered. However, I repeated running the problem for more than several days. I never hit the situation that the assertion (assert(z.load()!=0);) fires. I just use the default optimization and compile the code using g++ -std=c++11 -lpthread dataRaceAtomic.cpp Does anyone actually try it and hit the assertion? Could anyone give me an explanation about my test results? BTW, I also tried the version without using the atomic type, I got the same result. Currently, both programs are running healthily. Thanks.

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• Trying to Insert Text to Access Database with ExecuteNonQueryin VB

  - by user3673701

  I'm working on this feature were i save text from a textbox on my form to a access database file. With the click on my "store" button I want to save the text in the corresponding textbox fields to the fields in my access database for searching and retrieving purposes. Im doing this in VB The problem I run into is the INSERT TO error with my "store" button Any help or insight as to why im getting error would be greatly appreciated. here is my code: Dim con As System.Data.OleDb.OleDbConnection Dim cmd As System.Data.OleDb.OleDbCommand Dim dr As System.Data.OleDb.OleDbDataReader Dim sqlStr As String Private Sub btnStore_Click(sender As Object, e As EventArgs) Handles btnStore.Click con = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Eric\Documents\SPC1.2.accdb") con.Open() MsgBox("Initialized") sqlStr = "INSERT INTO Master FADV Calll info (First Name, Last Name, Phone Number, Email, User Id) values (" & txtFirstName.Text & " ' ,'" & txtLastName.Text & "','" & txtPhone.Text & "', '" & txtEmail.Text & "', '" & txtUserID.Text & "', '" & txtOtherOptionTxt.Text & "','" & txtCallDetail.Text & "');" cmd = New OleDb.OleDbCommand(sqlStr, con) cmd.ExecuteNonQuery() <------- **IM RECIVING THE ERROR HERE** MsgBox("Stored") ''pass ther parameter as sq; query, con " connection Obj)" con.Close()'

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• Is Subversion's 'Lazy Copy' still lazy when overwriting a previously deleted file?

  - by JW

  Is Subversion's 'Lazy Copy' still lazy when overwriting a previously deleted file? I store my externals in a separate folder for each version: i.e say for dojo I'd have: webroot\ scripts\ dojo-v-1.0.0\ dojo-v-1.1.0\ etc. By doing this, for me at least, I feel it makes it easier to switch over to a new version. By only adding each new version i am not really giving svn the history it needs to do lazy copies. So one tactic I have used is to svn copy over the old version over to where the new one will be then svn delete that whole folder then unpack my newer version into that place then svn add them The idea is to avoid having a massive amount of duplicated data in my repo. I hope svn is looking at the new files and saying, "hey, i already had this once, copied, then deleted...so i am only going to be lazy store the changes". That was my theory - but does that happen in practice? p.s. Yes I know an alternative is to set the 'externals properties on the folder' - but that's another question.

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• SQL Database Schema Design For Large 3 Billion Relationship Database.

  - by K-Bell

  Get your geek on. Can you solve this? I am designing a products database for SQL Server 2008 R2 Ed. (not Enterprise Ed.) that will be used to store custom product configurations for over 30,000 distinct products. The database will have up to 500 users at a time. Here is the design problem… Each Product has a collection of Parts (up to 50 parts per product). So if I have 30,000 Products and each of them can have up to 50 Parts, that’s 1.5 million distinct Product-to-Part relationships …or as an equation… 30,000 (Products) X 50 (Parts) = 1.5 million Product-to-Parts records. …and If… Each Part can have up to 2000 finish options (A finish is a paint color). NOTE: Only one finish will be selected by a user at run-time. The 2000 finish options I need to store are the allowed options for a specific part on a specific product. So if I have 1.5 million distinct product-to-part relationships/records and each of those parts can have up to 2,000 finishes that is 3 billion allowable product-to-part-to finish relationships/records …or as an equation… 1.5 million (Parts) x 2,000 (Finishes) = 3 Billion Product-to-Part-to-Finishes records. How can I design this database so that I can execute fast and efficient queries for a specific product and return its list of Parts and all the allowable Finishes for each part without 3 Billion Product-to-Part-to-Finish records? Read time is more important then write time. Please post your thoughts/suggestions if you have experience with large databases. Thanks!

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