Search Results

Search found 60744 results on 2430 pages for 'why we write'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 19/2430 | < Previous Page | 15 16 17 18 19 20 21 22 23 24 25 26  | Next Page >

  • Why doesn't my IDE do background compiling/building?

    - by MKO
    Today I develop on a fairly complex computer, it has multiple cores, SSD drives and what not. Still, most of the time I'm programming the computer is leasurely doing nothing. When I need to compile and run/deploy a somewhat complex project at best it still takes a couple of seconds. Why? Now that we're living more and more in the "age of instant" why can't I press F5 in Visual studio and launch/deploy my application instantly? A couple of seconds might not sound so bad but it's still cognitive friction and time that adds up, and frankly it makes programming less fun. So how could compilation be instant? Well, People tend to edit files in different assemblies, what if Visual Studio/The IDE constantly did compilation/and building of everything that I modified anytime that it might be appropriate. Heck if they wanted to go really advanced they could do per-class compilation. The compilation might not work but then it could just silently do nothing (except adding error messages to the error window). Surely todays computer could dedicate a core or two to this task, and if someone found it annoying it could be disabled by option. I know there's probably a thousand technical issues and some fancy shadow copying that would need to be resolved for this to be seamless and practical but it sure would make programming more seamless. Is there any practical reason why this scenario isn't possible? Would the wear and tear of continually writing binaries be too much? Couldn't assemblies be held in memory until deployed/run?

    Read the article

  • Why are embedded device apps still written in C/C++? Why not Java programming language?

    - by hinkmond
    At the recent Black Hat 2014 conference in Sin City, the Black Hatters were focusing on Embedded Devices and IoT. You know? Make your networked-toaster burn your bread 10,000 miles away, over the Web for grins and giggles. Well, apparently the Black Hatters say it can be done pretty easily these days, which is scary. See: Securing Embedded Devices & IoT Here's a quote: All these devices are still written in C and C++. The challenges associated with developing securely in these languages have been fought for nearly two decades. "You often hear people say, 'Well, why don't we just get rid of the C and C++ language if it's so problematic. Why don't we just write everything in C# or Java, or something that is a little safer to develop in?'," DeMott says. Gah! Why are all these IoT devices still using C/C++? Of course they should be using Java SE Embedded technology! It's a natural fit to use for better security on embedded devices. Or, I guess, developers really don't mind if their networked-toasters do char their breakfast. If it can be burned, it will be... That's what I say. Unless they use Java. Hinkmond

    Read the article

  • Why do we have to use break in switch

    - by trejder
    Who decided, and basing on what concepts, that switch construction (in many languages) has to be, like it is? Why do we have to use break in each statement? Why do we have to write something like this: switch(a) { case 1: result = 'one'; break; case 2: result = 'two'; break; default: result = 'not determined'; break; } I've noticed this construction in PHP and JS, but there are probably many other languages that uses it. If switch is an alternative of if, why we can't use the same construction for switch, as for if? I.e.: switch(a) { case 1: { result = 'one'; } case 2: { result = 'two'; } default: { result = 'not determined'; } } It is said, that break prevents execution of a blocks following current one. But, does someone really run into situation, where there was any need for execution of current block and following ones? I didn't. For me, break is always there. In every block. In every code.

    Read the article

  • Why can't I run any Android NDK commands?

    - by TheBuzzSaw
    I had been running Mint 12 before, and everything was working there. I switched to Ubuntu 12.04, and now I am very frustrated. When I run ndk-build, I get /home/buzz/ndk/prebuilt/linux-x86/bin/make: not found So, I changed to that folder directly. When I type in ./make, I get bash: ./make: No such file or directory Typing ls clearly shows the file where I am! I did some hacking around (pointing to external tools) to get past each error (just to experiment), and I ran into this! /home/buzz/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc: Command not found Why? Why are all these files unable to be found? As I said above, this was all working just fine in another distro. What changed? What's extra frustrating is that if I push TAB to auto-complete, it works. So, the file is clearly there (and clearly marked with execution permissions). So, why can't it be found?

    Read the article

  • Why not commit unresolved changes?

    - by Explosion Pills
    In a traditional VCS, I can understand why you would not commit unresolved files because you could break the build. However, I don't understand why you shouldn't commit unresolved files in a DVCS (some of them will actually prevent you from committing the files). Instead, I think that your repository should be locked from pushing and pulling, but not committing. Being able to commit during the merging process has several advantages (as I see it): The actual merge changes are in history. If the merge was very large, you could make periodic commits. If you made a mistake, it would be much easier to roll back (without having to redo the entire merge). The files could remain flagged as unresolved until they were marked as resolved. This would prevent pushing/pulling. You could also potentially have a set of changesets act as the merge instead of just a single one. This would allow you to still use tools such as git rerere. So why is committing with unresolved files frowned upon/prevented? Is there any reason other than tradition?

    Read the article

  • Why using Fragments?

    - by ahmed_khan_89
    I have read the documentation and some other questions' threads about this topic and I don't really feel convinced; I don't see clearly the limits of use of this technique. Fragments are now seen as a Best Practice; every Activity should be basically a support for one or more Fragments and not call a layout directly. Fragments are created in order to: allow the Activity to use many fragments, to change between them, to reuse these units... == the Fragment is totally dependent to the Context of an activity , so if I need something generic that I can reuse and handle in many Activities, I can create my own custom layouts or Views ... I will not care about this additional Complexity Developing Layer that fragments would add. a better handling to different resolution == OK for tablets/phones in case of long process that we can show two (or more) fragments in the same Activity in Tablets, and one by one in phones. But why would I use fragments always ? handling callbacks to navigate between Fragments (i.e: if the user is Logged-in I show a fragment else I show another fragment). === Just try to see how many bugs facebook SDK Log-in have because of this, to understand that it is really (?) ... considering that an Android Application is based on Activities... Adding another life cycles in the Activity would be better to design an Application... I mean the modules, the scenarios, the data management and the connectivity would be better designed, in that way. === This is an answer of someone who's used to see the Android SDK and Android Framework with a Fragments vision. I don't think it's wrong, but I am not sure it will give good results... And it is really abstract... ==== Why would I complicate my life, coding more, in using them always? else, why is it a best practice if it's just a tool for some cases? what are these cases?

    Read the article

  • Recognizing file - Python

    - by Francisco Aleixo
    Ok, so the title may trick you a bit, and I'm sorry for that but didn't find a better title. This question might be a bit hard to understand so I'll try my best. I have no idea how this works or if it is even possible but what I want to do is for example create a file type (lets imagine .test (in which a random file name would be random.test)). Now before I continue, its obviously easy to do this using for example: filename = "random.test" file = open(filename, 'w') file.write("some text here") But now what I would like to know is if it is possible to write the file .test so if I set it to open with a wxPython program, it recognizes it and for example opens up a Message Dialog automatically. I'm sorry if I'm being vague and in case you don't understand, let me know so I can try my best to explain you.

    Read the article

  • Sent Item code in java

    - by Farhan Khan
    I need urgent help, if any one can resolve my issue it will be very highly appriciated. I have create a SMS composer on jAVA netbians its on urdu language. the probelm is its not saving sent sms on Sent items.. i have tried my best to make the code but failed. Tomorrow is my last day to present the code on university please help me please below is the code that i have made till now. Please any one.... /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package newSms; import javax.microedition.io.Connector; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; import javax.wireless.messaging.MessageConnection; import javax.wireless.messaging.TextMessage; import org.netbeans.microedition.util.SimpleCancellableTask; /** * @author AHTISHAM */ public class composeurdu extends MIDlet implements CommandListener, ItemCommandListener, ItemStateListener { private boolean midletPaused = false; private boolean isUrdu; String numb=" "; Alert alert; //<editor-fold defaultstate="collapsed" desc=" Generated Fields ">//GEN-BEGIN:|fields|0| private Form form; private TextField number; private TextField textUrdu; private StringItem stringItem; private StringItem send; private Command exit; private Command sendMesg; private Command add; private Command urdu; private Command select; private SimpleCancellableTask task; //</editor-fold>//GEN-END:|fields|0| MessageConnection clientConn; private Display display; public composeurdu() { display = Display.getDisplay(this); } private void showMessage(){ display=Display.getDisplay(this); //numb=number.getString(); if(number.getString().length()==0 || textUrdu.getString().length()==0){ Alert alert=new Alert("error "); alert.setString(" Enter phone number"); alert.setTimeout(5000); display.setCurrent(alert); } else if(number.getString().length()>11){ Alert alert=new Alert("error "); alert.setString("invalid number"); alert.setTimeout(5000); display.setCurrent(alert); } else{ Alert alert=new Alert("error "); alert.setString("success"); alert.setTimeout(5000); display.setCurrent(alert); } } void showMessage(String message, Displayable displayable) { Alert alert = new Alert(""); alert.setTitle("Error"); alert.setString(message); alert.setType(AlertType.ERROR); alert.setTimeout(5000); display.setCurrent(alert, displayable); } //<editor-fold defaultstate="collapsed" desc=" Generated Methods ">//GEN-BEGIN:|methods|0| //</editor-fold>//GEN-END:|methods|0| //<editor-fold defaultstate="collapsed" desc=" Generated Method: initialize ">//GEN-BEGIN:|0-initialize|0|0-preInitialize /** * Initializes the application. It is called only once when the MIDlet is * started. The method is called before the * <code>startMIDlet</code> method. */ private void initialize() {//GEN-END:|0-initialize|0|0-preInitialize // write pre-initialize user code here //GEN-LINE:|0-initialize|1|0-postInitialize // write post-initialize user code here }//GEN-BEGIN:|0-initialize|2| //</editor-fold>//GEN-END:|0-initialize|2| //<editor-fold defaultstate="collapsed" desc=" Generated Method: startMIDlet ">//GEN-BEGIN:|3-startMIDlet|0|3-preAction /** * Performs an action assigned to the Mobile Device - MIDlet Started point. */ public void startMIDlet() {//GEN-END:|3-startMIDlet|0|3-preAction // write pre-action user code here switchDisplayable(null, getForm());//GEN-LINE:|3-startMIDlet|1|3-postAction // write post-action user code here form.setCommandListener(this); form.setItemStateListener(this); }//GEN-BEGIN:|3-startMIDlet|2| //</editor-fold>//GEN-END:|3-startMIDlet|2| //<editor-fold defaultstate="collapsed" desc=" Generated Method: resumeMIDlet ">//GEN-BEGIN:|4-resumeMIDlet|0|4-preAction /** * Performs an action assigned to the Mobile Device - MIDlet Resumed point. */ public void resumeMIDlet() {//GEN-END:|4-resumeMIDlet|0|4-preAction // write pre-action user code here //GEN-LINE:|4-resumeMIDlet|1|4-postAction // write post-action user code here }//GEN-BEGIN:|4-resumeMIDlet|2| //</editor-fold>//GEN-END:|4-resumeMIDlet|2| //<editor-fold defaultstate="collapsed" desc=" Generated Method: switchDisplayable ">//GEN-BEGIN:|5-switchDisplayable|0|5-preSwitch /** * Switches a current displayable in a display. The * <code>display</code> instance is taken from * <code>getDisplay</code> method. This method is used by all actions in the * design for switching displayable. * * @param alert the Alert which is temporarily set to the display; if * <code>null</code>, then * <code>nextDisplayable</code> is set immediately * @param nextDisplayable the Displayable to be set */ public void switchDisplayable(Alert alert, Displayable nextDisplayable) {//GEN-END:|5-switchDisplayable|0|5-preSwitch // write pre-switch user code here Display display = getDisplay();//GEN-BEGIN:|5-switchDisplayable|1|5-postSwitch if (alert == null) { display.setCurrent(nextDisplayable); } else { display.setCurrent(alert, nextDisplayable); }//GEN-END:|5-switchDisplayable|1|5-postSwitch // write post-switch user code here }//GEN-BEGIN:|5-switchDisplayable|2| //</editor-fold>//GEN-END:|5-switchDisplayable|2| //<editor-fold defaultstate="collapsed" desc=" Generated Method: commandAction for Displayables ">//GEN-BEGIN:|7-commandAction|0|7-preCommandAction /** * Called by a system to indicated that a command has been invoked on a * particular displayable. * * @param command the Command that was invoked * @param displayable the Displayable where the command was invoked */ public void commandAction(Command command, Displayable displayable) {//GEN-END:|7-commandAction|0|7-preCommandAction // write pre-action user code here if (displayable == form) {//GEN-BEGIN:|7-commandAction|1|16-preAction if (command == exit) {//GEN-END:|7-commandAction|1|16-preAction // write pre-action user code here exitMIDlet();//GEN-LINE:|7-commandAction|2|16-postAction // write post-action user code here } else if (command == sendMesg) {//GEN-LINE:|7-commandAction|3|18-preAction // write pre-action user code here String mno=number.getString(); String msg=textUrdu.getString(); if(mno.equals("")) { alert = new Alert("Alert"); alert.setString("Enter Mobile Number!!!"); alert.setTimeout(2000); display.setCurrent(alert); } else { try { clientConn=(MessageConnection)Connector.open("sms://"+mno); } catch(Exception e) { alert = new Alert("Alert"); alert.setString("Unable to connect to Station because of network problem"); alert.setTimeout(2000); display.setCurrent(alert); } try { TextMessage textmessage = (TextMessage) clientConn.newMessage(MessageConnection.TEXT_MESSAGE); textmessage.setAddress("sms://"+mno); textmessage.setPayloadText(msg); clientConn.send(textmessage); } catch(Exception e) { Alert alert=new Alert("Alert","",null,AlertType.INFO); alert.setTimeout(Alert.FOREVER); alert.setString("Unable to send"); display.setCurrent(alert); } } //GEN-LINE:|7-commandAction|4|18-postAction // write post-action user code here }//GEN-BEGIN:|7-commandAction|5|7-postCommandAction }//GEN-END:|7-commandAction|5|7-postCommandAction // write post-action user code here }//GEN-BEGIN:|7-commandAction|6| //</editor-fold>//GEN-END:|7-commandAction|6| //<editor-fold defaultstate="collapsed" desc=" Generated Method: commandAction for Items ">//GEN-BEGIN:|8-itemCommandAction|0|8-preItemCommandAction /** * Called by a system to indicated that a command has been invoked on a * particular item. * * @param command the Command that was invoked * @param displayable the Item where the command was invoked */ public void commandAction(Command command, Item item) {//GEN-END:|8-itemCommandAction|0|8-preItemCommandAction // write pre-action user code here if (item == number) {//GEN-BEGIN:|8-itemCommandAction|1|21-preAction if (command == add) {//GEN-END:|8-itemCommandAction|1|21-preAction // write pre-action user code here //GEN-LINE:|8-itemCommandAction|2|21-postAction // write post-action user code here }//GEN-BEGIN:|8-itemCommandAction|3|28-preAction } else if (item == send) { if (command == select) {//GEN-END:|8-itemCommandAction|3|28-preAction // write pre-action user code here //GEN-LINE:|8-itemCommandAction|4|28-postAction // write post-action user code here }//GEN-BEGIN:|8-itemCommandAction|5|24-preAction } else if (item == textUrdu) { if (command == urdu) {//GEN-END:|8-itemCommandAction|5|24-preAction // write pre-action user code here if (isUrdu) isUrdu = false; else { isUrdu = true; TextField tf = (TextField)item; } //GEN-LINE:|8-itemCommandAction|6|24-postAction // write post-action user code here }//GEN-BEGIN:|8-itemCommandAction|7|8-postItemCommandAction }//GEN-END:|8-itemCommandAction|7|8-postItemCommandAction // write post-action user code here }//GEN-BEGIN:|8-itemCommandAction|8| //</editor-fold>//GEN-END:|8-itemCommandAction|8| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: form ">//GEN-BEGIN:|14-getter|0|14-preInit /** * Returns an initialized instance of form component. * * @return the initialized component instance */ public Form getForm() { if (form == null) {//GEN-END:|14-getter|0|14-preInit // write pre-init user code here form = new Form("form", new Item[]{getNumber(), getTextUrdu(), getStringItem(), getSend()});//GEN-BEGIN:|14-getter|1|14-postInit form.addCommand(getExit()); form.addCommand(getSendMesg()); form.setCommandListener(this);//GEN-END:|14-getter|1|14-postInit // write post-init user code here form.setItemStateListener(this); // form.setCommandListener(this); }//GEN-BEGIN:|14-getter|2| return form; } //</editor-fold>//GEN-END:|14-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: number ">//GEN-BEGIN:|19-getter|0|19-preInit /** * Returns an initialized instance of number component. * * @return the initialized component instance */ public TextField getNumber() { if (number == null) {//GEN-END:|19-getter|0|19-preInit // write pre-init user code here number = new TextField("Number ", null, 11, TextField.PHONENUMBER);//GEN-BEGIN:|19-getter|1|19-postInit number.addCommand(getAdd()); number.setItemCommandListener(this); number.setDefaultCommand(getAdd());//GEN-END:|19-getter|1|19-postInit // write post-init user code here }//GEN-BEGIN:|19-getter|2| return number; } //</editor-fold>//GEN-END:|19-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: textUrdu ">//GEN-BEGIN:|22-getter|0|22-preInit /** * Returns an initialized instance of textUrdu component. * * @return the initialized component instance */ public TextField getTextUrdu() { if (textUrdu == null) {//GEN-END:|22-getter|0|22-preInit // write pre-init user code here textUrdu = new TextField("Message", null, 2000, TextField.ANY);//GEN-BEGIN:|22-getter|1|22-postInit textUrdu.addCommand(getUrdu()); textUrdu.setItemCommandListener(this);//GEN-END:|22-getter|1|22-postInit // write post-init user code here }//GEN-BEGIN:|22-getter|2| return textUrdu; } //</editor-fold>//GEN-END:|22-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: exit ">//GEN-BEGIN:|15-getter|0|15-preInit /** * Returns an initialized instance of exit component. * * @return the initialized component instance */ public Command getExit() { if (exit == null) {//GEN-END:|15-getter|0|15-preInit // write pre-init user code here exit = new Command("Exit", Command.EXIT, 0);//GEN-LINE:|15-getter|1|15-postInit // write post-init user code here }//GEN-BEGIN:|15-getter|2| return exit; } //</editor-fold>//GEN-END:|15-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: sendMesg ">//GEN-BEGIN:|17-getter|0|17-preInit /** * Returns an initialized instance of sendMesg component. * * @return the initialized component instance */ public Command getSendMesg() { if (sendMesg == null) {//GEN-END:|17-getter|0|17-preInit // write pre-init user code here sendMesg = new Command("send", Command.OK, 0);//GEN-LINE:|17-getter|1|17-postInit // write post-init user code here }//GEN-BEGIN:|17-getter|2| return sendMesg; } //</editor-fold>//GEN-END:|17-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: add ">//GEN-BEGIN:|20-getter|0|20-preInit /** * Returns an initialized instance of add component. * * @return the initialized component instance */ public Command getAdd() { if (add == null) {//GEN-END:|20-getter|0|20-preInit // write pre-init user code here add = new Command("add", Command.OK, 0);//GEN-LINE:|20-getter|1|20-postInit // write post-init user code here }//GEN-BEGIN:|20-getter|2| return add; } //</editor-fold>//GEN-END:|20-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: urdu ">//GEN-BEGIN:|23-getter|0|23-preInit /** * Returns an initialized instance of urdu component. * * @return the initialized component instance */ public Command getUrdu() { if (urdu == null) {//GEN-END:|23-getter|0|23-preInit // write pre-init user code here urdu = new Command("urdu", Command.OK, 0);//GEN-LINE:|23-getter|1|23-postInit // write post-init user code here }//GEN-BEGIN:|23-getter|2| return urdu; } //</editor-fold>//GEN-END:|23-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: stringItem ">//GEN-BEGIN:|25-getter|0|25-preInit /** * Returns an initialized instance of stringItem component. * * @return the initialized component instance */ public StringItem getStringItem() { if (stringItem == null) {//GEN-END:|25-getter|0|25-preInit // write pre-init user code here stringItem = new StringItem("string", null);//GEN-LINE:|25-getter|1|25-postInit // write post-init user code here }//GEN-BEGIN:|25-getter|2| return stringItem; } //</editor-fold>//GEN-END:|25-getter|2| //</editor-fold> //<editor-fold defaultstate="collapsed" desc=" Generated Getter: send ">//GEN-BEGIN:|26-getter|0|26-preInit /** * Returns an initialized instance of send component. * * @return the initialized component instance */ public StringItem getSend() { if (send == null) {//GEN-END:|26-getter|0|26-preInit // write pre-init user code here send = new StringItem("", "send", Item.BUTTON);//GEN-BEGIN:|26-getter|1|26-postInit send.addCommand(getSelect()); send.setItemCommandListener(this); send.setDefaultCommand(getSelect());//GEN-END:|26-getter|1|26-postInit // write post-init user code here }//GEN-BEGIN:|26-getter|2| return send; } //</editor-fold>//GEN-END:|26-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: select ">//GEN-BEGIN:|27-getter|0|27-preInit /** * Returns an initialized instance of select component. * * @return the initialized component instance */ public Command getSelect() { if (select == null) {//GEN-END:|27-getter|0|27-preInit // write pre-init user code here select = new Command("select", Command.OK, 0);//GEN-LINE:|27-getter|1|27-postInit // write post-init user code here }//GEN-BEGIN:|27-getter|2| return select; } //</editor-fold>//GEN-END:|27-getter|2| //<editor-fold defaultstate="collapsed" desc=" Generated Getter: task ">//GEN-BEGIN:|40-getter|0|40-preInit /** * Returns an initialized instance of task component. * * @return the initialized component instance */ public SimpleCancellableTask getTask() { if (task == null) {//GEN-END:|40-getter|0|40-preInit // write pre-init user code here task = new SimpleCancellableTask();//GEN-BEGIN:|40-getter|1|40-execute task.setExecutable(new org.netbeans.microedition.util.Executable() { public void execute() throws Exception {//GEN-END:|40-getter|1|40-execute // write task-execution user code here }//GEN-BEGIN:|40-getter|2|40-postInit });//GEN-END:|40-getter|2|40-postInit // write post-init user code here }//GEN-BEGIN:|40-getter|3| return task; } //</editor-fold>//GEN-END:|40-getter|3| /** * Returns a display instance. * @return the display instance. */ public Display getDisplay () { return Display.getDisplay(this); } /** * Exits MIDlet. */ public void exitMIDlet() { switchDisplayable (null, null); destroyApp(true); notifyDestroyed(); } /** * Called when MIDlet is started. * Checks whether the MIDlet have been already started and initialize/starts or resumes the MIDlet. */ public void startApp() { startMIDlet(); display.setCurrent(form); } /** * Called when MIDlet is paused. */ public void pauseApp() { midletPaused = true; } /** * Called to signal the MIDlet to terminate. * @param unconditional if true, then the MIDlet has to be unconditionally terminated and all resources has to be released. */ public void destroyApp(boolean unconditional) { } public void itemStateChanged(Item item) { if (item == textUrdu) { if (isUrdu) { stringItem.setText("urdu"); TextField tf = (TextField)item; String s = tf.getString(); char ch = s.charAt(s.length() - 1); s = s.substring(0, s.length() - 1); ch = Urdu.ToUrdu(ch); s = s + String.valueOf(ch); tf.setString(""); tf.setString(s); }//end if throw new UnsupportedOperationException("Not supported yet."); } } }

    Read the article

  • SQL University: What and why of database refactoring

    - by Mladen Prajdic
    This is a post for a great idea called SQL University started by Jorge Segarra also famously known as SqlChicken on Twitter. It’s a collection of blog posts on different database related topics contributed by several smart people all over the world. So this week is mine and we’ll be talking about database testing and refactoring. In 3 posts we’ll cover: SQLU part 1 - What and why of database testing SQLU part 2 - What and why of database refactoring SQLU part 3 - Tools of the trade This is a second part of the series and in it we’ll take a look at what database refactoring is and why do it. Why refactor a database To know why refactor we first have to know what refactoring actually is. Code refactoring is a process where we change module internals in a way that does not change that module’s input/output behavior. For successful refactoring there is one crucial thing we absolutely must have: Tests. Automated unit tests are the only guarantee we have that we haven’t broken the input/output behavior before refactoring. If you haven’t go back ad read my post on the matter. Then start writing them. Next thing you need is a code module. Those are views, UDFs and stored procedures. By having direct table access we can kiss fast and sweet refactoring good bye. One more point to have a database abstraction layer. And no, ORM’s don’t fall into that category. But also know that refactoring is NOT adding new functionality to your code. Many have fallen into this trap. Don’t be one of them and resist the lure of the dark side. And it’s a strong lure. We developers in general love to add new stuff to our code, but hate fixing our own mistakes or changing existing code for no apparent reason. To be a good refactorer one needs discipline and focus. Now we know that refactoring is all about changing inner workings of existing code. This can be due to performance optimizations, changing internal code workflows or some other reason. This is a typical black box scenario to the outside world. If we upgrade the car engine it still has to drive on the road (preferably faster) and not fly (no matter how cool that would be). Also be aware that white box tests will break when we refactor. What to refactor in a database Refactoring databases doesn’t happen that often but when it does it can include a lot of stuff. Let us look at a few common cases. Adding or removing database schema objects Adding, removing or changing table columns in any way, adding constraints, keys, etc… All of these can be counted as internal changes not visible to the data consumer. But each of these carries a potential input/output behavior change. Dropping a column can result in views not working anymore or stored procedure logic crashing. Adding a unique constraint shows duplicated data that shouldn’t exist. Foreign keys break a truncate table command executed from an application that runs once a month. All these scenarios are very real and can happen. With the proper database abstraction layer fully covered with black box tests we can make sure something like that does not happen (hopefully at all). Changing physical structures Physical structures include heaps, indexes and partitions. We can pretty much add or remove those without changing the data returned by the database. But the performance can be affected. So here we use our performance tests. We do have them, right? Just by adding a single index we can achieve orders of magnitude performance improvement. Won’t that make users happy? But what if that index causes our write operations to crawl to a stop. again we have to test this. There are a lot of things to think about and have tests for. Without tests we can’t do successful refactoring! Fixing bad code We all have some bad code in our systems. We usually refer to that code as code smell as they violate good coding practices. Examples of such code smells are SQL injection, use of SELECT *, scalar UDFs or cursors, etc… Each of those is huge code smell and can result in major code changes. Take SELECT * from example. If we remove a column from a table the client using that SELECT * statement won’t have a clue about that until it runs. Then it will gracefully crash and burn. Not to mention the widely unknown SELECT * view refresh problem that Tomas LaRock (@SQLRockstar on Twitter) and Colin Stasiuk (@BenchmarkIT on Twitter) talk about in detail. Go read about it, it’s informative. Refactoring this includes replacing the * with column names and most likely change to application using the database. Breaking apart huge stored procedures Have you ever seen seen a stored procedure that was 2000 lines long? I have. It’s not pretty. It hurts the eyes and sucks the will to live the next 10 minutes. They are a maintenance nightmare and turn into things no one dares to touch. I’m willing to bet that 100% of time they don’t have a single test on them. Large stored procedures (and functions) are a clear sign that they contain business logic. General opinion on good database coding practices says that business logic has no business in the database. That’s the applications part. Refactoring such behemoths requires writing lots of edge case tests for the stored procedure input/output behavior and then start to refactor it. First we split the logic inside into smaller parts like new stored procedures and UDFs. Those then get called from the master stored procedure. Once we’ve successfully modularized the database code it’s best to transfer that logic into the applications consuming it. This only leaves the stored procedure with common data manipulation logic. Of course this isn’t always possible so having a plethora of performance and behavior unit tests is absolutely necessary to confirm we’ve actually improved the codebase in some way.   Refactoring is not a popular chore amongst developers or managers. The former don’t like fixing old code, the latter can’t see the financial benefit. Remember how we talked about being lousy at estimating future costs in the previous post? But there comes a time when it must be done. Hopefully I’ve given you some ideas how to get started. In the last post of the series we’ll take a look at the tools to use and an example of testing and refactoring.

    Read the article

  • Why I lose certain values from array?

    - by blankon91
    I've the code to input the values dynamically, when I use it to add the values for the first time, it's fine, but when I want to edit it, the old values didn't inserted on sql query but the new values inserted Here is the example: http://i.stack.imgur.com/dwugS.jpg here is the code: ============the function================= sub ShowItemfgEdit(query,selItemName,defValue,num,cdisable) response.write "<select " & cdisable & " num=""" & num & """ id=""itemCombo"" name=""" & selItemName & """ class=""label"" onchange=""varUsage.ChangeSatuanDt(this)"">" if NOT query.BOF then query.moveFirst WHILE NOT query.EOF tulis = "" if trim(defValue) = trim(query("ckdbarang")) then tulis = "selected" end if response.write "<option value=""" & trim(query("ckdbarang")) & """" & tulis & ">" & trim(query("ckdbarang")) & " - " & trim(query("vnamabarang")) query.moveNext WEND end if response.write "</select>" end sub ============calling the function================ <td class="rb" align="left"><% call ShowItemfgEdit(qGetItemfgGrp,"fitem",qGetUsageDt("ckdfg"),countLine,readonlyfg) %></td> ==============post the value====================== <input type="hidden" name="fitem" value=""> ================get the value=================== for i = 1 to request.form("hdnOrderNum") if request.form("selOrdItem_" & i) <> "" then 'bla...blaa...blaa... ckdfg = trim(request.form("fitem_" & i)) '<==here is the problem objCommand.commandText = "INSERT INTO IcTrPakaiDt " &_ "(id, id_h, ckdunitkey, cnopakai, dtglpakai, ckdbarang, ckdgudang, nqty1, nqty2, csatuan1, csatuan2, nqtypakai, csatuanpakai, vketerangan, cJnsPakai, ckdprodkey, ckdfg, ncountstart, ncountstop, ncounttotal) " &_ " VALUES " &_ " (" & idDt & ",'" & idHd & "','" & selLoc & "','" & nopakai & "','" & cDate(request.form("hdnUsageDate")) & "','" & trim(ckdbarang) & "','" & trim(ckdgudang) & "'," & nqty1 & "," & nqty2 & ",'" & trim(csatuan1) & "','" & trim(csatuan2) & "'," & nqtypakai & ",'" & csatuanpakai & "','" & trim(keteranganItem) & "','" & trim(cjnspakai) & "','" & ckdprodkey & "','" &ckdfg& "'," & cnt1 & "," & cnt2 & "," & totalcnt & ")" set qInsertPakaiDt = objCommand.Execute end if next problem: old value of ckdfg didn't inserted to query, but the new value inserted. How to fix this bug?

    Read the article

  • Linux Unable to Write to Directory Despite Permissions

    - by Nick Q.
    I'm trying to give myself permissions to /var/www/ however for some reason I am unable to do so. Currently what I'm facing is this: nick@server1:/var$ ls -l drwxrwxr-x 5 root wwwusers 232 Mar 15 19:31 www nick@server1:/var$ groups nick wwwusers nick@server1:/var$ mkdir www/trying mkdir: cannot create directory `www/trying': Permission denied I am running Ubuntu 10.04 LTS on a VPS and am used to running unix on my own machine so I may be doing something absolutely stupid, but I would like to be able to have the group wwwusers be able to write to www.

    Read the article

  • Monitoring MySQL SELECT/WRITE/UPDATE/SLOW queries in Nagios

    - by imaginative
    There's ways to get performance graphs with several monitoring software packages out there such as ZenOSS. There's a plugin available that will graph MySQL based SELECT/WRITE/SLOW queries in a nice rrd style graph. I'm curious if there is a way to also get similar graphs available in Nagios 3.0? I know Nagios has tools like pnp and can integrate rrd, but is there something readily available that can plugin to monitor those MySQL specifics?

    Read the article

  • IIS 7.5 Unable to write configuration file

    - by flumeware
    I have a fault regarding IIS 7.5 on Win Server 2008 R2, whenever I try to change any site bindings or start an application pool I get the error below: Filename: \\?\C:\Windows\system32\inetsrv\config\applicationHost.config Error: Cannot write configuration file the application pools run as network service. None of the sites that are running have been affected however their configuration cannot be changed UPDATED 05/10/2012 A reboot fixed this issue, however I am curious to know what caused it in the first place.

    Read the article

  • Cannot write log file 'ffmpeg2pass-0.log' for pass-1 encoding: Permission denied

    - by matt_tm
    Our PHP application is installed as 'root' on a Redhat5/CentOS system at: /var/www/html/beta/ After disabling SELINUX in order to allow these scripts to execute other programs on the system - http://serverfault.com/questions/192951/what-permissions-are-needed-to-run-a-system-command-within-a-php-script-that-wr I faced the error that the Apache error_log showed this: Cannot write log file 'ffmpeg2pass-0.log' for pass-1 encoding: Permission denied

    Read the article

  • Can't write to raid on Fedora

    - by 99miles
    I just did a fresh install of Fedora 11 and added Raid 1 following this tutorial: http://www.optimiz3.com/installing-fedora-11-and-setting-up-a-raid-0-1-5-6-or-10-array/ Now I see the filesystem when I open 'Computer' in the GUI, and I open it and see 'lost+found', but i can't write to the drive. The option is simply greyed out. And when I view Properties on the drive and go to Permissions, it says 'The permissions of {driveid} could not be determined.' Any ideas?

    Read the article

  • Linux Unable to Write to Directory Despite Permissions

    - by Nick Q.
    I'm trying to give myself permissions to /var/www/ however for some reason I am unable to do so. Currently what I'm facing is this: nick@server1:/var$ ls -l drwxrwxr-x 5 root wwwusers 232 Mar 15 19:31 www nick@server1:/var$ groups nick wwwusers nick@server1:/var$ mkdir www/trying mkdir: cannot create directory `www/trying': Permission denied I am running Ubuntu 10.04 LTS on a VPS and am used to running unix on my own machine so I may be doing something absolutely stupid, but I would like to be able to have the group wwwusers be able to write to www.

    Read the article

  • What-causes-error-135-socket-write-error

    - by fmz
    I am trying to upload a 12MB .wav file on a Mac running Transmit to a Linux box running Apache and get the following error after uploading just 160KB of the file: error-135-socket-write-error Any clues why I may be getting this? I have successfully uploaded much larger files in the past and nothing has changed on the configuration. Thanks in advance.

    Read the article

  • Debian tuning for increasing read/write buffer.

    - by Claudiu
    Is there a way to modify Debian settings so the memory could be used more for disk read/write caching ? I am already using RAID 0 but thats not enough for multiple users, and the disk is almost struggled. Torrents use the disk very much and rTorrent doesn't have cache settings.

    Read the article

  • XP User account cannot write to USB

    - by Quick Joe Smith
    Is there a local security policy setting or somesuch to allow limited user accounts to modify the contents of USB drives? Currently I get an "Access denied" error, further saying "Make sure the disk is not full or write-protected and that the file is not currently in use." The Administrator account has no such obstacles. Update: The problem is at least solvable by altering NTFS permissions (granting Full Control to Users), and therefore I'm losing hope that there is a more global solution.

    Read the article

  • Freebsd write access to group directory

    - by Nikolay Sergeev
    Hi. I'm confused. I have two users in system: u1 and u2, and group u1. both u1 and u2 belong to g1. I've created directory /opt/d with properties: drwxrwxr-x 2 u1 u1 512B May 26 17:55 d AFAIK, this configuration allows both users write to directory. But, from u2: touch /opt/d/x touch: /opt/d/x: Permission denied And same configuration on RHEL5 works fine. What i've missed? Thanks.

    Read the article

  • Does SDHC have any write error recovery ?

    - by marc
    What happen if SDHC card get write error (damaged cell / bad sector) ? Whole card is unusable (to trash, all data written to that sector now and in future will be lost) ? or rewrite sector (flash memory get corrupted when writing so maybe have any function to check if sector was written successfully) to another and mark as fault as unusable what will be seen as reduction of capacity but no data lost. I have to do some research about SD card-s on disk less machines. regards

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 15 16 17 18 19 20 21 22 23 24 25 26  | Next Page >