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  • How to check if something is stored in CoreData

    - by Terrel Gibson
    Hi I want to be able to tore some information in core data and but i am unsure of how to check if the file was saved properly. I tried using NSLog but it returns null when its called. I have a dictionary which has a uniqueID and a title which I want to save. I pass this in along with the context of the database. I then sort the database to check if it has any duplicates or not, if not then I add the file. +(VacationPhoto*) photoWithFlickrInfo: (NSDictionary*) flickrInfo inManagedObjectContext: (NSManagedObjectContext*) context{ //returns the dictionary NSLog(@"Photo To Store =%@", flickrInfo); VacationPhoto * photo = nil; NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"VacationPhoto"]; request.predicate = [NSPredicate predicateWithFormat:@"uniqueID = %@", [flickrInfo objectForKey:FLICKR_PHOTO_ID]]; NSSortDescriptor * descriptor = [NSSortDescriptor sortDescriptorWithKey:@"title" ascending:YES]; request.sortDescriptors = [NSArray arrayWithObject:descriptor]; NSError *error = nil; NSArray *matches = [context executeFetchRequest:request error:&error]; if (!matches || [matches count] > 1) { // handle error } else if ( [matches count] == 0){ photo.title = [flickrInfo objectForKey:FLICKR_PHOTO_TITLE]; //Returns NULL when called NSLog(@"title = %@", photo.title); photo.uniqueID = [flickrInfo objectForKey:FLICKR_PHOTO_ID]; //Returns NULL when called NSLog(@"ID = %@", photo.uniqueID); } else { //If photo already exists this is called photo = [matches lastObject]; } return photo; }

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  • Javascript when to show results

    - by Pete
    This is my Javascript below I want to show records on load and also show new records when added to the database showrecords(); displays the records in the database where abouts can I put this in my code where it will work correctly. `$(document).ready(function() { //showrecords() function showrecords() { $.ajax({ type: "POST", url: "demo_show.php", cache: false, success: function(html){ $("#display").after(html); document.getElementById('content').value=''; $("#flash").hide(); } }); } $(".comment_button").click(function() { var element = $(this); var test = $("#content").val(); var dataString = 'content='+ test; if(test=='') { alert("Please Enter Some Text"); } else { $("#flash").show(); $("#flash").fadeIn(400).html('<img src="http://tiggin.com/ajax-loader.gif" align="absmiddle">&nbsp;<span class="loading">Loading Comment...</span>'); $.ajax({ type: "POST", url: "demo_insert.php", data: dataString, cache: false, success: function(html){ // $("#display").after(html); document.getElementById('content').value=''; $("#flash").hide(); //Function for showing records //showrecords(); } }); } return false; }); }); `

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  • A bit confused about OOP and PHP.

    - by Pirkka
    Hello I have programmed with procedural style a lot before and in these few months I have decided to go OOP. Im a bit confused about OOP and PHP. Lets say I have Categories table and Pages table in my database. I would like to do a page-class and a category-class. Lets say I would have a page that showed information about the category and there would be a list of pages that belong to the category. How would I implement that in OOP way? I have thought that the category class would have a property (array) that would contain all the pages that it has. Well then comes the part that I`m confused about. Should I have a method that would get all the pages with correct categoryID from the database and should I instantiate all the rows as an Page-object? Or should I have a setPages-method in the Category-class and getAllPages-method in the Pages-class and with that method I would set all the pages to the Category-class. Huh Im lost. :D

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  • handle large Parcelable ArrayList in Android

    - by Gal Ben-Haim
    I'm developing an Android app that is a client to a JSON webservice API. I have classes of resource objects (some are nested) and I pass results from an IntentService that access the webserive using the Parcelable interface for all the resource classes. the webservice returns arrays or results that can be potentially large (because of the nesting, for example, a post object also contains comments array, each comment also contains a user object). currently I'm either inserting the results into a SQlite database or displaying them in a ListView. (my relevant methods are accepting ArrayList<resourceClass> as arguments). (some data need to be persistent stored and some should not). since I don't know what size of lists I can handle this way without reaching the memory limits, is this a good practice ? is it a better idea to save the parsed JSON to a local file immediately and pass the file path to the ResultReceiver, then either insert to database from that file or display the data ? is there a better way to handle this ? btw - I'm parsing the JSON as a stream with Gson's Reader so there shouldn't be memory issues at that stage.

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  • FluentNHibernate mapping of composite foreign keys

    - by Faron
    I have an existing database schema and wish to replace the custom data access code with Fluent.NHibernate. The database schema cannot be changed since it already exists in a shipping product. And it is preferable if the domain objects did not change or only changed minimally. I am having trouble mapping one unusual schema construct illustrated with the following table structure: CREATE TABLE [Container] ( [ContainerId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Container] PRIMARY KEY ( [ContainerId] ASC ) ) CREATE TABLE [Item] ( [ItemId] [uniqueidentifier] NOT NULL, [ContainerId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Item] PRIMARY KEY ( [ContainerId] ASC, [ItemId] ASC ) ) CREATE TABLE [Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Property] PRIMARY KEY ( [ContainerId] ASC, [PropertyId] ASC ) ) CREATE TABLE [Item_Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [ItemId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Item_Property] PRIMARY KEY ( [ContainerId] ASC, [ItemId] ASC, [PropertyId] ASC ) ) CREATE TABLE [Container_Property] ( [ContainerId] [uniqueidentifier] NOT NULL, [PropertyId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_Container_Property] PRIMARY KEY ( [ContainerId] ASC, [PropertyId] ASC ) ) The existing domain model has the following class structure: The Property class contains other members representing the property's name and value. The ContainerProperty and ItemProperty classes have no additional members. They exist only to identify the owner of the Property. The Container and Item classes have methods that return collections of ContainerProperty and ItemProperty respectively. Additionally, the Container class has a method that returns a collection of all of the Property objects in the object graph. My best guess is that this was either a convenience method or a legacy method that was never removed. The business logic mainly works with Item (as the aggregate root) and only works with a Container when adding or removing Items. I have tried several techniques for mapping this but none work so I won't include them here unless someone asks for them. How would you map this?

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  • Requirements for connecting to Oracle with JDBC?

    - by Lord Torgamus
    I'm a newbie to Java-related web development, and I can't seem to get a simple program with JDBC working. I'm using off-the-shelf Oracle 10g XE and the Eclipse EE IDE. From the books and web pages I've checked so far, I've narrowed the problem down to either an incorrectly written database URL or a missing JAR file. I'm getting the following error: java.sql.SQLException: No suitable driver found for jdbc:oracle://127.0.0.1:8080 with the following code: import java.sql.*; public class DatabaseTestOne { public static void main(String[] args) { String url = "jdbc:oracle://127.0.0.1:8080"; String username = "HR"; String password = "samplepass"; String sql = "SELECT EMPLOYEE_ID FROM EMPLOYEES WHERE LAST_NAME='King'"; Connection connection; try { connection = DriverManager.getConnection(url, username, password); Statement statement = connection.createStatement(); System.out.println(statement.execute(sql)); connection.close(); } catch (SQLException e) { System.err.println(e); } } } What is the proper format for a database URL, anyways? They're mentioned a lot but I haven't been able to find a description. Thanks! EDIT (the answer): Based on duffymo's answer, I got ojdbc14.jar from http://www.oracle.com/technology/software/tech/java/sqlj_jdbc/htdocs/jdbc_10201.html and dropped it in the Eclipse project's Referenced Libraries. Then I changed the start of the code to ... try { Class.forName("oracle.jdbc.driver.OracleDriver"); } catch (ClassNotFoundException e) { System.err.println(e); } // jdbc:oracle:thin:@<hostname>:<port>:<sid> String url = "jdbc:oracle:thin:@GalacticAC:1521:xe"; ... and it worked.

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  • Which ORM to use?

    - by Paja
    I'm developing an application which will have these classes: class Shortcut { public string Name { get; } public IList<Trigger> Triggers { get; } public IList<Action> Actions { get; } } class Trigger { public string Name { get; } } class Action { public string Name { get; } } And I will have 20+ more classes, which will derive from Trigger or Action, so in the end, I will have one Shortcut class, 15 Action-derived classes and 5 Trigger-derived classes. My question is, which ORM will best suit this application? EF, NH, SubSonic, or maybe something else (Linq2SQL)? I will be periodically releasing new application versions, adding more triggers and actions (or changing current triggers/actions), so I will have to update database schema as well. I don't know if EF or NH provides any good methods to easily update the schema. Or if they do, is there any tutorial how to do that? I've already found this article about NH schema updating, quoting: Fortunately NHibernate provides us the possibility to update an existing schema, that is NHibernate creates an update script which can the be applied to the database. I've never found how to actually generate the update script, so I can't tell NH to update the schema. Maybe I've misread something, I just didn't found it. Last note: If you suggest EF, will be EF 1.0 suitable as well? I would rather use some older .NET than 4.0.

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  • A good solution for displaying galleries with lytebox and php

    - by Johann
    Hello I have thought for a while over an issue with the loading of images on a website-solution that I have programmed (For fun and the experience) The programming language used is PHP with MYSQL as the database language It also uses javascript, but not extensively I have recently realized that the engine I programmed, while it has it's smart solutions also carry a lot of flaws and redundant code. I have therefore decided to make a new one, now incorporating what I know, but didn't when I started the previous project. For the new system, there will be an option to add galleries to a site, and upload images to it. I have used the javascript image viewer Lytebox before. The screen goes dark and an image appears with a "Previous" and "next" button to view the other images. The problem is that I used groups with lytebox and the images themselves, resized as thumbs. This causes lytebox to work only when all the images have loaded. If you click a link before that, the image is shown as if you right click and choose "Show image" Information about these images is parsed from a database using a while statement with a counter that goes from 0 to sizeof() I'm thinking it probably isn't a good idea to have the images as the thumbs, even if you restrict the upload size. Likewise, adding thumbs at upload also seems like a hassle. It would be practical if the thumbs didn't show up before they were fully loaded. Has anyone got any good tips. Any help would be appreciated. Johann

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  • SQL 2 INNER JOINS with 3 tables

    - by Jelmer Holtes
    I've a question about a SQL query.. I'm building a prototype webshop in ASP.NET Visual Studio. Now I'm looking for a solution to view my products. I've build a database in MS Access, it consists of multiple tables. The tables which are important for my question are: Product Productfoto Foto Below you'll see the relations between the tables For me it is important to get three datatypes: Product title, price and image. The product title, and the price are in the Product table. The images are in the Foto table. Because a product can have more than one picture, there is a N - M relation between them. So I've to split it up, I did it in the Productfoto table. So the connection between them is: product.artikelnummer -> productfoto.artikelnummer productfoto.foto_id -> foto.foto_id Then I can read the filename (in the database: foto.bestandnaam) I've created the first inner join, and tested it in Access, this works: SELECT titel, prijs, foto_id FROM Product INNER JOIN Productfoto ON product.artikelnummer = productfoto.artikelnummer But I need another INNER JOIN, how could I create that? I guess something like this (this one will give me an error) SELECT titel, prijs, bestandnaam FROM Product (( INNER JOIN Productfoto ON product.artikelnummer = productfoto.artikkelnummer ) INNER JOIN foto ON productfoto.foto_id = foto.foto_id) Can anyone help me?

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  • how to check null value of Integer type field in ASP.NET MVC view?

    - by Vikas
    Hi, I have integer type field in database which is having property "Not Null". when i create a view & do a validation, if i left that field blank, it will consider it as 0 so i can not compare it with 0 because if someone insert a value 0 then it will be considered as error! one another problem is that i am using Model error as described in the book "ASP.NET MVC 1.0" @ Scott Gu blog. And I am checking the value in partial class of object (created by LINQ-To-SQL). i.e public partial class Person { public bool IsValid { get { return (GetRuleViolations().Count() == 0); } } public IEnumerable<RuleViolation> GetRuleViolations() { if (String.IsNullOrEmpty(Name)) yield return new RuleViolation("Name is Required", "Name"); if (Age == 0) yield return new RuleViolation("Age is Required", "Age"); yield break; } partial void OnValidate(ChangeAction action) { if (!IsValid) throw new ApplicationException("Rule violations prevent saving"); } } There is also problem with range. Like in database if i declared as smallint i.e. short in c#, now if i exceed that range then it gives error as "A Value is reguired". so finally is there any best way for validation in ASP.NET MVC?

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  • How to use Nhibernate Validator + NHib component + ddl

    - by mynkow
    I just configured my NHibValidator. My NHibernate creates the DB schema. When I set MaxLenght="20" to some property of a class then in the database the length appears in the database column. I am doing this in the NHibValidator xml file. But the problem is that I have components and cannot figure out how to achieve this behaviour. The component is configured correctly in the Customer.hbm.xml file. EDIT: Well, I found that Hibernate Validator users had the same problem two years ago. http://opensource.atlassian.com/projects/hibernate/browse/HV-25 Is this an issue for NHibernate Validator or it is fixed. If it is working tell me how please. ----------------------------------------------------- public class Customer { public virtual string Name{get;set;} public virtual Contact Contacts{ get; } } ----------------------------------------------------- public class Contact { public virtual string Address{get;set;} } ----------------------------------------------------- <?xml version="1.0" encoding="utf-8" ?> <nhv-mapping xmlns="urn:nhibernate-validator-1.0" namespace="MyNamespace" assembly="MyAssembly"> <class name="Customer"> <property name="Name"> <length max="20"/> </property> <property name="Contacts"> <notNull/> <valid/> </property> </class> </nhv-mapping> ----------------------------------------------------- <?xml version="1.0" encoding="utf-8" ?> <nhv-mapping xmlns="urn:nhibernate-validator-1.0" namespace="MyNamespace" assembly="MyAssembly"> <class name="Contact"> <property name="Address"> <length max="50"/> <valid/> </property> </class> </nhv-mapping> -----------------------------------------------------

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  • Update SQL Server 2000 to SQL Server 2008: Benefits please?

    - by Ciaran Archer
    Hi there I'm looking for the benefits of upgrading from SQL Server 2000 to 2008. I was wondering: What database features can we leverage with 2008 that we can't now? What new TSQL features can we look forward to using? What performance benefits can we expect to see? What else will make management go for it? And the converse: What problems can we expect to encounter? What other problems have people found when migrating? Why fix something that isn't (technically) broken? We work in a Java shop, so any .NET / CLR stuff won't rock our world. We also use Eclipse as our main development so any integration with Visual Studio won't be a plus. We do use SQL Server Management Studio however. Some background: Our main database machine is a 32bit Dell Intel Xeon MP CPU 2.0GHz, 40MB of RAM with Physical Address Extension running Windows Server 2003 Enterprise Edition. We will not be changing our hardware. Our databases in total are under a TB with some having more than 200 tables. But they are busy and during busy times we see 60-80% CPU utilisation. Apart form the fact that SQL Server 2000 is coming close to end of life, why should we upgrade? Any and all contributions are appreciated!

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  • In App Purchase Unique Identifying Data

    - by dageshi
    O.K so I'm writing a iPhone travel guide, you purchase a subscription to a travel guide for 3 months, it downloads a fairly hefty database and for 3 months that database gets updated weekly with new stuff. Now what I'd like to do is make the user enter their email address as a one off action before they purchase their first guide, for China say. The purpose for doing this is 1) To allow me to contact the user by email when they add a note/tip for a particular place (the app will allow them to send notes & information to me) 2) To Uniquely identify who has purchased the subscription so that if they wipe their device and reinstall the app they can plug the email address in and pickup their subscriptions again. Or so they can use the same subscription on another device they own. My concerns are 1) Will Apple allow the email method of restoring functionality to a second or restored device? 2) As long as I tell the user what I'm using their email address for (aka I won't sell it to anyone else and use it for X purposes) will it be o.k to ask for said email address? And as a side note, can I tack the devices unique id onto my server comms to track devices or is apple going to through a hissy fit about that as well?

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  • Turning on multiple result sets in an ODBC connection to SQL Server

    - by David Griffiths
    I have an application that originally needed to connect to Sybase (via ODBC), but I've needed to add the ability to connect to SQL Server as well. As ODBC should be able to handle both, I thought I was in a good position. Unfort, SQL Server will not let me, by default, nest ODBC commands and ODBCDataReaders - it complains the connection is busy. I know that I had to specify that multiple active result sets (MARS) were allowed in similar circumstances when connecting to SQL Server via a native driver, so I thought it wouldn't be an issue. The DSN wizard has no entr y when creating a SystemDSN. Some people have provided registry hacks to get around this, but this did not work (add a MARS_Connection with a value of Yes to HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI\system-dsn-name). Another suggestion was to create a file-dsn, and add "MARS_Connection=YES" to that. Didn't work. Finally, a DSN-less connection string. I've tried this one (using MultipleActiveResultSets - same variable as a Sql Server connection would use), "Driver={SQL Native Client};Server=xxx.xxx.xxx.xxx;Database=someDB;Uid=u;Pwd=p;MultipleActiveResultSets=True;" and this one: "Driver={SQL Native Client};Server=192.168.75.33\\ARIA;Database=Aria;Uid=sa;Pwd=service;MARS_Connection=YES;" I have checked the various connection-string sites - they all suggest what I've already tried.

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  • one table is shared between several websites

    - by sami
    I have a static table that's shared by several websites. By static, I mean that the data is read but never updated by the websites. Currently, all websites are served from the same server but that may change. I want to minimize the need for creating/maintaining this table for each of the websites, so I thought about turning it to an xml file that's stored in a shared library that all websites have access to. The problem is I use an ORM and use forign key constraints to ensure integrity of the ids used from that table, so by removing that table out of the MySQL database into an XML file, will this affect the integrity of the ids coming from that table? My table looks like this <table name="entry"> <column name="id" type="INTEGER" primaryKey="true" autoIncrement="true" /> <column name="title" type="VARCHAR" size="500" required="true" /> </table> and I use it as a foreign key in other tables <table name="refer"> <column name="id" type="INTEGER" primaryKey="true" autoIncrement="true" /> <column name="linkto" type="INTEGER"/> <foreign-key foreignTable="entry"> <reference local="linkto" foreign="id" /> </foreign-key> </table> So I'm wondering if I remove that table out of the database, is there a way to retain that referential integrity? And of course are these any other efficient ways to do the same thing? I just don't want to have to repeat that table for several websites.

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  • How to Store and Retrieve Images Using MsSQL (Server Management Studio)

    - by Joe Majewski
    I am having difficulties when trying to insert files into an MsSQL database. I'll try to break this down as best as I can: What data type should I be using to store image files (jpeg/png/gif/etc)? Right now my table is using the image data type, but I am curious if varbinary would be a better option. How would I go about inserting the image into the database? Does Microsoft SQL Server Management Studio have any built in functions that allow insertions of files into tables? If so, how is that done? Also, how could this be done through the use of an HTML form with PHP handling the input data and placing it into the table? How would I fetch the image from the table and display it on the page? I understand how to SELECT the cell's contents, but how would I go about translating that into a picture. Would I have to have a header(Content type: image/jpeg)? I have no problem doing any of these things with MySQL, but the MsSQL environment is still new to me, and I am working on a project for my job that requires the use of stored procedures to grab various data. Any and all help is appreciated. Thank you very much for your responses!

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  • Problems sorting by date

    - by Nathan
    I'm attempting to only display data added to my database 24 hours ago or less. However, for some reason, the code I've written isn't working, and both entries in my database, one from 1 hour ago, one from 2 days ago, show up. Is there something wrong with my equation? Thanks! public void UpdateValues() { double TotalCost = 0; double TotalEarned = 0; double TotalProfit = 0; double TotalHST = 0; for (int i = 0; i <= Program.TransactionList.Count - 1; i++) { DateTime Today = DateTime.Now; DateTime Jan2013 = DateTime.Parse("01-01-2013"); //Hours since Jan12013 int TodayHoursSince2013 = Convert.ToInt32(Math.Round(Today.Subtract(Jan2013).TotalHours)); //7 int ItemHoursSince2013 = Program.TransactionList[i].HoursSince2013; //Equals 7176, and 7130 if (ItemHoursSince2013 - TodayHoursSince2013 <= 24) { TotalCost += Program.TransactionList[i].TotalCost; TotalEarned += Program.TransactionList[i].TotalEarned; TotalProfit += Program.TransactionList[i].TotalEarned - Program.TransactionList[i].TotalCost; TotalHST += Program.TransactionList[i].TotalHST; } } label6.Text = "$" + String.Format("{0:0.00}", TotalCost); label7.Text = "$" + String.Format("{0:0.00}", TotalEarned); label8.Text = "$" + String.Format("{0:0.00}", TotalProfit); label10.Text = "$" + String.Format("{0:0.00}", TotalHST); }

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  • Moving front page (cursebird or foursquare)

    - by Dan Samuels
    Ok so I'll be honest, I have a good amount of experience with php/mysql, I've just started learning jQuery and I've done very little, but some with ajax. So using the terms ajax/jquery interchangeably are a bit confusing to me. Anyway as the title suggest I have a website with 5 items, and I want them to move (meaning, if a more recent one is entered, remove the last item, and put the new one on top), they are 5 of the most recent items in the database table, now I've coded jquery as a test so it fades out the last one, the whole thing moves down, makes room at the top, and fades in a new one. However, it's a test and has 0 interaction with the database, the one that fades in is just in a hidden div. So the jQuery part is taken care of. So I'm unsure how to go about this, I was thinking maybe have ajax check a website off the page that has those 5 items in raw format, and if they change then to refresh? Not looking for a "plz code 4 me" answer, just the concept of how it would work, or some links to get off to the right start. edit - Also, the 5 items are ranked, so if I click item 3 I need it to move above item 2 refreshlessly, so this causes a whole other issue I assume.

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  • Multi threading in WCF RIA Services

    - by synergetic
    I use WCF RIA Services to update customer database. In domain service: public void UpdateCustomer(Customer customer) { this.ObjectContext.Customers.AttachAsModified(customer); syncCustomer(customer); } After update, a database trigger launches and depending on the columns updated it may insert a new record in CustomerChange table. syncCustomer(customer) method is executed to check for a new record in the CustomerChange table and if found it will create a text file which contains customer information and forwards that file to external system for import. Now this synchronization may take a time so I wanted to execute it in different thread. So: private void syncCustomer(Customer customer) { this.ObjectContext.SaveChanges(); new Thread(() => syncCustomerInfo(customer.CustomerID)) { IsBackground = true }.Start(); } private void syncCustomerInfo(int customerID) { //Thread.Sleep(2000); //does real job here ... ... } The problem is in most cases syncCustomerInfo method cannot find any new CustomerChange record even if it was definitely there. If I force thread sleep then it finds a new record. I also looked Entity Framework events but the only event provided by object context is SavingChanges which occur before changes are saved. Please suggest me what else to try.

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  • How To Create a Flexible Plug-In Architecture?

    - by justkt
    A repeating theme in my development work has been the use of or creation of an in-house plug-in architecture. I've seen it approached many ways - configuration files (XML, .conf, and so on), inheritance frameworks, database information, libraries, and others. In my experience: A database isn't a great place to store your configuration information, especially co-mingled with data Attempting this with an inheritance hierarchy requires knowledge about the plug-ins to be coded in, meaning the plug-in architecture isn't all that dynamic Configuration files work well for providing simple information, but can't handle more complex behaviors Libraries seem to work well, but the one-way dependencies have to be carefully created. As I seek to learn from the various architectures I've worked with, I'm also looking to the community for suggestions. How have you implemented a solid plug-in architecture? What was your worst failure (or the worst failure you've seen)? What would you do if you were going to implement a new plug-in architecture? What SDK or open source project that you've worked with has the best example of a good architecture? A few examples I've been finding on my own: Perl's Module::Plugable An SO question with a list for Java (including Sever Provider Interfaces) An SO question for C++ pointing to a Dr. Dobbs article These examples seem to play to various language strengths. Is a good plugin architecture necessarily tied to the language? Is it best to use tools to create a plugin architecture, or to do it on one's own following models?

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  • Algorithm for finding similar users through a join table

    - by Gdeglin
    I have an application where users can select a variety of interests from around 300 possible interests. Each selected interest is stored in a join table containing the columns user_id and interest_id. Typical users select around 50 interests out of the 300. I would like to build a system where users can find the top 20 users that have the most interests in common with them. Right now I am able to accomplish this using the following query: SELECT i2.user_id, count(i2.interest_id) AS count FROM interests_users as i1, interests_users as i2 WHERE i1.interest_id = i2.interest_id AND i1.user_id = 35 GROUP BY i2.user_id ORDER BY count DESC LIMIT 20; However, this query takes approximately 500 milliseconds to execute with 10,000 users and 500,000 rows in the join table. All indexes and database configuration settings have been tuned to the best of my ability. I have also tried avoiding the use of joins altogether using the following query: select user_id,count(interest_id) count from interests_users where interest_id in (13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,508) group by user_id order by count desc limit 20; But this one is even slower (~800 milliseconds). How could I best lower the time that I can gather this kind of data to below 100 milliseconds? I have considered putting this data into a graph database like Neo4j, but I am not sure if that is the easiest solution or if it would even be faster than what I am currently doing.

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  • Hibernate saveorUpdate method problem

    - by umesh awasthi
    Hi all, i am trying to work on with Hibernate (Database side for first time) and some how struck in choosing best possible way to use saveOrUpdate or Save.Update i have a destination POJO class and its other attributes which needs to be updated along with the Destination entity. i am getting an XML file to be imported and i am using the following code to update/save the destination entity along with its attribute classes. try{ getSessionFactory().getCurrentSession().beginTransaction(); getSessionFactory().getCurrentSession().saveOrUpdate(entity); getSessionFactory().getCurrentSession().getTransaction().commit(); } catch(Exception e){ getSessionFactory().getCurrentSession().getTransaction().rollback(); } finally{ getSessionFactory().close(); } everything is working fine untill i am using the same session instance.but later on when i am using the same XML file to update the destination PO for certain attributes it giving me the following error. SEVERE: Duplicate entry 'MNLI' for key 'DESTINATIONID' 9 Jan, 2011 4:58:11 PM org.hibernate.event.def.AbstractFlushingEventListener performExecutions SEVERE: Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275) at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:114) at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:109) at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:244) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2242) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2678) at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79) i am using UUID as primary key for the Destination table and in destination table i have a destination id which is unique.but i can understand that in the secodn case hibernate is not able to find if there is already an entry for the same destination in the DB and trying to execute insert statement rather than update. one possible solution is i can user destinationid to check if there is already a destination inplace with the given id and based on the results i can issue save or update command. my question is can this be achieve by any other good way..? Thanks in advance

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  • Counting entries in a list of dictionaries: for loop vs. list comprehension with map(itemgetter)

    - by Dennis Williamson
    In a Python program I'm writing I've compared using a for loop and increment variables versus list comprehension with map(itemgetter) and len() when counting entries in dictionaries which are in a list. It takes the same time using a each method. Am I doing something wrong or is there a better approach? Here is a greatly simplified and shortened data structure: list = [ {'key1': True, 'dontcare': False, 'ignoreme': False, 'key2': True, 'filenotfound': 'biscuits and gravy'}, {'key1': False, 'dontcare': False, 'ignoreme': False, 'key2': True, 'filenotfound': 'peaches and cream'}, {'key1': True, 'dontcare': False, 'ignoreme': False, 'key2': False, 'filenotfound': 'Abbott and Costello'}, {'key1': False, 'dontcare': False, 'ignoreme': True, 'key2': False, 'filenotfound': 'over and under'}, {'key1': True, 'dontcare': True, 'ignoreme': False, 'key2': True, 'filenotfound': 'Scotch and... well... neat, thanks'} ] Here is the for loop version: #!/usr/bin/env python # Python 2.6 # count the entries where key1 is True # keep a separate count for the subset that also have key2 True key1 = key2 = 0 for dictionary in list: if dictionary["key1"]: key1 += 1 if dictionary["key2"]: key2 += 1 print "Counts: key1: " + str(key1) + ", subset key2: " + str(key2) Output for the data above: Counts: key1: 3, subset key2: 2 Here is the other, perhaps more Pythonic, version: #!/usr/bin/env python # Python 2.6 # count the entries where key1 is True # keep a separate count for the subset that also have key2 True from operator import itemgetter KEY1 = 0 KEY2 = 1 getentries = itemgetter("key1", "key2") entries = map(getentries, list) key1 = len([x for x in entries if x[KEY1]]) key2 = len([x for x in entries if x[KEY1] and x[KEY2]]) print "Counts: key1: " + str(key1) + ", subset key2: " + str(key2) Output for the data above (same as before): Counts: key1: 3, subset key2: 2 I'm a tiny bit surprised these take the same amount of time. I wonder if there's something faster. I'm sure I'm overlooking something simple. One alternative I've considered is loading the data into a database and doing SQL queries, but the data doesn't need to persist and I'd have to profile the overhead of the data transfer, etc., and a database may not always be available. I have no control over the original form of the data. The code above is not going for style points.

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  • Best way to dynamically get column names from oracle tables

    - by MNC
    Hi, We are using an extractor application that will export data from the database to csv files. Based on some condition variable it extracts data from different tables, and for some conditions we have to use UNION ALL as the data has to be extracted from more than one table. So to satisfy the UNION ALL condition we are using nulls to match the number of columns. Right now all the queries in the system are pre-built based on the condition variable. The problem is whenever there is change in the table projection (i.e new column added, existing column modified, column dropped) we have to manually change the code in the application. Can you please give some suggestions how to extract the column names dynamically so that any changes in the table structure do not require change in the code? My concern is the condition that decides which table to query. The variable condition is like if the condition is A, then load from TableX if the condition is B then load from TableA and TableY. We must know from which table we need to get data. Once we know the table it is straightforward to query the column names from the data dictionary. But there is one more condition, which is that some columns need to be excluded, and these columns are different for each table. I am trying to solve the problem only for dynamically generating the list columns. But my manager told me to make solution on the conceptual level rather than just fixing. This is a very big system with providers and consumers constantly loading and consuming data. So he wanted solution that can be general. So what is the best way for storing condition, tablename, excluded columns? One way is storing in database. Are there any other ways? If yes what is the best? As I have to give at least a couple of ideas before finalizing. Thanks,

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  • Unit testing code which uses Umbraco v4 API

    - by Jason Evans
    I'm trying to write a suite of integration tests, where I have custom code which uses the Umbraco API. The Umbraco database lives in a SQL Server CE 4.0 database (*.sdf file) and I've managed to get that association working fine. My problem looks to be dependancies in the Umbraco code. For example, I would like to create a new user for my tests, so I try: var user = User.MakeNew("developer", "developer", "mypassword", "[email protected]", adminUserType); Now as you can see, I have pass a user type which is an object. I've tried two separate ways to create the user type, both of which fail due to a null object exception: var adminUserType = UserType.GetUserType(1); var adminUserType2 = new UserType(1); The problem is that in each case the UserType code calls it's Cache method which uses the HttpRuntime class, which naturally is null. My question is this: Can someone suggest a way of writing integration tests against Umbraco code? Will I have to end up using a mocking framework such as TypeMock or JustMock?

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