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  • Expanding collapsed code in Eclipse IDE

    - by rabin
    Instead of going through each (+) sign at the left and clicking them to expand the collapsed code snippets, is there a shortcut or menu item (I couldn't find it, VS has that) to expand all the collapsed code/comments at once? Thanks.

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  • Cross-platform builds with OGRE3D via CMake. Any tips?

    - by frarees
    I've been trying to compile a simple project for both OSX and Windows platforms, using OGRE3D, but I've got some problems on the way. I'm using CMake to create my platform specific project files (VS solution & Xcode project). Some problems I found are: OGRE3D source is distributed in 2 flavors, Windows sources and UNIX/OSX sources. In OSX, compiling dependencies (freetype, FreeImage and specially OIS) is such a pain. I don't know how to handle precompiled dependencies (they exist for both Win & Mac). May sound like a noob question, but I would appreciate some tips on this. Resources, forum posts, anything. There exists any "cross-platform base project for OGRE3D" on the net? Would be really helpful if someone who already managed to do this can bring some light. Btw, I'm not basing the project on OGRE3D, it's just that is the biggest library I'm probably using, so I depend a lot on it. Thanks in advantage!

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  • SQL*Plus??? - SPOOL??????(????? ???Tips-5)

    - by Yuichi.Hayashi
    SQL??????????????????????????????????????SPOOL?????????????? ???SPOOL??????????????????????????????? ????????? ????????????????????????????????????????????????????????????????????    $ sqlplus @sample.sql > /dev/null ??????????????????????????????? ??????????SPOOL????????????????? arraysize???????? arraysize???????SELECT??????fetch?????????SQL*Plus????????? ????????SPOOL????????SELECT???????????? SPOOL????     SQL> set array[size] 100 ????????fetch?100?????????????15???? ???????????????????????????????????????????????????? ????????????????????????????????????????????????????????????? ?????????????????????????????????????????????? ?????????? SPOOL?????????????1?????linesize???????????????????????????????? ????????????????????????????????????????? ????????????SPOOL????    SQL> set trims[pool] on ????????????off???????????????? ?????????? ???????????????SQL*Plus????????????1????????????????????????????????????????????????????????? ??????????????????????   (Written by Hiroyuki Nakaie) ?????SQL*Plus TIPS???????????????? Oracle SQL*Plus - ??, ??, ?????

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  • Protecting an Application's Memory From Tampering

    - by Changeling
    We are adding AES 256 bit encryption to our server and client applications for encrypting the TCP/IP traffic containing sensitive information. We will be rotating the keys daily. Because of that, the keys will be stored in memory with the applications. Key distribution process: Each server and client will have a list of initial Key Encryption Key's (KEK) by day If the client has just started up or the server has just started up, the client will request the daily key from the server using the initial key. The server will respond with the daily key, encrypted with the initial key. The daily key is a randomly generated set of alphanumeric characters. We are using AES 256 bit encryption. All subsequent communications will be encrypted using that daily key. Nightly, the client will request the new daily key from the server using the current daily key as the current KEK. After the client gets the new key, the new daily key will replace the old daily key. Is it possible for another bad application to gain access to this memory illegally or is this protected in Windows? The key will not be written to a file, only stored in a variable in memory. If an application can access the memory illegally, how can you protect the memory from tampering? We are using C++ and XP (Vista/7 may be an option in the future so I don't know if that changes the answer).

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  • I need help to automate my concatenate to change daily without having to manually input the new data

    - by Harold Nottingham
    Hi there I use concatenate to pull data together from different cells in my spreadsheet. Since my data changes daily, I want the formula to also change daily without having to manually input the new cell in the concatenate formula. I am looking for a way to do this but not sure how. Can anyone out there help me out please!? I appreciate the assistance in advance!

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  • The ASP.NET Daily Community Spotlight - How posts get there, and how to make it your Visual Studio Start Page

    - by Jon Galloway
    One really cool part of my job is selecting the articles for the Daily Community Spotlight, on the home page of the ASP.NET website. The spotlight highlights a new post about ASP.NET development every day from a member of the ASP.NET community. You can find it on the home page of the ASP.NET site, at http://asp.net These posts aren't automatically drawn from a pool of RSS feeds or anything - I pick a new post for each day of the year. How I pick the posts I have a few important selection criteria: Interesting to well rounded ASP.NET developers The ASP.NET website has a lot of material for all skill and experience levels, from download / get started to advanced. I try to select community spotlight posts to round that out with fresh and timely information that working ASP.NET developers can really use. Posts highlight solutions to common problems, clever projects and code that helps you leverage ASP.NET, and important announcements about things you can use today. As part of that, I try to mix between ASP.NET MVC, Web Forms, and Web Pages (a.k.a. WebMatrix). As a professional developer, I want to keep on top of all of my options for ASP.NET development, and the common platform base they all share generally means that good ASP.NET code is good ASP.NET code. Exposing new and non-Microsoft community members as much as possible The exercise of selecting good ASP.NET community posts every day of the year has made me think about what the community is. Given the choice, I'll always favor non-Microsoft employees, but since Microsoft often hires ASP.NET community members and MVP's (myself included), I really think that the ASP.NET community includes developers who are using and writing about ASP.NET, both inside and outside of Microsoft. I'm especially excited about the opportunity to highlight new and lesser known bloggers. Usually being featured on the ASP.NET Community Spotlight gives a pretty good traffic bump, and I love being able to both provide great content to the community and encourage lesser known community members by giving them some (much deserved) attention. Announcements only when they're useful to working developers - not marketing Some of the posts are announcements about new releases, such as Scott Hanselman's post on ASP.NET Universal Providers for Session, Memebership, and Roles. I include those when I think they're interesting and of immediate use to you on projects. I occasionally get asked to link to new content from a team at Microsoft; if it's useful and timely content I'll ask them to point me to a blog post by an actual person rather than a faceless team. How the posts are managed This feed used to be managed by an internal spreadsheet on a Sharepoint site, which was painful for a lot of reasons. I took a cue from Jon Udell, who uses of a public Delicious feed feed for his Elm City project, and we moved the management of these posts over to a Delicious feed as well. You can hear more about Jon's use of Delicious in Elm City in our Herding Code interview - still one of my favorite interviews. We ended up with a simpler scenario, but Note: I watched the Yahoo/Delicious news over the past year and was happy to see that Delicious was recently acquired by the founders of YouTube. I investigated several other Delicious competitors, but am happy with Delicious for now. My Delicious feed here: http://www.delicious.com/jon_galloway You can also browse through this past year's ASP.NET Community Spotlight posts using the (pretty cool) Delicious Browse Bar Submitting articles I'm always on the lookout for new articles to feature. The best way to get them to me is to share them via Delicious. It's pretty easy - sign up for an account, then you can add a post and share it to me. Alternatively, you can send them to me via Twitter (@jongalloway) or e-mail (). If you do e-mail me, it helps to include a short description and your full name so I can credit you. Way too many developer blogs don't include names and pictures; if I can't find them I can't feature the post. Subscribing to the Community Spotlight feed The Community Spotlight is available as an RSS feed, so you might want to subscribe to it: http://www.asp.net/rss/spotlight Setting the ASP.NET Community Spotlight feed as your Visual Studio start page If you're an ASP.NET developer, you might consider setting the ASP.NET Community Spotlight as the content for your Visual Studio Start Page. It's really easy - here's how to do it in Visual Studio 2010: Display the Visual Studio Start Page if it's not already showing (View / Start Page) Click on the Latest News tab and enter the following RSS URL: http://www.asp.net/rss/spotlight If you didn't previously have RSS feeds enabled for your start page, click the Enable RSS Feed button Now, every time you start up Visual Studio you'll see great content from members of the ASP.NET community: You can also configure - and disable, if you'd like - the Visual Studio start page in the Tools / Options / Environment / Startup dialog. Credits I'll do a follow-up highlighting some places I commonly find great content for the feed, but I'd like to specifically point out two of them: Elijah Manor posts a lot of great content, which is available in his Twitter feed at @elijahmanor, on his Delicious feed, and on a dedicated website - Web Dev Tweets Chris Alcock's The Morning Brew is a must-read blog which highlights each day's best blog posts across the .NET community. He's an absolute machine, and no matter how obscure the post I find, I can guarantee he'll find it as well if he hasn't already. Did I say must read?

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  • rsnapshot intervals in configuration file…

    - by Patrick
    A simple question about rsnapshot. In order to perform daily backups I'm going to add lines to cron in my Ubuntu. Then, why do I have also these lines in the rsnapshot.conf ? ######################################### # BACKUP INTERVALS # # Must be unique and in ascending order # # i.e. hourly, daily, weekly, etc. # ######################################### interval hourly 6 interval daily 7 interval weekly 4 #interval monthly 3 If I use cron, should I disable them ? thanks ps. I've just realized that in the crontab I still have "hourly" and "daily". Should I then uncomment only the one I use in the crontab ? And what's the point to specify hourly if it is already specified in cron ? I'm a bit confused. # crontab -e 0 */4 * * * /usr/local/bin/rsnapshot hourly 30 23 * * * /usr/local/bin/rsnapshot daily

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  • "Backup Intervals" in rsnapshot.conf?

    - by Patrick
    A simple question about rsnapshot. In order to perform daily backups I'm going to add lines to cron in my Ubuntu. Then, why do I have also these lines in the rsnapshot.conf ? ######################################### # BACKUP INTERVALS # # Must be unique and in ascending order # # i.e. hourly, daily, weekly, etc. # ######################################### interval hourly 6 interval daily 7 interval weekly 4 #interval monthly 3 If I use cron, should I disable them ? thanks ps. I've just realized that in the crontab I still have "hourly" and "daily". Should I then uncomment only the one I use in the crontab ? And what's the point to specify hourly if it is already specified in cron ? I'm a bit confused. # crontab -e 0 */4 * * * /usr/local/bin/rsnapshot hourly 30 23 * * * /usr/local/bin/rsnapshot daily

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  • WP7 Tips–Part I– Media File Coding Techniques to help pass the Windows Phone 7 Marketplace Certification Requirements

    - by seaniannuzzi
    Overview Developing an application that plays media files on a Windows Phone 7 Device seems fairly straight forward.  However, what can make this a bit frustrating are the necessary requirements in order to pass the WP7 marketplace requirements so that your application can be published.  If you are new to this development, be aware of these common challenges that are likely to be made.  Below are some techniques and recommendations on how optimize your application to handle playing MP3 and/or WMA files that needs to adhere to the marketplace requirements.   Windows Phone 7 Certification Requirements Windows Phone 7 Developers Blog   Some common challenges are: Not prompting the user if another media file is playing in the background before playing your media file Not allowing the user to control the volume Not allowing the user to mute the sound Not allowing the media to be interrupted by a phone call  To keep this as simple as possible I am only going to focus on what “not to do” and what “to do” in order to implement a simple media solution. Things you will need or may be useful to you before you begin: Visual Studio 2010 Visual Studio 2010 Feature Packs Windows Phone 7 Developer Tools Visual Studio 2010 Express for Windows Phone Windows Phone Emulator Resources Silverlight 4 Tools For Visual Studio XNA Game Studio 4.0 Microsoft Expression Blend for Windows Phone Note: Please keep in mind you do not need all of these downloaded and installed, it is just easier to have all that you need now rather than add them on later.   Objective Summary Create a Windows Phone 7 – Windows Media Sample Application.  The application will implement many of the required features in order to pass the WP7 marketplace certification requirements in order to publish an application to WP7’s marketplace. (Disclaimer: I am not trying to indicate that this application will always pass as the requirements may change or be updated)   Step 1: – Create a New Windows Phone 7 Project   Step 2: – Update the Title and Application Name of your WP7 Application For this example I changed: the Title to: “DOTNETNUZZI WP7 MEDIA SAMPLE - v1.00” and the Page Title to:  “media magic”. Note: I also updated the background.   Step 3: – XAML - Media Element Preparation and Best Practice Before we begin the next step I just wanted to point out a few things that you should not do as a best practice when developing an application for WP7 that is playing music.  Please keep in mind that these requirements are not the same if you are playing Sound Effects and are geared towards playing media in the background.   If you have coded this – be prepared to change it:   To avoid a failure from the market place remove all of your media source elements from your XAML or simply create them dynamically.  To keep this simple we will remove the source and set the AutoPlay property to false to ensure that there are no media elements are active when the application is started. Proper example of the media element with No Source:   Some Additional Settings - Add XAML Support for a Mute Button   Step 4: – Boolean to handle toggle of Mute Feature Step 5: – Add Event Handler for Main Page Load   Step 6: – Add Reference to the XNA Framework   Step 7: – Add two Using Statements to Resolve the Namespace of Media and the Application Bar using Microsoft.Xna.Framework.Media; using Microsoft.Phone.Shell;   Step 8: – Add the Method to Check the Media State as Shown Below   Step 9: – Add Code to Mute the Media File Step 10: – Add Code to Play the Media File //if the state of the media has been checked you are good to go. media_sample.Play(); Note: If we tried to perform this operation at this point you will receive the following error: System.InvalidOperationException was unhandled Message=FrameworkDispatcher.Update has not been called. Regular FrameworkDispatcher.Update calls are necessary for fire and forget sound effects and framework events to function correctly. See http://go.microsoft.com/fwlink/?LinkId=193853 for details. StackTrace:        at Microsoft.Xna.Framework.FrameworkDispatcher.AddNewPendingCall(ManagedCallType callType, UInt32 arg)        at Microsoft.Xna.Framework.UserAsyncDispatcher.HandleManagedCallback(ManagedCallType managedCallType, UInt32 managedCallArgs) at Microsoft.Xna.Framework.UserAsyncDispatcher.AsyncDispatcherThreadFunction()            It is not recommended that you just add the FrameworkDispatcher.Update(); call before playing the media file. It is recommended that you implement the following class to your solution and implement this class in the app.xaml.cs file.   Step 11: – Add FrameworkDispatcher Features I recommend creating a class named XNAAsyncDispatcher and adding the following code:   After you have added the code accordingly, you can now implement this into your app.xaml.cs file as highlighted below.   Note:  If you application sound file is not playing make sure you have the proper “Build Action” set such as Content.   Running the Sample Now that we have some of the foundation created you should be able to run the application successfully.  When the application launches your sound options should be set accordingly when the “checkMediaState” method is called.  As a result the application will properly setup the media options and/or alert the user accordinglyper the certification requirements.  In addition, the sample also shows a quick way to mute the sound in your application by simply removing the URI source of the media file.  If everything successfully compiled the application should look similar to below.                 <sound playing>   Summary At this point we have a fully functional application that provides techniques on how to avoid some common challenges when working with media files and developing applications for Windows Phone 7.  The techniques mentioned above should make things a little easier and helpful in getting your WP7 application approved and published on the Marketplace.  The next blog post will be titled: WP7 Tips–Part II - How to write code that will pass the Windows Phone 7 Marketplace Requirements for Themes (light and dark). If anyone has any questions or comments please comment on this blog. 

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  • H1 Visa interview tips–What you must know before attending the interview?

    - by Gopinath
    USA’s H1 visa allows highly qualified professionals from other countries to work in America. Many IT professionals in India aspire to go to USA on H1 and work for their clients. Recently I had a chance to study H1 visa process to help one of my friends and I would like to share what I learned. With the assumption that your H1 petition is approved and you got an interview scheduled at US Embassy for your visa stamping, here are tips you must know before attending the interview Dress Code – Formals Say no to casuals or any fancy dress when you attend the interview. It’s not a party or friends home you are visiting. Consider H1 Visa interview as your job interview and dress up in formals. There is no option B for your, you must be in formals. A plain formal shirt with a matching pant is suggested for men. Tie and Suit would not be required, but if you are a professional at management level you can consider wearing suit. Women can wear either formal Salwar or formal pant-shirt. Avoid heavy jewellery, wear what is must as per your tradition or culture. Body Language -  Smile on your face Your body language reflects what you are and what’s going on in your mind. Don’t be nervous or restless, be relaxed and wear a beautiful smile on your face. A smile is a curve that sets everything straight. When you are called for the interview, greet the interviewer with a beautiful smile. Say Good Morning/Afternoon/Evening depending on time you are visiting them. Whenever appropriate say Thank You. Generally American professionals are very friendly people and they reciprocate for your greetings. Make sure that you make them comfortable to start the interview. Carry original documents in a separate folder I don’t want to talk much about the documents that are required for your H1B interview as it’s big subject on it’s own and it requires a separate post. I assume that your consultant or employer helped you in gathering all the required documents like – petition, DS 160 forms, education & job related documents, resume, interview call letters, client letters, etc. For all the documents you are going to submit at the interview make sure that you have originals in a separate folder.  If required interviewer may ask you show the originals of any of the document you submitted for visa processing. Don’t mix the original documents with the documents you need to submit for interview. Have a separate folder for them. For those who are going to stamping along with their spouse and children, they need to carry few extra original documents like – marriage certificate, marriage photos(30 numbers)/album, birth certificates, passports, education and profession related certificates of the spouse and children. Know your role & responsibilities The interviewer will ask you questions on your roles and responsibilities at client location. Be clear what is your day to day tasks at client place and prepared to face detailed questions on the same. When asked explain clearly and also make sure what you say is inline with what is mentioned in your petition and client invitation letter. At times they may ask you questions specific to the project/technology you are going to work. So doing some homework in this area will help you easily answer the questions. Failing to answer basic questions on your role & responsibilities may result in rejection. You work for your Employer at Client location but NOT FOR CLIENT One of the important things to keep in mind that you work for your employer and you are being deputed to client location on a work visa.  Your employer is going to be solely responsible for your salary, work, promotion, pay hikes or what so ever during your stay at USA. Your client will not be responsible for anything. Lets say you are employed with Company X in India and they are applying for H1B to work at your client(ex: Microsoft) in USA, you must keep in my mind that Microsoft is not your employer. Microsoft will not pay your salaries or responsible for any employment related activities. Company X will be solely responsible for all your employer related activities. If you don’t get this correctly and say to Visa interviewer that your client is responsible, then you may get into troubles. Know your client It’s always good to know the clients with whom you are going to work in USA and their business. If your client is a well know organisation then you may not get many questions from interviewer else you need to be well prepared to provide details like – nature of business, location, size of the organisation, etc.  Get to know the basic details about your client and be confident while providing those details to the interviewer. Also make sure that you never talk about any confidential details of your client projects and business. Revealing confidential details of your client may land your job itself in soup. Make sure that your spouse is also in sync with you If you’ve applied a H4 visa for your spouse along with your H1, make sure that spouse is in sync with you. Your spouse also should know the basic details of your job, your employer, client and location where you will be travelling. Your spouse should also be prepared to answers questions related to marriage, their profession(if working), kids, education, etc. Interviewers will try to asses your spouse communication skills, whereabouts while staying in USA and would they prefer to work USA or not. On H4, which is a dependent visa, your spouse is not allowed to work in USA and at any point your spouse should not show the intentions to search for work in USA. Less luggage more comfort You would have definitely heard that there are lot of restrictions on what you can carry along with you to an US Embassy while attending the interview. To be frank it’s not good to say there are many restrictions, but there are a hell a lot of restrictions. There are unbelievable restrictions and it’s for the safety of everyone. You are not allowed to carry mobile phones, CD/DVDs, USBs, bank cards, cameras, cosmetics, food(except baby food), water, wallets, backpacks, sealed covers, etc. Trust me most of the things we carry with us regularly every day are not allowed inside. As there are 100s of restrictions, it would be easier if you understand what you can carry along with you and just carry them alone. Ask your employer/consultant to provide you a checklist of items that you can carry. Most what you would require are H1B related documents provided by the employer/consultant Photographs All original documents supporting your H1B Passports Some cash for your travel expenses (avoid coins) Any important phone number / details written in a paper(like your cab driver number, etc.) If you carry restricted stuff then you will be stopped at security checks, you have to find people who can safely keep all the restricted items. Due to heavy restrictions in and around the US Embassy you will not find any  place to keep your luggage. So just carry the bare minimum things required so that you feel more comfortable. Useful Links THE U.S. NON IMMIGRANT VISA APPLICATION PROCESS U.S VISA SECURITY REGULATIONS GENERAL FAQS Hope this information is helpful to you and best of luck for your interview. Creative commons Image credit: Flickr/ alexfrance, vinothchandar. hughelectronic, architratan, striatic

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  • Entity Framework v1 &hellip; Brief Synopsis and Tips &ndash; Part 2

    - by Rohit Gupta
    Using Entity Framework with ASMX Web sErvices and WCF Web Service: If you use ASMX WebService to expose Entity objects from Entity Framework... then the ASMX Webservice does not  include object graphs, one work around is to use Facade pattern or to use WCF Service. The other important aspect of using ASMX Web Services along with Entity Framework is that the ASMX Client is not aware of the existence of EF v1 since the client solely deals with C# objects (not EntityObjects or ObjectContext). Since the client is not aware of the ObjectContext hence the client cannot participate in change tracking since the client only receives the Current Values and not the Orginal values when the service sends the the Entity objects to the client. Thus there are 2 drawbacks to using EntityFramework with ASMX Web Service: 1. Object state is not maintained... so to overcome this limitation we need insert/update single entity at a time and retrieve the original values for the entity being updated on the server/service end before calling Save Changes. 2. ASMX does not maintain object graphs... i.e. Customer.Reservations or Customer.Reservations.Trip relationships are not maintained. Thus you need to send these relationships separately from service to client. WCF Web Service overcomes the object graph limitation of ASMX Web Service, but we need to insure that we are populating all the non-null scalar properties of all the objects in the object graph before calling Update. WCF Web service still cannot overcome the second limitation of tracking changes to entities at the client end. Also note that the "Customer" class in the Client is very different from the "Customer" class in the Entity Framework Model Entities. They are incompatible with each other hence we cannot cast one to the other. However the .NET Framework translates the client "Customer" Entity to the EFv1 Model "customer" Entity once the entity is serialzed back on the ASMX server end. If you need change tracking enabled on the client then we need to use WCF Data Services which is available with VS 2010. ====================================================================================================== In WCF when adding an object that has relationships, the framework assumes that every object in the object graph needs to be added to store. for e.g. in a Customer.Reservations.Trip object graph, when a Customer Entity is added to the store, the EFv1 assumes that it needs to a add a Reservations collection and also Trips for each Reservation. Thus if we need to use existing Trips for reservations then we need to insure that we null out the Trip object reference from Reservations and set the TripReference to the EntityKey of the desired Trip instead. ====================================================================================================== Understanding Relationships and Associations in EFv1 The Golden Rule of EF is that it does not load entities/relationships unless you ask it to explicitly do so. However there is 1 exception to this rule. This exception happens when you attach/detach entities from the ObjectContext. If you detach an Entity in a ObjectGraph from the ObjectContext, then the ObjectContext removes the ObjectStateEntry for this Entity and all the relationship Objects associated with this Entity. For e.g. in a Customer.Order.OrderDetails if the Customer Entity is detached from the ObjectContext then you cannot traverse to the Order and OrderDetails Entities (that still exist in the ObjectContext) from the Customer Entity(which does not exist in the Object Context) Conversely, if you JOIN a entity that is not in the ObjectContext with a Entity that is in the ObjContext then the First Entity will automatically be added to the ObjContext since relationships for the 2 Entities need to exist in the ObjContext. ========================================================= You cannot attach an EntityCollection to an entity through its navigation property for e.g. you cannot code myContact.Addresses = myAddressEntityCollection ========================================================== Cascade Deletes in EDM: The Designer does not support specifying cascase deletes for a Entity. To enable cascasde deletes on a Entity in EDM use the Association definition in CSDL for the Entity. for e.g. SalesOrderDetail (SOD) has a Foreign Key relationship with SalesOrderHeader (SalesOrderHeader 1 : SalesOrderDetail *) if you specify a cascade Delete on SalesOrderHeader Entity then calling deleteObject on SalesOrderHeader (SOH) Entity will send delete commands for SOH record and all the SOD records that reference the SOH record. ========================================================== As a good design practise, if you use Cascade Deletes insure that Cascade delete facet is used both in the EDM as well as in the database. Even though it is not absolutely mandatory to have Cascade deletes on both Database and EDM (since you can see that just the Cascade delete spec on the SOH Entity in EDM will insure that SOH record and all related SOD records will be deleted from the database ... even though you dont have cascade delete configured in the database in the SOD table) ============================================================== Maintaining relationships in Code When Setting a Navigation property of a Entity (for e.g. setting the Contact Navigation property of Address Entity) the following rules apply : If both objects are detached, no relationship object will be created. You are simply setting a property the CLR way. If both objects are attached, a relationship object will be created. If only one of the objects is attached, the other will become attached and a relationship object will be created. If that detached object is new, when it is attached to the context its EntityState will be Added. One important rule to remember regarding synchronizing the EntityReference.Value and EntityReference.EntityKey properties is that when attaching an Entity which has a EntityReference (e.g. Address Entity with ContactReference) the Value property will take precedence and if the Value and EntityKey are out of sync, the EntityKey will be updated to match the Value. ====================================================== If you call .Load() method on a detached Entity then the .Load() operation will throw an exception. There is one exception to this rule. If you load entities using MergeOption.NoTracking, you will be able to call .Load() on such entities since these Entities are accessible by the ObjectContext. So the bottomline is that we need Objectontext to be able to call .Load() method to do deffered loading on EntityReference or EntityCollection. Another rule to remember is that you cannot call .Load() on entities that have a EntityState.Added State since the ObjectContext uses the EntityKey of the Primary (Parent) Entity when loading the related (Child) Entity (and not the EntityKey of the child (even if the EntityKey of the child is present before calling .Load()) ====================================================== You can use ObjContext.Add() to add a entity to the ObjContext and set the EntityState of the new Entity to EntityState.Added. here no relationships are added/updated. You can also use EntityCollection.Add() method to add an entity to another entity's related EntityCollection for e.g. contact has a Addresses EntityCollection so to add a new address use contact.Addresses.Add(newAddress) to add a new address to the Addresses EntityCollection. Note that if the entity does not already exist in the ObjectContext then calling contact.Addresses.Add(myAddress) will cause a new Address Entity to be added to the ObjContext with EntityState.Added and it will also add a RelationshipEntry (a relationship object) with EntityState.Added which connects the Contact (contact) with the new address newAddress. Note that if the entity already exists in the Objectcontext (being part theOtherContact.Addresses Collection), then calling contact.Addresses.Add(existingAddress) will add 2 RelationshipEntry objects to the ObjectStateEntry Collection, one with EntityState.Deleted and the other with EntityState.Added. This implies that the existingAddress Entity is removed from the theOtherContact.Addresses Collection and Added to the contact.Addresses Collection..effectively reassigning the address entity from the theOtherContact to "contact". This is called moving an existing entity to a new object graph. ====================================================== You usually use ObjectContext.Attach() and EntityCollection.Attach() methods usually when you need to reconstruct the ObjectGraph after deserializing the objects as received from a ASMX Web Service Client. Attach is usually used to connect existing Entities in the ObjectContext. When EntityCollection.Attach() is called the EntityState of the RelationshipEntry (the relationship object) remains as EntityState.unchanged whereas when EntityCollection.Add() method is called the EntityState of the relationship object changes to EntityState.Added or EntityState.Deleted as the situation demands. ========================================================= LINQ To Entities Tips: Select Many does Inner Join by default.   for e.g. from c in Contact from a in c.Address select c ... this will do a Inner Join between the Contacts and Addresses Table and return only those Contacts that have a Address. ======================================================== Group Joins Do LEFT Join by default. e.g. from a in Address join c in Contact ON a.Contact.ContactID == c.ContactID Into g WHERE a.CountryRegion == "US" select g; This query will do a left join on the Contact table and return contacts that have a address in "US" region The following query : from c in Contact join a in Address.Where(a1 => a1.CountryRegion == "US") on c.ContactID  equals a.Contact.ContactID into addresses select new {c, addresses} will do a left join on the Address table and return All Contacts. In these Contacts only those will have its Address EntityCollection Populated which have a Address in the "US" region, the other contacts will have 0 Addresses in the Address collection (even if addresses for those contacts exist in the database but are in a different region) ======================================================== Linq to Entities does not support DefaultIfEmpty().... instead use .Include("Address") Query Builder method to do a Left JOIN or use Group Joins if you need more control like Filtering on the Address EntityCollection of Contact Entity =================================================================== Use CreateSourceQuery() on the EntityReference or EntityCollection if you need to add filters during deferred loading of Entities (Deferred loading in EFv1 happens when you call Load() method on the EntityReference or EntityCollection. for e.g. var cust=context.Contacts.OfType<Customer>().First(); var sq = cust.Reservations.CreateSourceQuery().Where(r => r.ReservationDate > new DateTime(2008,1,1)); cust.Reservations.Attach(sq); This populates only those reservations that are older than Jan 1 2008. This is the only way (in EFv1) to Attach a Range of Entities to a EntityCollection using the Attach() method ================================================================== If you need to get the Foreign Key value for a entity e.g. to get the ContactID value from a Address Entity use this :                                address.ContactReference.EntityKey.EntityKeyValues.Where(k=> k.Key == "ContactID")

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  • Entity Framework v1 &ndash; tips and Tricks Part 3

    - by Rohit Gupta
    General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query  that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2:  3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17:  18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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  • ADF TaskFlows Communications

    - by raghu.yadav
    Here is the list of various ADF Taskflows communication examples. http://www.oracle.com/technology/products/jdev/tips/fnimphius/CtxEvent/CtxEvent.html http://thepeninsulasedge.com/frank_nimphius/2008/02/07/adf-faces-rc-refreshing-a-table-ui-from-a-contextual-event/ http://www.oracle.com/technology/products/jdev/tips/fnimphius/generictreeselectionlistener/index.html http://www.oracle.com/technology/products/jdev/tips/fnimphius/syncheditformwithtree/index.html http://biemond.blogspot.com/2009/01/passing-adf-events-between-task-flow.html http://www.oracle.com/technology/products/jdev/tips/fnimphius/opentaskflowintab/index.html http://lucbors.blogspot.com/2010/03/adf-11g-contextual-event-framework.html http://thepeninsulasedge.com/blog/?cat=2 http://www.ora600.be/news/adf-contextual-events-11g-r1-ps1

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  • Cannot install vlc in ubuntu 13.10

    - by nisargshah95
    for some reasons I cannot instal VLC media player on my Ubuntu Gnome 13.10 32bit. I added the VideoLAN PPA repository and ran sudo apt-get update and sudo apt-get install vlc Here's the log - nisarg@nisarg-ThinkPad-T61:~$ sudo apt-get install vlc Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: liba52-0.7.4 libaacs0 libass4 libavcodec53 libavformat53 libavutil51 libbluray1 libcddb2 libcrystalhd3 libdc1394-22 libdca0 libdirac-encoder0 libdirectfb-1.2-9 libdvbpsi8 libdvdnav4 libdvdread4 libebml3 libfaad2 libgsm1 libiso9660-8 libkate1 libmad0 libmatroska5 libmodplug1 libmpcdec6 libmpeg2-4 libopus0 libpostproc52 libresid-builder0c2a libschroedinger-1.0-0 libsdl-image1.2 libsdl1.2debian libsidplay2 libssh2-1 libswscale2 libtar0 libts-0.0-0 libtwolame0 libupnp6 libva-x11-1 libva1 libvcdinfo0 libvlc5 libvlccore5 libwebp4 libx264-123 libxcb-composite0 libxcb-keysyms1 libxcb-randr0 libxcb-xv0 libzvbi-common libzvbi0 tsconf vlc-data vlc-nox vlc-plugin-notify vlc-plugin-pulse Suggested packages: libbluray-bdj firmware-crystalhd libdvdcss2 debhelper opus-tools videolan-doc The following NEW packages will be installed: liba52-0.7.4 libaacs0 libass4 libavcodec53 libavformat53 libavutil51 libbluray1 libcddb2 libcrystalhd3 libdc1394-22 libdca0 libdirac-encoder0 libdirectfb-1.2-9 libdvbpsi8 libdvdnav4 libdvdread4 libebml3 libfaad2 libgsm1 libiso9660-8 libkate1 libmad0 libmatroska5 libmodplug1 libmpcdec6 libmpeg2-4 libopus0 libpostproc52 libresid-builder0c2a libschroedinger-1.0-0 libsdl-image1.2 libsdl1.2debian libsidplay2 libssh2-1 libswscale2 libtar0 libts-0.0-0 libtwolame0 libupnp6 libva-x11-1 libva1 libvcdinfo0 libvlc5 libvlccore5 libwebp4 libx264-123 libxcb-composite0 libxcb-keysyms1 libxcb-randr0 libxcb-xv0 libzvbi-common libzvbi0 tsconf vlc vlc-data vlc-nox vlc-plugin-notify vlc-plugin-pulse 0 upgraded, 58 newly installed, 0 to remove and 7 not upgraded. Need to get 16.7 MB of archives. After this operation, 75.0 MB of additional disk space will be used. Do you want to continue [Y/n]? y Get:1 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main vlc-data all 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [4,967 kB] Get:2 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main libvlccore5 i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [384 kB] Get:3 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main libvlc5 i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [42.4 kB] Get:4 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main vlc-nox i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [2,084 kB] Get:5 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main vlc i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [1,078 kB] Get:6 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main vlc-plugin-notify i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [5,836 B] Get:7 http://ppa.launchpad.net/videolan/stable-daily/ubuntu/ saucy/main vlc-plugin-pulse i386 2.0.8+git20131025+r620-0~r13~ubuntu13.10.1 [18.2 kB] Err http://archive.ubuntu.com/ubuntu/ saucy/universe libaacs0 i386 0.6.0-2 Connection failed [IP: 91.189.92.176 80] 51% [Waiting for headers] Now it doesn't move forward after this point. Any suggestions?

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  • ConfigServer Security and Firewall -- after setup, how much daily management required?

    - by Hope4You
    I'm looking at using ConfigServer Security and Firewall (CSF; iptables-based). After I configure it properly, how much daily ongoing management is required of me to keep my server secure? Am I going to be flooded with "alert" emails that I need to check? Or does the firewall automatically take care of most security threats for me? Note: I understand that there's more to server security than just a software firewall, but this question is specifically for CSF security management.

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  • Alternative site to Mike Gunderloy's "The Daily Grind" (Larkware)?

    - by splattne
    As a developer who is always looking for new resources and information, I loved Mike Gunderloy's blog "The Daily Grind" on www.larkware.com ("We get up early, so you don't have to.") Unfortunately (for me) Mike decided to discontinue the blog in December 2007. So, my question: is there a similar blog / site which provides such good links and resources on a daily basis? I couldn't find one. Thanks! Update: to be clear: I am specifically looking for a site like larkware.com, a kind of aggregator/meta-site of information about interesting articles, components, software for (.NET) developers.

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  • using Excel VBA, given the daily price of 50 stocks, choose 10 stocks such that they have the minumu

    - by correl
    The high-level goal is to choose 10 stocks that have the lowest correlation among one another, out of a pool of 50, so that I can have a well-diversified portfolio. I have managed to write some VBA macro to download the past 3 years of daily price data from Yahoo finance, and then compute the 50x50 correlation matrix (using the Correl function), using the daily close as the data. What I have tried so far is just some local-maximum heuristic: - For the two stocks that have the highest correlation with each other, remove one of them. Between the two, remove the one that has the higher average correlation with all the other stocks. - When I remove a stock from the pool, I just delete the correponding row and column, to give a smaller matrix. - Repeat until I have just 10 stocks remaining (a 10x10 matrix). I was wondering if there is some algorithm that already solves such a problem and gives the optimum solution?

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  • What are some general tips to make InnoDB for MySQL perform at its highest?

    - by James Simpson
    I've been using MyISAM exclusively for several years now and know the ins-and-outs pretty well of how to optimize it, but I've just recently started using InnoDB for some of my tables and don't know that much about it. What are some general tips to help improve the performance of these InnoDB tables (they were converted from MyISAM and have anywhere from 100k - 2M rows and most won't use transactions).

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  • Entity Framework version 1- Brief Synopsis and Tips &ndash; Part 1

    - by Rohit Gupta
    To Do Eager loading use Projections (for e.g. from c in context.Contacts select c, c.Addresses)  or use Include Query Builder Methods (Include(“Addresses”)) If there is multi-level hierarchical Data then to eager load all the relationships use Include Query Builder methods like customers.Include("Order.OrderDetail") to include Order and OrderDetail collections or use customers.Include("Order.OrderDetail.Location") to include all Order, OrderDetail and location collections with a single include statement =========================================================================== If the query uses Joins then Include() Query Builder method will be ignored, use Nested Queries instead If the query does projections then Include() Query Builder method will be ignored Use Address.ContactReference.Load() OR Contact.Addresses.Load() if you need to Deferred Load Specific Entity – This will result in extra round trips to the database ObjectQuery<> cannot return anonymous types... it will return a ObjectQuery<DBDataRecord> Only Include method can be added to Linq Query Methods Any Linq Query method can be added to Query Builder methods. If you need to append a Query Builder Method (other than Include) after a LINQ method  then cast the IQueryable<Contact> to ObjectQuery<Contact> and then append the Query Builder method to it =========================================================================== Query Builder methods are Select, Where, Include Methods which use Entity SQL as parameters e.g. "it.StartDate, it.EndDate" When Query Builder methods do projection then they return ObjectQuery<DBDataRecord>, thus to iterate over this collection use contact.Item[“Name”].ToString() When Linq To Entities methods do projection, they return collection of anonymous types --- thus the collection is strongly typed and supports Intellisense EF Object Context can track changes only on Entities, not on Anonymous types. If you use a Defining Query for a EntitySet then the EntitySet becomes readonly since a Defining Query is the same as a View (which is treated as a ReadOnly by default). However if you want to use this EntitySet for insert/update/deletes then we need to map stored procs (as created in the DB) to the insert/update/delete functions of the Entity in the Designer You can use either Execute method or ToList() method to bind data to datasources/bindingsources If you use the Execute Method then remember that you can traverse through the ObjectResult<> collection (returned by Execute) only ONCE. In WPF use ObservableCollection to bind to data sources , for keeping track of changes and letting EF send updates to the DB automatically. Use Extension Methods to add logic to Entities. For e.g. create extension methods for the EntityObject class. Create a method in ObjectContext Partial class and pass the entity as a parameter, then call this method as desired from within each entity. ================================================================ DefiningQueries and Stored Procedures: For Custom Entities, one can use DefiningQuery or Stored Procedures. Thus the Custom Entity Collection will be populated using the DefiningQuery (of the EntitySet) or the Sproc. If you use Sproc to populate the EntityCollection then the query execution is immediate and this execution happens on the Server side and any filters applied will be applied in the Client App. If we use a DefiningQuery then these queries are composable, meaning the filters (if applied to the entityset) will all be sent together as a single query to the DB, returning only filtered results. If the sproc returns results that cannot be mapped to existing entity, then we first create the Entity/EntitySet in the CSDL using Designer, then create a dummy Entity/EntitySet using XML in the SSDL. When creating a EntitySet in the SSDL for this dummy entity, use a TSQL that does not return any results, but does return the relevant columns e.g. select ContactID, FirstName, LastName from dbo.Contact where 1=2 Also insure that the Entity created in the SSDL uses the SQL DataTypes and not .NET DataTypes. If you are unable to open the EDMX file in the designer then note the Errors ... they will give precise info on what is wrong. The Thrid option is to simply create a Native Query in the SSDL using <Function Name="PaymentsforContact" IsComposable="false">   <CommandText>SELECT ActivityId, Activity AS ActivityName, ImagePath, Category FROM dbo.Activities </CommandText></FuncTion> Then map this Function to a existing Entity. This is a quick way to get a custom Entity which is regular Entity with renamed columns or additional columns (which are computed columns). The disadvantage to using this is that It will return all the rows from the Defining query and any filter (if defined) will be applied only at the Client side (after getting all the rows from DB). If you you DefiningQuery instead then we can use that as a Composable Query. The Fourth option (for mapping a READ stored proc results to a non-existent Entity) is to create a View in the Database which returns all the fields that the sproc also returns, then update the Model so that the model contains this View as a Entity. Then map the Read Sproc to this View Entity. The other option would be to simply create the View and remove the sproc altogether. ================================================================ To Execute a SProc that does not return a entity, use a EntityCommand to execute that proc. You cannot call a sproc FunctionImport that does not return Entities From Code, the only way is to use SSDL function calls using EntityCommand.  This changes with EntityFramework Version 4 where you can return Scalar Types, Complex Types, Entities or NonQuery ================================================================ UDF when created as a Function in SSDL, we need to set the Name & IsComposable properties for the Function element. IsComposable is always false for Sprocs, for UDF's set this to true. You cannot call UDF "Function" from within code since you cannot import a UDF Function into the CSDL Model (with Version 1 of EF). only stored procedures can be imported and then mapped to a entity ================================================================ Entity Framework requires properties that are involved in association mappings to be mapped in all of the function mappings for the entity (Insert, Update and Delete). Because Payment has an association to Reservation... hence we need to pass both the paymentId and reservationId to the Delete sproc even though just the paymentId is the PK on the Payment Table. ================================================================ When mapping insert, update and delete procs to a Entity, insure that all the three or none are mapped. Further if you have a base class and derived class in the CSDL, then you must map (ins, upd, del) sprocs to all parent and child entities in the inheritance relationship. Note that this limitation that base and derived entity methods must all must be mapped does not apply when you are mapping Read Stored Procedures.... ================================================================ You can write stored procedures SQL directly into the SSDL by creating a Function element in the SSDL and then once created, you can map this Function to a CSDL Entity directly in the designer during Function Import ================================================================ You can do Entity Splitting such that One Entity maps to multiple tables in the DB. For e.g. the Customer Entity currently derives from Contact Entity...in addition it also references the ContactPersonalInfo Entity. One can copy all properties from the ContactPersonalInfo Entity into the Customer Entity and then Delete the CustomerPersonalInfo entity, finall one needs to map the copied properties to the ContactPersonalInfo Table in Table Mapping (by adding another table (ContactPersonalInfo) to the Table Mapping... this is called Entity Splitting. Thus now when you insert a Customer record, it will automatically create SQL to insert records into the Contact, Customers and ContactPersonalInfo tables even though you have a Single Entity called Customer in the CSDL =================================================================== There is Table by Type Inheritance where another EDM Entity can derive from another EDM entity and absorb the inherted entities properties, for example in the Break Away Geek Adventures EDM, the Customer entity derives (inherits) from the Contact Entity and absorbs all the properties of Contact entity. Thus when you create a Customer Entity in Code and then call context.SaveChanges the Object Context will first create the TSQL to insert into the Contact Table followed by a TSQL to insert into the Customer table =================================================================== Then there is the Table per Hierarchy Inheritance..... where different types are created based on a condition (similar applying a condition to filter a Entity to contain filtered records)... the diference being that the filter condition populates a new Entity Type (derived from the base Entity). In the BreakAway sample the example is Lodging Entity which is a Abstract Entity and Then Resort and NonResort Entities which derive from Lodging Entity and records are filtered based on the value of the Resort Boolean field =================================================================== Then there is Table per Concrete Type Hierarchy where we create a concrete Entity for each table in the database. In the BreakAway sample there is a entity for the Reservation table and another Entity for the OldReservation table even though both the table contain the same number of fields. The OldReservation Entity can then inherit from the Reservation Entity and configure the OldReservation Entity to remove all Scalar Properties from the Entity (since it inherits the properties from Reservation and filters based on ReservationDate field) =================================================================== Complex Types (Complex Properties) Entities in EF can also contain Complex Properties (in addition to Scalar Properties) and these Complex Properties reference a ComplexType (not a EntityType) DropdownList, ListBox, RadioButtonList, CheckboxList, Bulletedlist are examples of List server controls (not data bound controls) these controls cannot use Complex properties during databinding, they need Scalar Properties. So if a Entity contains Complex properties and you need to bind those to list server controls then use projections to return Scalar properties and bind them to the control (the disadvantage is that projected collections are not tracked by the Object Context and hence cannot persist changes to the projected collections bound to controls) ObjectDataSource and EntityDataSource do account for Complex properties and one can bind entities with Complex Properties to Data Source controls and they will be tracked for changes... with no additional plumbing needed to persist changes to these collections bound to controls So DataBound controls like GridView, FormView need to use EntityDataSource or ObjectDataSource as a datasource for entities that contain Complex properties so that changes to the datasource done using the GridView can be persisted to the DB (enabling the controls for updates)....if you cannot use the EntityDataSource you need to flatten the ComplexType Properties using projections With EF Version 4 ComplexTypes are supported by the Designer and can add/remove/compose Complex Types directly using the Designer =================================================================== Conditional Mapping ... is like Table per Hierarchy Inheritance where Entities inherit from a base class and then used conditions to populate the EntitySet (called conditional Mapping). Conditional Mapping has limitations since you can only use =, is null and IS NOT NULL Conditions to do conditional mapping. If you need more operators for filtering/mapping conditionally then use QueryView(or possibly Defining Query) to create a readonly entity. QueryView are readonly by default... the EntitySet created by the QueryView is enabled for change tracking by the ObjectContext, however the ObjectContext cannot create insert/update/delete TSQL statements for these Entities when SaveChanges is called since it is QueryView. One way to get around this limitation is to map stored procedures for the insert/update/delete operations in the Designer. =================================================================== Difference between QueryView and Defining Query : QueryView is defined in the (MSL) Mapping File/section of the EDM XML, whereas the DefiningQuery is defined in the store schema (SSDL). QueryView is written using Entity SQL and is this database agnostic and can be used against any database/Data Layer. DefiningQuery is written using Database Lanaguage i.e. TSQL or PSQL thus you have more control =================================================================== Performance: Lazy loading is deferred loading done automatically. lazy loading is supported with EF version4 and is on by default. If you need to turn it off then use context.ContextOptions.lazyLoadingEnabled = false To improve Performance consider PreCompiling the ObjectQuery using the CompiledQuery.Compile method

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  • Any tips for designing the invoicing/payment system of a SaaS?

    - by Alexandru Trandafir Catalin
    The SaaS is for real estate companies, and they can pay a monthly fee that will offer them 1000 publications but they can also consume additional publications or other services that will appear on their bill as extras. On registration the user can choose one of the 5 available plans that the only difference will be the quantity of publications their plan allows them to make. But they can pass that limit if they wish, and additional payment will be required on the next bill. A publication means: Publishing a property during one day, for 1 whole month would be: 30 publications. And 5 properties during one day would be 5 publications. So basically the user can: Make publications (already paid in the monthly fee, extra payment only if it passes the limit) Highlight that publication (extra payment) Publish on other websites or printed catalogues (extra payment) Doubts: How to handle modifications in pricing plans? Let's say quantities change, or you want to offer some free stuff. How to handle unpaid invoices? I mean, freeze the service until the payment has been done and then resume it. When to make the invoices? The idea is to make one invoice for the monthly fee and a second invoice for the extra services that were consumed. What payment methods to use? The choosen now is by bank account, and mobile phone validation with a SMS. If user doesn't pay we call that phone and ask for payment. Any examples on billing online services will be welcome! Thanks!

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