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  • How do I implement Hibernate Pagination using a cursor (so the results stay consistent, despite new

    - by hunterae
    Hey all, Is there any way to maintain a database cursor using Hibernate between web requests? Basically, I'm trying to implement pagination, but the data that is being paged is consistently changing (i.e. new records are added into the database). We are trying to set it up such that when you do your initial search (returning a maximum of 5000 results), and you page through the results, those same records always appear on the same page (i.e. we're not continuously running the query each time next and previous page buttons are clicked). The way we're currently implementing this is by merely selecting 5000 (at most) primary keys from the table we're paging, storing those keys in memory, and then just using 20 primary keys at a time to fetch their details from the database. However, we want to get away from having to store these keys in memory and would much prefer a database cursor that we just keep going back to and moving backwards and forwards over the cursor to generate pages. I tried doing this with Hibernate's ScrollableResults but found that I could not call methods like next() and previous() would cause an exception if you within a different web request / Hibernate session (no surprise there). Is there any way to reattach a ScrollableResults object to a Session, much the same way you would reattach a detached database object to make it persistent? Are there any other approaches to implement this data paging with consistent paging results without caching the primary keys?

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  • Slow Response in checkbox using JQuery

    - by Dean
    Hi to all. I'm trying to optimize a website. The flow is i tried to query a certain table and all of its data entry in a page(w/ toolbars), work fine. When i tried to edit the page the problem is when i click the checkbox button i have to wait 2-5sec just by clicking it. I limit the viewing of entry to 5 only but the response on checkbox doesn't change. The tables have 100 entries in them. function checkAccess(celDiv,id) { var celValue = $(celDiv).html(); if (celValue==1) $(celDiv).html("<input type='checkbox' value='"+$(celDiv).html()+"' checked disabled>") else $(celDiv).html("<input type='checkbox' value='"+$(celDiv).html()+"' disabled>") $(celDiv).click ( function() { $('input',this).each( function(){ tr_idx = $('#detFlex1 tbody tr').index($(this).parent().parent().parent()); td_idx = $('#detFlex1 tbody tr:eq('+tr_idx+') td').index($(this).parent().parent()); td_last = 13; for(var td=td_idx+1; td<=td_last;td++) { if ($(this).attr('checked') == true) { df[0].rows[tr_idx].cell[td_idx] = 1;//index[1] = Full Access if (td_idx==3) { df[0].rows[tr_idx].cell[td] = 1; } df[0].rows[tr_idx].cell[2] = 1; if (td_idx > 3) { df[0].rows[tr_idx].cell[2] = 1; } } else { df[0].rows[tr_idx].cell[td_idx] = 0;//index[0] = With Access if (td_idx==2) { df[0].rows[tr_idx].cell[td] = 0; } else if (td_idx==3) { df[0].rows[tr_idx].cell[td] = 0; } if (td_idx > 3) { df[0].rows[tr_idx].cell[3] = 0; } } } $('#detFlex1').flexAddData(df[0]); $('.toolbar a[title=Edit Item]').trigger('click'); }); } ); } I've thought that the problem is this above code. Could anyone help me simplify this code.?

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  • MySQL + Joomla + remote c# access

    - by Jimmy
    Hello, I work on a Joomla web site, installed on a MySQL database and running on IIS7. It's all working fine. I now need to add functionality that lets (Joomla-)registered users change some configuration data. Though I haven't done this yet, it looks straightforward enough to do with Joomla. The data is private so all external access will be done through HTTPS. I also need an existing c# program, running on another machine, to read that configuration data. Sure enough, this data access needs to be as fast as possible. The data will be small (and filtered by query), but the latency should be kept to a minimum. A short-term, client-side cache (less than a minute, in case a user updates his configuration data) seems like a good idea. I have done practically zero database/asp programming so far, so what's the best way of doing that last step? Should the c# program access the database 'directly' (using what? LINQ?) or setup some sort of Facade (SOAP?) service? If a service should be used, should it be done through Joomla or with ASP on IIS? Thanks

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  • Why does the WCF 3.5 REST Starter Kit do this?

    - by Brandon
    I am setting up a REST endpoint that looks like the following: [WebInvoke(Method = "POST", UriTemplate = "?format=json", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json)] and [WebInvoke(Method = "DELETE", UriTemplate = "?token={token}&format=json", ResponseFormat = WebMessageFormat.Json)] The above throws the following error: UriTemplateTable does not support '?format=json' and '?token={token}&format=json' since they are not equivalent, but cannot be disambiguated because they have equivalent paths and the same common literal values for the query string. See the documentation for UriTemplateTable for more detail. I am not an expert at WCF, but I would imagine that it should map first by the HTTP Method and then by the URI Template. It appears to be backwards. If both of my URI templates are: ?token={token}&format=json This works because they are equivalent and it then appears to look at the HTTP Method where one is POST and the other is DELETE. Is REST supposed to work this way? Why are the URI Template Tables not being sorted first by HTTP Method and then by URI Template? This can cause some serious frustrations when 1 HTTP Method requires a parameter and another does not, or if I want to do optional parameters (e.g. if the 'format' parameter is not passed, default to XML).

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  • Bing search API and Azure

    - by Gapton
    I am trying to programatically perform a search on Microsoft Bing search engine. Here is my understanding: There was a Bing Search API 2.0 , which will be replaced soon (1st Aug 2012) The new API is known as Windows Azure Marketplace. You use different URL for the two. In the old API (Bing Search API 2.0), you specify a key (Application ID) in the URL, and such key will be used to authenticate the request. As long as you have the key as a parameter in the URL, you can obtain the results. In the new API (Windows Azure Marketplace), you do NOT include the key (Account Key) in the URL. Instead, you put in a query URL, then the server will ask for your credentials. When using a browser, there will be a pop-up asking for a/c name and password. Instruction was to leave the account name blank and insert your key in the password field. Okay, I have done all that and I can see a JSON-formatted results of my search on my browser page. How do I do this programmatically in PHP? I tried searching for the documentation and sample code from Microsoft MSDN library, but I was either searching in the wrong place, or there are extremely limited resources in there. Would anyone be able to tell me how do you do the "enter the key in the password field in the pop-up" part in PHP please? Thanks alot in advance.

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  • Hosting an Access DB

    - by Mitciv
    Hey, So I'm inexperienced in hosting DB's and I've always had the luxury of someone else getting the db setup. I was going to help a friend out with getting a webpage setup, I've got experience in Asp.Net MVC so I'm going with that. They want to setup a search page to query a db and display the results. My question I have is in getting the DB setup and hosted. They currently just have the Access DB on a local computer. There is basically only one table that would need to be queried for the search. What is the best approach to getting this table/db accessible? They would like to keep the main copy of the db on the local machine, so copying the entire db over to the hosted site would be time consuming, could the lone table needed be solely copied to the host? Should I try to convince them to make changes on the hosted db and just make copies of that for their local machines? Any suggestions are welcome, Again I'm a total noob when it comes to hosting databases. Thanks

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  • CodeIgniter: Where should a particular functionality go ?

    - by Samnan
    I have an application in codeigniter and a page needs to perform the following tasks 1 - controller decides which model to use based of the url and parameters 2 - controller loads the model and get the data from it 3 - controller formats the data in a particular format, depending on the items in it 4 - controller loads a common view, which will display the data (formatted data contains simple display fields) now there is a search page, which needs to do a text query against all of the possible text fields in database in all tables. It needs to show each type of data in its own formatted output on a single page as a list. The problem: The search controller can do the search, dynamically load model for each record type, and get the data from model. Problem comes when the data needs to be formatted. It looks that ideally the search controller should load another controller which will provide formatted data ... There is where it gets out of control ... My question is: What am I doing wrong? Is there any better way to do this? How would you do the same to solve the problem?

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  • T4MVC Optional Parameter Inferred From Current Context

    - by Itakou
    I have read the other post about this at T4MVC OptionalParameter values implied from current context and I am using the latest T4MVC (2.11.1) which is suppose to have the fix in. I even checked checked to make sure that it's there -- and it is. I am still getting the optional parameters filled in based on the current context. For example: Let's say I have a list that is by default ordered by a person's last name. I have the option to order by first name instead with the URL http://localhost/list/stuff?orderby=firstname When I am in that page, I want to go back to order by first name with the code: @Html.ActionLink("order by last name", MVC.List.Stuff(null)) the link I wanted was simply http://localhost/list/stuff without any parameters to keep the URL simple and short - invoking default behaviors within the action. But instead the orderby is kept and the url is still http://localhost/list/stuff?orderby=firstname Any help would be great. I know that in the most general cases, this does remove the query parameter - maybe I do have a specific case where it was not removed. I find that it only happens when I have the URL inside a page that I included with RenderPartial. My actual code is <li>@Html.ActionLink("Recently Updated", MVC.Network.Ticket.List(Model.UI.AccountId, "LastModifiedDate", null, null, null, null, null))</li> <li>@Html.ActionLink("Recently Created", MVC.Network.Ticket.List(Model.UI.AccountId, "CreatedDate", null, null, null, null, null))</li> <li>@Html.ActionLink("Most Severe", MVC.Network.Ticket.List(Model.UI.AccountId, "MostSevere", null, null, null, null, null))</li> <li>@Html.ActionLink("Previously Closed", MVC.Network.Ticket.List(Model.UI.AccountId, "LastModifiedDate", null, "Closed", null, null, null))</li> the problem happens when someone clicks Previously Closed and and go to ?status=closed. When they click Recently Updated, which I want to the ?status so that it shows the active ones, the ?status=closed stays. Any insight would be greatly appreciated.

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  • Average over a timeframe with missing data

    - by BHare
    Assuming a table such as: UID Name Datetime Users 4 Room 4 2012-08-03 14:00:00 3 2 Room 2 2012-08-03 14:00:00 3 3 Room 3 2012-08-03 14:00:00 1 1 Room 1 2012-08-03 14:00:00 2 3 Room 3 2012-08-03 14:15:00 1 2 Room 2 2012-08-03 14:15:00 4 1 Room 1 2012-08-03 14:15:00 3 1 Room 1 2012-08-03 14:30:00 6 1 Room 1 2012-08-03 14:45:00 3 2 Room 2 2012-08-03 14:45:00 7 3 Room 3 2012-08-03 14:45:00 8 4 Room 4 2012-08-03 14:45:00 4 I wanted to get the average user count of each room (1,2,3,4) from the time 2PM to 3PM. The problem is that sometimes the room may not "check in" at the 15 minute interval time, so the assumption has to be made that the previous last known user count is still valid. For example the check-in's for 2012-08-03 14:15:00 room 4 never checked in, so it must be assumed that room 4 had 3 users at 2012-08-03 14:15:00 because that is what it had at 2012-08-03 14:00:00 This follows on through so that the average user count I am looking for is as follows: Room 1: (2 + 3 + 6 + 3) / 4 = 3.5 Room 2: (3 + 4 + 4 + 7) / 4 = 4.5 Room 3: (1 + 1 + 1 + 8) / 4 = 2.75 Room 4: (3 + 3 + 3 + 4) / 4 = 3.25 where # is the assumed number based on the previous known check-in. I am wondering if it's possible to so this with SQL alone? if not I am curious of a ingenious PHP solution that isn't just bruteforce math, as such as my quick inaccurate pseudo code: foreach ($rooms_id_array as $room_id) { $SQL = "SELECT * FROM `table` WHERE (`UID` == $room_id && `Datetime` >= 2012-08-03 14:00:00 && `Datetime` <= 2012-08-03 15:00:00)"; $result = query($SQL); if ( count($result) < 4 ) { // go through each date and find what is missing, and then go to previous date and use that instead } else { foreach ($result) $sum += $result; $avg = $sum / 4; } }

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  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

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  • XAMPP, MAMP, MySQL, PDO - A deadly combination?

    - by Rich
    Hey folks, Previously I've worked on a Symfony project (MySQL PDO based) with XAMPP, with no problems. Since then, I've moved to MAMP - I prefer this - but have hit a snag with my database connection. I've created a test.php like this: <?php try { $dbh = new PDO('mysql:host=localhost;dbname=xxx;port=8889', 'xxx', 'xxx'); foreach($dbh->query('SELECT * from FOO') as $row) { print_r($row); } $dbh = null; } catch (PDOException $e) { print "Error!: " . $e->getMessage() . "<br/>"; die(); } ?> Obviously the *xxx*s are real db connection details. Which when served by MAMP seems to work fine. From terminal however I keep getting the following error when running the file: Error!: SQLSTATE[28000] [1045] Access denied for user 'xxx'@'localhost' (using password: YES) Not sure if the terminal is aiming at a different MySQL socket or something along those lines; but I've tried pointing it to the MAMP socket with a local php.ini file. Any help would be greatly appreciated.

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  • GWT + JDO + ArrayList

    - by dvieira
    Hi, I'm getting a Null ArrayList in a program i'm developing. For testing purposes I created this really small example that still has the same problem. I already tried diferent Primary Keys, but the problem persists. Any ideas or suggestions? 1-Employee class @PersistenceCapable(identityType = IdentityType.APPLICATION) public class Employee { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) @Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true") private String key; @Persistent private ArrayList<String> nicks; public Employee(ArrayList<String> nicks) { this.setNicks(nicks); } public String getKey() { return key; } public void setNicks(ArrayList<String> nicks) { this.nicks = nicks; } public ArrayList<String> getNicks() { return nicks; } } 2-EmployeeService public class BookServiceImpl extends RemoteServiceServlet implements EmployeeService { public void addEmployee(){ ArrayList<String> nicks = new ArrayList<String>(); nicks.add("name1"); nicks.add("name2"); Employee employee = new Employee(nicks); PersistenceManager pm = PMF.get().getPersistenceManager(); try { pm.makePersistent(employee); } finally { pm.close(); } } /** * @return * @throws NotLoggedInException * @gwt.typeArgs <Employee> */ public Collection<Employee> getEmployees() { PersistenceManager pm = getPersistenceManager(); try { Query q = pm.newQuery("SELECT FROM " + Employee.class.getName()); Collection<Employee> list = pm.detachCopyAll((Collection<Employee>)q.execute()); return list; } finally { pm.close(); } } }

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  • How can I take advantage of IObservable/IObserver to get rid of my "god object"?

    - by Will
    In a system I'm currently working on, I have many components which are defined as interfaces and base classes. Each part of the system has some specific points where they interact with other parts of the system. For example, the data readying component readies some data which eventually needs to go to the data processing portion, the communications component needs to query different components for their status for relaying to the outside, etc. Currently, I glue these parts of the system together using a "god object", or an object with intimate knowledge of different parts of the system. It registers with events over here and shuttles the results to methods over there, creates a callback method here and returns the result of that method over there, and passes many requests through a multi-threaded queue for processing because it "knows" certain actions have to run on STA threads, etc. While its convenient, it concerns me that this one type knows so much about how everybody else in the system is designed. I'd much prefer a more generic hub that can be given instances which can expose events or methods or callbacks or that can consume these. I've been seeing more about the IObservable/IObserver features of the reactive framework and that are being rolled into .NET 4.0 (I believe). Can I leverage this pattern to help replace my "god object"? How should I go about doing this? Are there any resources for using this pattern for this specific purpose?

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  • Assigning values to the lable through database depending on listbox values

    - by SurajVitekar
    I want to assign the values of five labels from database regarding to values selected in listbox. The db query returns single column with multiple records. Please help. I'm working with C# 2010 and MS SQL. My current code is: private void listBox1_SelectedIndexChanged(object sender, EventArgs e) { try { String c1, c2; c1 = "NULL"; MessageBox.Show("LB index :"+listBox1.SelectedIndex.ToString()); //p = listBox1.SelectedItem.ToString(); SqlConnection con = new SqlConnection(); con.ConnectionString = "Data Source=localhost;Initial Catalog=eVoting;Integrated Security=True;Pooling=False"; con.Open(); MessageBox.Show("List bOx sect :"+listBox1.SelectedValue.ToString()); SqlCommand cmd = new SqlCommand("select Firstname from candidates where position ='" + listBox1.SelectedValue.ToString() + "'", con); int index = 0; SqlDataReader reader = cmd.ExecuteReader(); while(reader.Read()) { if (index == 0) { c1 = reader[index].ToString(); radioButton1.Text = c1; } if (index == 1) { c1 = reader[index].ToString(); radioButton2.Text = c1; } if (index == 2) { c1 = reader[index].ToString(); radioButton3.Text = c1; } if (index == 3) { c1 = reader[index].ToString(); radioButton4.Text = c1; } if (index == 4) { c1 = reader[index].ToString(); radioButton4.Text = c1; } if (index == 5) { c1 = reader[index].ToString(); radioButton5.Text = c1; } MessageBox.Show("c1 :" + c1); index++; } } catch (Exception E) { } }

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  • Cross-Application User Authentication

    - by Chris Lieb
    We have a webapp written in .NET that uses NTLM for SSO. We are writing a new webapp in Java that will tightly integrate with the original application. Unfortunately, Java has no support for performing the server portion of NTLM authentication and the only library that I can find requires too much setup to be allowed by IT. To work around this, I came up with a remote authentication scheme to work across applications and would like your opinions on it. It does not need to be extremely secure, but at the same time not easily be broken. User is authenticated into .NET application using NTLM User clicks link that leaves .NET application .NET application generates random number and stores it in the user table along with the user's full username (domain\username) Insecure token is formed as random number:username Insecure token is run through secure cipher (likely AES-256) using pre-shared key stored within the application to produce a secure token The secure token is passed as part of the query string to the Java application The Java application decrypts the secure key using the same pre-shared key stored within its own code to get the insecure token The random number and username are split apart The username is used to retrieve the user's information from the user table and the stored random number is checked against the one pulled from the insecure token If the numbers match, the username is put into the session for the user and they are now authenticated If the numbers do not match, the user is redirected to the .NET application's home page The random number is removed from the database

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  • Multiple left joins, how to output in php

    - by Dan
    I have 3 tables I need to join. The contracts table is the main table, the 'jobs' and 'companies' table are extra info that can be associated to the contracts table. so, since I want all entries from my 'contracts' table, and the 'jobs' and 'companies' data only if it exists, I wrote the query like this.... $sql = "SELECT * FROM contracts LEFT JOIN jobs ON contracts.job_id = jobs.id LEFT JOIN companies ON contracts.company_id = companies.id ORDER BY contracts.end_date"; Now how would I output this in PHP? I tried this but kept getting an undefined error "Notice: Undefined index: contracts.id"... $sql_result = mysql_query($sql,$connection) or die ("Fail."); if(mysql_num_rows($sql_result) > 0){ while($row = mysql_fetch_array($sql_result)) { $contract_id = stripslashes($row['contracts.id']); $job_number = stripslashes($row['jobs.job_number']); $company_name = stripslashes($row['companies.name']); ?> <tr id="<?=$contract_id?>"> <td><?=$job_number?></td> <td><?=$company_name?></td> </tr> <? } }else{ echo "No records found"; } Any help is appreciated.

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  • Zend_Db Enum Values [Closed]

    - by scopus
    I find this solution $metadata = $result->getTable()->info('metadata'); echo $metadata['Continent']['DATA_TYPE']; Hi, I want to get enum values in Zend_Db. My Code: $select = $this->select(); $result = $select->fetchAll(); print_r($result->getTable()); Output: Example Object ( [_name] => country [query] => Zend_Db_Table_Select Object ( [_info:protected] => Array ( [schema] => [name] => country [cols] => Array ( [0] => Code [1] => Continent ) [primary] => Array ( [1] => Code ) [metadata] => Array ( [Continent] => Array ( [SCHEMA_NAME] => [TABLE_NAME] => country [COLUMN_NAME] => Continent [COLUMN_POSITION] => 3 [DATA_TYPE] => enum('Asia','Europe','North America','Africa','Oceania','Antarctica','South America') [DEFAULT] => Asia [NULLABLE] => [LENGTH] => [SCALE] => [PRECISION] => [UNSIGNED] => [PRIMARY] => [PRIMARY_POSITION] => [IDENTITY] => ) I see enum values in data_type but i don't get this values. How can get data_type?

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  • PROLOG - DCG parsing

    - by user2895589
    Hello I am new Prolog and DGC.I want to write a DCG to parse time expressions like 10.20 am or 12 oclock. how can I check 10.20 am is valid expression or not for Olcock I wrote some code. oclock --> digit1,phrase1. digit1 --> [T],{digit1(T)}. digit1(1). digit1(2). digit1(3). digit1(4). digit1(5). digit1(6). digit1(7). digit1(8). digit1(9). digit1(10). digit1(11). digit1(12). phrase1 --> [P],{phrase1(P)}. phrase1(Oclock). i ma checking by query oclock([1,oclock],[]). can someone help me on this.

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  • Best way to track the stages of a form across different controllers - $_GET or routing

    - by chrisj
    Hi, I am in a bit of a dilemma about how best to handle the following situation. I have a long registration process on a site, where there are around 10 form sections to fill in. Some of these forms relate specifically to the user and their own personal data, while most of them relate to the user's pets - my current set up handles user specific forms in a User_Controller (e.g via methods like user/profile, user/household etc), and similarly the pet related forms are handled in a Pet_Controller (e.g pet/health). Whether or not all of these methods should be combined into a single Registration_Controller, I'm not sure - I'm open to any advice on that. Anyway, my main issue is that I want to generate a progress bar which shows how far along in the registration process each user is. As the urls in each form section can potentially be mapping to different controllers, I'm trying to find a clean way to extract which stage a person is at in the overall process. I could just use the query string to pass a stage parameter with each request, e.g user/profile?stage=1. Another way to do it potentially is to use routing - e.g the urls for each section of the form could be set up to be registration/stage/1, registration/stage/2 - then i could just map these urls to the appropriate controller/method behind the scenes. If this makes any sense at all, does anyone have any advice for me?

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  • Caching queries in Django

    - by dolma33
    In a django project I only need to cache a few queries, using, because of server limitations, a cache table instead of memcached. One of those queries looks like this: Let's say I have a Parent object, which has a lot of Child objects. I need to store the result of the simple query parent.childs.all(). I have no problem with that, and everything works as expected with some code like key = "%s_children" %(parent.name) value = cache.get(key) if value is None: cache.set(key, parent.children.all(), CACHE_TIMEOUT) value = cache.get(key) But sometimes, just sometimes, the cache.set does nothing, and, after executing cache.set, cache.get(key) keeps returning None. After some test, I've noticed that cache.set is not working when parent.children.all().count() has higher values. That means that if I'm storing inside of key (for example) 600 children objects, it works fine, but it wont work with 1200 children. So my question is: is there a limit to the data that a key could store? How can I override it? Second question: which way is "better", the above code, or the following one? key = "%s_children" %(parent.name) value = cache.get(key) if value is None: value = parent.children.all() cache.set(key, value, CACHE_TIMEOUT) The second version won't cause errors if cache.set doesn't work, so it could be a workaround to my issue, but obviously not a solution. In general, let's forget about my issue, which version would you consider "better"?

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  • Calculating distance between two X,Y coordinates

    - by Umopepisdn
    I am writing a tool for a game that involves calculating the distance between two coordinates on a spherical plane 500 units across. That is, [0,0] through [499,499] are valid coordinates, and [0,0] and [499,499] are also right next to each other. Currently, in my application, I am comparing the distance between a city with an [X,Y] location respective to the user's own [X,Y] location, which they have configured in advance. To do this, I found this algorithm, which kind of works: Math.sqrt ( dx * dx + dy * dy ); Because sorting a paged list by distance is a useful thing to be able to do, I implemented this algorithm in a MySQL query and have made it available to my application using the following part of my SELECT statement: SQRT( POW( ( ".strval($sourceX)." - cityX ) , 2 ) + POW( ( ".strval($sourceY)." - cityY ) , 2 ) ) AS distance This works fine for many calculations, but does not take into account the fact that [0,0] and [499,499] are kitty-corner to one another. Is there any way I can tweak this algorithm to generate an accurate distance, given that 0 and 499 are adjacent? Thanks, -Umo

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  • How can I make hundreds of simultaneously running processes communicate with a database through one

    - by Olfan
    Long speech short: How can I make hundreds of simultaneously running processes communicate with a database through one or few permanent sessions? The whole story: I once built a number crunching engine that handles vast amounts of large data files by forking off one child after another giving each a small number of files to work on. File locking, progress monitoring and result propagation happen in an Oracle database which all (sub-)processes access at various times using an application-specific module which encapsulates DBI. This worked well at first, but now with higher volumes of input data, the number of database sessions (one per child, and they can be very short-lived) constantly being opened and closed is becoming an issue. I now want to centralise database access so that there are only one or few fixed database sessions which handle all database access for all the (sub-)processes. The presence of the database abstraction module should make the changes easy because the function calls in the worker instances can stay the same. My problem is that I cannot think of a suitable way to enhance said module in order to establish communication between all the processes and the database connector(s). I thought of message queueing, but couldn't come up with a way of connecting a large herd of requestors with one or few database connectors in a way so that bidirectional communication is possible (for collecting the query result). An asynchronous approach could help here in that all requests are written to the same queue and the database connector servicing the request will "call back" to submit the result. But my mind fails me in generating an image clear enough so that I can paint into code. Threading instead of forking might have given me an easier start, but this would now require massive changes to the code base that I'm not prepared to do to a live system. The more I think of it, the more the base idea looks like a pre-forked web server to me only that it doesn't serve web pages but database queries. Any ideas on what to dig into, and where? Sample (pseudo) code to inspire me, links to possibly related articles, ready solutions on CPAN maybe?

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  • Wrong label for a nodereference in Drupal content-type

    - by MPD
    We have a content-type built using CCK. One of the fields is a node reference. The node picker is using a view to build the options. A few days ago, everything was working well. Today, it looks like all node reference fields using views to populate the selection options are displaying the wrong label. Every single label in the option is ``A'', but the actual node number is correct. The form actually works, just the labels are incorrect. We have tried just about every combination of edit/save, disable/enable, reboot, clear cache, clone the view, rebuild the view, new view, etc, but we still have a big list of As. If we create a brand new content type with a brand new node reference field, we get the problem. Through some backup/restore exercises, we have determined that the problem is actually in the database and not in the code. We can restore our last good backup, but we will lose a decent amount of work we have put into other parts of the database. We enabled mysql query logging, and the view is actually being called properly, but we cannot track down where the problem is creeping in after that (unraveling the CCK / Views / Drupal plumbing is a challenge). The install was build with latest stable versions as of April. The problems referred to in http://drupal.org/node/624422 is similar, but our code versions include the patches mentioned. Any ideas would be appreciated. Thanks.

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  • iPhone - sorting the results of a core data entity

    - by Digital Robot
    I have a core data entity that represents the attributes of a product, as number, price, etc. The product number is a NSString property and follows the form X.y where X is a number variable of digits and Y is one digit. For example. 132.2, 99.4, etc. I am querying the database to obtain the list of product numbers in order: The code is like this: + (NSArray*)todosOsItens:(NSString *)pName inManagedObjectContext:(NSManagedObjectContext *)context { Product *aProduct = [Product productWithName:pName inManagedObjectContext:context]; NSArray *all = nil; NSFetchRequest *request = [[NSFetchRequest alloc] init]; request.entity = [NSEntityDescription entityForName:@"Attributes" inManagedObjectContext:context]; request.predicate = [NSPredicate predicateWithFormat: @"(belongsTo == %@)", aProduct]; [request setResultType:NSDictionaryResultType]; [request setReturnsDistinctResults:YES]; [request setPropertiesToFetch:[NSArray arrayWithObject:item]]; NSSortDescriptor *sortByItem = [NSSortDescriptor sortDescriptorWithKey:@"ProductNumber" ascending:YES]; NSArray *sortDescriptors = [NSArray arrayWithObject:sortByItem]; [request setSortDescriptors:sortDescriptors]; NSError *error = nil; all = [[context executeFetchRequest:request error:&error] mutableCopy]; [request release]; return all; } but this query is not returning the sorted results. The results are coming on their natural order on the database. How do I do that? thanks.

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  • insert data using sqlite issue on iphone ( not reflecting on table)

    - by prajakta
    i can insert my data but i cant show them on my table view ..i did [tableview reload data] but of no success here is my code -(void)gButtonTapped:(id)sender { NSLog(@"right nav bar button is hit%@ ",storePaths); //[self readAnimalsFromDatabase2]; appDelegate = (DatabaseTestAppDelegate *)[[UIApplication sharedApplication] delegate]; sqlite3 *database; sqlite3_stmt *compiled_statement1; if(sqlite3_open([storePaths UTF8String], &database) == SQLITE_OK) { //const char *sqlStatement = NSString *newQuery = [NSString stringWithFormat:@"insert into cat_tbl (cat_id,names,imgs) values ('12','test1','r.png')"]; // NSString *newQuery = [NSString stringWithFormat:@"select * from list_tbl"]; const char *sql = [newQuery cStringUsingEncoding:NSASCIIStringEncoding]; NSLog(@"update query is %@",newQuery); if(sqlite3_prepare_v2(database, sql, -1, &compiled_statement1, NULL) == SQLITE_OK) { int result = sqlite3_step(compiled_statement1); sqlite3_reset(compiled_statement1); NSLog(@"result %d", result); if(result != SQLITE_ERROR) { int lastInsertId = sqlite3_last_insert_rowid(database); NSLog(@"x %d", lastInsertId); } } } sqlite3_finalize(compiled_statement1); sqlite3_close(database); [tabelView reloadData];// this is also not working }

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