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• Letting Wcf data service implement another contract

  - by Wasim

  Hi all , I have a wcf data service with the standart configuration . I want to add another functionality to it , so I built a contract interface and let my wcf data service implements it . Now I see in the service the InitializeService method , and the contract interface methods . When I come to connect the service , I get an error , that there is no end point declared to the contract I added . How can do that ? examples ? links ? I choosed to add the contract interface to the wcf data service and not adding another service , because the client application uses the wcf data service generated objects , and I want to use the same obkject to make operations not related to data , for more coplex processing . If I do the methods in another service , then I have types incompatibility . Thanks in advance ...

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• JavaScript - question regarding data structure

  - by orokusaki

  I'm trying to calculate somebody's bowel health based on a points system. I can edit the data structure, or logic in any way. I'm just trying to write a function and data structure to handle this ability. Pseudo calculator function: // Bowel health calculator var points = 0; If age is from 30 and 34: points += 1 If age is from 35 and 40: points += 2 If daily BMs is from 1 and 3: points -= 1 If daily BMs is from 4 and 6: points -= 2 return points; Pseudo data structure: var points_map = { age: { '30-34': 1, '35-40': 2 }, dbm: { '1-3': -1, '4-6': -2 } }; I have a full spreadsheet of data like this, and I am trying to write a DRY version of code and a DRY version of this data (ie, probably not a string for the '30-34', etc) in order to handle this sort of thing without a humongous number of switch statements.

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• How to Embed/Link binary data into a C++ DLL

  - by CrimsonX

  So I have a Visual Studio 2008 project which has a large amount of binary data that it is currently referencing. I would like to package the binary data much like you can do with C# by adding it as a "resource" and compiling it as a DLL. Lets say all my data has an extension of ".data" and is currently being read from the visual studio project. Is there a way that you can compile or link the data into the .dll which it is calling? I've looked at some of the google link for this and so far I haven't come up with anything - the only possible solution I've come up with is to use something like ResGen to create a .resources file and then link it using AssemblyLinker with /Embed or /Link flags. I dont think it'd work properly though because I dont have text files to create the .resources files, but rather binary files themselves. Any advice?

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• Cloud HUGE data storage options?

  - by ToughPal

  Hi, Does anyone have a good suggestion on how to do video recording? We have a camera that can record and then stream live video to a server. So this means we can have 1000's of cameras sending data 24X7 for recording. We will store data for over 7 / 14 / 30 days depending on the package. Per day if a camera is sending data to the server then it will store 1.5GB. So that means there is a traffic of 1.5GB / day / camera Total monthly 45GB / month / camera (Data + bandwidth for one camera) Please let me know the most cost effective way to get this data stored? Thanks!

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• Find recipes that can be cooked from provided ingridients

  - by skaurus

  Sorry for bad English :( Suppose i can preliminary organize recipes and ingredients data in any way. How can i effectively conduct search of recipes by user-provided ingredients, preferably sorted by max match - so, first going recipes that use maximum of provided ingridients and do not contain any other ingrs, after them recipes that uses less of provided set and still not any other ingrs, after them recipes with minimum additional requirements and so on? All i can think about is represent recipe ingridients like bitmasks, and compare required bitmask with all recipes, but it is obviously a bad way to go. And related things like Levenstein distance i don't see how to use here. I believe it should be quite common task...

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• Why is there "data" and "newtype" in Haskell?

  - by martingw

  To me it seems that a newtype definition is just a data definition that obeys some restrictions (only one constructor and such), and that due to these restrictions the runtime system can handle newtypes more efficiently. Ok, and the handling of pattern matching for undefined values is slightly different. But suppose Haskell would only knew data definitions, no newtypes: Couldn't the compiler find out for himself whether a given data definition obeys these restrictions, and automatically treat it more efficiently? I'm sure I'm missing out on something, these Haskell designers are so clever, there must be some deeper reason for this...

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• Managing test data for Junit tests.

  - by nobody

  Hi, We are facing one problem in managing test data(xmls which is used to create mock objects). The data which we have currently has been evolved over a long period of time. Each time we add a new functionality or test case we add new data to test that functionality. Now, the problem is when the business requirement changes the format( like length or format of a variable) or any change which the test data doesn't support , we need to change the entire test data which is 100s of MBs in size. Could anyone suggest a better method or process to overcome this problem? Any suggestion would be appreciated.

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• How to extract data from Google Analytics and build a data warehouse (webhouse) from it?

  - by nkaur301

  I have click stream data such as referring URL, top landing pages, top exit pages and metrics such as page views, number of visits, bounces all in Google Analytics. I am required to build a data warehouse from scratch(which I believe is known as web-house) from this data. My questions are:- 1)Is it possible? Every day data increases (some in terms of metrics or measures such as visits and some in terms of new referring sites), how would the process of loading the warehouse go about? 2)What ETL tool would help me to achieve this? Pentaho I believe has a way to pull out data from Google Analytics, has anyone used it? How does that process go? Any references, links would be appreciated besides answers.

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• InfoPath 2010 Form Design and Web Part Deployment

  - by JKenderdine

  In January I had the pleasure to speak at SharePoint Saturday Virginia Beach.  I presented a session on InfoPath 2010 forms design which included some of the basics of Forms Design, description of some of the new options with InfoPath 2010 and SharePoint 2010, and other integration possibilities.  Included below is the information presented as well as the solution to create the demo: First thing you need to understand is what the difference is between an InfoPath List form and a Form Library Form?  SharePoint List Forms:  Store data directly in a SharePoint list.  Each control (e.g. text box) in the form is bound to a column in the list. SharePoint list forms are directly connected to the list, which means that you don’t have to worry about setting up the publish and submit locations. You also do not have the option for back-end code. Form Library Forms:  Store data in XML files in a SharePoint form library.  This means they are more flexible and you can do more with them.  For example, they can be configured to save drafts and submit to different locations. However, they are more complex to work with and require more decisions to be made during configuration.  You do have the option of back-end code with these type of forms. Next steps: You need to create your File Architecture Plan.  Plan the location for the saved template – both Test and Production (This is pretty much a given, but just in case - Always make sure to have a test environment) Plan for the location of the published template Then you need to document your Form Template Design Plan.  Some questions to ask to gather your requirements: What will the form be designed to do? Will it gather user information? Will it display data from a data source? Do we need to show different views to different users? What do we base this on? How will it be implemented for the users? Browser or Client based form Site collection content type – Published through Central Admin Form Library – Published directly to form library So what are the requirements for this template?  Business Card Request Form Template Design Plan Gather user information and requirements for card Pull in as much user information as possible. Use data from the user profile web services as a data source Show and hide fields as necessary for requirements Create multiple views – one for those submitting the form and another view for the executive assistants placing the orders. Browser based form integrated into SharePoint team site Published directly to form library The form was published through Central Administration and incorporated into the site as a content type. Utilizing the new InfoPath Web part, the form is integrated into the page and the users can complete the form directly from within that page. For now, if you are interested in the final form XSN, contact me using the Contact link above.   I will post soon with the details on how the form was created and how it integrated the requirements detailed above.

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• Multitenant Design for SQL Azure: White Paper Available

  - by Herve Roggero

  Cloud computing is about scaling out all your application tiers, from web application to the database layer. In fact, the whole promise of Azure is to pay for just what you need. You need more IIS servers? No problemo... just spin another web server. You expect to double your storage needs for Azure Tables? No problemo; you are covered there too... just pay for your storage needs. But what about the database tier, SQL Azure? How do you add new databases easily, and transparently, so that your application simply uses more of SQL Azure if its needs to? Without changing a single line of code? And what if you need to scale back down? Welcome to the world of database scalability. There are many terms that describe database scalability, including data federation, multitenant designs, and even NoSQL depending on the technical solution you are implementing.  Because SQL Azure is a transactional database system, NoSQL is not really an option. However data federation and multitenant designs offer some very interesting scalability options that are worth considering. Data federation, a feature of SQL Azure that will be offered in the future, offers very interesting capabilities available natively on the SQL Azure platform. More to come in a few weeks... Multitenant designs on the other hand are design practices and technologies designed to help you reach flexible scalability options not available otherwise. The first incarnation of such a method was made available on CodePlex as an open source project (http://enzosqlshard.codeplex.com).  This project was an attempt to provide a sharding library for educational purposes.  All that sounds really cool... and really esoteric... almost a form of database "voodoo"... However after being on multiple Azure projects I am starting to see a real need. Customers want to be able to free themselves from the database tier, so that if they have 10 new customers tomorrow, all they need to do is add 2 more SQL Azure instances. It's that simple. How you achieve this, and suggested application design guidelines, are available in a white paper I just published.  The white paper offers two primary sections. The first section describes the business and technical problem at hand, and how to classify it according to specific design patterns. For example, I discuss compressed shards through schema separation. The second section offers a method for addressing the needs of a multitenant design using a new library, the big bother of the codeplex project mentioned previously (that I created earlier this year), complete with management interface and such. A Beta of this platform will be made available within weeks; as soon as the documentation will be ready.   I would like to ask you to drop me a quick email at [email protected] if you are going to download the white paper. It's not required, but it would help me get in touch with you for feedback.  You can download this white paper here:   http://www.bluesyntax.net/files/EnzoFramework.pdf . Thank you, and I am looking for feedback, thoughts and implementation opportunities.

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• SQL SERVER – 5 Tips for Improving Your Data with expressor Studio

  - by pinaldave

  It’s no secret that bad data leads to bad decisions and poor results.  However, how do you prevent dirty data from taking up residency in your data store?  Some might argue that it’s the responsibility of the person sending you the data.  While that may be true, in practice that will rarely hold up.  It doesn’t matter how many times you ask, you will get the data however they decide to provide it. So now you have bad data.  What constitutes bad data?  There are quite a few valid answers, for example: Invalid date values Inappropriate characters Wrong data Values that exceed a pre-set threshold While it is certainly possible to write your own scripts and custom SQL to identify and deal with these data anomalies, that effort often takes too long and becomes difficult to maintain.  Instead, leveraging an ETL tool like expressor Studio makes the data cleansing process much easier and faster.  Below are some tips for leveraging expressor to get your data into tip-top shape. Tip 1:     Build reusable data objects with embedded cleansing rules One of the new features in expressor Studio 3.2 is the ability to define constraints at the metadata level.  Using expressor’s concept of Semantic Types, you can define reusable data objects that have embedded logic such as constraints for dealing with dirty data.  Once defined, they can be saved as a shared atomic type and then re-applied to other data attributes in other schemas. As you can see in the figure above, I’ve defined a constraint on zip code.  I can then save the constraint rules I defined for zip code as a shared atomic type called zip_type for example.   The next time I get a different data source with a schema that also contains a zip code field, I can simply apply the shared atomic type (shown below) and the previously defined constraints will be automatically applied. Tip 2:     Unlock the power of regular expressions in Semantic Types Another powerful feature introduced in expressor Studio 3.2 is the option to use regular expressions as a constraint.   A regular expression is used to identify patterns within data.   The patterns could be something as simple as a date format or something much more complex such as a street address.  For example, I could define that a valid IP address should be made up of 4 numbers, each 0 to 255, and separated by a period.  So 192.168.23.123 might be a valid IP address whereas 888.777.0.123 would not be.   How can I account for this using regular expressions? A very simple regular expression that would look for any 4 sets of 3 digits separated by a period would be:  ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ Alternatively, the following would be the exact check for truly valid IP addresses as we had defined above:  ^(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])$ .  In expressor, we would enter this regular expression as a constraint like this: Here we select the corrective action to be ‘Escalate’, meaning that the expressor Dataflow operator will decide what to do.  Some of the options include rejecting the offending record, skipping it, or aborting the dataflow. Tip 3:     Email pattern expressions that might come in handy In the example schema that I am using, there’s a field for email.  Email addresses are often entered incorrectly because people are trying to avoid spam.  While there are a lot of different ways to define what constitutes a valid email address, a quick search online yields a couple of really useful regular expressions for validating email addresses: This one is short and sweet:  \b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}\b (Source: http://www.regular-expressions.info/) This one is more specific about which characters are allowed:  ^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$ (Source: http://regexlib.com/REDetails.aspx?regexp_id=26 ) Tip 4:     Reject “dirty data” for analysis or further processing Yet another feature introduced in expressor Studio 3.2 is the ability to reject records based on constraint violations.  To capture reject records on input, simply specify Reject Record in the Error Handling setting for the Read File operator.  Then attach a Write File operator to the reject port of the Read File operator as such: Next, in the Write File operator, you can configure the expressor operator in a similar way to the Read File.  The key difference would be that the schema needs to be derived from the upstream operator as shown below: Once configured, expressor will output rejected records to the file you specified.  In addition to the rejected records, expressor also captures some diagnostic information that will be helpful towards identifying why the record was rejected.  This makes diagnosing errors much easier! Tip 5:    Use a Filter or Transform after the initial cleansing to finish the job Sometimes you may want to predicate the data cleansing on a more complex set of conditions.  For example, I may only be interested in processing data containing males over the age of 25 in certain zip codes.  Using an expressor Filter operator, you can define the conditional logic which isolates the records of importance away from the others. Alternatively, the expressor Transform operator can be used to alter the input value via a user defined algorithm or transformation.  It also supports the use of conditional logic and data can be rejected based on constraint violations. However, the best tip I can leave you with is to not constrain your solution design approach – expressor operators can be combined in many different ways to achieve the desired results.  For example, in the expressor Dataflow below, I can post-process the reject data from the Filter which did not meet my pre-defined criteria and, if successful, Funnel it back into the flow so that it gets written to the target table. I continue to be impressed that expressor offers all this functionality as part of their FREE expressor Studio desktop ETL tool, which you can download from here.  Their Studio ETL tool is absolutely free and they are very open about saying that if you want to deploy their software on a dedicated Windows Server, you need to purchase their server software, whose pricing is posted on their website. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Problem when trying to configure enterprise library 5.0 (Data Access Application Block)

  - by Phil

  Hi There Stackoverflow, I am running into some problems while trying to get DAAB from Enterprise library 5.0 running. I have followed the steps as per the tutorial, but am getting errors... 1) Download / install enterprise library 2) Add references to the blocks I need (common / data) 3) Imports Imports Microsoft.Practices.EnterpriseLibrary.Common Imports Microsoft.Practices.EnterpriseLibrary.Data 4) Through the enterprise library config software. I open up the web.config from my site. I then click Blocks, then Add data settings... fill in my details and save / close 5) I then (thinking setup is complete) try to get an instance of the database via Dim db As Database = DatabaseFactory.CreateDatabase() 6) I compile and receive the following error: Could not load file or assembly 'Microsoft.Practices.EnterpriseLibrary.Data, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) (C:\site\web.config line 4) Line 4 off my web.config was generated by the config tool and is: <section name="dataConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings, Microsoft.Practices.EnterpriseLibrary.Data, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> Am I missing a required step? Have I done the steps in the wrong order? Have I made a mistake? Thanks a lot for the assistance.

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• Removing and adding persistent stores to a core data application

  - by mkko

  I'm using core data on an iPhone application. I have multiple persisntent stores that I'm switching from one to another so that only one of the stores can be active at the time. I have one managed object context and the different persistent stores are similar in data format (sqlite) and share the same managed object model. I'm importing the data to each persistent store from a respective XML file. For the first import everything works fine, but after I remove the imported data (the persistent store and the physical file) and then re-import, core data gives me an error: *** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'The NSManagedObject with ID:0x3c14e00 <x-coredata://6D14F11E-2EA7-4141-9BE8-53747DE6FCC6/Book/p2> has been invalidated.' This error comes from the save: of NSManagedObjectContext. Before re-importing, i'm removing the persistent store from the persistent store coordinator and removing the physical file, so everything should be as if re-importing was done for the first time. Alos, the objects in managed object context are removed and the context is sent the reset: message (I don't know if this is actually needed). Could some one help me out here? How should the persistent store be switched? I'm basically using the same logic as tutored here: http://blog.sallarp.com/iphone-core-data-uitableview-drill-down/ Thanks in advance.

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• Core data and @unionOfSets

  - by KevinD

  Im having trouble using the @unionOfSets on my core-data objects. NSLog(@"%@", [NSApp valueForKeyPath:@"delegate.mainWindowController.sidebarViewController.arrayController.selection.list.listElement"]); Prints the set of listElements as expected 2010-03-24 18:11:15.844 Pirouette[7459:80f] Relationship objects for {( (entity: PRPlaylistElement; id: 0x10a71b0 ; data: ), (entity: PRPlaylistElement; id: 0x10ac7d0 ; data: ), (entity: PRPlaylistElement; id: 0x10acf60 ; data: ), (entity: PRPlaylistElement; id: 0x10a6850 ; data: ) However when I try to get the set of file objects for each of the list elements. NSLog(@"%@", [NSApp valueForKeyPath:@"delegate.mainWindowController.sidebarViewController.arrayController.selection.list.listElement.@unionOfArrays.file"]); I get the following error 2010-03-24 18:16:45.843 Pirouette[7505:80f] An uncaught exception was raised 2010-03-24 18:16:45.844 Pirouette[7505:80f] [<NSCFSet 0x10415e0> valueForKeyPath:]: this class does not implement the unionOfArrays operation. 2010-03-24 18:16:45.847 Pirouette[7505:80f] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '[<NSCFSet 0x10415e0> valueForKeyPath:]: this class does not implement the unionOfArrays operation.' Confused because I thought calling to-many relationships in core-data were NSSets.

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• Archiver Securing SQLite Data without using Encryption on iPhone

  - by Redrocks

  I'm developing an iphone app that uses Core Data with a SQLite data store and lots of images in the resource bundle. I want a "simple" way to obfuscate the file structure of the SQLite database and the image files to prevent the casual hacker/unscrupulous developer from gaining access to them. When the app is deployed, the database file and image files would be obfuscated. Upon launching the app it would read in and un-obfuscate the database file, write the un-obfuscated version to the users "tmp" directory for use by core data, and read/un-obfuscate image files as needed. I'd like to apply a simple algorithm to the files that would somehow scramble/manipulate the file data so that the sqlite database data isn't discernible when the db is opened in a text editor and so that neither is recognized by other applications (SQLite Manager, Photoshop, etc.) It seems, from the information I've read, that I could use NSFileManager, NSKeyedArchiver, and NSData to accomplish this but I'm not sure how to proceed. Been developing software for many years but I'm new to everything CocoaTouch, Mac and iPhone. Also never had to secure/encrypt my data so this is new. Any thoughts, suggestions, or links to solutions are appreciated.

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• Protocol specification in XML

  - by Mathijs

  Is there a way to specify a packet-based protocol in XML, so (de)serialization can happen automatically? The context is as follows. I have a device that communicates through a serial port. It sends and receives a byte stream consisting of 'packets'. A packet is a collection of elementary data types and (sometimes) other packets. Some elements of packets are conditional; their inclusion depends on earlier elements. I have a C# application that communicates with this device. Naturally, I don't want to work on a byte-level throughout my application; I want to separate the protocol from my application code. Therefore I need to translate the byte stream to structures (classes). Currently I have implemented the protocol in C# by defining a class for each packet. These classes define the order and type of elements for each packet. Making class members conditional is difficult, so protocol information ends up in functions. I imagine XML that looks like this (note that my experience designing XML is limited): <packet> <field name="Author" type="int32" /> <field name="Nickname" type="bytes" size="4"> <condition type="range"> <field>Author</field> <min>3</min> <max>6</min> </condition> </field> </packet> .NET has something called a 'binary serializer', but I don't think that's what I'm looking for. Is there a way to separate protocol and code, even if packets 'include' other packets and have conditional elements?

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• How to sort data in a table data structure in Java?

  - by rgksugan

  I need to sort data based on the third column of the table data structure. I tried based on the answers for the following question. But my sorting does not work. Please help me in this. Here goes my code. Object[] data = new Object[y]; rst.beforeFirst(); while (rst.next()) { int p_id = Integer.parseInt(rst.getString(1)); String sw2 = "select sum(quantity) from tbl_order_detail where product_id=" + p_id; rst1 = stmt1.executeQuery(sw2); rst1.next(); String sw3 = "select max(order_date) from tbl_order where tbl_order.`Order_ID` in (select tbl_order_detail.`Order_ID` from tbl_order_detail where product_id=" + p_id + ")"; rst2 = stmt2.executeQuery(sw3); rst2.next(); data[i] = new Object[]{new String(rst.getString(2)), new String(rst.getString(3)), new Integer(rst1.getString(1)), new String(rst2.getString(1))}; i++; } ColumnComparator cc = new ColumnComparator(2); Arrays.sort(data, cc); if (i == 0) { table.addCell(""); table.addCell(""); table.addCell(""); table.addCell(""); } else { for (int j = 0; j < y; j++) { Object[] theRow = (Object[]) data[j]; table.addCell((String) theRow[0]); table.addCell((String) theRow[1]); table.addCell((String) theRow[2]); table.addCell((String) theRow[3]); }

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• Moving UITableView cells and maintaining consistent data

  - by Mark F

  I've enabled editing mode and moving cells around to allow users to position table view content in the order they please. I'm using Core Data as the data source, which sorts the content by the attribute "userOrder". When content is first inserted, userOrder is set to a random value. The idea is that when the user moves a cell around, the userOrder of that cell changes to accomodate its new position. The following are problems I am running into while trying to accomplish this: Successfully saving the the new location of the cell and adjusting all changed locations of influenced cells. Getting the data to be consistent. For example, the TableView handles the movement fine, but when i click on the new location of the cell, it displays data for the old cell that used to be that location. Data of all influenced cells gets messed up as well. I know I have to implement this in: - (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath {} I just don't know how. The apple docs are not particularly helpful if you are using Core Data, as in my situation. Any guidance greatly appreciated!

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• Any sample C# project that highlights separate data access layer (using EF) to business logic layer

  - by Greg

  Hi, I'm interested in having a look at a small sample project that would highlight a good technique to separate data access layer (using Entity Framework) to business logic layer. In C# would be good. That is, it would highlight how to pass data between the layer without coupling them. That is, the assumption here is not to use the EF classes in the Business Logic layer, and how to achieve this low coupling, but minimizing plumbing code.

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• Ongoing confusion about ivars and properties in objective C

  - by Earl Grey

  After almost 8 months being in ios programming, I am again confused about the right approach. Maybe it is not the language but some OOP principle I am confused about. I don't know.. I was trying C# a few years back. There were fields (private variables, private data in an object), there were getters and setters (methods which exposed something to the world) ,and properties which was THE exposed thing. I liked the elegance of the solution, for example there could be a class that would have a property called DailyRevenue...a float...but there was no private variable called dailyRevenue, there was only a field - an array of single transaction revenues...and the getter for DailyRevenue property calculated the revenue transparently. If somehow the internals of daily revenue calculation would change, it would not affect somebody who consumed my DailyRevenue property in any way, since he would be shielded from getter implementation. I understood that sometimes there was , and sometimes there wasn't a 1-1 relationship between fields and properties. depending on the requirements. It seemed ok in my opinion. And that properties are THE way to acces the data in object. I know the difference betweeen private, protected, and public keyword. Now lets get to objectiveC. On what factor should I base my decision about making someting only an ivar or making it as a property? Is the mental model the same as I describe above? I know that ivars are "protected" by default, not "private" asi in c#..But thats ok I think, no big deal for my presnet level of understanding the whole ios development. The point is ivars are not accesible from outside (given i don't make them public..but i won't). The thing that clouds my clear understanding is that I can have IBOutlets from ivars. Why am I seeing internal object data in the UI? *Why is it ok?* On the other hand, if I make an IBOutlet from property, and I do not make it readonly, anybody can change it. Is this ok too? Let's say I have a ParseManager object. This object would use a built in Foundation framework class called NSXMLParser. Obviously my ParseManager will utilize this nsxmlparser's capabilities but will also do some additional work. Now my question is, who should initialize this NSXMLParser object and in which way should I make a reference to it from the ParseManager object, when there is a need to parse something. A) the ParseManager -1) in its default init method (possible here ivar - or - ivar+ppty) -2) with lazyloading in getter (required a ppty here) B) Some other object - who will pass a reference to NSXMLParser object to the ParseManager object. -1) in some custom initializer (initWithParser:(NSXMLPArser *) parser) when creating the ParseManager object.. A1 - the problem is, we create a parser and waste memory while it is not yet needed. However, we can be sure that all methods that are part ot ParserManager object, can use the ivar safely, since it exists. A2 - the problem is, the nsxmlparser is exposed to outside world, although it could be read only. Would we want a parser to be exposed in some scenario? B1 - this could maybe be useful when we would want to use more types of parsers..i dont know... I understand that architectural requirements and and language is not the same. But clearly the two are in relation. How to get out of that mess of my? Please bear with me, I wasn't able to come up with a single ultimate question. And secondly, it's better to not scare me with some superadvanced newspeak that talks about some crazy internals (what the compiler does) and edge cases.

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• how to design a database for a specific website.

  - by Steven Spielberg

  i want to design a Database for a website. how i can design it better. are you know any particular thing, tips , technique to design it in better way. in a table of information user can allow to website to show it or hide it. how can i do this like info1 = show info2 = show info3 = show i have a much more field that user can be showed and hide. how i can handle this situation or condition in Database

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• iPhone SDK / Core Data usage scenario, similar to GAE data store?

  - by boliva

  Hi all, I am currently rewriting a map based App which I wrote in the past, specifically for 2.2.1 devices. Originally I wrote it to make use of SQLite databases but I would like to try and migrate it over Core Data, now that it's available on 3.X (for which I am rewriting to). I am fairly experienced in iPhone/Obj-C development, SQL and server backend technologies, but I have never had the chance to work with Core Data so IDK really if it's the appropiate tool for what I am trying to accomplish. The App works on a limited area in a map over which there are about 4000 placemarks, with different kinds of icons and sizes. Of course not all 4000 placemarks are shown at once but only those currently visible in the map viewport, and depending on the zoom level. What I am doing right now is, after the user moves the map in any way (panning or zooming) I am requesting from the backend server the required information for the placemarks that would be visible given the viewport coordinates boundaries and zoom level, however the process isn't as smooth as I'd like (the backend is sending its response in XML and I am compressing it using gzip), it takes anywhere from 1 to 3 seconds to update the display of the placemarks after the user ends moving the map. What I would like to do is to prefetch all the placemarks data at the App launch and use it all through the app life time - I don't mind storing it for later use because the data should be dynamic. The way I would do it right now is, after retrieving all the data, to store it on an SQLite db which I would query later, whenever the user moves the map, to return only the placemarks inside the viewport coordinate boundaries and specific to a given zoom level. Now, the question itself is, if is it possible to use some more 'native', object driven way to carry this queries process, which got me thinking about Core Data and if it is in any way similar to what Google App Engine offers through its datastore where you can fetch a number of objects from the backend given a certain query or criteria, without resorting to an SQL query itself. Like I said before I don't have any experience on Core Data but I have a pretty deep understanding of Obj-C and iPhone development, as well as SQL databases. Any guides on how to achieve what I'm trying (if possible at all) would be greatly appreciated.

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• How to start recognizing design patterns as you are programming?

  - by Jon Erickson

  I have general academic knowledge of the various design patterns that are discussed in GoF and Head First Design Patterns, but I have a difficult time applying them to the code that I am writing. A goal for me this year is to be able to recognize design patterns that are emerging from the code that I write. Obviously this comes with experience (I have about 2 years in the field), but my question is how can I jumpstart my ability to recognize design patterns as I am coding, maybe a suggestion as to what patterns are easiest to start applying in client-server applications (in my case mainly c# webforms with ms sql db's, but this could definitely be language agnostic).

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• Classifying captured data in unknown format?

  - by monch1962

  I've got a large set of captured data (potentially hundreds of thousands of records), and I need to be able to break it down so I can both classify it and also produce "typical" data myself. Let me explain further... If I have the following strings of data: 132T339G1P112S 164T897F5A498S 144T989B9B223T 155T928X9Z554T ... you might start to infer the following: possibly all strings are 14 characters long the 4th, 8th, 10th and 14th characters may always be alphas, while the rest are numeric the first character may always be a '1' the 4th character may always be the letter 'T' the 14th character may be limited to only being 'S' or 'T' and so on... As you get more and more samples of real data, some of these "rules" might disappear; if you see a 15 character long string, then you have evidence that the 1st "rule" is incorrect. However, given a sufficiently large sample of strings that are exactly 14 characters long, you can start to assume that "all strings are 14 characters long" and assign a numeric figure to your degree of confidence (with an appropriate set of assumptions around the fact that you're seeing a suitably random set of all possible captured data). As you can probably tell, a human can do a lot of this classification by eye, but I'm not aware of libraries or algorithms that would allow a computer to do it. Given a set of captured data (significantly more complex than the above...), are there libraries that I can apply in my code to do this sort of classification for me, that will identify "rules" with a given degree of confidence? As a next step, I need to be able to take those rules, and use them to create my own data that conforms to these rules. I assume this is a significantly easier step than the classification, but I've never had to perform a task like this before so I'm really not sure how complex it is. At a guess, Python or Java (or possibly Perl or R) are possibly the "common" languages most likely to have these sorts of libraries, and maybe some of the bioinformatic libraries do this sort of thing. I really don't care which language I have to use; I need to solve the problem in whatever way I can. Any sort of pointer to information would be very useful. As you can probably tell, I'm struggling to describe this problem clearly, and there may be a set of appropriate keywords I can plug into Google that will point me towards the solution. Thanks in advance

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• When are you truly forced to use UUID as part of the design?

  - by Pyrolistical

  I don't really see the point of UUID. I know the probability of a collision is effectively nil, but effectively nil is not even close to impossible. Can somebody give an example where you have no choice but to use UUID? From all the uses I've seen, I can see an alternative design without UUID. Sure the design might be slightly more complicated, but at least it doesn't have a non-zero probability of failure. UUID smells like global variables to me. There are many ways global variables make for simpler design, but its just lazy design.

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