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  • this error appeared when upgrating 12.04 LTS to 12.10 [closed]

    - by habcity
    Possible Duplicate: How do I fix a “Problem with MergeList” error when trying to do an update? ryder@ryder-Q1500M:~$ do-release-upgrade Checking for a new Ubuntu release Get:1 Upgrade tool signature [198 B] Get:2 Upgrade tool [1,200 kB] Fetched 1,200 kB in 6s (6,988 B/s) authenticate 'quantal.tar.gz' against 'quantal.tar.gz.gpg' extracting 'quantal.tar.gz' [sudo] password for ryder: Reading cache A fatal error occurred Please report this as a bug and include the files /var/log/dist-upgrade/main.log and /var/log/dist-upgrade/apt.log in your report. The upgrade has aborted. Your original sources.list was saved in /etc/apt/sources.list.distUpgrade. Traceback (most recent call last): File "/tmp/update-manager-63XThv/quantal", line 10, in sys.exit(main()) File "/tmp/update-manager-63XThv/DistUpgrade/DistUpgradeMain.py", line 237, in main save_system_state(logdir) File "/tmp/update-manager-63XThv/DistUpgrade/DistUpgradeMain.py", line 130, in save_system_state scrub_sources=True) File "/tmp/update-manager-63XThv/DistUpgrade/apt_clone.py", line 146, in save_state self._write_state_installed_pkgs(sourcedir, tar) File "/tmp/update-manager-63XThv/DistUpgrade/apt_clone.py", line 173, in _write_state_installed_pkgs cache = self._cache_cls(rootdir=sourcedir) File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 102, in init self.open(progress) File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 145, in open self._cache = apt_pkg.Cache(progress) SystemError: E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_precise-backports_multiverse_i18n_Translation-en, E:The package lists or status file could not be parsed or opened.

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  • How to download a url as a file?

    - by Michelle
    A website url has "hidden" some mp3 files by embedding them as shockwave files, as follows: <span class="caption"><!-- Odeo player --><embed src="http://odeo.com/flash/audio_player_tiny_gray.swf"quality="high" name="audio_player_tiny_gray" align="middle" allowScriptAccess="always" wmode="transparent" type="application/x-shockwave-flash" flashvars="valid_sample_rate=true external_url=http://podcast.cbc.ca/mp3/sundayeditionstream_20081125_9524.mp3" pluginspage="http://www.macromedia.com/go/getflashplayer"></embed></span> How can I download the files for off-line listening? I've found two methods: 1. The StackOverflow Method Create a new local html file with just the links eg <a href="http://podcast.cbc.ca/mp3/sundayeditionstream_20081125_9524.mp3">Sunday Edition 25Nov2008</a> Open the file in the browser, right click the link and File Save Link As. 2. The SuperUser Method Install the Firefox addin Iget. (Be sure to use the right version for your Firefox version.) Tools Downloads Enter url in field. Are there any other ways?

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  • Tracking Outgoing Links With Google Analytics Events

    - by the_archer
    I've been trying to track clicks on external links on my website using the events tracking method. So I've got my Google Analytics code setup before body ends as shown below (note: quotes have been entitied by blogger, but it works fine): <script type='text/javascript'> var _gaq = _gaq || []; _gaq.push([&#39;_setAccount&#39;, &#39;UA-XXXXXXX-X#39;]); _gaq.push([&#39;_trackPageview&#39;]); (function() { var ga = document.createElement(&#39;script&#39;); ga.type = &#39;text/javascript&#39;; ga.async = true; ga.src = (&#39;https:&#39; == document.location.protocol ? &#39;https://ssl&#39; : &#39;http://www&#39;) + &#39;.google-analytics.com/ga.js&#39;; var s = document.getElementsByTagName(&#39;script&#39;)[0]; s.parentNode.insertBefore(ga, s); })(); </script> Now I wanted to track a link on the addthis.com follow widget. So there is a link of the type below to which following instructions from here I added the onclick event. <a addthis:url='http://feeds.feedburner.com/myfeedburnerlurl' onClick="_gaq.push(['_trackEvent', 'Subscription Clicks', 'RSS']);" class='addthis_button_rss_follow'/> I clicked on it a couple of times, left it for over a day now, but nothing shows up in google analytics events. It just says zero events. Here's a screenshot of the events page on GA: Could anybody help me? Am I doing anything wrong?

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  • Collision checking problem on a Tiled map

    - by nosferat
    I'm working on a pacman styled dungeon crawler, using the free oryx sprites. I've created the map using Tiled, separating the floor, walls and treasure in three different layers. After importing the map in libGDX, it renders fine. I also added the player character, for now it just moves into one direction, the player cannot control it yet. I wanted to add collision and I was planning to do this by checking if the player's new position is on a wall tile. Therefore as you can see in the following code snippet, I get the tile type of the appropriate tile and if it is not zero (since on that layer there is nothing except the wall tile) it is a collision and the player cannot move further: final Vector2 newPos = charController.move(warrior.getX(), warrior.getY()); if(!collided(newPos)) { warrior.setPosition(newPos.x, newPos.y); warrior.flip(charController.flipX(), charController.flipY()); } [..] private boolean collided(Vector2 newPos) { int row = (int) Math.floor((newPos.x / 32)); int col = (int) Math.floor((newPos.y / 32)); int tileType = tiledMap.layers.get(1).tiles[row][col]; if (tileType == 0) { return false; } return true; } The character only moves one tile with this code: If I reduce the col value by two it two more tiles. I think the problem will be around indexing, but I'm totally confused because the zero in the coordinate system of libGDX is in the bottom left corner of the screen, and I don't know the tiles array's indexing is similair or not. The size of the map is 19x21 tiles and looks like the following (the starting position of the player is marked with blue:

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  • Concurrency pattern of logger in multithreaded application

    - by Dipan Mehta
    The context: We are working on a multi-threaded (Linux-C) application that follows a pipeline model. Each module has a private thread and encapsulated objects which do processing of data; and each stage has a standard form of exchanging data with next unit. The application is free from memory leak and is threadsafe using locks at the point where they exchange data. Total number of threads is about 15- and each thread can have from 1 to 4 objects. Making about 25 - 30 odd objects which all have some critical logging to do. Most discussion I have seen about different levels as in Log4J and it's other translations. The real big questions is about how the overall logging should really happen? One approach is all local logging does fprintf to stderr. The stderr is redirected to some file. This approach is very bad when logs become too big. If all object instantiate their individual loggers - (about 30-40 of them) there will be too many files. And unlike above, one won't have the idea of true order of events. Timestamping is one possibility - but it is still a mess to collate. If there is a single global logger (singleton) pattern - it indirectly blocks so many threads while one is busy putting up logs. This is unacceptable when processing of the threads are heavy. So what should be the ideal way to structure the logging objects? What are some of the best practices in actual large scale applications? I would also love to learn from some of the real designs of large scale applications to get inspirations from!

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  • Thunderbird keeps crashing Ubuntu 12.04 64 bit

    - by maurizio ribera d'alcala'
    I have been using Thunderbird for years under different versions of Ubuntu, including 12.04 since its release. From a couple of days it keeps crashing after a few seconds after start. I tried to reinstall it creating a new profile and copying the old mail, file by file. After one day of normal functioning it started again to crash. Mozilla is receiving the crash reports. Following is the content of the last one: Add-ons: [email protected]:15.0,[email protected]:0.3.11,[email protected]:0.9.3,[email protected]:3.4.1,[email protected]:15.0,[email protected]:0.5.1,{b4447f60-db9c-11da-a94d-0800200c9a66}:0.9.1,{972ce4c6-7e08-4474-a285-3208198ce6fd}:15.0 BuildID: 20120827103657 CrashTime: 1347200254 EMCheckCompatibility: true Email: [email protected] FramePoisonBase: 7ffffffff0dea000 FramePoisonSize: 4096 InstallTime: 1346431480 Notes: OpenGL: Tungsten Graphics, Inc -- Mesa DRI Intel(R) Sandybridge Mobile -- 3.0 Mesa 8.0.2 -- texture_from_pixmap ProductID: {3550f703-e582-4d05-9a08-453d09bdfdc6} ProductName: Thunderbird ReleaseChannel: release SecondsSinceLastCrash: 1109 StartupTime: 1347200242 Theme: classic/1.0 Throttleable: 1 Vendor: Version: 15.0 I started Thunderbird in safe mode and tested all the add-ons. Apparently is the 'Unity Launcher Integration' that creates the problem. I say apparently because I want two wait for two-three days to be sure TB returns to its regular functioning. Is this a bug? can it be solved

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  • Is Oracle Database Appliance (ODA) A Best Kept Secret?

    - by Ravi.Sharma
    There is something about Oracle Database Appliance that underscores the tremendous value customers see in the product. Repeat purchases. When you buy “one” of something and come back to buy another, it confirms that the product met your expectations, you found good value in it, and perhaps you will continue to use it. But when you buy “one” and come back to buy many more on your very next purchase, it tells something else. It tells that you truly believe that you have found the best value out there. That you are convinced! That you are sold on the great idea and have discovered a product that far exceeds your expectations and delivers tremendous value! Many Oracle Database Appliance customers are such larger-volume-repeat-buyers. It is no surprise, that the product has a deeper penetration in many accounts where a customer made an initial purchase. The value proposition of Oracle Database Appliance is undeniably strong and extremely compelling. This is especially true for customers who are simply upgrading or “refreshing” their hardware (and reusing software licenses). For them, the ability to acquire world class, highly available database hardware along with leading edge management software and all of the automation is absolutely a steal. One customer DBA recently said, “Oracle Database Appliance is the best investment our company has ever made”. Such extreme statements do not come out of thin air. You have to experience it to believe it. Oracle Database Appliance is a low cost product. Not many sales managers may be knocking on your doors to sell it. But the great value it delivers to small and mid-size businesses and database implementations should not be underestimated. 

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  • Challenging Job after Graduate Studies

    - by sriram
    I worked with an M.N.C developing web applications in Java/J2EE related technologies(includes JSF,struts,hibernate etc.) now I quit my job to pursue Graduate Studies in the U.S.A. So I am a student in the middle of my Graduate studies. I had enough of developing mere CRUD applications in J2EE now I want to work in something exciting. The problem is I can't say what exactly but I can give you an examples. Say developing new JDK libraries or writing a kernel for some O.S. or something like that. So I have five questions here. Is it true that people in R & D often use C++ because of higher performance in that case should I consider switching my platform to C/C++? How should I use my time I have one year to graduate to prepare myself for Jobs Interviews for such positions? (e.g. Reading books on Algorithms etc.) How do I know about these jobs and how do I apply to those Jobs? Is it the right time for me to think about Jobs? Am I over ambitious because I am not in a Ivy League, just a normal school? (My GPA is not so high unfortunately).

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  • cURL looking for CA in the wrong place

    - by andrewtweber
    On Redhat Linux, in a PHP script I am setting cURL options as such: curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, True); curl_setopt($ch, CURLOPT_CAINFO, '/home/andrew/share/cacert.pem'); Yet I am getting this exception when trying to send data (curl error: 77) error setting certificate verify locations: CAfile: /etc/pki/tls/certs/ca-bundle.crt CApath: none Why is it looking for the CAfile in /etc/pki/tls/certs/ca-bundle.crt? I don't know where this folder is coming from as I don't set it anywhere. Shouldn't it be looking in the place I specified, /home/andrew/share/cacert.pem? I don't have write permission /etc/ so simply copying the file there is not an option. Am I missing some other curl option that I should be using? (This is on shared hosting - is it possible that it's disallowing me from setting a different path for the CAfile?)

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  • Moving while doing loop animation in RPGMaker

    - by AzDesign
    I made a custom class to display character portrait in RPGMaker XP Here is the class : class Poser attr_accessor :images def initialize @images = Sprite.new @images.bitmap = RPG::Cache.picture('Character.png') #100x300 @images.x = 540 #place it on the bottom right corner of the screen @images.y = 180 end end Create an event on the map to create an instance as global variable, tada! image popped out. Ok nice. But Im not satisfied, Now I want it to have bobbing-head animation-like (just like when we breathe, sometimes bob our head up and down) so I added another method : def move(x,y) @images.x += x @images.y += y end def animate(x,y,step,delay) forward = true 2.times { step.times { wait(delay) if forward move(x/step,y/step) else move(-x/step,-y/step) end } wait(delay*3) forward = false } end def wait(time) while time > 0 time -= 1 Graphics.update end end I called the method to run the animation and it works, so far so good, but the problem is, WHILE the portrait goes up and down, I cannot move my character until the animation is finished. So that's it, I'm stuck in the loop block, what I want is to watch the portrait moving up and down while I walk around village, talk to npc, etc. Anyone can solve my problem ? Or better solution ? Thanks in advance

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  • Wordpress network admin pointing to root as opposed to subdirectory

    - by Ian
    I've installed Wordpress on my nginx server in /blogs and new networks will be in /blogs/blogname. All my main site links point to example.com/blogs, but when I go to network admin the links point to http://www.example.com/wp-admin/network/ instead of http://www.example.com/blogs/wp-admin/network/ Here's the multisite section in my config: define('MULTISITE', true); define('SUBDOMAIN_INSTALL', false); $base = '/blogs'; define('DOMAIN_CURRENT_SITE', 'www.example.com'); define('PATH_CURRENT_SITE', '/'); define('SITE_ID_CURRENT_SITE', 1); define('BLOG_ID_CURRENT_SITE', 1); If I try changing PATH_CURRENT_SITE to /blogs, I get a db connection error. Thanks.

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  • this.BoundingBox.Intersects(Wall[0].BoundingBox) not working properly

    - by Pieter
    I seem to be having this problem a lot, I'm still learning XNA / C# and well, trying to make a classic paddle and ball game. The problem I run into (and after debugging have no answer) is that everytime I run my game and press either of the movement keys, the Paddle won't move. Debugging shows that it never gets to the movement part, but I can't understand why not? Here's my code: // This is the If statement for checking Left movement. if (keyboardState.IsKeyDown(Keys.Left) || keyboardState.IsKeyDown(Keys.A)) { if (!CheckCollision(walls[0])) { Location.X -= Velocity; } } //This is the CheckCollision(Wall wall) boolean public bool CheckCollision(Wall wall) { if (this.BoundingBox.Intersects(wall.BoundingBox)) { return true; } return false; } As far as I can tell there should be absolutely no problem with this, I initialize the bounding box in the constructor whenever a new instance of Walls and Paddle is created. this.BoundingBox = new Rectangle(0, 0, Sprite.Width, Sprite.Height); Any idea as to why this isn't working? I have previously succeeded with using the whole Location.X < Wall.Location.X + Wall.Texture.Width code... But to me that seems like too much coding if a simple boolean check could be done.

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  • two-part dice pool mechanic

    - by bythenumbers
    I'm working on a dice mechanic/resolution system based off of the Ghost/Echo (hereafter shortened to G/E) tabletop RPG. Specifically, since G/E can be a little harsh with dealing out consequences and failure, I was hoping to soften the system and add a little more player control, as well as offer the chance for players to evolve their characters into something unique, right from creation. So, here's the mechanic: Players roll 2d12 against the two statistics for their character (each is a number from 2-11, and may be rolled above or below depending on the nature of the action attempted, rolling your stat exactly always fails). Depending on the success for that roll, they add dice to the pool rolled for a modified G/E style action. The acting player gets two dice anyhow, and I am debating offering a bonus die for each success, or a single bonus die for succeeding on both of the statistic-compared rolls. One the size of the dice pool is set, the entire pool is rolled, and the players are allowed to assign rolled dice to a goal and a danger. Assigned results are judged as follows: 1-4 means the attempted goal fails, or the danger comes true. 5-8 is a partial success at the goal, or partially avoiding the danger. 9-12 means the goal is achieved, or the danger avoided. My concerns are twofold: Firstly, that the two-stage action is too complicated, with two rolls to judge separately before anything can happen. Secondly, that the statistics involved go too far in softening the game. I've run some basic simulations, and the approximate statistics follow: 2 dice (up to) 3 dice (up to) 4 dice failure ~33% ~25% ~20% partial ~33% ~35% ~35% success ~33% ~40% ~45% I'd appreciate any advice that addresses my concerns or offers to refine my simulation (right now the first roll is statistically modeled as sign(1d12-1d12), where 0 is a success).

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  • FTP - 530 Sorry, the maximum number of clients…?

    - by Luca Filosofi
    Hi All! My problem is that my FTP work great, exept when i upload files on a particular client server! on this server happen that some files are uploaded fine and others not, they stop while uploading at half of it's size, then this error is displayed: 530 Sorry, the maximum number of clients (4) from your host are already connected. Unable to make a connection. Please try again. Obviously this is not true, i'm the only one that is uploading! Anyone had the same experience with this!? PS: i have tried many different FTP, all display the same error or just hung up! Thank's

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  • JBox2D applyLinearImpulse doesn't work

    - by Romeo
    So i have this line of code: if(input.isKeyDown(Input.KEY_W)&&canJump()) { body.applyLinearImpulse(new Vec2(0, 30), cam.screenToWorld(body.getPosition())); System.out.println("I can jump!"); } My problem is that the console display I can jump! but the body doesn't do that. Can you explain to me if i do something wrong? Some more code. This function creates my 'hero' the one supposed to jump. private Body setDynamic(float width, float height, float x, float y) { PolygonShape shape = new PolygonShape(); shape.setAsBox(width/2, height/2); BodyDef bd = new BodyDef(); bd.allowSleep = true; bd.position = new Vec2(cam.screenToWorld(new Vec2(x + width / 2, y + height / 2))); bd.type = BodyType.DYNAMIC; bd.userData = new BodyInfo(width, height); Body body = world.createBody(bd); body.createFixture(shape, 10); return body; } And this is the main update loop: if(input.isKeyDown(Input.KEY_A)) { body.setLinearVelocity(new Vec2(-10*delta, body.getLinearVelocity().y)); } else if (input.isKeyDown(Input.KEY_D)) { body.setLinearVelocity(new Vec2(10*delta, body.getLinearVelocity().y)); } else { body.setLinearVelocity(new Vec2(0, body.getLinearVelocity().y)); } if(input.isKeyDown(Input.KEY_W)&&canJump()) { body.applyLinearImpulse(new Vec2(0, 30), body.getPosition()); System.out.println("I can jump!"); } world.step(delta * 0.001f, 10, 5); }

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  • How do I make a privileged port non-privileged in Redhat 5?

    - by Jason Thompson
    So I have a RedHat 5 box that I'm wanting to run an application that I wrote that implements SLP. SLP uses port 427 for answering service queries. My understanding is that ports below 1024 are "privileged" and thus cannot be bound to by anyone that's not root. I cannot run this application as root as it is launched via tomcat. One creative solution I really like was simply writing an iptables rule to route the privileged port to a non-privileged. In my proof of concept tests, this works wonderfully. Unfortunately, it would be greatly (and understandably) desired by the powers if my application did not require screwing around with iptables upon installation. So I heard a rumor and cannot find anything to verify this that there was some sort of command or parameter that could be set to make any port I want be non-privileged. Is this true? If so, how is this done? Thanks!

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  • Radiation from a UPS

    - by Erel Segal
    In our office, there are frequent eletric shortages that harm my desktop computer, so I wanted to install a UPS. However, my office-mates pointed me to papers talking about hazardous radiation from the UPS. The UPS manufacturers themselves recommend to put the UPS several meters away from humans, which is not possible because our office is small (the power is about 0.5 meters from us). As an alternative to UPS, my office-mates recommended that I switch to a laptop, which has a battery so it's immune to shortages. I have several questions: Is it true that the radiation from a laptop battery is lower than the radiation from a UPS? They do just the same thing - supply power using a battery! If the answer to 1 is yes - is there an alternative way to attach a battery, similar to a laptop battery, to a desktop computer? If the answer to 1 is no - how can I prove this to my office-mates, so that they let me use UPS?

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  • Implementing a switch statement based on user input

    - by Dave Voyles
    I'm trying to delay the time it takes for the main menu screen to pop up after a user has won / lost a match. As it stands, the game immediately displays a message stating "you won / lost" and waits for 6 seconds before loading the menu screen. I would also like players to have the ability to press a key to advance to the menu screen immediately but thus far my switch statement doesn't seem to do the trick. I've included the switch statement, along with my (theoretical) inputs. What could I be doing wrong here? if (gamestate == GameStates.End) switch (input.IsMenuDown(ControllingPlayer)) { case true: ScreenManager.AddScreen(new MainMenuScreen(), null); // Draws the MainMenuScreen break; case false: if (screenLoadDelay > 0) { screenLoadDelay -= gameTime.ElapsedGameTime.TotalSeconds; } ScreenManager.AddScreen(new MainMenuScreen(), null); // Draws the MainMenuScreen break; } /// <summary> /// Checks for a "menu down" input action. /// The controllingPlayer parameter specifies which player to read /// input for. If this is null, it will accept input from any player. /// </summary> public bool IsMenuDown(PlayerIndex? controllingPlayer) { PlayerIndex playerIndex; return IsNewKeyPress(Keys.Down, controllingPlayer, out playerIndex) || IsNewButtonPress(Buttons.DPadDown, controllingPlayer, out playerIndex) || IsNewButtonPress(Buttons.LeftThumbstickDown, controllingPlayer, out playerIndex); }

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  • Ubuntu One has high CPU usage but no syncing

    - by Peter
    over the weekend I updated my computer to Windows 8. So far Ubuntu One was running smoothly, but ever since the update (clean, new install) Ubuntu doesn't sync any more. In Windows 7 it would start to sync at full internet speed as soon as I drop a file. But now in Windows 8, as soon as I drop a new file into the Ubuntu One folder, CPU usage goes up to about 50 % and no network traffic occurs. This stays like that for a couple of minutes, CPU usage goes back to normal and then the client says that all is in sync - which isn't true. Is it too early for Windows 8? Do others have the same problem or is there something I can do about it? I try a couple of different things, and realized that if the file size is 20 MB the files get uploaded. The original file was 1.5 GB. I also didn't work with 200, 100 and 50 MB large files. But even with 20 MB large files, the upload is very slow and not steady. The log give plenty of this error: - twisted - ERROR - Failure: exceptions.TypeError About which I don't know the meaning. By the way, the account works just fine on the Ubuntu 12.04 partition. Any help is greatly appreciated. -Peter

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  • Do I need to have a company so that I can buy an SSL certificate that will display green at the address bar?

    - by André Pena
    I have a non-comercial website in which the users store some sensitive information so I feel the need to have a SSL certificate, but it seems that if I don't have a registered company I can't buy a green certificate. I have some related questions: Is it true that if I don't have a company, I can't have a green certificate? If I issue a standard (non-business) certificate that won't go green (from GoDadday, for instance), will it go red? Or will it have a less ugly display.. something more neutral that won't scary the user.

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  • How do I create a free server-side database to be accessed via Windows forms and/or browser?

    - by NoCatharsis
    I have no formal education in databasing or programming, but I've learned enough SQL, C++, and C# to at least get started setting up a small database on my company's server. Using MS SQL Server 2008 R2, I have created the database and set up columns with proper data types. However, there seems to be a lot of tweaks and details that are way over my head. Since I would like these data to be accessible to the other 7 or 8 people in my office (preferably via web browser), I'm wondering whether this is the best setup for my situation. The other option I've read about is a LAMPP server, which I assume is the competing free option to Microsoft's Express packages. I know nothing of LAMP servers except from the articles I've read on how to set them up (and I believe I even saw a detailed tutorial somewhere). To summarize, my question is this: Which of these (or any other) server setups would best suit my purposes, keeping in mind that I'm a true novice (but willing to learn), and would like to keep it free until I get more experience?

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • Do objects maintain identity under all non-cloning conditions in PHP?

    - by Buttle Butkus
    PHP 5.5 I'm doing a bunch of passing around of objects with the assumption that they will all maintain their identities - that any changes made to their states from inside other objects' methods will continue to hold true afterwards. Am I assuming correctly? I will give my basic structure here. class builder { protected $foo_ids = array(); // set in construct protected $foo_collection; protected $bar_ids = array(); // set in construct protected $bar_collection; protected function initFoos() { $this->foo_collection = new FooCollection(); foreach($this->food_ids as $id) { $this->foo_collection->addFoo(new foo($id)); } } protected function initBars() { // same idea as initFoos } protected function wireFoosAndBars(fooCollection $foos, barCollection $bars) { // arguments are passed in using $this->foo_collection and $this->bar_collection foreach($foos as $foo_obj) { // (foo_collection implements IteratorAggregate) $bar_ids = $foo_obj->getAssociatedBarIds(); if(!empty($bar_ids) ) { $bar_collection = new barCollection(); // sub-collection to be a component of each foo foreach($bar_ids as $bar_id) { $bar_collection->addBar(new bar($bar_id)); } $foo_obj->addBarCollection($bar_collection); // now each foo_obj has a collection of bar objects, each of which is also in the main collection. Are they the same objects? } } } } What has me worried is that foreach supposedly works on a copy of its arrays. I want all the $foo and $bar objects to maintain their identities no matter which $collection object they become of a part of. Does that make sense?

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  • Is the hosts file ignored in windows if DNS Client service is running?

    - by Mnebuerquo
    I've seen a number of articles about how to edit the hosts file in Windows 7, but it's all about how to open notepad as administrator, not the actual behavior of the dns lookups afterward. I've read that the hosts file is ignored in XP SP2 if DNS Client service is running. I have tried this on my XP machine and it seems to be true. I can see how it is a security danger to have a hosts file that user programs could modify. If it could write to hosts, then any malware could spoof dns locally with minimal difficulty. I'm trying to use the hosts file for testing stuff on my local network without it going to the live site on the internet. At the same time I want to be able to use dns on the normal internet. Mostly though I just want to understand the rules on the newer windows systems. Thanks!

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  • Will I have internet connection issues next day, if I unplug router at night?

    - by headskracher77
    I did this regularly a few years ago and used to feel like I was 'being punished' by the Interent svc provider for disabling access to my computer, because trying to re-connect the next day became a constant pain. I have the same linksys router, a comcast modem, and hi-speed broadband through their LAN. Question: who or what is at fault for lousy internet connections, slow connections, or no connections: (everybody's tech dept. blames everybody else) The router? 10 year olds, maybe obsolete? The modem? came with the service plan - can connect three devices on a sharedconnection. The ISP: I read they not only even control and completely regulate bandwidth usage, but they also ration it!! (true?) So can I safely 'pull the plug' each night for security or not? thnx

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