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• how to troubleshoot sql server issues

  - by joe

  i have an ASP .net application with sql server database, and i am wondering if you can give your ideas on how to troubleshoot the following issue: i can insert / update / delete from any table, but i have one page that uses transactions to insert into different tables. the c# code is correct and very simple, but it fails. i used the sql profiler to see how my app interacts with the DB, especially that the app is using stored procedures, i can catch the exec procedure statement and run it manually from SSMS and it works fine, but the same stored procedure fails from the application!!! which lead me to think that issue is coming from the user account and settings, i am no expert in sql server and wondering if anyone can explain how to verify the required settings for user account. thanks EDIT: in web.config here is how i reference my connection <connectionStrings> <add name="Conn" connectionString="Data Source=localhost;Initial Catalog=myDB;Persist Security Info=True;User ID=DbUser;Password=password1254_3" providerName="System.Data.SqlClient"> </connectionstring> EDIT: i will try to describe the process here: 1- i begin a transaction 2- i call a stored proc to insert (which succeeds) and return the scope identity ( that will be used in the next step) 3- i call another stored procedure to insert some more info + scope identity from step 2, which is a foreign key here 4- i get error, foreign key violation 5- transaction rolled back, now tables empty again... thanks

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• Be liberal in what you accept... or not?

  - by Matthieu M.

  [Disclaimer: this question is subjective, but I would prefer getting answers backed by facts and/or reflexions] I think everyone knows about the Robustness Principle, usually summed up by Postel's Law: Be conservative in what you send; be liberal in what you accept. I would agree that for the design of a widespread communication protocol this may make sense (with the goal of allowing easy extension), however I have always thought that its application to HTML / CSS was a total failure, each browser implementing its own silent tweak detection / behavior, making it near impossible to obtain a consistent rendering across multiple browsers. I do notice though that there the RFC of the TCP protocol deems "Silent Failure" acceptable unless otherwise specified... which is an interesting behavior, to say the least. There are other examples of the application of this principle throughout the software trade that regularly pop up because they have bitten developpers, from the top off my head: Javascript semi-colon insertion C (silent) builtin conversions (which would not be so bad if it did not truncated...) and there are tools to help implement "smart" behavior: name matching phonetic algorithms (Double Metaphone) string distances algorithms (Levenshtein distance) However I find that this approach, while it may be helpful when dealing with non-technical users or to help users in the process of error recovery, has some drawbacks when applied to the design of library/classes interface: it is somewhat subjective whether the algorithm guesses "right", and thus it may go against the Principle of Least Astonishment it makes the implementation more difficult, thus more chances to introduce bugs (violation of YAGNI ?) it makes the behavior more susceptible to change, as any modification of the "guess" routine may break old programs, nearly excluding refactoring possibilities... from the start! And this is what led me to the following question: When designing an interface (library, class, message), do you lean toward the robustness principle or not ? I myself tend to be quite strict, using extensive input validation on my interfaces, and I was wondering if I was perhaps too strict.

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• Why is NDA so hard to understand?

  - by Dave Campbell

  Maybe this concept is simpler for me because of all the jobs I've been on over the years requiring security clearances. I've signed quite a few NDA forms. Some for big companies, some for small, but the meaning of "NDA" remains constant: Non-Disclosure Agreement. To me, that takes no further explanation, but apparently it's confusing to some people, and I don't understand how you can be confused. The papers I signed with the U.S. Army in 1970 read "10 years and $10,000" for a violation... can't imagine what it's up to now, but THAT is a strict NDA :) So those things I've been told, I cannot talk about, period. Even if the entire world knows about them, I cannot speak about them until the information goes off NDA. An example was a Silverlight release a while back. It might have been Silverlight 3, I don't remember. Everyone was anxiously awaiting the release so they could post their material. Of course the entire world knew it was coming out and imminently so. Some enterprising folks had even found the bits on a server before the official announcement. So then the situation became: everyone knew about it, some were even coding with it and blogging about it and yet we couldn't talk about it. Scott Guthrie's posting about it opened the flood gates and then it went off NDA, but up until that moment, we were locked. Sitting out on the edge you're uninstalling and re-installing all the time and you get frustrated when things that used to work don't, but hey... those bits were still warm when you got 'em, and that's the fun. But that fun comes at a price, and the price is the NDA. Awkward yes, confusing no... See you at MIX10, and Stay in the 'Light! MIX10

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• Adding custom attribute to openldap

  - by arukaen

  I am attempting to setup ConTagged - The LDAP Address Book but I am having a few issues with some of the attributes. The problem is that some of them are undefined and they do not seem to be in the inetorgperson.schema. How do I set these custom attributes? For reference, here is the exact error I receive whenever I make a change to a contact. The LDAP server returned the following errors Invalid syntax Undefined attribute type(del anniversary) Undefined attribute type(del marker) Object class violation(mod c) Undefined attribute type(del custom1) Undefined attribute type(del custom2) Undefined attribute type(del custom3) Undefined attribute type(del custom4)

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• Pursuing violators of software license/copyright

  - by Dmitry Brant

  I've recently discovered a seller on eBay who is selling CDs with my (trialware) software on it. The seller is clearly trying to pass the software off as his own; he's copied all the verbiage from my software's website, except its actual name. This seller also sells a whole bunch of other CDs with free software for which he's misrepresenting authorship. For example, this listing contains screen shots that are obviously of the free program InfraRecorder. However, the name InfraRecorder or its authors aren't mentioned anywhere. Before I splurge on official legal assistance, does the community have any recommendations or past experiences with these kinds of matters? What's the best way to proceed, and at the very least, have the eBay listings taken down? Is it possible to reclaim the earnings from the sales of these CDs (not just for me, but for the other authors of the free software that this person is selling)? I realize that GPL'd software doesn't have any restrictions on "selling" the software, but this person has gone to great lengths to obfuscate the software's authorship, which is surely a violation of the license. (My software is not GPL; it's a custom license, and it does not permit redistribution of any kind without permission)

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• How do I create my own programming language and a compiler for it

  - by Dave

  I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, JavaScript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist someone like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (i.e. like Thread, Synchronization, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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• Looking for suggestions: becoming a hireable, young programmer [closed]

  - by Dan

  I am a 17 year old Java programmer that has filled the last year with learning all of the ins and outs of Java - Using Eclipse, and the help of a friend of the family (a Java programming architect for some company), I have learned everything from serializing objects, basic networking, generics, reflection, multi-threading, code optimization and efficiency & some concurrency safety - built my own proxy class, and nowadays, I answer questions on Project Euler. I am seeking some suggestions though on where I go next, or where I go from here to get a job in programming. I dedicate at least an hour every day to coding, sometimes literally, the entire day, and I really have come to love the process. I just started reading Effective Java (v2), and learning Scala (as I see often, possibly the Java replacement) I will be going to college for Computer Science next year - and taking AP computer science this year (however, I took a practice exam and got an 87, only need a 60to70 to pass, so no need to study for it too much) -- I was wondering if getting the SE 7 OCA and OCP would help me in trying to get a programming job. I looked around and most people have said online that an OCA/OCP are practically useless, but, at my age do they make me any more credible? More or less, what would you recommend to get a job in programming these days - or distinguish yourself from the crowd? I have enough time and dedication to learn another language, or anything really. Thank you very much.

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• What the Hekaton?

  - by Tony Davis

  Hekaton, the power behind SQL Server 2014′s In-Memory OLTP technology, is intended to make data operations run orders of magnitude faster on SQL Server. This works its magic partly by serving database workloads entirely from main memory, using memory-optimized table structures. It replaces the relational engine’s standard locking model with an optimistic concurrency model based on time-stamped row versions. Deeper down the Hekaton engine uses new, ‘latch free’ data structures. So far, so good, but performance improvements on this scale require a compromise, and the compromise is that these aren’t tables as we understand them. For the database developer, these differences are painful because they involve sacrificing some very important bits of the relational model. Most importantly, Hekaton tables don’t currently support FOREIGN KEY constraints or CHECK constraints, and you can’t put the checks in triggers because there aren’t any DML triggers either. Constraints allow a relational designer to enforce relational integrity and data integrity. Without them, of course, ‘bad data’ can get into our Hekaton tables. There is no easy way of preventing it. For several classes of database and data, this is a show-stopper. One may regard all these restrictions regretfully, seeing limited opportunity to try out Hekaton with current databases, but perhaps there is also a sudden glow of recognition. Isn’t this how we all originally imagined table variables were going to be, back in SQL 2005? And they have much the same restrictions. Maybe, instead of pretending that a currently-designed database can be ‘Hekatonized’ with a few mouse clicks, we should redesign databases for SQL 2014 to replace table variables with Hekaton tables, exploiting this technology for fast intermediate processing, and for the most part forget, for now, the idea of trying to convert our base relational tables into Hekaton tables. Few database developers would be averse to having their working tables running an order of magnitude faster, as long as it didn’t compromise the integrity of the data in the base tables.

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• Code contracts and inheritance

  - by DigiMortal

  In my last posting about code contracts I introduced you how to force code contracts to classes through interfaces. In this posting I will go step further and I will show you how code contracts work in the case of inherited classes. As a first thing let’s take a look at my interface and code contracts. [ContractClass(typeof(ProductContracts))] public interface IProduct {     int Id { get; set; }     string Name { get; set; }     decimal Weight { get; set; }     decimal Price { get; set; } }   [ContractClassFor(typeof(IProduct))] internal sealed class ProductContracts : IProduct {     private ProductContracts() { }       int IProduct.Id     {         get         {             return default(int);         }         set         {             Contract.Requires(value > 0);         }     }       string IProduct.Name     {         get         {             return default(string);         }         set         {             Contract.Requires(!string.IsNullOrWhiteSpace(value));             Contract.Requires(value.Length <= 25);         }     }       decimal IProduct.Weight     {         get         {             return default(decimal);         }         set         {             Contract.Requires(value > 3);             Contract.Requires(value < 100);         }     }       decimal IProduct.Price     {         get         {             return default(decimal);         }         set         {             Contract.Requires(value > 0);             Contract.Requires(value < 100);         }     } } And here is the product class that inherits IProduct interface. public class Product : IProduct {     public int Id { get; set; }     public string Name { get; set; }     public virtual decimal Weight { get; set; }     public decimal Price { get; set; } } if we run this code and violate the code contract set to Id we will get ContractException. public class Program {     static void Main(string[] args)     {         var product = new Product();         product.Id = -100;     } }   Now let’s make Product to be abstract class and let’s define new class called Food that adds one more contract to Weight property. public class Food : Product {     public override decimal Weight     {         get         {             return base.Weight;         }         set         {             Contract.Requires(value > 1);             Contract.Requires(value < 10);               base.Weight = value;         }     } } Now we should have the following rules at place for Food: weight must be greater than 1, weight must be greater than 3, weight must be less than 100, weight must be less than 10. Interesting part is what happens when we try to violate the lower and upper limits of Food weight. To see what happens let’s try to violate rules #2 and #4. Just comment one of the last lines out in the following method to test another assignment. public class Program {     static void Main(string[] args)     {         var food = new Food();         food.Weight = 12;         food.Weight = 2;     } } And here are the results as pictures to see where exceptions are thrown. Click on images to see them at original size. Violation of lower limit. Violation of upper limit. As you can see for both violations we get ContractException like expected. Code contracts inheritance is powerful and at same time dangerous feature. Although you can always narrow down the conditions that come from more general classes it is possible to define impossible or conflicting contracts at different points in inheritance hierarchy.

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• Rails: Law of Demeter Confusion

  - by user2158382

  I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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• Generalist Languages: Dying or Alive and Well?

  - by dsimcha

  Around here, it seems like there's somewhat of a consensus that generalist programming languages (that try to be good at everything, support multiple paradigms, support both very high- and very low-level programming), etc. are a bad idea, and that it's better to pick the right tool for the job and use lots of different languages. I see three major areas where this is flawed: Interfacing multiple languages is always at least a source of friction and is sometimes practically impossible. How severe a problem this is depends on how fine-grained the interfacing is. Near the boundary between the two languages, though, you're basically limited to the intersection of their features, and you have to care about things like binary interfaces that you usually wouldn't. Passing complex data structures (i.e. not just primitives and arrays of primitives) between languages is almost always a hassle. Furthermore, shifting between different syntaxes, different conventions, etc. can be confusing and annoying, though this is a fairly minor complaint. Requirements are never set in stone. I hate picking a language thinking it's the right tool for the job, then realizing that, when some new requirement surfaces, it's actually a terrible choice for that requirement. This has happened to me several times before, usually when working with languages that are very slow, very domain specific and/or has very poor concurrency/parallelism support. When you program in a language for a while, you start to build up a personal toolbox of small utility functions/classes/programs. The value of these goes drastically down if you're forced to use a different language than the one you've accumulated all this code in. What am I missing here? Why shouldn't more focus be placed on generalist languages? Are generalist languages as a category dying or alive and well?

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• Calling COM from Intel Fortran?

  - by user57460

  I'm trying to get COM working from my Fortran application. I do a "COMINITIALIZE" followed by a "COMCreateObjectByProgID". Both of these appear to be successful and return a status of zero. However, when I try to use the COM object, I get "Unhandled exception at 0x00000000 in FortranProg01.exe: 0xC0000005: Access violation." I realize that this error can mean almost anything, but has anyone got some suggestions of common problems with COM that produce this problem? Here are some more details. My program code: program FortranProg01 use myolepg implicit none integer*4 comInitStatus integer:: comCreateStatus INTEGER(INT_PTR_KIND()) $OBJECT INTEGER(4) funcResult REAL(8) pkgVersion call COMINITIALIZE(comInitStatus) print *, comInitStatus call COMCreateObjectByProgID('MyOlePg.MyOlePkg', $OBJECT, comCreateStatus) print *, comCreateStatus funcResult = IMyOlePkg_GetPackageVersion($OBJECT, pkgVersion) print *, funcResult call COMUNINITIALIZE() end program FortranProg01 The wizard-generated interface code: INTERFACE !property PackageVersion INTEGER(4) FUNCTION IMyOlePkg_GetPackageVersion($OBJECT, pVal) INTEGER(INT_PTR_KIND()), INTENT(IN) :: $OBJECT ! Object Pointer !DEC$ ATTRIBUTES VALUE :: $OBJECT REAL(8), INTENT(OUT) :: pVal !DEC$ ATTRIBUTES REFERENCE :: pVal !DEC$ ATTRIBUTES STDCALL :: IMyOlePkg_GetPackageVersion END FUNCTION IMyOlePkg_GetPackageVersion END INTERFACE Any help would be much appreciated! Thanks! Brad.

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• Java Virtual Developer Day Session Videos Available

  - by Tori Wieldt

  How are Lambdas handled on a bytecode level? How does replacing assembly code with Java code improve performance? Can we send flat files/comma separated/XML files to process in Batch? In a Java EE app, can I inject an EJB bean inside a REST POJO using @EJB annotation? Where I can find JavaFX UI controls? At OTN's Virtual Developer Day, Java experts answered these questions and more. Session are now available for you to view on demand (registration required). This is limited time offer: the sessions will be up to view for free for the next two weeks.  You can view sessions from these tracks: Java SE 8 Track Learn about the features scheduled for Java SE 8, including Lambda expressions, extension methods for interfaces and a new Date and Time API. Learn how to create basic apps with JavaFX.  Java EE Track Take a close look at the new functionality in Java EE 7. Get presentations and demos on JSON, WebSockets, Batch, Concurrency, JAX-RS 2, JMS 2,  Java Embedded Track Provides an introductions to the Raspberry Pi, the Keil board, ARM architecture, and how to make it all work with Java Embedded. You know Java, now really know Java. Check out the OTN Virtual Developer Day sessions!

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• The Oracle Platform

  - by Naresh Persaud

  Today’s enterprises typically create identity management infrastructures using ad-hoc, multiple point solutions. Relying on point solutions introduces complexity and high cost of ownership leading many organizations to rethink this approach. In a recent worldwide study of 160 companies conducted by Aberdeen Research, there was a discernible shift in this trend as businesses are now looking to move away from the point solution approach from multiple vendors and adopt an integrated platform approach. By deploying a comprehensive identity and access management strategy using a single platform, companies are saving as much as 48% in IT costs, while reducing audit deficiencies by nearly 35%. According to Aberdeen's research, choosing an integrated suite or “platform” of solutions for Identity Management from a single vendor can have many advantages over choosing “point solutions” from multiple vendors. The Oracle Identity Management Platform is uniquely designed to offer several compelling benefits to our customers.  Shared Services: Instead of separate solutions for - Administration, Authentication, Authorization, Audit and so on–  Oracle Identity Management offers a set of share services that allows these services to be consumed by each component in the stack and by developers of new applications  Actionable Intelligence: The most compelling benefit of the Oracle platform is ” Actionable intelligence” which means if there is a compliance violation, the same platform can fix it. And If a user is logging in from an un-trusted device or we detect an attack and act proactively on that information. Suite Interoperability: With the oracle platform the components all connect and integrated with each other. So if an organization purchase the platform for provisioning and wants to manage access, then the same platform can offer access management which leads to cost savings. Extensible and Configurable: With point solutions – you typically get limited ability to extend the tool to address custom requirements. But with the Oracle platform all of the components have a common way to extend the UI and behavior Find out more about the Oracle Platform approach in this presentation. Platform approach-series-the oracleplatform-final View more PowerPoint from OracleIDM

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• AdvanceTimePolicy and Point Event Streams In StreamInsight.

  There are a number of ways to issues CTIs (Current Time Increments) into your StreamInsight streams but a quite useful way is to do it declaratively on your source factory like this public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(InputConfig configInfo, EventShape eventShape) {     return new AdapterAdvanceTimeSettings(         new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)),         AdvanceTimePolicy.Adjust); } This will issue a CTI after every event and allows no delay (for delayed events) by stamping the CTI with the timestamp of the last event minus 1 tick. The very last statement "AdvanceTimePolicy.Adjust" tells the adapter what to do with events that violate the policy (arrive late).  From BOL "Events that violate the inserted CTI are moved in time if their lifetime overlaps with the CTI timestamp. That is, the start timestamp of the events is set to the most recent CTI timestamp, which renders those events valid. If both start and end time of an event fall before the CTI timestamp, then the event is dropped." This means that if you are using this method of inserting CTIs for a Point event stream and have specified "AdvanceTimePolicy.Adjust" for the violation policy, this setting will be ignored and instead it will use "AdvanceTimePolicy.Drop" because a Point event can never straddle a CTI.

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• C++ and system exceptions

  - by Abyx

  Why standard C++ doesn't respect system (foreign or hardware) exceptions? E.g. when null pointer dereference occurs, stack isn't unwound, destructors aren't called, and RAII doesn't work. The common advice is "to use system API". But on certain systems, specifically Win32, this doesn't work. To enable stack unwinding for this C++ code // class Foo; // void bar(const Foo&); bar(Foo(1, 2)); one should generate something like this C code Foo tempFoo; Foo_ctor(&tempFoo); __try { bar(&tempFoo); } __finally { Foo_dtor(&tempFoo); } Foo_dtor(&tempFoo); and it's impossible to implement this as C++ library. Upd: Standard doesn't forbid handling system exceptions. But it seems that popular compilers like g++ doesn't respect system exceptions on any platforms just because standard doesn't require this. The only thing that I want - is to use RAII to make code readable and program reliable. I don't want to put hand-crafted try\finally around every call to unknown code. For example in this reusable code, AbstractA::foo is such unknown code: void func(AbstractA* a, AbstractB* b) { TempFile file; a->foo(b, file); } Maybe one will pass to func such implementation of AbstractA, which every Friday will not check if b is NULL, so access violation will happen, application will terminate and temporary file will not be deleted. How many months uses will suffer because of this issue, until either author of func or author of AbstractA will do something with it? Related: Is `catch(...) { throw; }` a bad practice?

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• How do I create my own programming language and a compiler for it

  - by Dave

  I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, Javascript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist some one like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (ie like Thread, Synchronisation, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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• NHibernate Pitfalls: Cascades

  - by Ricardo Peres

  This is part of a series of posts about NHibernate Pitfalls. See the entire collection here. For entities that have associations – one-to-one, one-to-many, many-to-one or many-to-many –, NHibernate needs to know what to do with their related entities, in three particular moments: when saving, updating or deleting. In particular, there are two possible behaviors: either ignore these related entities or cascade changes to them. NHibernate allows setting the cascade behavior for each association, and the default behavior is not to cascade (ignore). The possible cascade options are: None Ignore, this is the default Save-Update If the entity is being saved or updated, also save any related entities that are either not saved or have been modified and associate these related entities to the root entity. Generally safe Delete If the entity is being deleted, also delete the related entities. This is only useful for parent-child relations Delete-Orphan Identical to Delete, with the addition that if once related entity is removed from the association – orphaned –, also delete it. Also only for parent-child All Combination of Save-Update and Delete, usually that’s what we want (for parent-child relations, of course) All-Delete-Orphan Same as All plus delete any related entities who lose their relationship In summary, Save-Update is generally what you want in most cases. As for the Delete variations, they should only be used if the related entities depend on the root entity (parent-child), so that deleting the root entity and not their related entities would result in a constraint violation on the database.

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• Using Clojure instead of Python for scalability (multi core) reasons, good idea?

  - by Vandell

  After reading http://clojure.org/rationale and other performance comparisons between Clojure and many languages, I started to think that apart from ease of use, I shouldn't be coding in Python anymore, but in Clojure instead. Actually, I began to fill irresponsisble for not learning clojure seeing it's benefits. Does it make sense? Can't I make really efficient use of all cores using a more imperative language like Python, than a lisp dialect or other functional language? It seems that all the benefits of it come from using immutable data, can't I do just that in Python and have all the benefits? I once started to learn some Common Lisp, read and done almost all exercices from a book I borrowod from my university library (I found it to be pretty good, despite it's low popularity on Amazon). But, after a while, I got myself struggling to much to do some simple things. I think there's somethings that are more imperative in their nature, that makes it difficult to model those thins in a functional way, I guess. The thing is, is Python as powerful as Clojure for building applications that takes advantages of this new multi core future? Note that I don't think that using semaphores, lock mechanisms or other similar concurrency mechanism are good alternatives to Clojure 'automatic' parallelization.

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• Rails: The Law of Demeter [duplicate]

  - by user2158382

  This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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• How do I analyze an Apache Bench result?

  - by Alan Hoffmeister

  I need some help with analyzing a log from Apache Bench: Benchmarking texteli.com (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Completed 600 requests Completed 700 requests Completed 800 requests Completed 900 requests Completed 1000 requests Finished 1000 requests Server Software: Server Hostname: texteli.com Server Port: 80 Document Path: /4f84b59c557eb79321000dfa Document Length: 13400 bytes Concurrency Level: 200 Time taken for tests: 37.030 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 Total transferred: 13524000 bytes HTML transferred: 13400000 bytes Requests per second: 27.01 [#/sec] (mean) Time per request: 7406.024 [ms] (mean) Time per request: 37.030 [ms] (mean, across all concurrent requests) Transfer rate: 356.66 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 27 37 19.5 34 319 Processing: 80 6273 1673.7 6907 8987 Waiting: 47 3436 2085.2 3345 8856 Total: 115 6310 1675.8 6940 9022 Percentage of the requests served within a certain time (ms) 50% 6940 66% 6968 75% 6988 80% 7007 90% 7025 95% 7078 98% 8410 99% 8876 100% 9022 (longest request) What this results can tell me? Isn't 27 rps too slow?

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• Stylecop 4.7.36.0 is out!

  - by TATWORTH

  Stylecop 4.7.36.0 has been released at http://stylecop.codeplex.com/releases/view/79972This is an update to coincide with the latest ReSharper. The full fix list is:4.7.36.0 (508dbac00ffc)=======================Fix for 7344. Don't throw 1126 inside default expressions.Fix for 7371. Compare Namespace parts using the CurrentCulture and not InvariantCulture.Fix for 7386. Don't throw casing violations for filed names in languages that do not support case (like Chinese). Added new tests.fix for 7380. Catch Exception caused by CRM Toolkit.Update ReSharper 7.0 dependency to 7.0.1 (7.0.1098.2760)Fix for 7358. Use the RuleId in the call to MSBuild Logging.Fix for 7348. Update suggestion text for constructors.Fix for 7364. Don't throw 1126 for New Array Expressions.Fix for 7372. Throw 1126 inside catch blocks wasn't working. Add new tests.Fix for 7369. Await is allowed to be inside parenthesis. Add new tests.Fix testsCorrect styling issues.Fix for 7373. Typeparam violations were not being thrown in all cases. Added new tests.Fix for 7361. Rule 1120 was logging against the root element and so Suppressions wouldn't work. Fixed and added tests.Updating de-DE resources - from Michael Diermeier - thank you.Change for 7368. Add the violation count into the Task outputs.Fix for 7383. Fix for memory leak in plugins.Update environment to detect ReSharper 7Fix for 7378. Null reference exception from command line run in message output.Update release history.

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• Twitter Tuesday - Top 10 @ArchBeat Tweets - June 3-9, 2014

  - by OTN ArchBeat

  The Top 10 tweets from @OTNArchBeat for the last seven days. RT @DBAKevlar: #EM12c rel4 is out! Woohoo!! Jun 3, 2014 at 10:36 AM Top 10 Arch Community Articles for May 2014 >> props to @markrittman @kevin_mcginley @porushh et al Jun 4, 2014 at 12:52 PM Architecture of Analytics: @markrittman @kevin_mcginley >> Free OTN Virtual Tech Summit - July 9 Jun 4, 2014 at 09:13 AM My Top 10 Tweets - May 27 - June 2 #ADF #Essbase #FusionApps #Goldengate #Kscope14 #WebLogic. Jun 3, 2014 at 10:27 AM Starting and Stopping a #JavaEE Environment when using Oracle #WebLogic | Rene van Wijk #oracleace Jun 5, 2014 at 11:00 AM Video: #KScope14 Preview: @DebraLilley never stops moving, never stops learning. Jun 3, 2014 at 11:19 AM The OTNArchBeat Daily is out! Stories via @oraclebase Jun 9, 2014 at 01:47 PM Where did my MDB concurrency go? | Eric Gross #weblogic Jun 9, 2014 at 08:48 AM Exalogic Tech tips and code samples from A-Team architect Andrew Hopkinson Jun 6, 2014 at 11:47 AM The OTNArchBeat Daily is out! Stories via @KentGraziano @DBAKevlar @dbasolved Jun 3, 2014 at 01:48 PM adf, essbase,

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• A better alternative to incompatible implementations for the same interface?

  - by glenatron

  I am working on a piece of code which performs a set task in several parallel environments where the behaviour of the different components in the task are similar but quite different. This means that my implementations are quite different but they are all based on the relationships between the same interfaces, something like this: IDataReader -> ContinuousDataReader -> ChunkedDataReader IDataProcessor -> ContinuousDataProcessor -> ChunkedDataProcessor IDataWriter -> ContinuousDataWriter -> ChunkedDataWriter So that in either environment we have an IDataReader, IDataProcessor and IDataWriter and then we can use Dependency Injection to ensure that we have the correct one of each for the current environment, so if we are working with data in chunks we use the ChunkedDataReader, ChunkedDataProcessor and ChunkedDataWriter and if we have continuous data we have the continuous versions. However the behaviour of these classes is quite different internally and one could certainly not go from a ContinuousDataReader to the ChunkedDataReader even though they are both IDataProcessors. This feels to me as though it is incorrect ( possibly an LSP violation? ) and certainly not a theoretically correct way of working. It is almost as though the "real" interface here is the combination of all three classes. Unfortunately in the project I am working on with the deadlines we are working to, we're pretty much stuck with this design, but if we had a little more elbow room, what would be a better design approach in this kind of scenario?

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• Virtual Developer Day - EMEA-friendly time

  - by Tori Wieldt

  OTN's Virtual Developer Day lets you learn about the latest technical improvements in Java without leaving your desk/couch/park bench. Watch informative tutorials on your laptop and improve your Java programming expertise and engage in live chat sessions with Java experts, all for FREE.  OTN Virtual Developer Day: Java Europe/Africa/Middle East - June 25 09:00 to 13:00 BST / 10:00 to 14:00 CEST / 13:30 to 17:30 IST / 12:00 to 16:00 MSK / 08:00 to 12:00 Corresponding UTC (GMT) After a short keynote, you can dive into one of these three tracks:  Java SE 8 Track Learn about the features scheduled for Java SE 8, including Lambda expressions, extension methods for interfaces and a new Date and Time API. Learn how to create basic apps with JavaFX.  Java EE Track Take a close look at the new functionality in Java EE 7. Get presentations and demos on JSON, WebSockets, Batch, Concurrency, JAX-RS 2, JMS 2,  Java Embedded Track Provides an introductions to the Raspberry Pi, the Keil board, ARM architecture, and how to make it all work with Java Embedded. You know Java, now really know Java. Register now!

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