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  • Transfer data between C++ classes efficiently

    - by David
    Hi, Need help... I have 3 classes, Manager which holds 2 pointers. One to class A another to class B . A does not know about B and vise versa. A does some calculations and at the end it puts 3 floats into the clipboard. Next, B pulls from clipboard the 3 floats, and does it's own calculations. This loop is managed by the Manager and repeats many times (iteration after iteration). My problem: Now class A produces a vector of floats which class B needs. This vector can have more than 1000 values and I don't want to use the clipboard to transfer it to B as it will become time consumer, even bottleneck, since this behavior repeats step by step. Simple solution is that B will know A (set a pointer to A). Other one is to transfer a pointer to the vector via Manager But I'm looking for something different, more object oriented that won't break the existent separation between A and B Any ideas ? Many thanks David

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  • Need help in displaying data insider marquee

    - by user59637
    Hi all, I want to display news inside the marquee markup in my banking application but its not happening.Please somebody help me what is the error in my code.Here is my code: <marquee bgcolor="silver" direction="left" id="marq1" runat="server" behavior="scroll" scrolldelay="80" style="height: 19px" width="565"> <% String se = Session["countnews"].ToString(); for (int i = 0; i < int.Parse("" +se); i++) { %> <strong><%Response.Write("&nbsp;&nbsp;" + Session["news"+i] + "&nbsp;&nbsp;"); %></strong> <% } %> </marquee> public class News { DataSet ds = new DataSet("Bank"); SqlConnection conn; String check; SqlDataAdapter sda; int i; public string News_Name; public int Count_News; public int newsticker() { conn = new SqlConnection(ConfigurationManager.ConnectionStrings["BankingTransaction"].ConnectionString.ToString()); check = "Select NewsTitle from News where NewsStatus = 'A'"; sda = new SqlDataAdapter(check, conn); sda.Fill(ds, "News"); if (ds.Tables[0].Rows.Count > 0) { for (i = 0; i < ds.Tables[0].Rows.Count; i++) { News_Name =i+ ds.Tables[0].Rows[i].ItemArray[0].ToString(); } Count_News = ds.Tables[0].Rows.Count; } else { News_Name =0+ "Welcome to WestSide Bank Online Web site!"; Count_News = 1; } return int.Parse(Count_News.ToString()); } protected void Page_Load(object sender, EventArgs e) { News obj = new News(); try { obj.newsticker(); Session["news"] = obj.News_Name.ToString(); Session["countnews"] = obj.Count_News.ToString(); } catch (SqlException ex) { Response.Write("Error in login" + ex.Message); Response.Redirect("Default.aspx"); } finally { obj = null; } }

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  • DB Design Question

    - by hazimdikenli
    I am designing an Org Chart, model is almost ready and simplified a bit for clarity here. OrgUnit (OrgUnitId, Name, ReportsToOrgUnitId, ...) OrgUnitJobs (OrgUnitJobId, OrgUnitId, JobName, ReportsToOrgUnitJobId, ... ,IsJobGroup) Employee (EmployeeId, ........) OrgUnitJobEmployee (OrgUnitJobId, EmployeeId, AssignedDate, .....,) so I want to know every OrgUnit's ManagerEmployee (should have one), and Employees can have more than one job, but one of them has to be the main job, so I know whats his manager and other stuff. This is going to support a little workflow behind the scnese, so that is why it is not a very simple Org chart Model. so what would you do, would you add properties like (IsManager property to OrgUnitJobs model) or add ManagerOrgUnitJobId to OrgUnitModel. and why? Likewise, for employees would you add IsPrimaryJob property to OrgUnitJobEmployee model, or add PrimaryJobId to Employee Model.

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  • How do I modify an attribute across all rows in a table?

    - by prgmatic
    Hi folks, My apologies for asking such a novice question but, I need help building a script using either PHP or directly in MySQL that can do the following: Take the values of a column in a table (text) Change them into capitalized words (from "this is a title" to "This Is A Title") Replace the old values (uncapitalized) with the new values (capitalized). Thanks for the help and support.

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  • Data binding manually update in WPF MVVM

    - by Benny
    My ViewModel: class ViewModel { public string FileName {get;set;} } and in my View I bind a label's content to ViewModel's FileName. now When I do drag-drop a file to my View, How can I update the label's Content property, so that the ViewMode's FileName also get updated via binding? Directly set the label's Content property won't work, it just simply clear the binding.

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  • WPF: Editable ComboBox; how to make search/auto-fill functionality case sensitive?

    - by unforgiven3
    Say I have a ComboBox, like so: <ComboBox IsEditable="True" Height="30"> <ComboBoxItem>robot</ComboBoxItem> <ComboBoxItem>Robot</ComboBoxItem> </ComboBox> If a user comes along and starts by typing a lower-case 'r' into that ComboBox when it is empty, the ComboBox predictably auto-fills itself with the word 'robot'. Great. Now the same user comes along and starts typing an upper-case 'R' into that ComboBox when it is again empty. Unpredictable, the ComboBox auto-fills itself with the lower-case word 'robot'. Not great. I desperately want it to auto-fill itself with 'Robot', but WPF does not seem to want to smile down upon me. No matter what you do (CAPS lock, shift+key), the ComboBox will always auto-fill with the lower case 'robot', provided that the lower case 'robot' precedes the upper case 'Robot' in the ComboBox's items collection. Is there any way to prevent this? This behavior is maddening and makes for an absolutely abysmal user experience.

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  • Row selection based on subtable data in MySQL

    - by Felthragar
    I've been struggling with this selection for a while now, I've been searching around StackOverflow and tried a bunch of stuff but nothing that helps me with my particular issue. Maybe I'm just missing something obvious. I have two tables: Measurements, MeasurementFlags "Measurements" contain measurements from a device, and each measurement can have properties/attributes attached to them (commonly known as "flags") to signify that the measurement in question is special in some way or another (for instance, one flag may signify a test or calibration measurement). Note: One record per flag! Right, so a record from the "Measurements" table can theoreticly have an unlimited amount of MeasurementFlags attached to it, or it can have none. Now, I need to select records from "Measurements", that have an attached "MeasurementFlag" valued "X", but it must also NOT have a flag valued "Y" attached to it. We're talking about a fairly large database with hundreds of millions of rows, which is why I'm trying to keep all of this logic within one query. Splitting it up would create too many queries, however if it's not possible to do in one query I guess I don't have a choise. Thanks in advance.

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  • XSL: Get variable data without exslt:node-set

    - by Louis W
    Using native XSL lib in PHP. Is it possible to get a node value inside a variable without having to call it through exslt:node-set every time.... it long and ugly. <xsl:variable name="mydata"> <foo>1</foo> <bar>2</bar> </xsl:variable> <!-- How currently being done --> <xsl:value-of select="exslt:node-set($mydata)/foo" /> <!-- I want to be able to do this --> <xsl:value-of select="$mydata/foo" />

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  • Calculating Length Based on Sensor Data

    - by BSchlinker
    I've got an IR sensor which writes its current information to a token which I then interpret in a C# application. That's all good -- no problems there, heres my code: SetLabelText(tokens [1],label_sensorValue); sensorreading = Int32.Parse(tokens[0]); sensordistance = (mathfunctionhere); Great. So the further away the IR sensor is from an object, the lower the sensor reading (as less light is reflected back and received by the sensor). My problem is in interpreting that length. I can go ahead and get lets say "110" as a value when an object is 5 inches away, and then "70" as a value when an object is 6 inches away. Now I want to be able to calculate the distance of an object using these constants for any length. Any ideas?

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  • What is the best method for updating all changed data in EF 4?

    - by Soul_Master
    I try to create some method that can update any changed data from changed Data object (this object is generated by ASP.NET MVC) to old Data object (this object is retrieved from current data in DBMS) like the following code. public static bool UpdateSomeData(SomeEntities context, SomeModelType changedData) { var oldData = GetSomeModelTypeById(context, changedData.ID); UpdateModel(oldData, changedData); return context.SaveChanges() > 0; } I try to create method for saving any changed data without affects other unchanged data like the following source code. public static void UpdateModel<TModel>(TModel oldData, TModel changedData) { foreach (var pi in typeof(TModel).GetProperties() .Where ( // Ignore Change ID property for security reason x => x.Name.ToUpper() != "ID" && x.CanRead && x.CanWrite && ( // It must be primitive type or Guid x.PropertyType.FullName.StartsWith("System") && !x.PropertyType.FullName.StartsWith("System.Collection") && !x.PropertyType.FullName.StartsWith("System.Data.Entity.DynamicProxies") ) ) { var oldValue = pi.GetValue(oldData, null); var newValue = pi.GetValue(changedData, null); if (!oldValue.Equals(newValue)) { pi.SetValue(oldData, newValue, null); } } } I am not sure about the above method because it is so ugly method for updating data. From recent bug, it realizes me that if you update some property like Navigation Properties (related data from other table), it will remove current record from database. I don't understand why it happened. But it is very dangerous for me. So, do you have any idea for this question to ensure me about updating data from ASP.NET MVC? Thanks,

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  • ViewController access data

    - by Giovanni Filaferro
    Today i would ask you if there is a way to call a method of another view controller just not initializing it or just how to get that viewController as a global variable declared in .h file. Help me please. I'm using a PageViewController and I have to use a method of the contentViewController alredy initialized. here I create my ViewControllers: - (void)createTheContent { NSLog(@"createTheContent"); pageController = nil; //[pageController removeFromParentViewController]; //[pageController awakeFromNib]; NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithInteger:UIPageViewControllerSpineLocationMin] forKey: UIPageViewControllerOptionSpineLocationKey]; self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options: options]; pageController.dataSource = self; [[pageController view] setFrame:CGRectMake(0, 0, 320, 365)]; initialViewController = [self viewControllerAtIndex:0]; NSMutableArray *viewControllers = [NSArray arrayWithObject:initialViewController]; [pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil]; [self addChildViewController:pageController]; [[self view] addSubview:[pageController view]]; [pageController didMoveToParentViewController:self]; } here are my propertys in .h file: contentViewController *initialViewController; } //Page View Controller Properties @property (strong, nonatomic) UIPageViewController *pageController; @property (strong, nonatomic) NSArray *pageContent; @property (strong, nonatomic) NSMutableArray *pageStrings; @property (strong, nonatomic) id dataObject;

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  • How to have combobox take data from a child datasource

    - by SkollSunman
    I am trying to have a datagridview with two comboboxes, a company name and a supplier account number. When a company name is selected the relevant supplier account numbers (a company can have more than one supplier account) should be filtered for that company in that row. I have a datagridview with two bindingsources: supplierBindingSource and companyBindingSource and the Supplier account combobox uses the supplierBindingSource for its datasource and company name uses the companyBindingSource for its datasource. A company can have a supplier and/or customer account so the supplierBindingSource is a child or a companyBindingSource. The supplier accounts correctly filter based on the selected company name however when another company name is selected in another row all the supplier accounts are filtered for that company. Saving still works properly, regardless of what the combo box show but currently it is very confusing for a user to select a supplier account when the labels don't show what is being saved. Is it possible to have only the selected row to filter based on the company name rather than every row? EDIT: Thanks to the answer from http://social.msdn.microsoft.com/Forums/windows/en-US/b23d9e8f-a00a-49ba-adf5-52d87c1b2890/parent-child-comboboxes-in-datagridview I have been able to make some progress. The supplier account gets filtered when the drop down box is selected and restored to the full list when selection is finished. However now I am trying to have the company selected (and not filtered) when a supplier account is selected. The issue I've run into now is that I can get the companyID (which is the valuemember for the company combobox) but I cannot select the appropriate company without just setting the value of the combobox to the companyID which displays the companyID instead of the company name. Is there a way to select the company using the companyID while preserving the displaymember/valuemember dynamic? EDIT 2: The wall of text may be off putting. Some code to help elucidate my issue DataGridViewComboBoxCell dgcb2 = (DataGridViewComboBoxCell)sdgvSalesOrderLines[cmbSupplierName.Index, e.RowIndex]; var companyID = col.FirstOrDefault(c => c.AccountID == Convert.ToInt32(dgcb.Value)).CompanyID; dgcb2.Value = companyID.toString(); The second line gets the companyID and that works just fine, the final line sets the combobox to display the companyID whereas I would like it to set the valuemember value to companyID so that it would display the corresponding company name. I can set the second line to give me the company name instead but if the value of the combobox isn't the companyID then the supplier account cannot filter based on the company selected.

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  • Matplotlib: plotting discrete values

    - by Arkapravo
    I am trying to plot the following ! from numpy import * from pylab import * import random for x in range(1,500): y = random.randint(1,25000) print(x,y) plot(x,y) show() However, I keep getting a blank graph (?). Just to make sure that the program logic is correct I added the code print(x,y), just the confirm that (x,y) pairs are being generated. (x,y) pairs are being generated, but there is no plot, I keep getting a blank graph. Any help ?

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  • problem in fetching data from several tables in one query

    - by Mac Taylor
    hey guys in an attempt to union my querries into one query to database , now im in need of geting username of first poster and last poster of a topic in my forums here is my code to do as i told :: $result = $db->sql_query("SELECT t.*,p.*,u.* SUM(t.topic_approved='1') AS Amount_Of_Topics, SUM(p.post_approved ='1') AS Amount_Of_Posts FROM bb3topics t, bb3posts p, bb3users u GROUP BY t.topic_last_post_id ORDER BY t.topic_last_post_id DESC LIMIT 10 " ); while( $row = $db->sql_fetchrow($result) ) { $Amount_Of_Topics = $row['Amount_Of_Topics']; $Amount_Of_Posts = $row['Amount_Of_Posts']; $Amount_Of_Topic_Replies = $Amount_Of_Topic_Replies + $row['topic_replies']; $Amount_Of_Topic_Views = $Amount_Of_Topic_Views + $row['topic_views']; $topic_id = $row['topic_id']; $forum_id = $row['forum_id']; $topic_last_post_id = $row['topic_last_post_id']; $topic_title = $row['topic_title']; $topic_poster = $row['topic_poster']; $topic_views = $row['topic_views']; $topic_replies = $row['topic_replies']; $topic_moved_id = $row['topic_moved_id']; $topic_time = $row['topic_time']; $result2 = $db->sql_query( "SELECT topic_id, poster_id, post_time FROM bb3posts where post_id = '$topic_last_post_id'" ); list( $topic_id, $poster_id, $post_time ) = $db->sql_fetchrow( $result2 ); $result3 = $db->sql_query( "SELECT username, user_id FROM bb3users where user_id='$poster_id'" ); list( $uname, $uid ) = $db->sql_fetchrow( $result3 ); $LastPoster = "$uname"; $result4 = $db->sql_query( "SELECT username, user_id FROM bb3users where user_id='$topic_poster'" ); list( $uname, $uid ) = $db->sql_fetchrow( $result4 ); $OrigPoster = "$uname"; now i need to query all this together not in separated ones i tried using left join but didn't worked what mysql conjunction should i use ?!

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  • Problem while inserting data from GUI layer to database

    - by Rahul
    Hi all, I am facing problem while i am inserting new record from GUI part to database table. I have created database table Patient with id, name, age etc....id is identity primary key. My problem is while i am inserting duplicate name in table the control should go to else part, and display the message like...This name is already exits, pls try with another name... but in my coding not getting..... Here is all the code...pls somebody point me out whats wrong or how do this??? GUILayer: protected void BtnSubmit_Click(object sender, EventArgs e) { if (!Page.IsValid) return; int intResult = 0; string name = TxtName.Text.Trim(); int age = Convert.ToInt32(TxtAge.Text); string gender; if (RadioButtonMale.Checked) { gender = RadioButtonMale.Text; } else { gender = RadioButtonFemale.Text; } string city = DropDownListCity.SelectedItem.Value; string typeofdisease = ""; foreach (ListItem li in CheckBoxListDisease.Items) { if (li.Selected) { typeofdisease += li.Value; } } typeofdisease = typeofdisease.TrimEnd(); PatientBAL PB = new PatientBAL(); PatientProperty obj = new PatientProperty(); obj.Name = name; obj.Age = age; obj.Gender = gender; obj.City = city; obj.TypeOFDisease = typeofdisease; try { intResult = PB.ADDPatient(obj); if (intResult > 0) { lblMessage.Text = "New record inserted successfully."; TxtName.Text = string.Empty; TxtAge.Text = string.Empty; RadioButtonMale.Enabled = false; RadioButtonFemale.Enabled = false; DropDownListCity.SelectedIndex = 0; CheckBoxListDisease.SelectedIndex = 0; } else { lblMessage.Text = "Name [<b>" + TxtName.Text + "</b>] alredy exists, try another name"; } } catch (Exception ex) { lblMessage.Text = ex.Message.ToString(); } finally { obj = null; PB = null; } } BAL layer: public class PatientBAL { public int ADDPatient(PatientProperty obj) { PatientDAL pdl = new PatientDAL(); try { return pdl.InsertData(obj); } catch { throw; } finally { pdl=null; } } } DAL layer: public class PatientDAL { public string ConString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString; public int InsertData(PatientProperty obj) { SqlConnection con = new SqlConnection(ConString); con.Open(); SqlCommand com = new SqlCommand("LoadData",con); com.CommandType = CommandType.StoredProcedure; try { com.Parameters.AddWithValue("@Name", obj.Name); com.Parameters.AddWithValue("@Age",obj.Age); com.Parameters.AddWithValue("@Gender",obj.Gender); com.Parameters.AddWithValue("@City", obj.City); com.Parameters.AddWithValue("@TypeOfDisease", obj.TypeOFDisease); return com.ExecuteNonQuery(); } catch { throw; } finally { com.Dispose(); con.Close(); } } } Property Class: public class PatientProperty { private string name; private int age; private string gender; private string city; private string typedisease; public string Name { get { return name; } set { name = value; } } public int Age { get { return age; } set { age = value; } } public string Gender { get { return gender; } set { gender = value; } } public string City { get { return city; } set { city = value; } } public string TypeOFDisease { get { return typedisease; } set { typedisease = value; } } } This is my stored Procedure: CREATE PROCEDURE LoadData ( @Name varchar(50), @Age int, @Gender char(10), @City char(10), @TypeofDisease varchar(50) ) as insert into Patient(Name, Age, Gender, City, TypeOfDisease)values(@Name,@Age, @Gender, @City, @TypeofDisease) GO

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  • calender with multiple data sources at once??

    - by Sune
    Im looking for a (free) solution to a bookingcalender. Among many candidates Ive found the Jquery Full Calender which has many cool features. One of the reason that I like this one is because it has "drag and drop" and resize, which I also need. But I also need to have the dayview where I the columms monday, tuesday, wedensday, thursday friday .... gets replaced with fx. Room1, Room2, Room3, Room4, Room5, Room6, Room7. Ive found some examples on: http://www.devexpress.com/Products/NET/Controls/ASP/Scheduler/resources.xml http://demos.telerik.com/aspnet-ajax/scheduler/examples/resourceavailability/defaultcs.aspx which has the functionality im after. Ive read others who has raised the same quistion on: http://code.google.com/p/jquery-week-calendar/issues/detail?id=35 but with no final solution. Are there any out there who has or knows some good links for want Im looking for?

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  • TStringList, Dynamic Array or Linked List in Delphi?

    - by lkessler
    I have a choice. I have an array of ordered strings that I need to store and access. It looks like I can choose between using: A TStringList A Dynamic Array of strings, and A Linked List of strings In what circumstances is each of these better than the others? Which is best for small lists (under 10 items)? Which is best for large lists (over 1000 items)? Which is best for huge lists (over 1,000,000 items)? Which is best tor minimize memory use? Which is best to minimize loading and/or access time? For reference, I am using Delphi 2009.

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  • Django Database design -- Is this a good stragety for overriding defaults

    - by rh0dium
    Hi SO's I have a question on good database design practices and I would like to leverage you guys for pointers. The project started out simple. Hey we have a bunch of questions we want answered for every project (no problem) Which turned into... Hey we have so many questions can we group them into sections (yup we can do that) Which lead into.. Can we weight these questions and I don't really want some of these questions for my project (Yes but we are getting difficult) And then I'm thinking they will want to have each section have it's own weight.. Requirements So there's the requirements - For n number of project Allow a admin member the ability select the questions for a project Allow the admin member to re-weigh or use the default weights for the questions Allow the admin member to re-weight the sections Allow team members to answer the questions. So here is what I came up with. Please feel free to comment and provide better examples models.py from django.db import models from django.contrib.sites.models import Site from django.conf import settings class Section(models.Model): """ This describes the various sections for a checklist: """ name = models.CharField(max_length=64) description = models.TextField() class Question(models.Model): """ This simply provides a simple way to list out the questions. """ question = models.CharField(max_length=255) answer_type = models.CharField(max_length=16) description = models.TextField() section = models.ForeignKey(Section) class ProjectQuestion(models.Model): """ These are the questions relevant to the project """ question = models.ForeignKey(Question) answer = models.CharField(max_length=255) required = models.BooleanField(default=True) weight = models.FloatField(default = XXX) class Project(models.Model): """ Here is where we want to gather our questions """ questions = models.ManyToManyField(ProjectQuestion) Immediate questions: - When I start a project - any ideas on how to "pre-populate" the questions (and ultimately the weights) for the project? - Is there a generally accepted method for doing this process that I am missing? Basically the idea that you refer to the questions overide your own default weight, and store the answer? - It appears that a good chuck of the work will be done in the views and that a lot of checking will need to occur there? Is that OK? Again - feel free to give me better strategies!! Thanks

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  • Avoid loading unnecessary data from db into objects (web pages)

    - by GmGr
    Really newbie question coming up. Is there a standard (or good) way to deal with not needing all of the information that a database table contains loaded into every associated object. I'm thinking in the context of web pages where you're only going to use the objects to build a single page rather than an application with longer lived objects. For example, lets say you have an Article table containing id, title, author, date, summary and fullContents fields. You don't need the fullContents to be loaded into the associated objects if you're just showing a page containing a list of articles with their summaries. On the other hand if you're displaying a specific article you might want every field loaded for that one article and maybe just the titles for the other articles (e.g. for display in a recent articles sidebar). Some techniques I can think of: Don't worry about it, just load everything from the database every time. Have several different, possibly inherited, classes for each table and create the appropriate one for the situation (e.g. SummaryArticle, FullArticle). Use one class but set unused properties to null at creation if that field is not needed and be careful. Give the objects access to the database so they can load some fields on demand. Something else? All of the above seem to have fairly major disadvantages. I'm fairly new to programming, very new to OOP and totally new to databases so I might be completely missing the obvious answer here. :)

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  • SQL to CodeIgniter Array Missing Data Issue

    - by SamD
    $query = $this->db->query("SELECT t1.numberofbets, t1.profit, t2.seven_profit, t3.28profit, user.user_id, username, password, email, balance, user.date_added, activation_code, activated FROM user LEFT JOIN (SELECT user_id, SUM(amount_won) AS profit, count(tip_id) AS numberofbets FROM tip GROUP BY user_id) as t1 ON user.user_id = t1.user_id LEFT JOIN (SELECT user_id, SUM(amount_won) AS seven_profit FROM tip WHERE date_settled > '$seven_daystime' GROUP BY user_id) as t2 ON user.user_id = t2.user_id LEFT JOIN (SELECT user_id, SUM(amount_won) AS 28profit FROM tip WHERE date_settled > '$twoeight_daystime' GROUP BY user_id) as t3 ON user.user_id = t3.user_id where activated = 1 GROUP BY user.user_id ORDER BY user.date_added DESC"); return $query->result_array(); The query works fine running it in phpMyAdmin and returns complete results (in image attached). However, printing the array in CodeIgniter, it has no value for one field ,seven_profit, where it is there in the SQL query ran in phpMyAdmin, just the discrepancy in this one field, from sql to php array... I just can’t see why, when printing the array, that one field, which should have value of 26, contains nothing? Any ideas? I changed the field name from starting with a number in attempt to fix it, but no difference. I know this is complex and looks horrible, any help or just people coming across something similar would be great to know about, thanks. Sam

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  • Memory efficient int-int dict in Python

    - by Bolo
    Hi, I need a memory efficient int-int dict in Python that would support the following operations in O(log n) time: d[k] = v # replace if present v = d[k] # None or a negative number if not present I need to hold ~250M pairs, so it really has to be tight. Do you happen to know a suitable implementation (Python 2.7)? EDIT Removed impossible requirement and other nonsense. Thanks, Craig and Kylotan! To rephrase. Here's a trivial int-int dictionary with 1M pairs: >>> import random, sys >>> from guppy import hpy >>> h = hpy() >>> h.setrelheap() >>> d = {} >>> for _ in xrange(1000000): ... d[random.randint(0, sys.maxint)] = random.randint(0, sys.maxint) ... >>> h.heap() Partition of a set of 1999530 objects. Total size = 49161112 bytes. Index Count % Size % Cumulative % Kind (class / dict of class) 0 1 0 25165960 51 25165960 51 dict (no owner) 1 1999521 100 23994252 49 49160212 100 int On average, a pair of integers uses 49 bytes. Here's an array of 2M integers: >>> import array, random, sys >>> from guppy import hpy >>> h = hpy() >>> h.setrelheap() >>> a = array.array('i') >>> for _ in xrange(2000000): ... a.append(random.randint(0, sys.maxint)) ... >>> h.heap() Partition of a set of 14 objects. Total size = 8001108 bytes. Index Count % Size % Cumulative % Kind (class / dict of class) 0 1 7 8000028 100 8000028 100 array.array On average, a pair of integers uses 8 bytes. I accept that 8 bytes/pair in a dictionary is rather hard to achieve in general. Rephrased question: is there a memory-efficient implementation of int-int dictionary that uses considerably less than 49 bytes/pair?

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  • Java MapReduce read data

    - by Tatiana
    Hi I am having following map-reduce code by which I am trying to read records from my database. There's code: import java.io.*; import java.util.ArrayList; import java.util.List; import org.apache.hadoop.fs.*; import org.apache.hadoop.io.*; import org.apache.hadoop.mapred.*; import org.apache.hadoop.mapred.lib.db.DBConfiguration; import org.apache.hadoop.mapred.lib.db.DBInputFormat; import org.apache.hadoop.mapred.lib.db.DBWritable; import org.apache.hadoop.util.*; import org.apache.hadoop.conf.*; public class Connection extends Configured implements Tool { public int run(String[] args) throws IOException { JobConf conf = new JobConf(getConf(), Connection.class); conf.setInputFormat(DBInputFormat.class); DBConfiguration.configureDB(conf, "com.sun.java.util.jar.pack.Driver", "jdbc:postgresql://localhost:5432/polyclinic", "postgres", "12345"); String[] fields = { "name" }; DBInputFormat.setInput(conf, MyRecord.class, "doctors", null, null, fields); conf.setMapOutputKeyClass(LongWritable.class); conf.setMapOutputValueClass(MyRecord.class); conf.setOutputKeyClass(LongWritable.class); conf.setOutputValueClass(TextOutputFormat.class); TextOutputFormat.setOutputPath(conf, new Path(args[0])); JobClient.runJob(conf); return 0; } public static void main(String[] args) throws Exception { int exitCode = ToolRunner.run(new Connection(), args); System.exit(exitCode); } } Class Mapper: import java.io.IOException; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapred.MapReduceBase; import org.apache.hadoop.mapred.Mapper; import org.apache.hadoop.mapred.OutputCollector; import org.apache.hadoop.mapred.Reporter; public class MyMapper extends MapReduceBase implements Mapper<LongWritable, MyRecord, Text, IntWritable> { public void map(LongWritable key, MyRecord val, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException { output.collect(new Text(val.name), new IntWritable(1)); } } Class Record: import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.Writable; import org.apache.hadoop.mapred.lib.db.DBWritable; class MyRecord implements Writable, DBWritable { String name; public void readFields(DataInput in) throws IOException { this.name = Text.readString(in); } public void readFields(ResultSet resultSet) throws SQLException { this.name = resultSet.getString(1); } public void write(DataOutput out) throws IOException { } public void write(PreparedStatement stmt) throws SQLException { } } After this I got error: WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String). Can you give me any suggestion how to solve this problem?

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