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  • access properties of current model in has_many declaration

    - by seth.vargo
    Hello, I didn't exactly know how to pose this question other than through example... I have a class we will call Foo. Foo :has_many Bar. Foo has a boolean attribute called randomize that determines the order of the the Bars in the :has_many relationship: class CreateFoo < ActiveRecord::Migration def self.up create_table :foos do |t| t.string :name t.boolean :randomize, :default => false end end end   class CreateBar < ActiveRecord::Migration def self.up create_table :bars do |t| t.string :name t.references :foo end end end   class Bar < ActiveRecord::Base belongs_to :foo end   class Foo < ActiveRecord::Base # this is the line that doesn't work has_many :bars, :order => self.randomize ? 'RAND()' : 'id' end How do I access properties of self in the has_many declaration? Things I've tried and failed: creating a method of Foo that returns the correct string creating a lambda function crying Is this possible? UPDATE The problem seems to be that the class in :has_many ISN'T of type Foo: undefined method `randomize' for #<Class:0x1076fbf78> is one of the errors I get. Note that its a general Class, not a Foo object... Why??

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  • Keep the images downloaded in the listview during scrolling

    - by Paveliko
    I'm developing my first app and have been reading a LOT here. I've been trying to find a solution for the following issue for over a week with no luck. I have an Adapter that extends ArrayAdapter to show image and 3 lines of text in each row. Inside the getView I assign relevant information for the TextViews and use ImageLoader class to download image and assign it to the ImageView. Everything works great! I have 4.5 rows visible on my screen (out of total of 20). When I scroll down for the first time the images continue to download and be assigned in right order to the list. BUT when I scroll back the list looses all the images and start redrawing them again (0.5-1 sec per image) in correct order. From what I've been reading it's the standard list performance but I want to change it. I want that, once the image was downloaded, it will be "sticked" to the list for the whole session of the current window. Just like in Contacts list or in the Market. It is only 20 images (6-9kb each). Hope I managed to explain myself.

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  • Hibernate NamingStrategy implementation that maintains state between calls

    - by Robert Petermeier
    Hi, I'm working on a project where we use Hibernate and JBoss 5.1. We need our entity classes to be mapped to Oracle tables that follow a certain naming convention. I'd like to avoid having to specify each table and column name in annotations. Therefore, I'm currently considering implementing a custom implementation of org.hibernate.cfg.NamingStrategy. The SQL naming conventions require the name of columns to have a suffix that is equivalent to a prefix of the table name. If there is a table "T100_RESOURCE", the ID column would have to be named "RES_ID_T100". In order to implement this in a NamingStrategy, the implementation would have to maintain state, i.e. the current class name it is creating the mappings for. It would rely on Hibernate to always call classToTableName() before propertyToColumnName() and to determine all column names by calling propertyToColumnName() before the next call to classToTableName() Is it safe to do that or are there situations where Hibernate will mix things up? I am not thinking of problems through multiple threads here (which can be solved by keeping the last class name in a ThreadLocal) but also of Hibernate deliberately calling this out of order in certain circumstances. For example Hibernate asking for mappings of three properties of class A, then one of class B, then again more attributes of class A.

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  • Cascading Dropdown List

    - by user333831
    I am working on a web app and trying to code a form with two dropdown lists. The list in the second dropdown will be dependent on the selection from the first one. The task itself isn’t too complicated except that once the first selection is made, I need to make a database call to pull the data for the second dropdown. This is where I am having difficulty. Both lists are in fact populated from a database. I am working on this in a python script and have been trying to do this w/ an onChange javascript function. The web app is built in Zope and page templates may be an option along w/ the python scripts.

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  • Why does this javascript code have an infinite loop?

    - by asdas
    optionElements is a 2d array. Each element has an array of length 2. These are an integer number and an element. I have a select list called linkbox, and i want to add all of the elements to the select list. The order I want them to go in is important, and is determined by the number each element has. It should be smallest to highest. So think of it like this: optionElements is: [ [5, <option>], [3, <option], [4, <option], [1, <option], [2, <option]] and it would add them to link box in order of those numbers. BUT that is not what happens. It is an infinite loop after the first time. I added the x constraint just to stop it from freezing my browser but you can ignore it. var b; var smallest; var samllestIndex; var x = 0; while(optionElements.length > 0 && ++x < 100) { smallestIndex = 0; smallest = optionElements[0][0]; b = 0; while( ++b < optionElements.length) { if(optionElements[b][0] > smallest) { smallestIndex = b; smallest = optionElements[b][0]; } } linkbox.appendChild(optionElements[smallestIndex][1]); optionElements.unshift(optionElements[smallestIndex]); } can someone point out to me where my problem is?

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  • How to make ActiveRecord work with legacy partitioned/sharded databases/tables?

    - by Utensil
    thanks for your time first...after all the searching on google, github and here, and got more confused about the big words(partition/shard/fedorate),I figure that I have to describe the specific problem I met and ask around. My company's databases deals with massive users and orders, so we split databases and tables in various ways, some are described below: way database and table name shard by (maybe it's should be called partitioned by?) YZ.X db_YZ.tb_X order serial number last three digits YYYYMMDD. db_YYYYMMDD.tb date YYYYMM.DD db_YYYYMM.tb_ DD date too The basic concept is that databases and tables are seperated acording to a field(not nessissarily the primary key), and there are too many databases and too many tables, so that writing or magically generate one database.yml config for each database and one model for each table isn't possible or at least not the best solution. I looked into drnic's magic solutions, and datafabric, and even the source code of active record, maybe I could use ERB to generate database.yml and do database connection in around filter, and maybe I could use named_scope to dynamically decide the table name for find, but update/create opertions are bounded to "self.class.quoted_table_name" so that I couldn't easily get my problem solved. And even I could generate one model for each table, because its amount is up to 30 most. But this is just not DRY! What I need is a clean solution like the following DSL: class Order < ActiveRecord::Base shard_by :order_serialno do |key| [get_db_config_by(key), #because some or all of the databaes might share the same machine in a regular way or can be configed by a hash of regex, and it can also be a const get_db_name_by(key), get_tb_name_by(key), ] end end Can anybody enlight me? Any help would be greatly appreciated~~~~

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  • Help with porting thread functionality: Win32 --> .Net

    - by JimDaniel
    Hi, I am responsible for porting a class from legacy Win32 code to .Net and I have come across a threading model that I'm not sure how best to implement in .Net. Basically the Win32 has one worker thread, which calls WaitForMultipleObjects() and executes the particular piece of code when a particular object has been triggered. This has a sort of first-come-first-serve effect that I need to emulate in my own code. But I'm not sure how best to do this in .Net. Does anyone have any idea? I see that there is no equivalent of WaitForMultipleObjects() in .Net, only the ThreadPool class, which seems to provide most of what I need, but I'm not sure if it's the best, since I only have four objects total to wait and execute code for. Thanks, Daniel

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  • Rails 3 remote resubmit form with dynamic fields

    - by montrealmike
    I have a form which has remote => true. When i submit it the first time everything works well. If there are any errors i want to add new fields to this form. I did this with update.js.erb. The problem is that when i resubmit this form, the result js file is rendered as html (ie i see the js file text on the screen). This is the same update.js.erb file that was rendered as js the first time... Any idea what i'm missing?

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  • Php Two Combo box in a form control each other. How?

    - by azad
    On php page in a form, One combo box has list of my Customer from mysql table customer. Another combo box has invoiceno stored in invoice table which has respective customer records. I want to select customer from first combo box and filter invoiceno from the second one according to the customer. Any one help me for php or java or Jquery or both codeings? Means if I select customer1 then in the second combo box should show all invoiceno respective to the custermer1. No Refresh or ReLoad or Post form Pl. If I get the first selection in a php variable format example $customer, it is enough for me. Thanks for any one help me.

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  • Why do the following expanded if shorthand statements not work in javascript?

    - by PeanutsMonkey
    This is my first attempt to write shorthand if statements however am befuddled by why the expanded versions don't work quite the way I imagined they would. Code 1 - Does not work if(document.getElementById == true) { alert("The document object model is supported by: " + navigator.appName); } Code 2 - Does work if(document.getElementById != false) { alert("The document object model is supported by: " + navigator.appName); } Code 3 - The shorthand that does work if(document.getElementById) { alert("The document object model is supported by: " + navigator.appName); } Why is that if I expand the shorthand in 3 to the first code sample not work and why does it work if I have it equal to != false?

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  • 3D and AI basics. The foundation before the coding.

    - by Allan
    Hi, everyone. (If you have the time and patience:) I've recently made the decision to study programming seriously and I'm about to order TAOCP and Concrete Mathematics to begin my studies (please don't get caught up on this). I'm very much interested in learning and understanding how 3D works but I'm aware that if I plan to do it right there's still a long walk before I get to actually play with 3D coding. Now to the question.. (tl;dr) Excluding programming itself, what disciplines do I have to be familiar with to code 3D? What kinds of mathematics? Physics? What else? What books do you recommend on such subjects? Now read it all again but replacing "3D" with "AI". Please don't recommend computer-specific books. The question is about the foundation to be learned before using the machine. Also, if possible, please keep the list brief; I plan to order one book on each subject but no more than that for now. Excuse me for any English mistakes, it's not my first language. Thank you.

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  • mysql add auto increment and a additional key

    - by Lee
    Hey all I am trying to alter a table with adding a new column setting it as auto increment and with a key. The table already has one key and this one will be an addition. The error I get is the following. error : Multiple primary key defined My code is: alter table user add column id int (11) NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST; I have also tries wrapping the key name ie alter table user add column id int (11) NOT NULL AUTO_INCREMENT PRIMARY (id) KEY FIRST; But still no luck. How can it be done ?

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  • a Facebook app beginner question

    - by Robert
    Dear all, I have written up my first php script to learn facebook API stuff.It goes like this: require_once('facebook/client/facebook.php'); $facebook = new Facebook('0fff13540b7ff2ae94be38463cb4fa67','8a029798dd463be6c94cb8d9ca851696'); http://stackoverflow.com/questions/ask $fb_user = $facebook-require_login(); ? Hello ' useyou='false' possessive='true' /! Welcome to my first application! I put "facebook.php" in the same directory as my php script. However,after I deploy the php on a web server and link it with facebook and run it,I got error saying: "Fatal error: Call to undefined method Facebook::require_login() in /home/a2660104/public_html/facebook-php-sdk-94fcb13/src/default.php on line 16" Could anyone help me a bit on this?I am a beginner to the facebook app programming.Thanks a lot!

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  • Using a variable derived from a drop-down list as the column name in a select statement ... Access DB

    - by user1459698
    I'm working with the world's worst DB that was already here so don't blame me for that. So, here's what I have so far ... module = txtModule.value presstype = txtPressType.value SQL_query = "SELECT * FROM tbl_spareparts WHERE '"& module &"' <> '""' AND '"& module &"' = '"& presstype &"' AND Manufacturer = '"& txtsrch.value &"' ORDER BY SAP_Part_No" Set rsData = conn.Execute(SQL_query) This brings up the following SQL statement: SELECT * FROM tbl_spareparts WHERE 'Banyan_Module' <> '"' AND 'Banyan_Module' = 'PB' AND Manufacturer = 'Tester' ORDER BY SAP_Part_No Is there any way I can use the module variable as a column name - obviously the ''s around the column name are causing an error. This is really bothering me. BTW, I'm writing this in VBScript inside a .HTA application page as it has to run locally on tech PCs. Thanks. R.

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  • Marionette js itemview not defined: then on browser refresh it is defined and all works well - race condition?

    - by Robert
    Yeah it's just the initial browser load or two after a cache clear. Subsequent refreshes clear the problem up. I'm thinking the item views just aren't fully constructed in time to be used in the collection views on the first load. But then they are on a refresh? Don't know. There must be something about the code sequence or loading or the load time itself. Not sure. I'm loading via require.js. Have two collections - users and messages. Each renders in its own list view. Each works, just not the first time or two the browser loads. The first time you load after clearing browser cache the console reports, for instance: "Uncaught ReferenceError: MessageItemView is not defined" A simple browser refresh clears it up. Same goes for the user collection. It's collection view says it doesn't know anything about its item view. But a simple browser refresh and all is well. My views (item and collection) are in separate files. Is that the problem? For instance, here is my message collection view in its own file: messagelistview.js var MessageListView = Marionette.CollectionView.extend({ itemView: MessageItemView, el: $("#messages") }); And the message item view is in a separate file: messageview.js var MessageItemView = Marionette.ItemView.extend({ tagName: "div", template: Handlebars.compile( '<div>{{fromUserName}}:</div>' + '<div>{{message}}</div>' + ) }); Then in my main module file, which references each of those files, the collection view is constructed and displayed: main.js //Define a model MessageModel = Backbone.Model.extend(); //Make an instance of MessageItemView - code in separate file, messagelistview.js MessageView = new MessageItemView(); //Define a message collection var MessageCollection = Backbone.Collection.extend({ model: MessageModel }); //Make an instance of MessageCollection var collMessages = new MessageCollection(); //Make an instance of a MessageListView - code in separate file, messagelistview.js var messageListView = new MessageListView({ collection: collMessages }); App.messageListRegion.show(messageListView); Do I just have things sequenced wrong? I'm thinking it's some kind of race condition only because over 3G to an iPad the item views are always undefined. They never seem to get constructed in time. PC on a hard wired connection does see success after a browser refresh or two.

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  • Getting all pdf files from a domain (for example *.adomain.com)

    - by Zack
    I need to download all pdf files from a certain domain. There are about 6000 pdf on that domain and most of them don't have an html link (either they have removed the link or they never put one in the first place). I know there are about 6000 files because I'm googling: filetype:pdf site:*.adomain.com However, Google lists only the first 1000 results. I believe there are two ways to achieve this: a) Use Google. However, how I can get all 6000 results from Google? Maybe a scraper? (tried scroogle, no luck) b) Skip Google and search directly on domain for pdf files. How do I do that when most them are not linked?

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  • Why the compiler doesn't complain about this error ?

    - by M.H
    Hi I am writing some java questions to help my friends in the java exam. I wrote a question and I supposed that three errors will occurred in the code but the compiler complained only about two. the code is : class MyClass { static MyClass() { System.out.println("I am The First Statement here!"); this(); } } I expected the following errors : the constructor can't be static this can't be in a static function (since the constructor isn't valid) this here should be the first statement. NetBeans isn't complaining about the second error here. why ?

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  • How do I resolve this scope issue in VB .NET?

    - by froadie
    I have a code structure something like this: For row = 1 To numRows Dim arrayIndex As Integer = 0 For column As Integer = bucketStartColumn To bucketEndColumn ' whatever code arrayIndex = arrayIndex + 1 Next Next Dim arrayIndex As Integer = 0 For column As Integer = bucketStartColumn To bucketEndColumn ' whatever code arrayIndex = arrayIndex + 1 Next Not exactly the code, so I don't really need suggestions about refactoring, but my problem is this - with this code I get a compiler error for the first Dim arrayIndex As Integer = 0 - "Variable 'arrayIndex' hides a variable in an enclosing block." As far as I can tell, arrayIndex is local to the first for loop and shouldn't exist by the time we reach the second loop. If I try to change the second declaration of arrayIndex to arrayIndex = 0, I get the error "Name 'arrayIndex' is not declared", as I expected. So is it visible, or not? Does this have something to do with the Dim keyword? Any suggestions of how to get around this, other than naming the second index variable something else?

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  • C#: Populating a UI using separate threads.

    - by Andrew
    I'm trying to make some sense out of an application Ive been handed in order to track down the source of an error. Theres a bit of code (simplified here) which creates four threads which in turn populate list views on the main form. Each method gets data from the database and retrieves graphics from a resource dll in order to directly populate an imagelist and listview. From what Ive read on here (link) updating UI elements from any thread other than the UI thread should not be done, and yet this appears to work? Thread t0 = new Thread(new ThreadStart(PopulateListView1)); t0.IsBackground = true; t0.Start(); Thread t1 = new Thread(new ThreadStart(PopulateListView2)); t1.Start(); Thread t2 = new Thread(new ThreadStart(PopulateListView3)); t2.Start(); Thread t3 = new Thread(new ThreadStart(PopulateListView4)); t3.Start(); The error itself is a System.InvalidOperationException "Image cannot be added to the ImageList." which has me wondering if the above code is linked in some way. Iis this method of populating the UI recommended and if not what are the possible complications resulting from it?

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  • How to get attributes values separately for each container present on the webpage in jquery ?

    - by Rachel
    This question is in continuation to How to get attributes of container in jquer, I have different containers on my webpage and all of them have <div id = "some values"> now how can I get attributes values separately for each component ? Is there any way I can know which attribute id belong to which container div ? Currently I am using : var id = $( '.promotion' ).attr( 'id' ); But if I have multiple promotional components on page and all have same div attribute as id than how can I relate that this particular attribute id belonged to this specific container ? Update: I am having a function which is called for each container present on the page and so if I am using above mentioned code than will it not always return me the first match for id in the div and would never go to other divs and so I will always get same value for id which is for the first container ? If so than what is the work around for this ? Hope this question is clear.

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  • C# expression tree for ordinary code

    - by rwallace
    It's possible to create an expression tree, if you declare it as such. But is it possible to get an expression tree for an ordinary chunk of code such as a method or property getter? What I'm trying to do is, let's say for an order processing system, I have a class for order items: class Item : Entity { [Cascade] public Document document { get; set; } public int line { get; set; } public Product product { get; set; } public string description { get; set; } public decimal qty { get; set; } public decimal price { get; set; } public decimal net { get { return qty * price; } } public VatCode vat_code { get; set; } } where the net value equals qty * price, so I'd like to declare it as such, either with a property or method, and then also have the framework introspect that expression so it can generate appropriate SQL for defining a corresponding calculated column in a corresponding database view. The most obvious way to do this would be to get the expression tree for a property getter or a method, but I can't find any indication how to do this, or that it is possible. (I have found a way to get a method body as a byte stream, but that's not what's desired here.) If that isn't possible, I suppose the recommended solution would be to declare something like a static field that is an expression tree, and compile/run it at run time for internal use, and also introspect as normal for SQL generation?

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  • Line graph disappears after new line is added

    - by tonystinge
    I am having trouble uploading a large .csv file to my HIGHCHART graph. I've been able to graph an 85KB up to 1486 lines by 9 (I) columns. Here is an example: TimeStamp Temp_1_01 Temp_1_02 Temp_2_01 Temp_2_02 Temp_3_01 Temp_3_02 Temp_4_01 Temp_4_02 5/15/2014, 3:25 408 487 63 84 67 91 63 78 5/15/2014 3:30 408 487 63 84 67 91 63 78 5/15/2014 3:35 407 489 63 84 67 91 63 78 5/15/2014 3:40 408 488 63 84 67 91 63 78 5/15/2014 3:44 408 488 63 84 67 91 63 78 ... 5/22/2014 9:40 483 421 0 93 76 95 72 89 When I add a new line the line graph disappears. Any suggestions? Here is the javascript: $.get('Dropbox/geo/sites/GC_Room/loveland.csv', function(data) { // Split the lines var lines = data.split('\n'); var i = 0; var csvData = []; // Iterate over the lines and add categories or series $.each(lines, function(lineNo, line) { csvData[i] = line.split(','); i = i + 1; }); var columns = csvData[0]; var categories = [], series = []; for(var colIndex=0,len=columns.length; colIndex<len; colIndex++) { //first row data as series's name var seriesItem= { data:[], name:csvData[0][colIndex] }; for(var rowIndex=1,rowCnt=csvData.length; rowIndex<rowCnt; rowIndex++) { //first column data as categories, if (colIndex == 0) { categories.push(csvData[rowIndex][0]); } else if(parseFloat(csvData[rowIndex][colIndex])) // <-- here { seriesItem.data.push(parseFloat(csvData[rowIndex][colIndex])); } }; //except first column if(colIndex>0)series.push(seriesItem); } // Create the chart var chart = new Highcharts.Chart( { chart: { alignTick: false, renderTo: 'LANE_METALS', type: 'line' }, title: { text: 'Monthly Average Temperature', x: -20 //center }, subtitle: { text: 'Source: LANE METALS', x: -20 }, xAxis: { categories: categories, labels: { step: 200, text: 'Time', }, tickWidth: 0 }, yAxis: { title: { text: 'Temperature (\xB0C)' }, min: 0 }, tooltip: { formatter: function() { return '<b>'+ this.series.name +'</b><br/>'+ this.x +': '+ this.y +'\xB0C'; } }, legend: { layout: 'vertical', //backgroundColor: '#FFFFFF', //floating: true, align: 'left', //x: 100, verticalAlign: 'top', //y: 70, borderWidth: 0 }, plotOptions: { area: { turboThreshold: 0, stacking: 'normal', lineColor: '#666666', lineWidth: 1, marker: { lineWidth: 1, lineColor: '#666666' } } }, series: series }); });

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  • How to install the new apk file without uninstall the old apk file on an Android device?

    - by naresh
    My apk file size is 2MB. First time installing the apk file in the device there is no problem. Suppose some changes in the application after that generated the new apk file. I am try to install the new apk file in the same device then it shows some message first uninstall the previous one(i.e. , same application) in the device. But small apk files, I am not facing this problem. Is it possible to install the new apk file without uninstall the old one?

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  • What's the difference between /123 and /?123?

    - by BoltClock
    I've noticed that some sites (including http://jobs.stackoverflow.com) have query strings that look like this: http://somewebapp.example/?123 as compared to: http://somewebapp.example/123 or http://somewebapp.example/id/123 What are the reasons that developers choose to implement their web apps' URLs using the first example instead of the second and third examples? And as a bonus, how would one implement the first example in PHP, given that 123 is the primary key of some row in a database table? (I just need to know how to retrieve 123 from the URL; I already know how to query the database for a primary key of 123.)

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  • WPF tabswitch/ render takes too much time..

    - by Socrates
    I have a WPF application with many tabs.. in one tab.. i make a verycomplex vector drawing consisting of thousands of drawing visuals.. (this represents a machine and all elements need to be interactable..) It takes 3/4 seconds for drawing this for the first time..After the first draw it should be done.. The problem is if i switch to another tab and comeback, it takes atlease 2,3 seconds to show the tabpage with drawing again.. Since there is no redraw, why should it take so much time..?

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