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• Hibernate - EhCache - Which region to Cache associations/sets/collections ??

  - by lifeisnotfair

  Hi all, I am a newcomer to hibernate. It would be great if someone could comment over the following query that i have: Say i have a parent class and each parent has multiple children. So the mapping file of parent class would be something like: parent.hbm.xml <hibernate-mapping > <class name="org.demo.parent" table="parent" lazy="true"> <cache usage="read-write" region="org.demo.parent"/> <id name="id" column="id" type="integer" length="10"> <generator class="native"> </generator> </id> <property name="name" column="name" type="string" length="50"/> <set name="children" lazy="true"> <cache usage="read-write" region="org.demo.parent.children" /> <key column="parent_id"/> <one-to-many class="org.demo.children"/> </set> </class> </hibernate-mapping> children.hbm.xml <hibernate-mapping > <class name="org.demo.children" table="children" lazy="true"> <cache usage="read-write" region="org.demo.children"/> <id name="id" column="id" type="integer" length="10"> <generator class="native"> </generator> </id> <property name="name" column="name" type="string" length="50"/> <many-to-one name="parent_id" column="parent_id" type="integer" length="10" not-null="true"/> </class> </hibernate-mapping> So for the set children, should we specify the region org.demo.parent.children where it should cache the association or should we use the cache region of org.demo.children where the children would be getting cached. I am using EHCache as the 2nd level cache provider. I tried to search for the answer to this question but couldnt find any answer in this direction. It makes more sense to use org.demo.children but I dont know in which scenarios one should use a separate cache region for associations/sets/collections as in the above case. Kindly provide your inputs also let me know if I am not clear in my question. Thanks all.

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• Can I write a test that succeeds if and only if a statement does not compile?

  - by Billy ONeal

  I'd like to prevent clients of my class from doing something stupid. To that end, I have used the type system, and made my class only accept specific types as input. Consider the following example (Not real code, I've left off things like virtual destructors for the sake of example): class MyDataChunk { //Look Ma! Implementation! }; class Sink; class Source { virtual void Run() = 0; Sink *next_; void SetNext(Sink *next) { next_ = next; } }; class Sink { virtual void GiveMeAChunk(const MyDataChunk& data) { //Impl }; }; class In { virtual void Run { //Impl } }; class Out { }; //Note how filter and sorter have the same declaration. Concrete classes //will inherit from them. The seperate names are there to ensure only //that some idiot doesn't go in and put in a filter where someone expects //a sorter, etc. class Filter : public Source, public Sink { //Drop objects from the chain-of-command pattern that don't match a particular //criterion. }; class Sorter : public Source, public Sink { //Sorts inputs to outputs. There are different sorters because someone might //want to sort by filename, size, date, etc... }; class MyClass { In i; Out o; Filter f; Sorter s; public: //Functions to set i, o, f, and s void Execute() { i.SetNext(f); f.SetNext(s); s.SetNext(o); i.Run(); } }; What I don't want is for somebody to come back later and go, "Hey, look! Sorter and Filter have the same signature. I can make a common one that does both!", thus breaking the semantic difference MyClass requires. Is this a common kind of requirement, and if so, how might I implement a test for it?

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• How can I execute an insert with data from a repeater-generated form whose data source is SQL?

  - by Duke

  I'm storing multilingual data in a database whose model is language normalized (like this). For this particular problem the key for the table in question consists of a value entered by the user and a language from the language table. I'd like to dynamically generate a form with input fields for all available languages. The user inputs a key value then goes down a list of field sets filling out the information in each language. In this case there are two fields for every language, a name and a value (the value is language dependent.) I have all existing information displayed on the page with a gridview, below which I have a formview that is always in insert mode allowing the user to enter new data. Within the formview I have a repeater with an SQLDataSource that gets a list of available languages: <asp:Repeater ID="SessionLocaleRepeater" runat="server" DataSourceID="LocaleSQLDataSource" EnableViewState="false"> <ItemTemplate> <tr> <th scope="row"><%# DataBinder.Eval(Container.DataItem, "LocaleName") %></th> <td>Name:</td> <td><asp:TextBox ID="TextBox1" runat="server" Text="" /></td> <td>Number:</td> <td><asp:TextBox ID="TextBox2" runat="server" Text="" /></td> </tr> </ItemTemplate> </asp:Repeater> I figured that in order to insert this data I'd have to execute my sql server insert stored procedure for each item in the repeater; I am trying to use the formview inserting event. The problem is that the repeater isn't databound to the SQLDataSource until after the formview inserting event (inserting event is in PostBackEvent and databind is in PreRender), which means the controls and data are not available when the inserting event is fired. I tried databinding the repeater during the formview inserting event; the controls were available but the data was not. Would this have something to do with how/when the viewstate information is re-added to the controls? From what I've read, Viewstate is one of the first things to be restored. Given the order of events how can I get the data I need for the insert? I'm open to other solutions to creating dynamic input controls, but they will have to query the database to determine how many sets of controls to create.

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• Building a DataTable in C# with one column at a time

  - by Awaken

  I am trying to build a Retirement Calculator as a chance to make something useful and learn C# better. Currently, I am trying to build a DataTable with a dynamic amount of rows/columns. For context, I ask the user for some inputs regarding salary, % of salary being invested, and expected ROI. I have some other stuff too, but it isn't really part of the issue I am having. Because the number of columns I need for the DataTable is unknown until the formula is run (while+for loop completes), I am having trouble doing things as DataColumns. Hopefully the code below will help. I am really trying to build the table one column at a time. I realize I could reverse it to build it one row at a time because the Years before retirement (yearsRetire) is known, but I would prefer not to and I want to learn more. Sorry for the indentation and commenting. I tried to leave some of my commented coding attempts in there. Thanks for any help. public double calcROI() { double testROI = 0.00; double tempRetireAmount = 0; double adjustRetire = goalAmount * (1 + (Math.Pow(inflation,yearsRetire))); // Loop through ROI values until the calculated retire amount with the test ROI // is greater than the target amount adjusted for inflation while (tempRetireAmount < adjustRetire) { //Increment ROI by 1% per while iteration testROI += .01; //Make a new Column to hold the values for ROI for this while iteration //dtMain.Columns.Add(Convert.ToString(testROI)); //DataColumn tempdc = new DataColumn(Convert.ToString(testROI)); //Loop through the number of years entered by user and see the amount //at Retirement with current ROI for (int i = 0; i < yearsRetire; i++) { //Main formula to calculate amount after i years tempRetireAmount = (tempRetireAmount + salary*savingsPct) * (1 + testROI); // Add value for this year/ROI to table/column //DataRow dr = .NewRow(); //dr tempRetireAmount; //tempdc[i] = tempRetireAmount; } //Need to add column of data to my Main DataTable //dtMain.Rows.Add(dr); //dtMain.Columns.Add(tempdc); } return testROI; }

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• Nested WHILE loops not acting as expected - Javascript / Google Apps Script

  - by dthor

  I've got a function that isn't acting as intended. Before I continue, I'd like preface this with the fact that I normally program in Mathematica and have been tasked with porting over a Mathematica function (that I wrote) to JavaScript so that it can be used in a Google Docs spreadsheet. I have about 3 hours of JavaScript experience... The entire (small) project is calculating the Gross Die per Wafer, given a wafer and die size (among other inputs). The part that isn't working is where I check to see if any corner of the die is outside of the effective radius, Reff. The function takes a list of X and Y coordinates which, when combined, create the individual XY coord of the center of the die. That is then put into a separate function "maxDistance" that calculates the distance of each of the 4 corners and returns the max. This max value is checked against Reff. If the max is inside the radius, 1 is added to the die count. // Take a list of X and Y values and calculate the Gross Die per Wafer function CoordsToGDW(Reff,xSize,ySize,xCoords,yCoords) { // Initialize Variables var count = 0; // Nested loops create all the x,y coords of the die centers for (var i = 0; i < xCoords.length; i++) { for (var j = 0; j < yCoords.length, j++) { // Add 1 to the die count if the distance is within the effective radius if (maxDistance(xCoords[i],yCoords[j],xSize,ySize) <= Reff) {count = count + 1} } } return count; } Here are some examples of what I'm getting: xArray={-52.25, -42.75, -33.25, -23.75, -14.25, -4.75, 4.75, 14.25, 23.75, 33.25, 42.75, 52.25, 61.75} yArray={-52.5, -45.5, -38.5, -31.5, -24.5, -17.5, -10.5, -3.5, 3.5, 10.5, 17.5, 24.5, 31.5, 38.5, 45.5, 52.5, 59.5} CoordsToGDW(45,9.5,7.0,xArray,yArray) returns: 49 (should be 72) xArray={-36, -28, -20, -12, -4, 4, 12, 20, 28, 36, 44} yArray={-39, -33, -27, -21, -15, -9, -3, 3, 9, 15, 21, 27, 33, 39, 45} CoordsToGDW(32.5,8,6,xArray,yArray) returns: 39 (should be 48) I know that maxDistance() is returning the correct values. So, where's my simple mistake? Also, please forgive me writing some things in Mathematica notation... Edit #1: A little bit of formatting. Edit #2: Per showi, I've changed WHILE loops to FOR loops and replaced <= with <. Still not the right answer. It did clean things up a bit though... Edit #3: What I'm essentially trying to do is take [a,b] and [a,b,c] and return [[a,a],[a,b],[a,c],[b,a],[b,b],[b,c]]

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• Change HttpContext.Request.InputStream

  - by user320478

  I am getting lot of errors for HttpRequestValidationException in my event log. Is it possible to HTMLEncode all the inputs from override of ProcessRequest on web page. I have tried this but it gives context.Request.InputStream.CanWrite == false always. Is there any way to HTMLEncode all the feilds when request is made? public override void ProcessRequest(HttpContext context) { if (context.Request.InputStream.CanRead) { IEnumerator en = HttpContext.Current.Request.Form.GetEnumerator(); while (en.MoveNext()) { //Response.Write(Server.HtmlEncode(en.Current + " = " + //HttpContext.Current.Request.Form[(string)en.Current])); } long nLen = context.Request.InputStream.Length; if (nLen > 0) { string strInputStream = string.Empty; context.Request.InputStream.Position = 0; byte[] bytes = new byte[nLen]; context.Request.InputStream.Read(bytes, 0, Convert.ToInt32(nLen)); strInputStream = Encoding.Default.GetString(bytes); if (!string.IsNullOrEmpty(strInputStream)) { List<string> stream = strInputStream.Split('&').ToList<string>(); Dictionary<int, string> data = new Dictionary<int, string>(); if (stream != null && stream.Count > 0) { int index = 0; foreach (string str in stream) { if (str.Length > 3 && str.Substring(0, 3) == "txt") { string textBoxData = str; string temp = Server.HtmlEncode(str); //stream[index] = temp; data.Add(index, temp); index++; } } if (data.Count > 0) { List<string> streamNew = stream; foreach (KeyValuePair<int, string> kvp in data) { streamNew[kvp.Key] = kvp.Value; } string newStream = string.Join("", streamNew.ToArray()); byte[] bytesNew = Encoding.Default.GetBytes(newStream); if (context.Request.InputStream.CanWrite) { context.Request.InputStream.Flush(); context.Request.InputStream.Position = 0; context.Request.InputStream.Write(bytesNew, 0, bytesNew.Length); //Request.InputStream.Close(); //Request.InputStream.Dispose(); } } } } } } base.ProcessRequest(context); }

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• True / false evaluation doesn't work as expected in Scheme

  - by ron

  I'm trying to compare two booleans : (if (equal? #f (string->number "123b")) "not a number" "indeed a number") When I run this in the command line of DrRacket I get "not a number" , however , when I put that piece of code in my larger code , the function doesn't return that string ("not a number") , here's the code : (define (testing x y z) (define badInput "ERROR") (if (equal? #f (string->number "123b")) "not a number" "indeed a number") (display x)) And from command line : (testing "123" 1 2) displays : 123 Why ? Furthermore , how can I return a value , whenever I choose ? Here is my "real" problem : I want to do some input check to the input of the user , but the thing is , that I want to return the error message if I need , before the code is executed , because if won't - then I would run the algorithm of my code for some incorrect input : (define (convert originalNumber s_oldBase s_newBase) (define badInput "ERROR") ; Input check - if one of the inputs is not a number then return ERROR (if (equal? #f (string->number originalNumber)) badInput) (if (equal? #f (string->number s_oldBase)) badInput) (if (equal? #f (string->number s_newBase)) badInput) (define oldBase (string->number s_oldBase)) (define newBase (string->number s_newBase)) (define outDecimal (convertIntoDecimal originalNumber oldBase)) (define result "") ; holds the new number (define remainder 0) ; remainder for each iteration (define whole 0) ; the whole number after dividing (define temp 0) (do() ((= outDecimal 0)) ; stop when the decimal value reaches 0 (set! whole (quotient outDecimal newBase)) ; calc the whole number (set! temp (* whole newBase)) (set! remainder (- outDecimal temp)) ; calc the remainder (set! result (appending result remainder)) ; append the result (set! outDecimal (+ whole 0)) ; set outDecimal = whole ) ; end of do (if (> 1 0) (string->number (list->string(reverse (string->list result))))) ) ;end of method This code won't work since it uses another method that I didn't attach to the post (but it's irrelevant to the problem . Please take a look at those three IF-s ... I want to return "ERROR" if the user put some incorrect value , for example (convert "23asb4" "b5" "9") Thanks

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• 2 dimensional arraylists in java

  - by Chris Maness

  So here's the deal I'm working on a project that requires me to have a 2 dimensional arraylist of 1 dimensional arrays. But every time I try to load in my data I get an error: Can't do this opperation because of bad input java.lang.IndexOutOfBoundsException: Index: 1, Size: 0 On some of the inputs. I've got no idea where I'm going wrong on this one. A little help please? Source Code: import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.util.ArrayList; import java.util.Scanner; import javax.swing.JOptionPane; import java.io.InputStream; public class Facebull { public static void main (String[] args) { if(args.length != 0){ load(args[0]); } else{ load("testFile"); } } public static void load(String fname) { int costOfMach = 0; ArrayList <Integer> finalMach = new ArrayList<Integer>(); ArrayList <ArrayList<int[]>>machines = new ArrayList<ArrayList<int[]>>(); Scanner inputFile = null; File f = new File(fname); if (f.exists ()) { try { inputFile = new Scanner (f); } catch (FileNotFoundException e) { JOptionPane.showMessageDialog(null,"Can't find the file\n" + e); } int i = 0; while (inputFile.hasNext ( )) { String str = inputFile.nextLine ( ); String [ ] fields = str.split ("[\t ]"); System.out.println(str); if (!(fields[0].isEmpty() || fields[0].equals (""))){ fields[0] = fields[0].substring(1); fields[1] = fields[1].substring(1); fields[2] = fields[2].substring(1); try { //data to be inputed is 0 and 3 location of data is 1 and 2 int[] item = new int[2]; item[1] = Integer.parseInt(fields[0]); item[0] = Integer.parseInt(fields[3]); if(machines.size() < Integer.parseInt(fields[1])){ ArrayList<int[]> column = new ArrayList<int[]>(); machines.add (Integer.parseInt(fields[1])-1, column); System.out.println("we're in the if"); } machines.get(Integer.parseInt(fields[1])-1).add(Integer.parseInt(fields[2])-1, item); } //catches any exception catch (Exception e) { System.out.println("Can't do this opperation because of bad input \n" + e); } } } inputFile.close ( ); } System.out.print(machines); }//end load }

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• Rails nested form for belongs_to

  - by user1232533

  I'm new to rails and have some troubles with creating a nested form. My models: class User < ActiveRecord::Base belongs_to :company accepts_nested_attributes_for :company, :reject_if => :all_blank end class Company < ActiveRecord::Base has_many :users end Now i would like to create a new company from the user sign_up page (i use Devise btw) by given only a company name. And have a relation between the new User and new Company. In the console i can create a company for a existing User like this: @company = User.first.build_company(:name => "name of company") @company.save That works, but i can't make this happen for a new user, in my new user sign_up form i tried this (i know its wrong by creating a new User fist but im trying to get something working here..): <%= simple_form_for(resource, :as => resource_name, :html => { :class => 'form-horizontal' }, :url => registration_path(resource_name)) do |f| %> <%= f.error_notification %> <div class="inputs"> <% @user = User.new company = @user.build_company() %> <% f.fields_for company do |builder| %> <%= builder.input :name, :required => true, :autofocus => true %> <% end %> <%= f.input :email, :required => true, :autofocus => true %> <%= f.input :password, :required => true %> <%= f.input :password_confirmation, :required => true %> </div> <div class="form-actions"> <%= f.button :submit, :class => 'btn-primary', :value => 'Sign up' %> </div> I did my best to google for a solution/ example.. found some nested form examples but it's just not clear to me how to do this. Really hope somebody can help me with this. Any help on this would be appreciated. Thanks in advance! Greets, Daniel

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• php web services not getting data from iphone application

  - by user317192

  Hi, I am connecting with a php web service from my iphone application, I am doing a simple thing i.e. 1. Getting user inputs for: username password in a text field from the iphone form and sending the same to the PHP Post request web service. At the web service end I receive nothing other than blank fields that are inserted into the MySQL Database....... The code for sample web service is: ***********SAMPLE CODE FOR WEB SERVICES***** mysql_select_db("eventsfast",$con); $username = $_REQUEST['username']; $password = $_REQUEST['password']; echo $username; echo $password; $data = $_REQUEST; $fp = fopen("log.txt", "w"); fwrite($fp, $data['username']); fwrite($fp, $data['password']); $sql="INSERT INTO users(username,password) VALUES('{$username}','{$password}')"; if(!mysql_query($sql,$con)) { die('Error:'.mysql_error()); } echo json_encode("1 record added to users table"); mysql_close($con); echo "test"; ? ***************PHP******** ****** **************IPHONE EVENT CODE******* import "postdatawithphpViewController.h" @implementation postdatawithphpViewController @synthesize userName,password; -(IBAction) postdataid) sender { NSLog(userName.text); NSLog(password.text); NSString * dataTOB=[userName.text stringByAppendingString:password.text]; NSLog(dataTOB); NSData * postData=[dataTOB dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; NSLog(postLength); NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://localhost:8888/write.php"]]; [request setURL:url]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSURLResponse *response; NSError *error; [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; if(error==nil) NSLog(@"Error is nil"); else NSLog(@"Error is not nil"); NSLog(@"success!"); } Please help.............

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• Fill 4 input with one textarea

  - by Patrice Poliquin

  I have a question for the community. My problem is that I have 4 input files with a maxlength of 60 caracters for a total of 240 caracters. Because the "backend" of the customer's system, it need to be 4 differents inputs max to be inserted and they say it is not user-friendly to fill 4 fields. My solution I want to make a textarea and when you fill it, il complete the 4 fields. [input text #1] max60 [input text #2] max60 [input text #3] max60 [input text #4] max60 [textarea max 240] What I am trying to do is to make by javascript/jQuery to fill up the four field while typing in. At the moment, here is my code. $(document).ready(function() { // My text area $("#inf_notes").bind('keydown', function () { var maxLength = 240; if ($(this).val().length <= 60) { // The first 60 caracters $('#inf_notes_1').val($(this).val()); } if ($(this).val().length > 60 && $(this).val().length <= 120) { // If more then 60, fill the second field $('#inf_notes_2').val($(this).val()); } // If 121 - 180 ... // If 181 - 240 ... if($(this).val().length == 240) { $(this).val($(this).val().substring(0, maxLength)); $('.alert_textarea').show(); // Simple alert else { $('.alert_textarea').hide(); } }); }); It actually works for the first one, but I would like to have some feedbacks to help me complete the script to fill the 3 nexts. Any guess to complete it? -- EDIT #1 I found a way that could maybe work! When the first input is completly filled, it will jump to the next field with a .focus() $(".inf_notes").bind('keydown', function () { var notes1 = $('#inf_notes_1').val(); var notes2 = $('#inf_notes_2').val(); var notes3 = $('#inf_notes_3').val(); if (notes1.length == 60) { $('#inf_notes_2').focus(); } if (notes2.length == 60) { $('#inf_notes_3').focus(); } if (notes3.length == 60) { $('#inf_notes_4').focus(); } });

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• can't read from stream until child exits?

  - by BobTurbo

  OK I have a program that creates two pipes - forks - the child's stdin and stdout are redirected to one end of each pipe - the parent is connected to the other ends of the pipes and tries to read the stream associated with the child's output and print it to the screen (and I will also make it write to the input of the child eventually). The problem is, when the parent tries to fgets the child's output stream, it just stalls and waits until the child dies to fgets and then print the output. If the child doesn't exit, it just waits forever. What is going on? I thought that maybe fgets would block until SOMETHING was in the stream, but not block all the way until the child gives up its file descriptors. Here is the code: #include <stdlib.h> #include <stdio.h> #include <string.h> #include <sys/types.h> #include <unistd.h> int main(int argc, char *argv[]) { FILE* fpin; FILE* fpout; int input_fd[2]; int output_fd[2]; pid_t pid; int status; char input[100]; char output[100]; char *args[] = {"/somepath/someprogram", NULL}; fgets(input, 100, stdin); // the user inputs the program name to exec pipe(input_fd); pipe(output_fd); pid = fork(); if (pid == 0) { close(input_fd[1]); close(output_fd[0]); dup2(input_fd[0], 0); dup2(output_fd[1], 1); input[strlen(input)-1] = '\0'; execvp(input, args); } else { close(input_fd[0]); close(output_fd[1]); fpin = fdopen(input_fd[1], "w"); fpout = fdopen(output_fd[0], "r"); while(!feof(fpout)) { fgets(output, 100, fpout); printf("output: %s\n", output); } } return 0; }

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• Cannot get document.getElementById() to find my textarea

  - by Slruh

  Maybe I've been working on my site for to long, but I can't get the following to work. I am having my textarea fire an onkeyup() event called limiter which is supposed to check the textarea and limit the text in the box, while updated another readonly input field that shows the amount of characters left. This is the javascript code: <script type="text/javascript"> var count = "500"; function limiter(){ var comment = document.getElementById("comment"); var form = this.parent; var tex = comment.value; var len = tex.length; if(len > count){ tex = tex.substring(0,count); comment.value =tex; return false; } form.limit.value = count-len; } </script> The form looks like this: <form id="add-course-rating" method="post" action="/course_ratings/add/8/3/5/3" accept- charset="utf-8"><div style="display:none;"><input type="hidden" name="_method" value="POST" /> //Other inputs here <div id="comment-name" style="margin-top:10px"> <div id="comment-name-text"> <b>Comments</b><br /> Please leave any comments that you think will help anyone else. </div> <style type="text/css"> .rating-form-box textarea { -moz-border-radius:5px 5px 5px 5px; } </style> <div class="rating-form-box"> <textarea name="data[CourseRatings][comment]" id="comment" onkeyup="limiter()" cols="115" rows="5" ></textarea> <script type="text/javascript"> document.write("<input type=text name=limit size=4 readonly value="+count+">"); </script> </div> <input type="submit" value="Add Rating" style="float: right;"> </form> If anyone can help that would be great.

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• How to use enumeration types in C++? Apply within example.

  - by Sagistic

  I do not understand how to use enumeration types. I understand what they are, but I don't quite get their purpose. I have made a program that inputs three sides of a triangle and outputs whether or not they are isosceles, scalene, or equilateral. I'm suppose to incorporate the enumeration type somewhere, but don't get where and how to use them. Any help would be appreciated. // h8p466x1.cpp : Defines the entry point for the console application. // include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { return 0; } include using namespace std; enum triangleType {scalene, isosceles, equilateral, noTriangle}; void triangleShape(double x, double y, double z); int main() { double x, y, z; cout << "Please enter the three sides of a triangle:" << endl; cout << "Enter side 1: "; cin >> x; cout << endl; cout << "Enter side 2: "; cin >> y; cout << endl; cout << "Enter side 3: "; cin >> z; cout << endl; triangleShape(x, y, z); return 0; } void triangleShape(double x, double y, double z) { if (((x+y) z) && ((x+z) y) && ((y+z) x)) { cout << "You have a triangle!" << endl; if (x == y && y == z) cout << "Your triangle is an equilateral" << endl; else if (x == y || x == z || y == z) cout << "Your triangle is an isosceles" << endl; else cout << "Your triangle is a scalene" << endl; } else if ((x+y) <= z || ((x+z) <= y) || ((y+z) <= x)) cout << "You do not have a triangle." << endl; }

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• How to use enumeration types in C++?

  - by Sagistic

  I do not understand how to use enumeration types. I understand what they are, but I don't quite get their purpose. I have made a program that inputs three sides of a triangle and outputs whether or not they are isosceles, scalene, or equilateral. I'm suppose to incorporate the enumeration type somewhere, but don't get where and how to use them. Any help would be appreciated. #include <iostream> using namespace std; enum triangleType {scalene, isosceles, equilateral, noTriangle}; void triangleShape(double x, double y, double z); int main() { double x, y, z; cout << "Please enter the three sides of a triangle:" << endl; cout << "Enter side 1: "; cin >> x; cout << endl; cout << "Enter side 2: "; cin >> y; cout << endl; cout << "Enter side 3: "; cin >> z; cout << endl; triangleShape(x, y, z); return 0; } void triangleShape(double x, double y, double z) { if (((x+y) > z) && ((x+z) > y) && ((y+z) > x)) { cout << "You have a triangle!" << endl; if (x == y && y == z) cout << "Your triangle is an equilateral" << endl; else if (x == y || x == z || y == z) cout << "Your triangle is an isosceles" << endl; else cout << "Your triangle is a scalene" << endl; } else if ((x+y) <= z || ((x+z) <= y) || ((y+z) <= x)) cout << "You do not have a triangle." << endl; }

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• Command prompt in debug mode for Eclipse? (OpenCV + Eclipse + Win7)

  - by Tony

  I am a beginner for Eclipse. I now have Eclipse C/C++ IDE with OpenCV library running on Windows 7. So far it works after spending hours trying to get it running. But then I realize that Eclipse does not pop up a command prompt as VS2010 does while debugging. And moreover Eclipse's debug mode is just stuck in there and refuse to output anything. But if the code doesn't involve the OpenCV things it works again. Below is the code I use for testing. It captures images from webcam and output it to the screen. The infinite loop (until you press 'q') makes sure it constantly grabs new inputs from the camera. I browsed through the workspace and run the exe just compiled and it worked flawlessly. So I don't think there's anything wrong in the code (it's an example code anyway In brief, can I just pop up a command prompt window in debug mode? And why is Eclipse console stuck when the code involves some OpenCV functions? #include <stdio.h> #include <stdlib.h> #include <tchar.h> #include <cv.h> #include <cxcore.h> #include <highgui.h> #include <iostream> int _tmain(int argc, _TCHAR* argv[]) { CvCapture *capture = 0; IplImage *frame = 0; int key = 0; /* initialize camera */ capture = cvCaptureFromCAM( 0 ); /* always check */ if ( !capture ) { printf("Cannot open initialize webcam!\n"); return 1; } /* create a window for the video */ cvNamedWindow( "result", CV_WINDOW_AUTOSIZE ); while( key != 'q' ) { /* get a frame */ frame = cvQueryFrame( capture ); /* always check */ if( !frame ) break; /* display current frame */ cvShowImage( "result", frame ); /* exit if user press 'q' */ key = cvWaitKey( 1 ); } /* free memory */ cvDestroyWindow( "result" ); cvReleaseCapture( &capture ); return 0; }

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• Need advice about pointers and time elapsed program. How to fix invalid operands and cannot convert errors?

  - by user1781382

  I am trying to write a program that tells the difference between the two times the user inputs. I am not sure how to go about this. I get the errors : Line 27|error: invalid operands of types 'int' and 'const MyTime*' to binary 'operator-'| Line |39|error: cannot convert 'MyTime' to 'const MyTime*' for argument '1' to 'int DetermineElapsedTime(const MyTime*, const MyTime*)'| I also need a lot of help in this problem. I don't have a good curriculum, and my class textbook is like cliffnotes for programming. This will be my last class at this university. The C++ teztbook I use(my own not for class) is Sam's C++ One hour a day. #include <iostream> #include<cstdlib> #include<cstring> using namespace std; struct MyTime { int hours, minutes, seconds; }; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2); long t1, t2; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2) { return((int)t2-t1); } int main(void) { char delim1, delim2; MyTime tm, tm2; cout << "Input two formats for the time. Separate each with a space. Ex: hr:min:sec\n"; cin >> tm.hours >> delim1 >> tm.minutes >> delim2 >> tm.seconds; cin >> tm2.hours >> delim1 >> tm2.minutes >> delim2 >> tm2.seconds; DetermineElapsedTime(tm, tm2); return 0; } I have to fix the errors first. Anyone have any ideas??

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• C# setting case constant expressions, do they have to follow a specific order?

  - by Umeed

  Say I'm making a simple program, and the user is in the menu. And the menu options are 1 3 5 7 (i wouldn't actually do that but lets just go with it). and I want to make my switch statement using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DecisionMaking2 { class Program { static void Main(string[] args) { Console.WriteLine("Please choose an option: "); string SelectedOpt = Console.ReadLine(); double Selection = Convert.ToDouble(SelectedOpt); double MenuOption = (Selection); switch (MenuOption) { case 1: Console.WriteLine("Selected option #1"); break; case 2: Console.WriteLine("Selected option #3"); break; case 3: Console.WriteLine("Selected option #5"); break; case 4: Console.WriteLine("Selected option #7"); break; default: Console.WriteLine("Please choose from the options List!"); break; } } } } would that work? or would I have to name each case constant expression the option number I am using? I went to the microsoft website and I didn't quite pick up on anything i was looking for. . Also while I have your attention, how would I make it so the user chooses from either option and because I don't know which option the user will select " double MenuOption = " could be anything, whatever the user inputs right? so would what I have even work? I am doing this all by hand, and don't get much lab time to work on this as I have tons of other courses to work on and then a boring job to go to, and my PC at home has a restarting issue lol. soo any and all help is greatly appreciated. p.s the computer I'm on right now posting this, doesn't have any compilers, coding programs, and it's not mine just to get that out of the way. Thanks again!

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• Difficulty with jQuery and input keydown event

  - by Rosarch

  I am making a simple JavaScript enhanced list. I want it to be a list of inputs, each with an 'Add' and 'Remove' button. If the user clicks 'Add', a new li will be added. If the user clicks 'Remove', that li will be removed. It works fine, except for hitting "enter" in an <input>. Currently, it always causes the Remove.click event handler to fire, unless there's only one item in the list. I'm not sure why. How can I suppress this? Here is the complete jQuery. My attempt to fix the "enter" issue is commented out, and it doesn't work. I suspect that I could be designing this code better; if you see an improvement I'd love to hear it. function make_smart_list(list) { var ADD_CLASS = 'foo-widget-Add'; var REMOVE_CLASS = 'foo-widget-Remove'; var jq_list = $(list); jq_list.parents('form').submit(function() { return false; }); function refresh_handlers() { jq_list.find(sprintf('.%s, .%s', REMOVE_CLASS, ADD_CLASS)).unbind('click'); // jq_list.find('input').unbind('submit'); // // jq_list.find('input').submit(function() { // var jq_this = $(this); // var next_button = jq_this.nextAll('button'); // if (next_button.hasClass(ADD_CLASS)) { // next_button.nextAll('button').click(); // return; // } // // if (next_button.hasClass(REMOVE_CLASS)) { // return false; // } // // }); jq_list.find("." + REMOVE_CLASS).click(function() { var jq_this = $(this); jq_this.parent().remove(); refresh_handlers(); return false; }); jq_list.find("." + ADD_CLASS).click(function() { var jq_this = $(this); if (jq_this.prevAll('input').val() == '') { return; } jq_this.parent().clone().appendTo(jq_this.parent().parent()); jq_this.parent().next().find('input').val('').focus(); jq_this.removeClass(ADD_CLASS).addClass(REMOVE_CLASS); jq_this.text('Remove'); refresh_handlers(); return false; }); } refresh_handlers(); } (sprintf is another script I have.)

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• Changing a select input to a checkbox acting as an on/off toggle switch in Rails

  - by Ribena

  I have a set of 7 dropdown inputs allowing admins to say whether they are open or closed for business on a given day. I'd like that changed to 7 open/closed switches (presumably styled checkboxes?) but can't figure out how to do this! Here are the relevant bits of code I currently have (prior to any change): app/view/backend/inventory_pool/edit.html.haml - content_for :title, @inventory_pool = form_for [:backend, @inventory_pool], html: {name: "form"} do |f| .content - if is_admin? %a.button{:href => root_path}= _("Cancel") %button.button{:type => :submit}= _("Save %s") % _("Inventory Pool") %section %h2= _("Basic Information") .inner .field.text .key %h3= "#{_("Print Contracts")}" %p.description .value .input %input{type: "checkbox", name: "inventory_pool[print_contracts]", checked: @inventory_pool.print_contracts} %section#workdays %h2= _("Workdays") .inner - [1,2,3,4,5,6,0].each do |i| .field.text .key %h3= "#{I18n.t('date.day_names')[i]}" .value .input %select{:name => "store[workday_attributes][workdays][]"} %option{:label => _("Open"), :value => Workday::WORKDAYS[i]}= _("Open") %option{:label => _("Closed"), :value => "", :selected => @store.workday.closed_days.include?(i) ? true : nil}= _("Closed") app/models/workday.rb class Workday < ActiveRecord::Base belongs_to :inventory_pool WORKDAYS = ["sunday", "monday", "tuesday", "wednesday", "thursday", "friday", "saturday"] def is_open_on?(date) return false if date.nil? case date.wday when 1 return monday when 2 return tuesday when 3 return wednesday when 4 return thursday when 5 return friday when 6 return saturday when 0 return sunday else return false #Should not be reached end end def closed_days days = [] days << 0 unless sunday days << 1 unless monday days << 2 unless tuesday days << 3 unless wednesday days << 4 unless thursday days << 5 unless friday days << 6 unless saturday days end def workdays=(wdays) WORKDAYS.each {|workday| write_attribute(workday, wdays.include?(workday) ? true : false)} end end And in app/controllers/backend/inventory_pools_controller I have this (abridged): def update @inventory_pool ||= InventoryPool.find(params[:id]) process_params params[:inventory_pool] end def process_params ip ip[:print_contracts] ||= "false" # unchecked checkboxes are *not* being sent ip[:workday_attributes][:workdays].delete "" if ip[:workday_attributes] end

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• Else without if

  - by user2808951

  I'm trying to write a code for my computer programming class for a project due Monday, and I'm pretty new to Java, but I'm trying to write a program that will first determine if a number the user inputs is even or odd and then determine if the number is prime or not. I'm not sure if I did the algorithm right or not, so if anyone has any corrections on the program to my algorithm or anything else please say so, but my real issue is that the program is refusing to compile. Every time I try, it says it's having an else without if problem. Here's a link to my command box: http://s1341.photobucket.com/user/Emi_Nightshade/media/Capture_zps45f9a2ea.png.html Here's my code: import java.io.*; import java.util.*; public class Lesson9p1_ThuotteEmily { public static void main(String args[]) { Scanner kbReader0=new Scanner(System.in); System.out.print("\n\nPlease enter an integer. An integer is whole number, and it can be either negative or positive. Please enter your number: "); long num=kbReader0.nextLong(); if(num%2==0) //if and else with braces { System.out.println("Your integer " + num + " is even."); } else { System.out.println("Your integer " + num + " is odd."); } Scanner kbReader1=new Scanner(System.in); System.out.print("\n\nWould you like to know if your number is prime? Please enter yes or no: "); String yn=kbReader1.nextLine(); if(yn.equals.IgnoreCase("Yes")) { System.out.println("Okay. Give me a moment."); { if(num%2==0) { System.out.println("Your number isn't prime."); } else if(num==2) { System.out.println("Your number is 2, which is the only even prime number in existence. Cool, right?"); } for(int i=3;i*i<=n;i+=2) { if(n%1==0) { System.out.println("Your number isn't prime."); } } else { System.out.println("Your number is prime!"); } } } if(yn.equals.IgnoreCase("No")) { System.out.println("Okay."); } } } If anyone could help me out with this and also any problems I may have made elsewhere in the program, I'd be very grateful! Thanks.

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• Session memory – who’s this guy named Max and what’s he doing with my memory?

  - by extended_events

  SQL Server MVP Jonathan Kehayias (blog) emailed me a question last week when he noticed that the total memory used by the buffers for an event session was larger than the value he specified for the MAX_MEMORY option in the CREATE EVENT SESSION DDL. The answer here seems like an excellent subject for me to kick-off my new “401 – Internals” tag that identifies posts where I pull back the curtains a bit and let you peek into what’s going on inside the extended events engine. In a previous post (Option Trading: Getting the most out of the event session options) I explained that we use a set of buffers to store the event data before  we write the event data to asynchronous targets. The MAX_MEMORY along with the MEMORY_PARTITION_MODE defines how big each buffer will be. Theoretically, that means that I can predict the size of each buffer using the following formula: max memory / # of buffers = buffer size If it was that simple I wouldn’t be writing this post. I’ll take “boundary” for 64K Alex For a number of reasons that are beyond the scope of this blog, we create event buffers in 64K chunks. The result of this is that the buffer size indicated by the formula above is rounded up to the next 64K boundary and that is the size used to create the buffers. If you think visually, this means that the graph of your max_memory option compared to the actual buffer size that results will look like a set of stairs rather than a smooth line. You can see this behavior by looking at the output of dm_xe_sessions, specifically the fields related to the buffer sizes, over a range of different memory inputs: Note: This test was run on a 2 core machine using per_cpu partitioning which results in 5 buffers. (Seem my previous post referenced above for the math behind buffer count.) input_memory_kb total_regular_buffers regular_buffer_size total_buffer_size 637 5 130867 654335 638 5 130867 654335 639 5 130867 654335 640 5 196403 982015 641 5 196403 982015 642 5 196403 982015 This is just a segment of the results that shows one of the “jumps” between the buffer boundary at 639 KB and 640 KB. You can verify the size boundary by doing the math on the regular_buffer_size field, which is returned in bytes: 196403 – 130867 = 65536 bytes 65536 / 1024 = 64 KB The relationship between the input for max_memory and when the regular_buffer_size is going to jump from one 64K boundary to the next is going to change based on the number of buffers being created. The number of buffers is dependent on the partition mode you choose. If you choose any partition mode other than NONE, the number of buffers will depend on your hardware configuration. (Again, see the earlier post referenced above.) With the default partition mode of none, you always get three buffers, regardless of machine configuration, so I generated a “range table” for max_memory settings between 1 KB and 4096 KB as an example. start_memory_range_kb end_memory_range_kb total_regular_buffers regular_buffer_size total_buffer_size 1 191 NULL NULL NULL 192 383 3 130867 392601 384 575 3 196403 589209 576 767 3 261939 785817 768 959 3 327475 982425 960 1151 3 393011 1179033 1152 1343 3 458547 1375641 1344 1535 3 524083 1572249 1536 1727 3 589619 1768857 1728 1919 3 655155 1965465 1920 2111 3 720691 2162073 2112 2303 3 786227 2358681 2304 2495 3 851763 2555289 2496 2687 3 917299 2751897 2688 2879 3 982835 2948505 2880 3071 3 1048371 3145113 3072 3263 3 1113907 3341721 3264 3455 3 1179443 3538329 3456 3647 3 1244979 3734937 3648 3839 3 1310515 3931545 3840 4031 3 1376051 4128153 4032 4096 3 1441587 4324761 As you can see, there are 21 “steps” within this range and max_memory values below 192 KB fall below the 64K per buffer limit so they generate an error when you attempt to specify them. Max approximates True as memory approaches 64K The upshot of this is that the max_memory option does not imply a contract for the maximum memory that will be used for the session buffers (Those of you who read Take it to the Max (and beyond) know that max_memory is really only referring to the event session buffer memory.) but is more of an estimate of total buffer size to the nearest higher multiple of 64K times the number of buffers you have. The maximum delta between your initial max_memory setting and the true total buffer size occurs right after you break through a 64K boundary, for example if you set max_memory = 576 KB (see the green line in the table), your actual buffer size will be closer to 767 KB in a non-partitioned event session. You get “stepped up” for every 191 KB block of initial max_memory which isn’t likely to cause a problem for most machines. Things get more interesting when you consider a partitioned event session on a computer that has a large number of logical CPUs or NUMA nodes. Since each buffer gets “stepped up” when you break a boundary, the delta can get much larger because it’s multiplied by the number of buffers. For example, a machine with 64 logical CPUs will have 160 buffers using per_cpu partitioning or if you have 8 NUMA nodes configured on that machine you would have 24 buffers when using per_node. If you’ve just broken through a 64K boundary and get “stepped up” to the next buffer size you’ll end up with total buffer size approximately 10240 KB and 1536 KB respectively (64K * # of buffers) larger than max_memory value you might think you’re getting. Using per_cpu partitioning on large machine has the most impact because of the large number of buffers created. If the amount of memory being used by your system within these ranges is important to you then this is something worth paying attention to and considering when you configure your event sessions. The DMV dm_xe_sessions is the tool to use to identify the exact buffer size for your sessions. In addition to the regular buffers (read: event session buffers) you’ll also see the details for large buffers if you have configured MAX_EVENT_SIZE. The “buffer steps” for any given hardware configuration should be static within each partition mode so if you want to have a handy reference available when you configure your event sessions you can use the following code to generate a range table similar to the one above that is applicable for your specific machine and chosen partition mode. DECLARE @buf_size_output table (input_memory_kb bigint, total_regular_buffers bigint, regular_buffer_size bigint, total_buffer_size bigint) DECLARE @buf_size int, @part_mode varchar(8) SET @buf_size = 1 -- Set to the begining of your max_memory range (KB) SET @part_mode = 'per_cpu' -- Set to the partition mode for the table you want to generate WHILE @buf_size <= 4096 -- Set to the end of your max_memory range (KB) BEGIN     BEGIN TRY         IF EXISTS (SELECT * from sys.server_event_sessions WHERE name = 'buffer_size_test')             DROP EVENT SESSION buffer_size_test ON SERVER         DECLARE @session nvarchar(max)         SET @session = 'create event session buffer_size_test on server                         add event sql_statement_completed                         add target ring_buffer                         with (max_memory = ' + CAST(@buf_size as nvarchar(4)) + ' KB, memory_partition_mode = ' + @part_mode + ')'         EXEC sp_executesql @session         SET @session = 'alter event session buffer_size_test on server                         state = start'         EXEC sp_executesql @session         INSERT @buf_size_output (input_memory_kb, total_regular_buffers, regular_buffer_size, total_buffer_size)             SELECT @buf_size, total_regular_buffers, regular_buffer_size, total_buffer_size FROM sys.dm_xe_sessions WHERE name = 'buffer_size_test'     END TRY     BEGIN CATCH         INSERT @buf_size_output (input_memory_kb)             SELECT @buf_size     END CATCH     SET @buf_size = @buf_size + 1 END DROP EVENT SESSION buffer_size_test ON SERVER SELECT MIN(input_memory_kb) start_memory_range_kb, MAX(input_memory_kb) end_memory_range_kb, total_regular_buffers, regular_buffer_size, total_buffer_size from @buf_size_output group by total_regular_buffers, regular_buffer_size, total_buffer_size Thanks to Jonathan for an interesting question and a chance to explore some of the details of Extended Event internals. - Mike

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• A Guided Tour of Complexity

  - by JoshReuben

  I just re-read Complexity – A Guided Tour by Melanie Mitchell , protégé of Douglas Hofstadter ( author of “Gödel, Escher, Bach”) http://www.amazon.com/Complexity-Guided-Tour-Melanie-Mitchell/dp/0199798109/ref=sr_1_1?ie=UTF8&qid=1339744329&sr=8-1 here are some notes and links:   Evolved from Cybernetics, General Systems Theory, Synergetics some interesting transdisciplinary fields to investigate: Chaos Theory - http://en.wikipedia.org/wiki/Chaos_theory – small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for chaotic systems, rendering long-term prediction impossible. System Dynamics / Cybernetics - http://en.wikipedia.org/wiki/System_Dynamics – study of how feedback changes system behavior Network Theory - http://en.wikipedia.org/wiki/Network_theory – leverage Graph Theory to analyze symmetric  / asymmetric relations between discrete objects Algebraic Topology - http://en.wikipedia.org/wiki/Algebraic_topology – leverage abstract algebra to analyze topological spaces There are limits to deterministic systems & to computation. Chaos Theory definitely applies to training an ANN (artificial neural network) – different weights will emerge depending upon the random selection of the training set. In recursive Non-Linear systems http://en.wikipedia.org/wiki/Nonlinear_system – output is not directly inferable from input. E.g. a Logistic map: Xt+1 = R Xt(1-Xt) Different types of bifurcations, attractor states and oscillations may occur – e.g. a Lorenz Attractor http://en.wikipedia.org/wiki/Lorenz_system Feigenbaum Constants http://en.wikipedia.org/wiki/Feigenbaum_constants express ratios in a bifurcation diagram for a non-linear map – the convergent limit of R (the rate of period-doubling bifurcations) is 4.6692016 Maxwell’s Demon - http://en.wikipedia.org/wiki/Maxwell%27s_demon - the Second Law of Thermodynamics has only a statistical certainty – the universe (and thus information) tends towards entropy. While any computation can theoretically be done without expending energy, with finite memory, the act of erasing memory is permanent and increases entropy. Life & thought is a counter-example to the universe’s tendency towards entropy. Leo Szilard and later Claude Shannon came up with the Information Theory of Entropy - http://en.wikipedia.org/wiki/Entropy_(information_theory) whereby Shannon entropy quantifies the expected value of a message’s information in bits in order to determine channel capacity and leverage Coding Theory (compression analysis). Ludwig Boltzmann came up with Statistical Mechanics - http://en.wikipedia.org/wiki/Statistical_mechanics – whereby our Newtonian perception of continuous reality is a probabilistic and statistical aggregate of many discrete quantum microstates. This is relevant for Quantum Information Theory http://en.wikipedia.org/wiki/Quantum_information and the Physics of Information - http://en.wikipedia.org/wiki/Physical_information. Hilbert’s Problems http://en.wikipedia.org/wiki/Hilbert's_problems pondered whether mathematics is complete, consistent, and decidable (the Decision Problem – http://en.wikipedia.org/wiki/Entscheidungsproblem – is there always an algorithm that can determine whether a statement is true).  Godel’s Incompleteness Theorems http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems  proved that mathematics cannot be both complete and consistent (e.g. “This statement is not provable”). Turing through the use of Turing Machines (http://en.wikipedia.org/wiki/Turing_machine symbol processors that can prove mathematical statements) and Universal Turing Machines (http://en.wikipedia.org/wiki/Universal_Turing_machine Turing Machines that can emulate other any Turing Machine via accepting programs as well as data as input symbols) that computation is limited by demonstrating the Halting Problem http://en.wikipedia.org/wiki/Halting_problem (is is not possible to know when a program will complete – you cannot build an infinite loop detector). You may be used to thinking of 1 / 2 / 3 dimensional systems, but Fractal http://en.wikipedia.org/wiki/Fractal systems are defined by self-similarity & have non-integer Hausdorff Dimensions !!!  http://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension – the fractal dimension quantifies the number of copies of a self similar object at each level of detail – eg Koch Snowflake - http://en.wikipedia.org/wiki/Koch_snowflake Definitions of complexity: size, Shannon entropy, Algorithmic Information Content (http://en.wikipedia.org/wiki/Algorithmic_information_theory - size of shortest program that can generate a description of an object) Logical depth (amount of info processed), thermodynamic depth (resources required). Complexity is statistical and fractal. John Von Neumann’s other machine was the Self-Reproducing Automaton http://en.wikipedia.org/wiki/Self-replicating_machine  . Cellular Automata http://en.wikipedia.org/wiki/Cellular_automaton are alternative form of Universal Turing machine to traditional Von Neumann machines where grid cells are locally synchronized with their neighbors according to a rule. Conway’s Game of Life http://en.wikipedia.org/wiki/Conway's_Game_of_Life demonstrates various emergent constructs such as “Glider Guns” and “Spaceships”. Cellular Automatons are not practical because logical ops require a large number of cells – wasteful & inefficient. There are no compilers or general program languages available for Cellular Automatons (as far as I am aware). Random Boolean Networks http://en.wikipedia.org/wiki/Boolean_network are extensions of cellular automata where nodes are connected at random (not to spatial neighbors) and each node has its own rule –> they demonstrate the emergence of complex  & self organized behavior. Stephen Wolfram’s (creator of Mathematica, so give him the benefit of the doubt) New Kind of Science http://en.wikipedia.org/wiki/A_New_Kind_of_Science proposes the universe may be a discrete Finite State Automata http://en.wikipedia.org/wiki/Finite-state_machine whereby reality emerges from simple rules. I am 2/3 through this book. It is feasible that the universe is quantum discrete at the plank scale and that it computes itself – Digital Physics: http://en.wikipedia.org/wiki/Digital_physics – a simulated reality? Anyway, all behavior is supposedly derived from simple algorithmic rules & falls into 4 patterns: uniform , nested / cyclical, random (Rule 30 http://en.wikipedia.org/wiki/Rule_30) & mixed (Rule 110 - http://en.wikipedia.org/wiki/Rule_110 localized structures – it is this that is interesting). interaction between colliding propagating signal inputs is then information processing. Wolfram proposes the Principle of Computational Equivalence - http://mathworld.wolfram.com/PrincipleofComputationalEquivalence.html - all processes that are not obviously simple can be viewed as computations of equivalent sophistication. Meaning in information may emerge from analogy & conceptual slippages – see the CopyCat program: http://cognitrn.psych.indiana.edu/rgoldsto/courses/concepts/copycat.pdf Scale Free Networks http://en.wikipedia.org/wiki/Scale-free_network have a distribution governed by a Power Law (http://en.wikipedia.org/wiki/Power_law - much more common than Normal Distribution). They are characterized by hubs (resilience to random deletion of nodes), heterogeneity of degree values, self similarity, & small world structure. They grow via preferential attachment http://en.wikipedia.org/wiki/Preferential_attachment – tipping points triggered by positive feedback loops. 2 theories of cascading system failures in complex systems are Self-Organized Criticality http://en.wikipedia.org/wiki/Self-organized_criticality and Highly Optimized Tolerance http://en.wikipedia.org/wiki/Highly_optimized_tolerance. Computational Mechanics http://en.wikipedia.org/wiki/Computational_mechanics – use of computational methods to study phenomena governed by the principles of mechanics. This book is a great intuition pump, but does not cover the more mathematical subject of Computational Complexity Theory – http://en.wikipedia.org/wiki/Computational_complexity_theory I am currently reading this book on this subject: http://www.amazon.com/Computational-Complexity-Christos-H-Papadimitriou/dp/0201530821/ref=pd_sim_b_1   stay tuned for that review!

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• Big Data&rsquo;s Killer App&hellip;

  - by jean-pierre.dijcks

  Recently Keith spent  some time talking about the cloud on this blog and I will spare you my thoughts on the whole thing. What I do want to write down is something about the Big Data movement and what I think is the killer app for Big Data... Where is this coming from, ok, I confess... I spent 3 days in cloud land at the Cloud Connect conference in Santa Clara and it was quite a lot of fun. One of the nice things at Cloud Connect was that there was a track dedicated to Big Data, which prompted me to some extend to write this post. What is Big Data anyways? The most valuable point made in the Big Data track was that Big Data in itself is not very cool. Doing something with Big Data is what makes all of this cool and interesting to a business user! The other good insight I got was that a lot of people think Big Data means a single gigantic monolithic system holding gazillions of bytes or documents or log files. Well turns out that most people in the Big Data track are talking about a lot of collections of smaller data sets. So rather than thinking "big = monolithic" you should be thinking "big = many data sets". This is more than just theoretical, it is actually relevant when thinking about big data and how to process it. It is important because it means that the platform that stores data will most likely consist out of multiple solutions. You may be storing logs on something like HDFS, you may store your customer information in Oracle and you may store distilled clickstream information in some distilled form in MySQL. The big question you will need to solve is not what lives where, but how to get it all together and get some value out of all that data. NoSQL and MapReduce Nope, sorry, this is not the killer app... and no I'm not saying this because my business card says Oracle and I'm therefore biased. I think language is important, but as with storage I think pragmatic is better. In other words, some questions can be answered with SQL very efficiently, others can be answered with PERL or TCL others with MR. History should teach us that anyone trying to solve a problem will use any and all tools around. For example, most data warehouses (Big Data 1.0?) get a lot of data in flat files. Everyone then runs a bunch of shell scripts to massage or verify those files and then shoves those files into the database. We've even built shell script support into external tables to allow for this. I think the Big Data projects will do the same. Some people will use MapReduce, although I would argue that things like Cascading are more interesting, some people will use Java. Some data is stored on HDFS making Cascading the way to go, some data is stored in Oracle and SQL does do a good job there. As with storage and with history, be pragmatic and use what fits and neither NoSQL nor MR will be the one and only. Also, a language, while important, does in itself not deliver business value. So while cool it is not a killer app... Vertical Behavioral Analytics This is the killer app! And you are now thinking: "what does that mean?" Let's decompose that heading. First of all, analytics. I would think you had guessed by now that this is really what I'm after, and of course you are right. But not just analytics, which has a very large scope and means many things to many people. I'm not just after Business Intelligence (analytics 1.0?) or data mining (analytics 2.0?) but I'm after something more interesting that you can only do after collecting large volumes of specific data. That all important data is about behavior. What do my customers do? More importantly why do they behave like that? If you can figure that out, you can tailor web sites, stores, products etc. to that behavior and figure out how to be successful. Today's behavior that is somewhat easily tracked is web site clicks, search patterns and all of those things that a web site or web server tracks. that is where the Big Data lives and where these patters are now emerging. Other examples however are emerging, and one of the examples used at the conference was about prediction churn for a telco based on the social network its members are a part of. That social network is not about LinkedIn or Facebook, but about who calls whom. I call you a lot, you switch provider, and I might/will switch too. And that just naturally brings me to the next word, vertical. Vertical in this context means per industry, e.g. communications or retail or government or any other vertical. The reason for being more specific than just behavioral analytics is that each industry has its own data sources, has its own quirky logic and has its own demands and priorities. Of course, the methods and some of the software will be common and some will have both retail and service industry analytics in place (your corner coffee store for example). But the gist of it all is that analytics that can predict customer behavior for a specific focused group of people in a specific industry is what makes Big Data interesting. Building a Vertical Behavioral Analysis System Well, that is going to be interesting. I have not seen much going on in that space and if I had to have some criticism on the cloud connect conference it would be the lack of concrete user cases on big data. The telco example, while a step into the vertical behavioral part is not really on big data. It used a sample of data from the customers' data warehouse. One thing I do think, and this is where I think parts of the NoSQL stuff come from, is that we will be doing this analysis where the data is. Over the past 10 years we at Oracle have called this in-database analytics. I guess we were (too) early? Now the entire market is going there including companies like SAS. In-place btw does not mean "no data movement at all", what it means that you will do this on data's permanent home. For SAS that is kind of the current problem. Most of the inputs live in a data warehouse. So why move it into SAS and back? That all worked with 1 TB data warehouses, but when we are looking at 100TB to 500 TB of distilled data... Comments? As it is still early days with these systems, I'm very interested in seeing reactions and thoughts to some of these thoughts...

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• Listing common SQL Code Smells.

  - by Phil Factor

  Once you’ve done a number of SQL Code-reviews, you’ll know those signs in the code that all might not be well. These ’Code Smells’ are coding styles that don’t directly cause a bug, but are indicators that all is not well with the code. . Kent Beck and Massimo Arnoldi seem to have coined the phrase in the "OnceAndOnlyOnce" page of www.C2.com, where Kent also said that code "wants to be simple". Bad Smells in Code was an essay by Kent Beck and Martin Fowler, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677) Although there are generic code-smells, SQL has its own particular coding habits that will alert the programmer to the need to re-factor what has been written. See Exploring Smelly Code   and Code Deodorants for Code Smells by Nick Harrison for a grounding in Code Smells in C# I’ve always been tempted by the idea of automating a preliminary code-review for SQL. It would be so useful to trawl through code and pick up the various problems, much like the classic ‘Lint’ did for C, and how the Code Metrics plug-in for .NET Reflector by Jonathan 'Peli' de Halleux is used for finding Code Smells in .NET code. The problem is that few of the standard procedural code smells are relevant to SQL, and we need an agreed list of code smells. Merrilll Aldrich made a grand start last year in his blog Top 10 T-SQL Code Smells.However, I'd like to make a start by discovering if there is a general opinion amongst Database developers what the most important SQL Smells are. One can be a bit defensive about code smells. I will cheerfully write very long stored procedures, even though they are frowned on. I’ll use dynamic SQL occasionally. You can only use them as an aid for your own judgment and it is fine to ‘sign them off’ as being appropriate in particular circumstances. Also, whole classes of ‘code smells’ may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a ‘code smell’ if there is a chance that the database will have to be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. As the saying goes,  a CodeSmell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist. Plamen Ratchev’s wonderful article Ten Common SQL Programming Mistakes lists some of these ‘code smells’ along with out-and-out mistakes, but there are more. The use of nested transactions, for example, isn’t entirely incorrect, even though the database engine ignores all but the outermost: but it does flag up the possibility that the programmer thinks that nested transactions are supported. If anything requires some sort of general agreement, the definition of code smells is one. I’m therefore going to make this Blog ‘dynamic, in that, if anyone twitters a suggestion with a #SQLCodeSmells tag (or sends me a twitter) I’ll update the list here. If you add a comment to the blog with a suggestion of what should be added or removed, I’ll do my best to oblige. In other words, I’ll try to keep this blog up to date. The name against each 'smell' is the name of the person who Twittered me, commented about or who has written about the 'smell'. it does not imply that they were the first ever to think of the smell! Use of deprecated syntax such as *= (Dave Howard) Denormalisation that requires the shredding of the contents of columns. (Merrill Aldrich) Contrived interfaces Use of deprecated datatypes such as TEXT/NTEXT (Dave Howard) Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) The use of Hints in queries, especially NOLOCK (Dave Howard /Mike Reigler) Few or No comments. Use of functions in a WHERE clause. (Anil Das) Overuse of scalar UDFs (Dave Howard, Plamen Ratchev) Excessive ‘overloading’ of routines. The use of Exec xp_cmdShell (Merrill Aldrich) Excessive use of brackets. (Dave Levy) Lack of the use of a semicolon to terminate statements Use of non-SARGable functions on indexed columns in predicates (Plamen Ratchev) Duplicated code, or strikingly similar code. Misuse of SELECT * (Plamen Ratchev) Overuse of Cursors (Everyone. Special mention to Dave Levy & Adrian Hills) Overuse of CLR routines when not necessary (Sam Stange) Same column name in different tables with different datatypes. (Ian Stirk) Use of ‘broken’ functions such as ‘ISNUMERIC’ without additional checks. Excessive use of the WHILE loop (Merrill Aldrich) INSERT ... EXEC (Merrill Aldrich) The use of stored procedures where a view is sufficient (Merrill Aldrich) Not using two-part object names (Merrill Aldrich) Using INSERT INTO without specifying the columns and their order (Merrill Aldrich) Full outer joins even when they are not needed. (Plamen Ratchev) Huge stored procedures (hundreds/thousands of lines). Stored procedures that can produce different columns, or order of columns in their results, depending on the inputs. Code that is never used. Complex and nested conditionals WHILE (not done) loops without an error exit. Variable name same as the Datatype Vague identifiers. Storing complex data  or list in a character map, bitmap or XML field User procedures with sp_ prefix (Aaron Bertrand)Views that reference views that reference views that reference views (Aaron Bertrand) Inappropriate use of sql_variant (Neil Hambly) Errors with identity scope using SCOPE_IDENTITY @@IDENTITY or IDENT_CURRENT (Neil Hambly, Aaron Bertrand) Schemas that involve multiple dated copies of the same table instead of partitions (Matt Whitfield-Atlantis UK) Scalar UDFs that do data lookups (poor man's join) (Matt Whitfield-Atlantis UK) Code that allows SQL Injection (Mladen Prajdic) Tables without clustered indexes (Matt Whitfield-Atlantis UK) Use of "SELECT DISTINCT" to mask a join problem (Nick Harrison) Multiple stored procedures with nearly identical implementation. (Nick Harrison) Excessive column aliasing may point to a problem or it could be a mapping implementation. (Nick Harrison) Joining "too many" tables in a query. (Nick Harrison) Stored procedure returning more than one record set. (Nick Harrison) A NOT LIKE condition (Nick Harrison) excessive "OR" conditions. (Nick Harrison) User procedures with sp_ prefix (Aaron Bertrand) Views that reference views that reference views that reference views (Aaron Bertrand) sp_OACreate or anything related to it (Bill Fellows) Prefixing names with tbl_, vw_, fn_, and usp_ ('tibbling') (Jeremiah Peschka) Aliases that go a,b,c,d,e... (Dave Levy/Diane McNurlan) Overweight Queries (e.g. 4 inner joins, 8 left joins, 4 derived tables, 10 subqueries, 8 clustered GUIDs, 2 UDFs, 6 case statements = 1 query) (Robert L Davis) Order by 3,2 (Dave Levy) MultiStatement Table functions which are then filtered 'Sel * from Udf() where Udf.Col = Something' (Dave Ballantyne) running a SQL 2008 system in SQL 2000 compatibility mode(John Stafford)

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