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  • Codeigniter Pagination: Run the Query Twice?

    - by Frank
    I'm using codeigniter and the pagination class. This is such a basic question, but I need to make sure I'm not missing something. In order to get the config items necessary to paginate results getting them from a MySQL database it's basically necessary to run the query twice is that right? In other words, you have to run the query to determine the total number of records before you can paginate. So I'm doing it like: Do this query to get number of results $this->db->where('something', $something); $query = $this->db->get('the_table_name'); $num_rows = $query->num_rows(); Then I'll have to do it again to get the results with the limit and offset. Something like: $this->db->where('something', $something); $this->db->limit($limit, $offset); $query = $this->db->get('the_table_name'); if($query->num_rows()){ foreach($query->result_array() as $row){ ## get the results here } } I just wonder if I'm actually doing this right in that the query always needs to be run twice? The queries I'm using are much more complex than what is shown above.

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  • Ajax long polling (comet) + php on lighttpd v1.4.22 multiple instances problem.

    - by fibonacci
    Hi, I am new to this site, so I really hope I will provide all the necessary information regarding my question. I've been trying to create a "new message arrived notification" using long polling. Currently I am initiating the polling request by window.onLoad event of each page in my site. On the server side I have an infinite loop: while(1){ if(NewMessageArrived($current_user))break; sleep(10); } echo $newMessageCount; On the client side I have the following (simplified) ajax functions: poll_new_messages(){ xmlhttp=GetXmlHttpObject(); //... xmlhttp.onreadystatechange=got_new_message_count; //... xmlhttp.send(); } got_new_message_count(){ if (xmlhttp.readyState==4){ updateMessageCount(xmlhttp.responseText); //... poll_new_messages(); } } The problem is that with each page load, the above loop starts again. The result is multiple infinite loops for each user that eventually make my server hang. *The NewMessageArived() function queries MySQL DB for new unread messages. *At the beginning of the php script I run start_session() in order to obtain the $current_user value. I am currently the only user of this site so it is easy for me to debug this behavior by writing time() to a file inside this loop. What I see is that the file is being written more often than once in 10 seconds, but it starts only when I go from page to page. Please let me know if any additional information might help. Thank you.

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  • How to nest joins with CakePHP?

    - by Daren Thomas
    I'm trying to behave. So, instead of using following SQL syntax: select * from tableA INNER JOIN tableB on tableA.id = tableB.tableA_id LEFT OUTER JOIN ( tableC INNER JOIN tableD on tableC.tableD_id = tableD.id) on tableC.tableA_id = tableA.id I'd like to use the CakePHP model->find(). This will let me use the Paginator too, since that will not work with custom SQL queries as far as I understand (unless you hardcode one single pagination query to the model which seems a little inflexible to me). What I've tried so far: /* inside tableA_controller.php, inside an action, e.g. "view" */ $this->paginate['recursive'] = -1; # suppress model associations for now $this->paginate['joins'] = array( array( 'table' => 'tableB', 'alias' => 'TableB', 'type' => 'inner', 'conditions' => 'TableB.tableA_id = TableA.id', ), array( 'table' => 'tableC', 'alias' => 'TableC', 'type' => 'left', 'conditions' => 'TableC.tableA_id = TableA.id', 'joins' = array( # this would be the obvious way to do it, but doesn't work array( 'table' => 'tableD', 'alias' => 'TableD', 'type' => 'inner', 'conditions' => 'TableC.tableD_id = TableD.id' ) ) ) ) That is, nesting the joins into the structure. But that doesn't work (CakePHP just ignores the nested 'joins' element which was kind of what I expected, but sad. I have seen hints in comments on how to do subqueries (in the where clause) using a statement builder. Can a similar trick be used here?

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  • MySQL Query That Can Pull the Data I am Seeking?

    - by Amy
    On the project I am working on, I am stuck with the table structure from Hades. Two things to keep in mind: I can't change the table structure right now. I'm stuck with it for the time being. The queries are dynamically generated and not hard coded. So, while I am asking for a query that can pull this data, what I am really working toward is an algorithm that will generate the query I need. Hopefully, I can explain the problem without making your eyes glaze over and your brain implode. We have an instance table that looks (simplified) along these lines: Instances InstanceID active 1 Y 2 Y 3 Y 4 N 5 Y 6 Y Then, there are multiple data tables along these lines: Table1 InstanceID field1 reference_field2 1 John 5 2 Sally NULL 3 Fred 6 4 Joe NULL Table2 InstanceID field3 5 1 6 1 Table3 InstanceID fieldID field4 5 1 Howard 5 2 James 6 2 Betty Please note that reference_field2 in Table1 contains a reference to another instance. Field3 in Table2 is a bit more complicated. It contains a fieldID for Table 3. What I need is a query that will get me a list as follows: InstanceID field1 field4 1 John Howard 2 Sally 3 Fred The problem is, in the query I currently have, I do not get Fred because there is no entry in Table3 for fieldID 1 and InstanceID 6. So, the very best list I have been able to get thus far is InstanceID field1 field4 1 John Howard 2 Sally In essence, if there is an entry in Table1 for Field 2, and there is not an entry in Table 3 that has the instanceID contained in field2 and the field ID contained in field3, I don't get the data from field1. I have looked at joins till I'm blue in the face, and I can't see a way to handle the case when table3 has no entry.

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  • CascadingDropDown ViewState Problem

    - by Steven
    I have two Ajax CascadingDropDown extenders on my page. After a postback, the value of the first dropdown is set (presumably) triggering an event for the second dropdown to refresh. Question: How do I maintain both the contents (from queries) and selected value of both dropdowns after postback? C# answers also welcome. Default.aspx Active States<br /><asp:DropDownList ID="StatesDrop" runat="server" /><br /> Active Cities<br /><asp:DropDownList ID="CitiesDrop" runat="server" /><br /> <ajax:CascadingDropDown ID="StatesCasc" TargetControlID="StatesDrop" ServicePath="WebService1.asmx" ServiceMethod="GetActiveStates" Category="States" runat="server" PromptText="Select a State" PromptValue="?" /> <ajax:CascadingDropDown ID="CitiesCasc" TargetControlID="CitiesDrop" ServicePath="WebService1.asmx" ServiceMethod="GetActiveCities" Category="Cities" runat="server" ParentControlID="StatesDrop" PromptText="Select a City" PromptValue="?" /> WebService1.asmx.vb Imports System.Web.Services Imports System.Web.Services.Protocols Imports System.ComponentModel Imports System.Web.Script.Services Imports AjaxControlToolkit <System.Web.Script.Services.ScriptService()> _ <System.Web.Services.WebService(Namespace:="http://tempuri.org/")> _ <System.Web.Services.WebServiceBinding _ (ConformsTo:=WsiProfiles.BasicProfile1_1)> _ <ToolboxItem(False)> _ Public Class WebService1: Inherits System.Web.Services.WebService <WebMethod()> _ Public Function GetActiveStates (ByVal knownCategoryValues As String, _ ByVal category As String) As CascadingDropDownNameValue() Dim values As New List(Of CascadingDropDownNameValue)() 'Populate values with query' Return values.ToArray() End Function <WebMethod()> _ Public Function GetActiveCities (ByVal knownCategoryValues As String, _ ByVal category As String) As CascadingDropDownNameValue() Dim kv As StringDictionary = _ CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues) Dim SelState As String = "" If kv.ContainsKey("State") Then SelState = kv("State") Dim values As New List(Of CascadingDropDownNameValue)() ' Populate values with query.' Return values.ToArray() End Function End Class

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  • Personal Cache vs Memcache?

    - by Kerry
    I have a personal caching class, which can be seen here ( based off WordPress' ): http://pastie.org/988427 I recently learned about memcache and it said to memcache EVERYTHING: http://highscalability.com/blog/2010/5/17/7-lessons-learned-while-building-reddit-to-270-million-page.html My first thought was just to keep my class with the current functions and make it use memcache instead -- is there any downside to doing this? The main difference I see is that memcache stays on with the server from page to page, while mine is for 1 page load. The problem I see arising, and this is with any system, is that they're dynamic. They change all the time. Whether its search results, visible products, etc. etc. If it's all cached, won't the create a problem? Is there a way to handle this? Obviously if something is bringing back the same results everytime it would be cached, but that's why I was doing it on a per page load basis. I'm sure there is a way to handle this, or is the cache time usually set between 5 minutes and an hour?

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  • Codeigniter common templates

    - by Darthg8r
    Let's say that I have a website that has 100 different pages. Each page uses a common header and footer. Inside the header is some dynamic content that comes from a database. I'd like to avoid having to have code in every single controller and action that passes this common code into the view. function index() { // It sucks to have to include this on every controller action. data['title'] = "This is the index page"; data['currentUserName'] = "John Smith"; $this->load->view("main_view", data); } function comments() { // It sucks to have to include this on every controller action. data['title'] = "Comment list"; data['currentUserName'] = "John Smith"; $this->load->view("comment_view", data); } I realize that I could refactor the code so that the common parts are in a single function and the function is called by the action. Doing so would reduce SOME of the pain, but it still doesn't feel right since I'd still have to make a call to that function every time. What's the correct way to handle this?

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  • Trim characters from RSS feed

    - by egr103
    I'm calling in a RSS feed to my website using PHP. Currently my code below is calling in the entire contents for pubDate: <pubDate>Thu, 12 Sep 2013 07:23:59 +0000</pubDate> How do I just display the day and month from the above example i.e. 12 Sep? EDIT I should clarify, the above line of code is an example output I currently get but as I'm calling the latest 3 posts from an RSS feed, this date and time will vary. I therefore need the code to be more dynamic (if that's the right term!) This code is my full code that fetches the contents of an RSS feed: <?php $counter = 0; $xml=simplexml_load_file("http://tutorial.world.edu/feed/"); foreach ($xml->channel->item as $item) { $title = (string) $item->title; // Title Post $link = (string) $item->link; // Url Link $pubDate = (string) $item->pubDate; // date $description = (string) $item->description; //Description Post echo '<div class="display-rss-feed"><a href="'.$link.'" target="_blank" title="" >'.$title.' </a><br/><br/>'; echo $description.'<hr><p style="background-color:#e4f;">'.$pubDate.'</p></div>'; if($counter == 2 ) { break; } else { $counter++; } } ?>

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  • Reuse, Rewrite, or Refactor?

    - by Jon Purdy
    At work I inherited development of a PHP-based Web site after the consultant who originally produced it bailed out and left without a trace. Literally half of the code is ripped from online tutorials, and there are thousands of lines of cruft that, being incomplete, do precious little. Hardly any of it actually works. I've been trying to pull out the usable components, such as the layout (cleverly intermixed with code), session management (delicately seasoned with unescaped, unvalidated SQL queries), and a few other things, but it's very difficult to force all of this junk into place. Further, I don't speak idiomatic PHP, being more of a Perl user, and I'm supposed to be on this project principally for maintenance, so rewriting everything seems like it would take just as long as wrestling the existing monster back into place. As an aside, I have literally never seen anything as badly written as this. Welcome me to the world of working with other people's code, I guess, but I do hope it's not this common in the real world to have such gems as these: // WHY IS THIS NOT WORKING // I know this is bad but were going for working stuff right now... // This is a PHP code outputing Javascript code outputting HTML...do not go further // Not userful I'm looking for the best advice I can get here. What would you do if you were in my position?

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  • Why does Hibernate 2nd level cache only cache within a session?

    - by Synesso
    Using a named query in our application and with ehcache as the provider, it seems that the query results are tied to the session. Any attempt to access the value from the cache for a second time results in a LazyInitializationException We have set lazy=true for the following mapping because this object is also used by another part of the system which does not require the reference... and we want to keep it lean. <class name="domain.ReferenceAdPoint" table="ad_point" mutable="false" lazy="false"> <cache usage="read-only"/> <id name="code" type="long" column="ad_point_id"> <generator class="assigned" /> </id> <property name="name" column="ad_point_description" type="string"/> <set name="synonyms" table="ad_point_synonym" cascade="all-delete-orphan" lazy="true"> <cache usage="read-only"/> <key column="ad_point_id" /> <element type="string" column="synonym_description" /> </set> </class> <query name="find.adpoints.by.heading">from ReferenceAdPoint adpoint left outer join fetch adpoint.synonyms where adpoint.adPointField.headingCode = ?</query> Here's a snippet from our hibernate.cfg.xml <property name="hibernate.cache.provider_class">net.sf.ehcache.hibernate.SingletonEhCacheProvider</property> <property name="hibernate.cache.use_query_cache">true</property> It doesn't seem to make sense that the cache would be constrained to the session. Why are the cached queries not usable outside of the (relatively short-lived) sessions?

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  • RichEdit VCL and URLs. Workarounds for OnPaint Issues.

    - by HX_unbanned
    So, issue is with the thing Delphi progies scare to death - Rich Edit in Windows ( XP and pre-XP versions ). Situation: I have added EM_AUTOURLDETECTION in OnCreate of form. Target - RichEdit1. Then, I have form, that is "collapsed" after showing form. RichEdit Control is sattic, visible and enabled, but it is "hidden" because form window is collapsed. I can expand and collapse form, using Button1 and changing forms Constraints and Size properties. After first time I expand form, the URL inside RichEdit1 control is highlighted. BUT - After second, third, fourth, etc... time I Collapse and Expand form, the RichEdit1 Control does not highlight URL anymore. I have tried EM_SETTEXTMODE messages, also WM_UPDATEUISTATE, also basic WM_TEXT message - no luck. It sems like this merssage really works ( enables detection ) while sending keyboard strokes ( virtual keycodes ), but not when text has been modified. Also - I am thinking to rewrite code to make RichEdit Control dynamic. Would this fix the problem? Maybe solution is to override OnPaint / OnDraw method to avoid highlight ( formatting ) losing when collapsing or expanding form? Weird is that my Embarcadero Documentation says this function must work in any moment text has been modified. Why it does not work? Any help appreciated. I am making this Community Wiki because this is common problem and togewther we cam find solution, right? :) Also - follow-ups and related Question: http://stackoverflow.com/questions/738694/override-onpaint http://stackoverflow.com/questions/478071/how-to-autodetect-urls-in-richedit-2-0 http://www.vbforums.com/archive/index.php/t-59959.html

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  • Jquery Tabs Help

    - by Jacinto
    So I am trying to make a tabs in a menu but cant make the whole width of each of the tabs 219px. it only allows me to make the li 219 but I wanna make the li a 219px. I cant seem to figure it out. Also is there a way to make a next button or would the best way to go to each tab and literally put in the next tab in a type of way? any help would be greatly appreciated Css .servicesNavigation li { float: left; list-style: none; width: 219px; } ul.servicesNavigation li a { padding: 3px 5px; background-color: #ccc; color: #000; text-decoration: none; width: 219px; } ul.servicesNavigation li a.selected, ul.tabNavigation li a:hover { background-color: #333; color: #fff; padding-top: 7px; } ul.servicesNavigation li a:focus { outline: 0; } HTML <ul class="servicesNavigation"> <li><a href="#Web">Web</a></li> <li><a href="#Print">Print</a></li> <li><a href="#DynamicContent">Dynamic Content</a></li> <li><a href="#Hosting">Hosting</a></li> </ul> Jquery var tabContainers = $('div.servicesInfo > div'); tabContainers.hide().filter(':first').show(); $('div.servicesInfo ul.servicesNavigation a').click(function () { tabContainers.hide(); tabContainers.filter(this.hash).show(); $('div.servicesInfo ul.servicesNavigation a').removeClass('selected'); $(this).addClass('selected'); return false; }).filter(':first').click();

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  • SEO: Where do I start?

    - by James
    Hi, I am primarily a software developer however I tend to delve in some web development from time to time. I have recently been asked to have a look at a friends website as they are wanting to improve their position in search engine results i.e. google/yahoo etc. I am aware there is no guarentee that their position will change, however, I do know there are techniques/ways to make your website more visible to search engine spiders and to consequently improve your position in the rankings i.e. performing SEO. Before I started looking at the SEO of the site I did the following prerequsite checks: Ran the website through the W3C Markup Validator and the W3C CSS Validator services. Looked through the markup code manually (check for meta tags etc) Performed a thorough cross browser compatibility test. From those checks, the following was evident: No SEO has been performed on the site before. The website has been developed using a visual editing tool such as dreamweaver (as it failed the validation services miserably and tables where being used everywhere!) The site is fairly cross browser compatibile (only some slight issues with IE8 which are easily resolved). How the site navigation is, isn't very search engine friendly (e.g. index.php?page=home) I can see right away a major improvement for SEO (or I at least think) would be to change the way the website is structured i.e. change from using dynamic pages such as "index.php?page=home" and actually having pages called "home.html". Other area's would be to add meta tags to identify keywords, and then sprinkling these keywords over the pages. As I am a rookie in this department, could anyone give me some advice on how I could perform thorough SEO on this website? Thanks in advance.

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  • MySQL Stored Procedures not working with SELECT (basic question)

    - by TMG
    Hello, I am using a platform (perfectforms) that requires me to use stored procedures for most of my queries, and having never used stored procedures, I can't figure out what I'm doing wrong. The following statement executes without error: DELIMITER // DROP PROCEDURE IF EXISTS test_db.test_proc// CREATE PROCEDURE test_db.test_proc() SELECT 'foo'; // DELIMITER ; But when I try to call it using: CALL test_proc(); I get the following error: #1312 - PROCEDURE test_db.test_proc can't return a result set in the given context I am executing these statements from within phpmyadmin 3.2.4, PHP Version 5.2.12 and the mysql server version is 5.0.89-community. When I write a stored procedure that returns a parameter, and then select it, things work fine (e.g.): DELIMITER // DROP PROCEDURE IF EXISTS test_db.get_sum// CREATE PROCEDURE test_db.get_sum(out total int) BEGIN SELECT SUM(field1) INTO total FROM test_db.test_table; END // DELIMITER ; works fine, and when I call it: CALL get_sum(@t); SELECT @t; I get the sum no problem. Ultimately, what I need to do is have a fancy SELECT statement wrapped up in a stored procedure, so I can call it, and return multiple rows of multiple fields. For now I'm just trying to get any select working. Any help is greatly appreciated.

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  • Oracle output: cursor, file, or very long string?

    - by Klay
    First, the setup: I have a table in an Oracle10g database with spatial columns. I need to be able to pass in a spatial reference so that I can reproject the geometry into an arbitrary coordinate system. Ultimately, I need to compress the results of this projection to a zip file and make it available for download through a Silverlight project. I would really appreciate ideas as to the best way to accomplish this. In the examples below, the SRID is the Spatial reference ID integer used to convert the geometric points into a new coordinate system. In particular, I can see a couple of possibilities. There are many more, but this is an idea of how I'm thinking: a) Pass SRID to a dynamic view -- perform projection, output a cursor -- send cursor to UTL_COMPRESS -- write output to a file (somehow) -- send URL to Silverlight app b) Use SRID to call Oracle function from Silverlight app -- perform projection, output a string -- build strings into a file -- compress file using SharpZipLib library in .NET -- send bytestream back to Silverlight app I've done the first two steps of b), and the conversion of 100 points took about 7 seconds, which is unacceptably slow. I'm hoping it would be faster doing the processing totally in Oracle. If anyone can see potential problems with either way of doing this, or can suggest a better way, it would be very helpful. Thanks!

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  • Combining aggregate functions in an (ANSI) SQL statement

    - by morpheous
    I have aggregate functions foo(), foobar(), fredstats(), barneystats() I want to create a domain specific query language (DSQL) above my DB, to facilitate using using a domain language to query the DB. The 'language' comprises of boolean expressions (or more specifically SQL like criteria) which I then 'translate' back into pure (ANSI) SQL and send to the underlying Db. The following lines are examples of what the language statements will look like, and hopefully, it will help further clarify the concept: **Example 1** DQL statement: foobar('yellow') between 1 and 3 and fredstats('weight') > 42 Translation: fetch all rows in an underlying table where computed values for aggregate function foobar() is between 1 and 3 AND computed value for AGG FUNC fredstats() is greater than 42 **Example 2** DQL statement: fredstats('weight') < barneystats('weight') AND foo('fighter') in (9,10,11) AND foobar('green') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 3** DQL statement: foobar('green') / foobar('red') <> 42 Translation: Fetch all rows where the specified criteria matches **Example 4** DQL statement: foobar('green') - foobar('red') >= 42 Translation: Fetch all rows where the specified criteria matches Given the following information: The table upon which the queries above are being executed is called 'tbl' table 'tbl' has the following structure (id int, name varchar(32), weight float) The result set returns only the tbl.id, tbl.name and the names of the aggregate functions as columns in the result set - so for example the foobar() AGG FUNC column will be called foobar in the result set. So for example, the first DQL query will return a result set with the following columns: id, name, foobar, fredstats Given the above, my questions then are: What would be the underlying SQL required for Example1 ? What would be the underlying SQL required for Example3 ? Given an algebraic equation comprising of AGGREGATE functions, Is there a way of generalizing the algorithm needed to generate the required ANSI SQL statement(s)? I am using PostgreSQL as the db, but I would prefer to use ANSI SQL wherever possible.

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  • Search and replace hundreds of strings in tens of thousands of files?

    - by C Johnson
    I am looking into changing the file name of hundreds of files in a (C/C++) project that I work on. The problem is our software has tens of thousands of files that including (i.e. #include) these hundreds of files that will get changed. This looks like a maintenance nightmare. If I do this I will be stuck in Ultra-Edit for weeks, rolling hundreds of regex's by hand like so: ^\#include.*["<\\/]stupid_name.*$ with #include <dir/new_name.h> Such drudgery would be worse than peeling hundreds of potatoes in a sunken submarine in the antarctic with a spoon. I think it would rather be ideal to put the inputs and outputs into a table like so: stupid_name.h <-> <dir/new_name.h> stupid_nameb.h <-> <dir/new_nameb.h> stupid_namec.h <-> <dir/new_namec.h> and feed this into a regular expression engine / tool / app / etc... My Ultimate Question: Is there a tool that will do that? Bonus Question: Is it multi-threaded? I looked at quite a few search and replace topics here on this website, and found lots of standard queries that asked a variant of the following question: standard question: Replace one term in N files. as opposed to: my question: Replace N terms in N files. Thanks in advance for any replies.

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  • DataReader-DataSet Hybrid solution

    - by G33kKahuna
    My solution architects and I have exhausted both pure Dataset and Datareader solutions. Basically we have a Microsoft.NET 2.0 windows service application that pulls data based on a query and processes additional tasks per record; almost a poor mans workflow system. The recordsets are broader (in terms of the columns) and deeper (in terms of number of records). We observed that DataSet performs much better in terms of performance but runs into contraints as # of records increase say 100K+ we start seeing System.OutOfMemoryException on a 4G machine with processModel configured to run at memoryLimit set to 85. Since this is a multi-threaded app, there could be multiple threads processing different queries and building different DataSets, so we run into the exception sooner in that case DataReader on the other hand works but is a lot slower and hits other contraints; if there is some sort of disconnect it has to start over again or leaves open connections on the DB side and worst case takes down the service completely etc. So, we decided the best option would be some sort of hybrid solution. I'm open to guidance and suggestions. Are there any hybrid solutions available? Any other suggestions

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  • how can i store value in button at runtime?

    - by SHASHANK
    Hello all I have a problem i have some dynamic button.and i want to store integer value in that. and get that value on that click event of that button how can i achieve it thanks in advance shashank DataView dv = new DataView(dtCat, "PK_CATEGORY_ID IN(" + categoryIds.ToString() + "0)", "PK_CATEGORY_ID", DataViewRowState.CurrentRows); foreach (DataRowView rr in dv) { //MessageBox.Show(rr[0].ToString() + "------------" + rr[1].ToString()); Button b2 = new Button(); //b2.Name = rr[0].ToString(); b2.Name = ""; b2.Height = 200; b2.Width = 200; b2.Margin = new Thickness(0, -100, 0, 0); b2.HorizontalAlignment = HorizontalAlignment.Left; b2.Content = rr[1].ToString(); b2.Background = System.Windows.Media.Brushes.Pink; b2.Click += new RoutedEventHandler(b2_Click); btncanvas.Children.Add(b2); Canvas.SetLeft(b2, b2.Width * i); i = i + 1; MessageBox.Show(rr[0].ToString()); b2.Tag = rr[0].ToString(); } void b2_Click(object sender, RoutedEventArgs e) { Button clicked = (Button)sender; categoryname = clicked.Name; }

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  • How would the 'Model' in a Rails-type webapp be implemented in a functional programming langauge?

    - by ceptorial
    In MVC web development frameworks such as Ruby on Rails, Django, and CakePHP, HTTP requests are routed to controllers, which fetch objects which are usually persisted to a backend database store. These objects represent things like users, blog posts, etc., and often contain logic within their methods for permissions, fetching and/or mutating other objects, validation, etc. These frameworks are all very much object oriented. I've been reading up recently on functional programming and it seems to tout tremendous benefits such as testability, conciseness, modularity, etc. However most of the examples I've seen for functional programming implement trivial functionality like quicksort or the fibonnacci sequence, not complex webapps. I've looked at a few 'functional' web frameworks, and they all seem to implement the view and controller just fine, but largely skip over the whole 'model' and 'persistence' part. (I'm talking more about frameworks like Compojure which are supposed to be purely functional, versus something Lift which conveniently seems to use the OO part of Scala for the model -- but correct me if I'm wrong here.) I haven't seen a good explanation of how functional programming can be used to provide the metaphor that OO programming provides, i.e. tables map to objects, and objects can have methods which provide powerful, encapsulated logic such as permissioning and validation. Also the whole concept of using SQL queries to persist data seems to violate the whole 'side effects' concept. Could someone provide an explanation of how the 'model' layer would be implemented in a functionally programmed web framework?

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  • Can I use a specific model from within a behavior in CakePHP?

    - by Paul Willy
    I'm trying to write a behavior that will give my models access to a simple workflow engine I've devised. The workflow engine itself works as a CakePHP model, with workflow data stored in the database just as any other model data is stored. Basically what I want to do is have the behavior use the workflow model whenever an action is called on the base model. For example, if the edit() action is executed for Posts, then the Post (with the behavior attached) will trigger the workflow behavior with its own model name, action, and id as arguments (e.g. [Post, edit, 1]). Then the behavior will invoke the functionality of the Workflow model, which has a record for what to do when edit is run on Posts (e.g. send e-mail to users who are subscribed to that post) and will carry that out. My question is, what is the proper way to invoke model/controller methods from within the behavior? The model to be used from within the behavior will always be Workflow, but the behavior should be usable from basically any model (aside from Workflow itself). I know I could run SQL queries directly from the behavior, but of course this is not the Cake way :-) Or, am I going about this in the wrong way? I want to store a certain amount of logic in the database so that it is easily configurable by different users, and not have endless configuration checks within the model/controller logic itself so that workflow steps can be easily added/changed/removed in the future.

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  • Port Win32 DLL hook to Linux

    - by peachykeen
    I have a program (NWShader) which hooks into a second program's OpenGL calls (NWN) to do post-processing effects and whatnot. NWShader was originally built for Windows, generally modern versions (win32), and uses both DLL exports (to get Windows to load it and grab some OpenGL functions) and Detours (to hook into other functions). I'm using the trick where Win will look in the current directory for any DLLs before checking the sysdir, so it loads mine. I have on DLL that redirects with this method: #pragma comment(linker, "/export:oldFunc=nwshader.newFunc) To send them to a different named function in my own DLL. I then do any processing and call the original function from the system DLL. I need to port NWShader to Linux (NWN exists in both flavors). As far as I can tell, what I need to make is a shared library (.so file). If this is preloaded before the NWN executable (I found a shell script to handle this), my functions will be called. The only problem is I need to call the original function (I would use various DLL dynamic loading methods for this, I think) and need to be able to do Detour-like hooking of internal functions. At the moment I'm building on Ubuntu 9.10 x64 (with the 32-bit compiler flags). I haven't been able to find much on Google to help with this, but I don't know exactly what the *nix community refers to it as. I can code C++, but I'm more used to Windows. Being OpenGL, the only part the needs modified to be compatible with Linux is the hooking code and the calls. Is there a simple and easy way to do this, or will it involve recreating Detours and dynamically loading the original function addresses?

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  • Oracle command hangs when using view for "WHILE x IN..." subquery

    - by Calvin Fisher
    I'm working on a web service that fetches data from an oracle data source in chunks and passes it back to an indexing/search tool in XML format. I'm the C#/.NET guy, and am kind of fuzzy on parts of Oracle. Our Oracle team gave us the following script to run, and it works well: SELECT ROWID, [columns] FROM [table] WHERE ROWID IN ( SELECT ROWID FROM ( SELECT ROWID FROM [table] WHERE ROWID > '[previous_batch_last_rowid]' ORDER BY ROWID ) WHERE ROWNUM <= 10000 ) ORDER BY ROWID 10,000 rows is an arbitrary but reasonable chunk size and ROWID is sufficiently unique for our purposes to use as a UID since each indexing run hits only one table at a time. Bracketed values are filled in programmatically by the web service. Now we're going to start adding views to the indexing, each of which will union a few separate tables. Since ROWID would no longer function as a unique identifier, they added a column to the views (VIEW_UNIQUE_ID) that concatenates the ROWIDs from the component tables to construct a UID for each union. But this script does not work, even though it follows the same form as the previous one: SELECT VIEW_UNIQUE_ID, [columns] FROM [view] WHERE VIEW_UNIQUE_ID IN ( SELECT VIEW_UNIQUE_ID FROM ( SELECT VIEW_UNIQUE_ID FROM [view] WHERE ROWID > '[previous_batch_last_view_unique_id]' ORDER BY VIEW_UNIQUE_ID ) WHERE ROWNUM <= 10000 ) ORDER BY VIEW_UNIQUE_ID It hangs indefinitely with no response from the Oracle server. I've waited 20+ minutes and the SQLTools dialog box indicating a running query remains the same, with no progress or updates. I've tested each subquery independently and each works fine and takes a very short amount of time (<= 1 second), so the view itself is sound. But as soon as the inner two SELECT queries are added with "WHERE VIEW_UNIQUE_ID IN...", it hangs. Why doesn't this query work for views? In what important way are they not interchangeable here?

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  • How can I work around WinXP using ports 1025-5000 as ephemeral?

    - by Chris Dolan
    If you create a TCP client socket with port 0 instead of a non-zero port, then the operating system chooses any free ephemeral port for you. Most OSes choose ephemeral ports from the IANA dynamic port range of 49152-65535. However in Windows Server 2003 and earlier (including XP) Microsoft used ports 1025-5000 as the ephemeral range, according to their bind() documentation. I run multiple Java services on the same hardware. On rare occasions, this range collides with well-known ports that I use for other services (e.g. port 4160 for Jini discovery). While rare, this has caused real problems. Is there any easy way to tell Windows or Java to use a different port range for client sockets? Microsoft's docs indicate that I can change the high end of that range via the MaxUserPort TcpIP registry setting, but I see no way to change the low end. Update: I've made some progress on this. It looks like Microsoft has a concept of reserved ports that are exceptions to the ephemeral port range. There's a registry setting that lets you change this permanently and apparently there must be an API to do the same thing because there's a data structure that holds high/low values for reserved port ranges, but I can't find the actual function call anywhere... The registry solution may work, but now I'm fixated on this API.

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  • Legitimate uses of the Function constructor

    - by Marcel Korpel
    As repeatedly said, it is considered bad practice to use the Function constructor (also see the ECMAScript Language Specification, 5th edition, § 15.3.2.1): new Function ([arg1[, arg2[, … argN]],] functionBody) (where all arguments are strings containing argument names and the last (or only) string contains the function body). To recapitulate, it is said to be slow, as explained by the Opera team: Each time […] the Function constructor is called on a string representing source code, the script engine must start the machinery that converts the source code to executable code. This is usually expensive for performance – easily a hundred times more expensive than a simple function call, for example. (Mark ‘Tarquin’ Wilton-Jones) Though it's not that bad, according to this post on MDC (I didn't test this myself using the current version of Firefox, though). Crockford adds that [t]he quoting conventions of the language make it very difficult to correctly express a function body as a string. In the string form, early error checking cannot be done. […] And it is wasteful of memory because each function requires its own independent implementation. Another difference is that a function defined by a Function constructor does not inherit any scope other than the global scope (which all functions inherit). (MDC) Apart from this, you have to be attentive to avoid injection of malicious code, when you create a new Function using dynamic contents. Lots of disadvantages and it is intelligible that ECMAScript 5 discourages the use of the Function constructor by throwing an exception when using it in strict mode (§ 13.1). That said, T.J. Crowder says in an answer that [t]here's almost never any need for the similar […] new Function(...), either, again except for some advanced edge cases. So, now I am wondering: what are these “advanced edge cases”? Are there legitimate uses of the Function constructor?

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