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• Declarative Architectures in Infrastructure as a Service (IaaS)

  - by BuckWoody

  I deal with computing architectures by first laying out requirements, and then laying in any constraints for it's success. Only then do I bring in computing elements to apply to the system. As an example, a requirement might be "world-side availability" and a constraint might be "with less than 80ms response time and full HA" or something similar. Then I can choose from the best fit of technologies which range from full-up on-premises computing to IaaS, PaaS or SaaS. I also deal in abstraction layers - on-premises systems are fully under your control, in IaaS the hardware is abstracted (but not the OS, scale, runtimes and so on), in PaaS the hardware and the OS is abstracted and you focus on code and data only, and in SaaS everything is abstracted - you merely purchase the function you want (like an e-mail server or some such) and simply use it. When you think about solutions this way, the architecture moves to the primary factor in your decision. It's problem-first architecting, and then laying in whatever technology or vendor best fixes the problem. To that end, most architects design a solution using a graphical tool (I use Visio) and then creating documents that  let the rest of the team (and business) know what is required. It's the template, or recipe, for the solution. This is extremely easy to do for SaaS - you merely point out what the needs are, research the vendor and present the findings (and bill) to the business. IT might not even be involved there. In PaaS it's not much more complicated - you use the same Application Lifecycle Management and design tools you always have for code, such as Visual Studio or some other process and toolset, and you can "stamp out" the application in multiple locations, update it and so on. IaaS is another story. Here you have multiple machines, operating systems, patches, virus scanning, run-times, scale-patterns and tools and much more that you have to deal with, since essentially it's just an in-house system being hosted by someone else. You can certainly automate builds of servers - we do this as technical professionals every day. From Windows to Linux, it's simple enough to create a "build script" that makes a system just like the one we made yesterday. What is more problematic is being able to tie those systems together in a coherent way (as a solution) and then stamp that out repeatedly, especially when you might want to deploy that solution on-premises, or in one cloud vendor or another. Lately I've been working with a company called RightScale that does exactly this. I'll point you to their site for more info, but the general idea is that you document out your intent for a set of servers, and it will deploy them to on-premises clouds, Windows Azure, and other cloud providers all from the same script. In other words, it doesn't contain the images or anything like that - it contains the scripts to build them on-premises or on a cloud vendor like Microsoft. Using a tool like this, you combine the steps of designing a system (all the way down to passwords and accounts if you wish) and then the document drives the distribution and implementation of that intent. As time goes on and more and more companies implement solutions on various providers (perhaps for HA and DR) then this becomes a compelling investigation. The RightScale information is here, if you want to investigate it further. Yes, there are other methods I've found, but most are tied to a single kind of cloud, and I'm not into vendor lock-in. Poppa Bear Level - Hands-on EvaluateRightScale at no cost.  Just bring your Windows Azurecredentials and follow the these tutorials: Sign Up for Windows Azure Add     Windows Azure to a RightScale Account Windows Azure Virtual Machines     3-tier Deployment Momma Bear Level - Just the Right level... ;0)  WindowsAzure Evaluation Guide - if you are new toWindows Azure Virtual Machines and new to RightScale, we recommend that youread the entire evaluation guide to gain a more complete understanding of theWindows Azure + RightScale solution.    WindowsAzure Support Page @ support.rightscale.com - FAQ's, tutorials,etc. for  Windows Azure Virtual Machines (Work in Progress) Baby Bear Level - Marketing WindowsAzure Page @ www.rightscale.com - find overview informationincluding solution briefs and presentation & demonstration videos   Scale     and Automate Applications on Windows Azure  Solution Brief     - how RightScale makes Windows Azure Virtual Machine even better SQL     Server on Windows Azure  Solution Brief   -       Run Highly Available SQL Server on Windows Azure Virtual Machines

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• Professional Development – Difference Between Bio, CV and Resume

  - by Pinal Dave

  Applying for work can be very stressful – you want to put your best foot forward, and it can be very hard to sell yourself to a potential employer while highlighting your best characteristics and answering questions.  On top of that, some jobs require different application materials – a biography (or bio), a curriculum vitae (or CV), or a resume.  These things seem so interchangeable, so what is the difference? Let’s start with the one most of us have heard of – the resume.  A resume is a summary of your job and education history.  If you have ever applied for a job, you will have used a resume.  The ability to write a good resume that highlights your best characteristics and emphasizes your qualifications for a specific job is a skill that will take you a long way in the world.  For such an essential skill, unfortunately it is one that many people struggle with. RESUME So let’s discuss what makes a great resume.  First, make sure that your name and contact information are at the top, in large print (slightly larger font than the rest of the text, size 14 or 16 if the rest is size 12, for example).  You need to make sure that if you catch the recruiter’s attention and they know how to get a hold of you. As for qualifications, be quick and to the point.  Make your job title and the company the headline, and include your skills, accomplishments, and qualifications as bullet points.  Use good action verbs, like “finished,” “arranged,” “solved,” and “completed.”  Include hard numbers – don’t just say you “changed the filing system,” say that you “revolutionized the storage of over 250 files in less than five days.”  Doesn’t that sentence sound much more powerful? Curriculum Vitae (CV) Now let’s talk about curriculum vitae, or “CVs”.  A CV is more like an expanded resume.  The same rules are still true: put your name front and center, keep your contact info up to date, and summarize your skills with bullet points.  However, CVs are often required in more technical fields – like science, engineering, and computer science.  This means that you need to really highlight your education and technical skills. Difference between Resume and CV Resumes are expected to be one or two pages long – CVs can be as many pages as necessary.  If you are one of those people lucky enough to feel limited by the size constraint of resumes, a CV is for you!  On a CV you can expand on your projects, highlight really exciting accomplishments, and include more educational experience – including GPA and test scores from the GRE or MCAT (as applicable).  You can also include awards, associations, teaching and research experience, and certifications.  A CV is a place to really expand on all your experience and how great you will be in this particular position. Biography (Bio) Chances are, you already know what a bio is, and you have even read a few of them.  Think about the one or two paragraphs that every author includes in the back flap of a book.  Think about the sentences under a blogger’s photo on every “About Me” page.  That is a bio.  It is a way to quickly highlight your life experiences.  It is essentially the way you would introduce yourself at a party. Where a bio is required for a job, chances are they won’t want to know about where you were born and how many pets you have, though.  This is a way to summarize your entire job history in quick-to-read format – and sometimes during a job hunt, being able to get to the point and grab the recruiter’s interest is the best way to get your foot in the door.  Think of a bio as your entire resume put into words. Most bios have a standard format.  In paragraph one, talk about your most recent position and accomplishments there, specifically how they relate to the job you are applying for.  If you have teaching or research experience, training experience, certifications, or management experience, talk about them in paragraph two.  Paragraph three and four are for highlighting publications, education, certifications, associations, etc.  To wrap up your bio, provide your contact info and availability (dates and times). Where to use What? For most positions, you will know exactly what kind of application to use, because the job announcement will state what materials are needed – resume, CV, bio, cover letter, skill set, etc.  If there is any confusion, choose whatever the industry standard is (CV for technical fields, resume for everything else) or choose which of your documents is the strongest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, PostADay, Professional Development, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Database Rebuild

  - by Robert May

  I promised I’d have a simpler mechanism for rebuilding the database.  Below is a complete MSBuild targets file for rebuilding the database from scratch.  I don’t know if I’ve explained the rational for this.  The reason why you’d WANT to do this is so that each developer has a clean version of the database on their local machine.  This also includes the continuous integration environment.  Basically, you can do whatever you want to the database without fear, and in a minute or two, have a completely rebuilt database structure. DBDeploy (including the KTSC build task for dbdeploy) is used in this script to do change tracking on the database itself.  The MSBuild ExtensionPack is used in this target file.  You can get an MSBuild DBDeploy task here. There are two database scripts that you’ll see below.  First is the task for creating an admin (dbo) user in the system.  This script looks like the following: USE [master] GO If not Exists (select Name from sys.sql_logins where name = '$(User)') BEGIN CREATE LOGIN [$(User)] WITH PASSWORD=N'$(Password)', DEFAULT_DATABASE=[$(DatabaseName)], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF END GO EXEC master..sp_addsrvrolemember @loginame = N'$(User)', @rolename = N'sysadmin' GO USE [$(DatabaseName)] GO CREATE USER [$(User)] FOR LOGIN [$(User)] GO ALTER USER [$(User)] WITH DEFAULT_SCHEMA=[dbo] GO EXEC sp_addrolemember N'db_owner', N'$(User)' GO The second creates the changelog table.  This script can also be found in the dbdeploy.net install\scripts directory. CREATE TABLE changelog ( change_number INTEGER NOT NULL, delta_set VARCHAR(10) NOT NULL, start_dt DATETIME NOT NULL, complete_dt DATETIME NULL, applied_by VARCHAR(100) NOT NULL, description VARCHAR(500) NOT NULL ) GO ALTER TABLE changelog ADD CONSTRAINT Pkchangelog PRIMARY KEY (change_number, delta_set) GO Finally, Here’s the targets file. <Projectxmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0" DefaultTargets="Update">   <PropertyGroup>     <DatabaseName>TestDatabase</DatabaseName>     <Server>localhost</Server>     <ScriptDirectory>.\Scripts</ScriptDirectory>     <RebuildDirectory>.\Rebuild</RebuildDirectory>     <TestDataDirectory>.\TestData</TestDataDirectory>     <DbDeploy>.\DBDeploy</DbDeploy>     <User>TestUser</User>     <Password>TestPassword</Password>     <BCP>bcp</BCP>     <BCPOptions>-S$(Server) -U$(User) -P$(Password) -N -E -k</BCPOptions>     <OutputFileName>dbDeploy-output.sql</OutputFileName>     <UndoFileName>dbDeploy-output-undo.sql</UndoFileName>     <LastChangeToApply>99999</LastChangeToApply>   </PropertyGroup>     <ImportProject="$(MSBuildExtensionsPath)\ExtensionPack\4.0\MSBuild.ExtensionPack.tasks"/>   <UsingTask TaskName="Ktsc.Build.DBDeploy" AssemblyFile="$(DbDeploy)\Ktsc.Build.dll"/>   <ItemGroup>     <VariableInclude="DatabaseName">       <Value>$(DatabaseName)</Value>     </Variable>     <VariableInclude="Server">       <Value>$(Server)</Value>     </Variable>     <VariableInclude="User">       <Value>$(User)</Value>     </Variable>     <VariableInclude="Password">       <Value>$(Password)</Value>     </Variable>   </ItemGroup>     <TargetName="Rebuild">     <!--Take the database offline to disconnect any users. Requires that the current user is an admin of the sql server machine.-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd Variables="@(Variable)" Database="$(DatabaseName)" TaskAction="Execute" CommandLineQuery ="ALTER DATABASE $(DatabaseName) SET OFFLINE WITH ROLLBACK IMMEDIATE"/>         <!--Bring it back online.  If you don't, the database files won't be deleted.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="SetOnline" DatabaseItem="$(DatabaseName)"/>     <!--Delete the database, removing the existing files.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Delete" DatabaseItem="$(DatabaseName)"/>     <!--Create the new database in the default database path location.-->     <MSBuild.ExtensionPack.Sql2008.DatabaseTaskAction="Create" DatabaseItem="$(DatabaseName)" Force="True"/>         <!--Create admin user-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" InputFiles="$(RebuildDirectory)\0002 Create Admin User.sql" Variables="@(Variable)" />     <!--Create the dbdeploy changelog.-->     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(RebuildDirectory)\0003 Create Changelog.sql" Variables="@(Variable)" />     <CallTarget Targets="Update;ImportData"/>     </Target>    <TargetName="Update" DependsOnTargets="CreateUpdateScript">     <MSBuild.ExtensionPack.SqlServer.SqlCmd TaskAction="Execute" Server="(local)" Database="$(DatabaseName)" LogOn="$(User)" Password="$(Password)" InputFiles="$(OutputFileName)" Variables="@(Variable)" />   </Target>   <TargetName="CreateUpdateScript">     <ktsc.Build.DBDeploy DbType="mssql"                                        DbConnection="User=$(User);Password=$(Password);Data Source=$(Server);Initial Catalog=$(DatabaseName);"                                        Dir="$(ScriptDirectory)"                                        OutputFile="..\$(OutputFileName)"                                        UndoOutputFile="..\$(UndoFileName)"                                        LastChangeToApply="$(LastChangeToApply)"/>   </Target>     <TargetName="ImportData">     <ItemGroup>       <TestData Include="$(TestDataDirectory)\*.dat"/>     </ItemGroup>     <ExecCommand="$(BCP) $(DatabaseName).dbo.%(TestData.Filename) in&quot;%(TestData.Identity)&quot;$(BCPOptions)"/>   </Target> </Project> Technorati Tags: MSBuild

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• Speakers, Please Check Your Time

  - by AjarnMark

  Woodrow Wilson was once asked how long it would take him to prepare for a 10 minute speech. He replied "Two weeks". He was then asked how long it would take for a 1 hour speech. "One week", he replied. 2 hour speech? "I'm ready right now," he replied.  Whether that is a true story or an urban legend, I don’t really know, but either way, it is a poignant reminder for all speakers, and particularly apropos this week leading up to the PASS Community Summit. (Cross-posted to the PASS Professional Development Virtual Chapter blog #PASSProfDev.) What’s the point of that story?  Simply this…if you have plenty of time to do your presentation, you don’t need to prepare much because it is easy to throw in more and more material to stretch out to your allotted time.  But if you are on a tight time constraint, then it will take significant preparation to distill your talk down to only the essential points. I have attended seven of the last eight North American Summit events, and every one of them has been fantastic.  The speakers are great, the material is timely and relevant, and the networking opportunities are awesome.  And every year, there is one little thing that just bugs me…speakers going over their allotted time.  Why does it bother me so?  Well, if you look at a typical schedule for a Summit, you’ll see that there are six or more sessions going on at the same time, and only 15 minutes to move from one to another.  If you’re trying to maximize your training dollar by attending something during every session time slot, and you don’t want to be the last guy trying to squeeze into the middle of the row, then those 15 minutes can be critical.  All the more so if you need to stop and use the bathroom or if you have to hike to the opposite end of the convention center.  It is really a bad position to find yourself having to choose between learning the last key points of Speaker A who is going over time, and getting over to Speaker B on time so you don’t miss her key opening remarks. And frankly, I think it is just rude.  Yes, the speakers are the function, after all they are bringing the content that the rest of us are paying to learn.  But it is also an honor to be given the opportunity to speak at a conference like this, and no one speaker is so important that the conference would be a disaster without him.  Speakers know when they submit their abstract, long before the conference, how much time they will have.  It has been the same pattern at the Summit for at least the last eight years.  Program Sessions are 75 minutes long.  Some speakers who have a good track record, and meet other qualifying criteria, are extended an invitation to present a Spotlight Session which is 90 minutes (a 20% increase).  So there really is no excuse.  It’s not like you were promised a 2-hour segment and then discovered when you got here that it was only 75 minutes.  In fact, it’s not like PASS advertised 90-minute sessions for everyone and then a select few were cut back to only 75.  As a speaker, you know well before you get here which type of session you are doing and how long it is, so as a professional, you should plan accordingly. Now you might think that this only happens to rookies, but I’ll tell you that some of the worst offenders are big-name veterans who draw huge attendance numbers for their sessions.  Some attendees blow this off as, “Hey, it’s so-and-so, and I’d stay here for hours and listen to him/her talk.”  To which I would reply, “Then they should have submitted for a pre- or post-conference day-long seminar instead, but don’t try to squeeze your day-long talk into a 90-minute session.”  Now I don’t really believe that these speakers are being malicious or just selfishly trying to extend their time in the spotlight.  I think that most of them are merely being undisciplined and did not trim their presentation sufficiently, or allowed themselves to get off-track (often in a generous attempt to help someone in the audience with a question or problem that really should have been noted for further discussion after the session). So here is my recommendation…my plea, even.  TRIM THE FAT!  Now.  Before it’s too late.  Before you even get on the airplane, take a long, hard look at your presentation and eliminate some of the points that you originally thought you had to make, but in reality are not truly crucial to your main topic.  Delete a few slides.  Test your demos and have them already scripted rather than typing them during your talk.  It is better to cut out too much and end up with plenty of time at the end for Questions & Answers.  And you can always keep some notes on the stuff that you cut out so that you could fill it back in at the end as bonus material if you really do end up with a whole bunch of time on your hands.  But I don’t think you will.  And if you do, that will look even better to the audience as it will look like you’re giving them something extra that not every audience gets.  And they will thank you for that.

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• Tip #19 Module Private Visibility in OSGi

  - by ByronNevins

  I hate public and protected methods and classes.  It requires so much work to change them in a huge project like GlassFish.  Not to mention that you may well have to support those APIs forever.  They are highly overused in GlassFish.  In fact I'd bet that > 95% of classes are marked as public for no good reason.  It's just (bad) habit is my guess. private and default visibility (I call it package-private) is easier to maintain.  It is much much easier to change such classes and methods around.  If you have ANY public method or public class in GlassFish you'll need to grep through a tremendous amount of source code to find all callers.  But even that won't be theoretically reliable.  What if a caller is using reflection to access public methods?  You may never find such usages. If you have package private methods, it's easy.  Simply grep through all the code in that one package.  As long as that package compiles ok you're all set.  There can' be any compile errors anywhere else.  It's a waste of time to even look around or build the "outside" world.  So you may be thinking: "Aha!  I'll just make my module have one giant package with all the java files.  Then I can use the default visibility and maintenance will be much easier.  But there's a problem.  You are wasting a very nice feature of java -- organizing code into separate packages.  It also makes the code much more encapsulated.  Unfortunately to share code between the packages you have no choice but to declare public visibility. What happens in practice is that a module ends up having tons of public classes and methods that are used exclusively inside the module.  Which finally brings me to the point of this blog:  If Only There Was A Module-Private Visibility Available Well, surprise!  There is such a mechanism.  If your project is running under OSGi that is.  Like GlassFish does!  With this mechanism you can easily add another level of visibility by telling OSGi exactly which public you want to be exposed outside of the module.  You get the best of both worlds: Better encapsulation of your code so that maintenance is easier and productivity is increased. Usage of public visibility inside the module so that you can encapsulate intra-module better with packages. How I do this in GlassFish: Carefully plan out at least one package that will contain "true" publics.  This is the package that will be exported by OSGi.  I recommend just one package. Here is how to tell OSGi to use it in GlassFish -- edit osgi.bundle like so:-exportcontents:     org.glassfish.mymodule.truepublics;  version=${project.osgi.version} Now all publics declared in any other packages will be visible module-wide but not outside the module. There is one caveat: Accessing "module-private" items outside of the module is controlled at run-time, not compile-time.  The compiler has no clue that a public in a dependent module isn't really public.  it will happily compile it.  At runtime you will definitely see fireworks.  The good news is that you don't have to wait for the code path that tries to use the "module-private" items to fire.  OSGi will complain loudly when that module gets loaded.  OSGi will refuse to load it.  You will see an error like this: remote failure: Error while loading FOO: Exception while adding the new configuration : Error occurred during deployment: Exception while loading the app : org.osgi.framework.BundleException: Unresolved constraint in bundle com.oracle.glassfish.miscreant.code [115]: Unable to resolve 115.0: missing requirement [115.0] osgi.wiring.package; (osgi.wiring.package=org.glassfish.mymodule.unexported). Please see server.log for more details. That is if you accidentally change code in module B to use a public that is really a "module-private" in module A, then you will see the error immediately when you try to test whatever you were changing in module B.

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• NRF Online Merchandising Workshop: Where Online Retailers Are Focusing for Holiday and Beyond

  - by Rose Spicer-Oracle

  0 0 1 1204 6863 Oracle Corporation 57 16 8051 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Last month we attended the NRF Online Merchandising Workshop in LA, and it was a great opportunity to catch up with our customers, meet new retailers, and hear some great presentations from VF Corporation, Zazzle, Julep Beauty, Backcountry, eBags and more. The one-on-one conversations with Merchants and the keynote presentations carry the same themes across companies of all sizes and across verticals. With only 125 days left (and counting) until Black Friday, these conversations provided some great insight in to what’s top of mind for retailers during the most stressful time of their year, and a sneak peek in to what they will deliver this holiday season.  Some of the most popular topics were: When to start promoting for holiday: seems like a funny conversation to have in July, but a number of retailers said they already had their holiday shopping gift guides live on their site, and it was attracting a significant portion of their onsite traffic. When it comes to timing, most retailers were questioning when to begin their holiday promotions -- carefully balancing when to release pricing and specials, and knowing that customers are holding out for last-minute deals and price drops. Many retailers noted the frustrations around transparent pricing by Amazon and a few other mega-retailers last year, publishing their “lowest prices of the season” as early as October – ensuring shoppers that those prices were the best they could get all season long. Many retailers felt their hands were forced to drop prices. Others kept their set pricing with negative customer reaction, causing some to miss their holiday goals. The pressure is on, and most retailers identified November 1 as their target start date for the holiday promotions blitz. Some are even waiting for the big guys to release their “lowest prices of the season” guides and will then follow suit.      Attribution is tough – and a huge focus: understanding the path to conversion is a tough nut to crack, especially in the new omnichannel world where consumers use multiple touchpoints to make a single purchase, and internal management wants to know hard data. This has lead many retailers to invest in attribution; carefully tracking their online marketing efforts to determine what gets “credit” for the sale, instead of giving credit to the “last click.” Retailers noted that it is very difficult to determine the numbers when online and offline worlds collide – like when a shopper uses digital channels for research and then makes a purchase in a store. As one of the presenters from The North Face mentioned in her keynote, a key to enabling better customer service and satisfaction when it comes to converged online and offline sales is training the in-store staff, and creating a culture where it eventually “doesn’t matter what group gets the credit” if they all add to the sale. No doubt, the area of attribution will be a big area of retail investment in the coming years.      How to plan for the converged world: planning to ensure inventory gets where it needs to be was another concern. In conversations with retailers, we advised them to analyze customer patterns: where shoppers purchase items, where the items were sourced from and even where items are returned. This analysis is very valuable in determining inventory plans. From there, retailers can more accurately plan and allocate inventory to support both the online and offline customer behavior. As we head into the holiday season, the need for accurate enterprise-wide inventory visibility, and providing that information to associates, is even more critical to the brand-wide customer experience.       Improving the search / navigation / usability of the site(s): Aside from some of the big ideas and standard holiday pricing pressure, most conversations we had centered around continuing to improve the basics of the site. Reinvesting in search and navigation came up time and time again (FitForCommerce blogged about what a big topic it was at the event as well). Obviously getting shoppers on their path quickly and allowing them to find what they need fast is critical, but it was definitely interesting to hear just how much effort is still going in to honing the search and navigation experience. Adding new elements to search and navigation like typeahed, inventive navigation refinements, and new navigation categories like gift guides, specialized boutiques and flash sales were top of mind, in addition to searchandising and making search-driven product recommendations. (Oracle can help!)       Reducing cart abandonment: always a hot topic that is top of mind for every online retailer. Getting shoppers to the cart is often less then half the battle; getting them to click “buy” and complete the transaction is much more difficult. While retailers carefully study the checkout process and where shoppers tend to bounce, they know that how they design their checkout page is critical. We’re all online shoppers in our personal lives and we know how frustrating it can be when total prices are not transparent (i.e. shipping, processing, taxes is not included until the very last possible screen before clicking that buy button). Online retailers are struggling with where in the checkout process to surface the total price to be charged to reduce cart abandonment, while not showing the total figure too early in the process that it keeps shoppers from getting to checkout altogether. Recent research shows that providing total pricing prior to the checkout process dramatically reduces cart abandonment – as it serves as a filter to those shopping within a specific price band. Much of the cart abandonment discussion leads us to…       The free shipping / free returns question: it’s no secret that because of Amazon and programs like Prime, consumers expect free shipping, much to the chagrin of the smaller retailer. The reality is that if you’re not a mega-retailer, shipping is an expensive part of doing business that doesn’t allow most retailers to keep their prices low and offer free shipping. This has many retailers venturing out on the “free returns” path, especially in apparel. A number of retailers we spoke with are testing a flat rate shipping fee with free returns to see if they can crack the price threshold where shoppers are willing to pay for shipping with an added service. But, free shipping remains king.      Social ads and retargeting: they are working, but do they turn off consumers? That’s the big question. Every retailer we spoke with during a roundtable on the topic said that social ads and retargeting (where that pair of boots you’re been eyeing on a site magically follows you around the Internet) work and are meeting campaign goals. The larger question many retailers are asking is if this type of tactic is turning off a large number of shoppers, even if these campaigns are meeting their early goals. Retailers also mentioned that Facebook ads are working very well for them, especially when it comes to new customer acquisition, serving as a complimentary a channel to SEO when it comes to engaging new customers. While there are always new things to experiment with in retail, standard challenges are top of mind as retailers scramble to get ready for holiday. It will undoubtedly be another record-breaking online shopping season, but as retailers get more and more advanced with each Black Friday, expect some exciting things. This excitement needs to be backed by sound solutions and optimized operations. Then again, consumers are expecting more than ever, so I don’t doubt that retailers are already thinking about the possibilities of holiday 2015… and beyond. Customers who read this article, also found value in the following stories: Personalization for Retail: http://blogs.oracle.com/retail/entry/personalization_for_retailShop Direct User Experience Focus Drives Sales:https://blogs.oracle.com/retail/entry/shop_direct_user_experience_focusMaking Waves: Australian Online Retailer SurfStitch: https://blogs.oracle.com/oracleretail/entry/surf_stitchWhat’s new in Oracle Commerce v11.1 for RetailWhat the Content+Commerce Equation is Missing

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• Windows 8 Will be Here Tomorrow; but Should Silverlight be Gone Today?

  - by andrewbrust

  The software industry lives within an interesting paradox. IT in the enterprise moves slowly and cautiously, upgrading only when safe and necessary.  IT interests intentionally live in the past.  On the other hand, developers, and Independent Software Vendors (ISVs) not only want to use the latest and greatest technologies, but this constituency prides itself on gauging tech’s future, and basing its present-day strategy upon it.  Normally, we as an industry manage this paradox with a shrug of the shoulder and musings along the lines of “it takes all kinds.”  Different subcultures have different tendencies.  So be it. Microsoft, with its Windows operating system (OS), can’t take such a laissez-faire view of the world though.  Redmond relies on IT to deploy Windows and (at the very least) influence its procurement, but it also relies on developers to build software for Windows, especially software that has a dependency on features in new versions of the OS.  It must indulge and nourish developers’ fetish for an early birthing of the next generation of software, even as it acknowledges the IT reality that the next wave will arrive on-schedule in Redmond and will travel very slowly to end users. With the move to Windows 8, and the corresponding shift in application development models, this paradox is certainly in place. On the one hand, the next version of Windows is widely expected sometime in 2012, and its full-scale deployment will likely push into 2014 or even later.  Meanwhile, there’s a technology that runs on today’s Windows 7, will continue to run in the desktop mode of Windows 8 (the next version’s codename), and provides absolutely the best architectural bridge to the Windows 8 Metro-style application development stack.  That technology is Silverlight.  And given what we now know about Windows 8, one might think, as I do, that Microsoft ecosystem developers should be flocking to it. But because developers are trying to get a jump on the future, and since many of them believe the impending v5.0 release of Silverlight will be the technology’s last, not everyone is flocking to it; in fact some are fleeing from it.  Is this sensible?  Is it not unprecedented?  What options does it lead to?  What’s the right way to think about the situation? Is v5.0 really the last major version of the technology called Silverlight?  We don’t know.  But Scott Guthrie, the “father” and champion of the technology, left the Developer Division of Microsoft months ago to work on the Windows Azure team, and he took his people with him.  John Papa, who was a very influential Redmond-based evangelist for Silverlight (and is a Visual Studio Magazine author), left Microsoft completely.  About a year ago, when initial suspicion of Silverlight’s demise reached significant magnitude, Papa interviewed Guthrie on video and their discussion served to dispel developers’ fears; but now they’ve moved on. So read into that what you will and let’s suppose, for the sake of argument, speculation that Silverlight’s days of major revision and iteration are over now is correct.  Let’s assume the shine and glimmer has dimmed.  Let’s assume that any Silverlight application written today, and that therefore any investment of financial and human resources made in Silverlight development today, is destined for rework and extra investment in a few years, if the application’s platform needs to stay current. Is this really so different from any technology investment we make?  Every framework, language, runtime and operating system is subject to change, to improvement, to flux and, yes, to obsolescence.  What differs from project to project, is how near-term that obsolescence is and how disruptive the change will be.  The shift from .NET 1.1. to 2.0 was incremental.  Some of the further changes were too.  But the switch from Windows Forms to WPF was major, and the change from ASP.NET Web Services (asmx) to Windows Communication Foundation (WCF) was downright fundamental. Meanwhile, the transition to the .NET development model for Windows 8 Metro-style applications is actually quite gentle.  The finer points of this subject are covered nicely in Magenic’s excellent white paper “Assessing the Windows 8 Development Platform.” As the authors of that paper (including Rocky Lhotka)  point out, Silverlight code won’t just “port” to Windows 8.  And, no, Silverlight user interfaces won’t either; Metro always supports XAML, but that relationship is not commutative.  But the concepts, the syntax, the architecture and developers’ skills map from Silverlight to Windows 8 Metro and the Windows Runtime (WinRT) very nicely.  That’s not a coincidence.  It’s not an accident.  This is a protected transition.  It’s not a slap in the face. There are few things that are unnerving about this transition, which make it seem markedly different from others: The assumed end of the road for Silverlight is something many think they can see.  Instead of being ignorant of the technology’s expiration date, we believe we know it.  If ignorance is bliss, it would seem our situation lacks it. The new technology involving WinRT and Metro involves a name change from Silverlight. .NET, which underlies both Silverlight and the XAML approach to WinRT development, has just about reached 10 years of age.  That’s equivalent to 80 in human years, or so many fear. My take is that the combination of these three factors has contributed to what for many is a psychologically compelling case that Silverlight should be abandoned today and HTML 5 (the agnostic kind, not the Windows RT variety) should be embraced in its stead.  I understand the logic behind that.  I appreciate the preemptive, proactive, vigilant conscientiousness involved in its calculus.  But for a great many scenarios, I don’t agree with it.  HTML 5 clients, no matter how impressive their interactivity and the emulation of native application interfaces they present may be, are still second-class clients.  They are getting better, especially when hardware acceleration and fast processors are involved.  But they still lag.  They still feel like they’re emulating something, like they’re prototypes, like they’re not comfortable in their own skins.  They are based on compromise, and they feel compromised too. HTML 5/JavaScript development tools are getting better, and will get better still, but they are not as productive as tools for other environments, like Flash, like Silverlight or even more primitive tooling for iOS or Android.  HTML’s roots as a document markup language, rather than an application interface, create a disconnect that impedes productivity.  I do not necessarily think that problem is insurmountable, but it’s here today. If you’re building line-of-business applications, you need a first-class client and you need productivity.  Lack of productivity increases your costs and worsens your backlog.  A second class client will erode user satisfaction, which is never good.  Worse yet, this erosion will be inconspicuous, rather than easily identified and diagnosed, because the inferiority of an HTML 5 client over a native one is hard to identify and, notably, doing so at this juncture in the industry is unpopular.  Why would you fault a technology that everyone believes is revolutionary?  Instead, user disenchantment will remain latent and yet will add to the malaise caused by slower development. If you’re an ISV and you’re coveting the reach of running multi-platform, it’s a different story.  You’ve likely wanted to move to HTML 5 already, and the uncertainty around Silverlight may be the only remaining momentum or pretext you need to make the shift.  You’re deploying many more copies of your application than a line-of-business developer is anyway; this makes the economic hit from lower productivity less impactful, and the wider potential installed base might even make it profitable. But no matter who you are, it’s important to take stock of the situation and do it accurately.  Continued, but merely incremental changes in a development model lead to conservatism and general lack of innovation in the underlying platform.  Periods of stability and equilibrium are necessary, but permanence in that equilibrium leads to loss of platform relevance, market share and utility.  Arguably, that’s already happened to Windows.  The change Windows 8 brings is necessary and overdue.  The marked changes in using .NET if we’re to build applications for the new OS are inevitable.  We will ultimately benefit from the change, and what we can reasonably hope for in the interim is a migration path for our code and skills that is navigable, logical and conceptually comfortable. That path takes us to a place called WinRT, rather than a place called Silverlight.  But considering everything that is changing for the good, the number of disruptive changes is impressively minimal.  The name may be changing, and there may even be some significance to that in terms of Microsoft’s internal management of products and technologies.  But as the consumer, you should care about the ingredients, not the name.  Turkish coffee and Greek coffee are much the same. Although you’ll find plenty of interested parties who will find the names significant, drinkers of the beverage should enjoy either one.  It’s all coffee, it’s all sweet, and you can tell your fortune from the grounds that are left at the end.  Back on the software side, it’s all XAML, and C# or VB .NET, and you can make your fortune from the product that comes out at the end.  Coffee drinkers wouldn’t switch to tea.  Why should XAML developers switch to HTML?

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• Issue 15: SVP Focus

  - by rituchhibber

       SVP FOCUS FOCUS -- Chris Baker SVP Oracle Worldwide ISV-OEM-Java Sales Chris Baker is the Global Head of ISV/OEM Sales responsible for working with ISV/OEM partners to maximise Oracle's business through those partners, whilst maximising those partners’ business to their end users. Chris works with partners, customers, innovators, investors and employees to develop innovative business solutions using Oracle products, services and skills. RESOURCES -- Oracle PartnerNetwork (OPN) OPN Solutions Catalog Oracle Exastack Program Oracle Exastack Optimized Oracle Cloud Computing Oracle Engineered Systems Oracle and Java SUBSCRIBE FEEDBACK PREVIOUS ISSUES "By taking part in marketing activities, our partners accelerate their sales cycles." -- Firstly, could you please explain Oracle's current strategy for ISV partners, globally and in EMEA? Oracle customers use independent software vendor (ISV) applications to run their businesses. They use them to generate revenue and to fulfil obligations to their own customers. Our strategy is very straight-forward. We want all of our ISV partners and OEMs to concentrate on the things that they do the best—building applications to meet the unique industry and functional requirements of their customer. We want to ensure that we deliver a best-in-class application platform so ISVs are free to concentrate their effort on their application functionality and user experience We invest over four billion dollars in research and development every year, and we want our ISVs to benefit from all of that investment in operating systems, virtualisation, databases, middleware, engineered systems, and other hardware. By doing this, we help them to reduce their costs, gain more consistency and agility for quicker implementations, and also rapidly differentiate themselves from other application vendors. It's all about simplification because we believe that around 25 to 30 percent of the development costs incurred by many ISVs are caused by customising infrastructure and have nothing to do with their applications. Our strategy is to enable our ISV partners to standardise their application platform using engineered architecture, so they can write once to the Oracle stack and deploy seamlessly in the cloud, on-premise, or in hybrid deployments. It's really important that architecture is the same in order to keep cost and time overheads at a minimum, so we provide standardisation and an environment that enables our ISVs to concentrate on the core business that makes them the most money and brings them success. How do you believe this strategy is helping the ISVs to work hand-in-hand with Oracle to ensure that end customers get the industry-leading solutions that they need? We work with our ISVs not just to help them be successful, but also to help them market themselves. We have something called the 'Oracle Exastack Ready Program', which enables ISVs to publicise themselves as 'Ready' to run the core software platforms that run on Oracle's engineered systems including Exadata and Exalogic. So, for example, they can become 'Database Ready' which means that they use the latest version of Oracle Database and therefore can run their application without modification on Exadata or the Oracle Database Appliance. Alternatively, they can become WebLogic Ready, Oracle Linux Ready and Oracle Solaris Ready which means they run on the latest release and therefore can run their application, with no new porting work, on Oracle Exalogic. Those 'Ready' logos are important in helping ISVs advertise to their customers that they are using the latest technologies which have been fully tested. We now also have Exadata Ready and Exalogic Ready programmes which allow ISVs to promote the certification of their applications on these platforms. This highlights these partners to Oracle customers as having solutions that run fluently on the Oracle Exadata Database Machine, the Oracle Exalogic Elastic Cloud or one of our other engineered systems. This makes it easy for customers to identify solutions and provides ISVs with an avenue to connect with Oracle customers who are rapidly adopting engineered systems. We have also taken this programme to the next level in the shape of 'Oracle Exastack Optimized' for partners whose applications run best on the Oracle stack and have invested the time to fully optimise application performance. We ensure that Exastack Optimized partner status is promoted and supported by press releases, and we help our ISVs go to market and differentiate themselves through the use of our technology and the standardisation it delivers. To date we have had several hundred organisations successfully work through our Exastack Optimized programme. How does Oracle's strategy of offering pre-integrated open platform software and hardware allow ISVs to bring their products to market more quickly? One of the problems for many ISVs is that they have to think very carefully about the technology on which their solutions will be deployed, particularly in the cloud or hosted environments. They have to think hard about how they secure these environments, whether the concern is, for example, middleware, identity management, or securing personal data. If they don't use the technology that we build-in to our products to help them to fulfil these roles, they then have to build it themselves. This takes time, requires testing, and must be maintained. By taking advantage of our technology, partners will now know that they have a standard platform. They will know that they can confidently talk about implementation being the same every time they do it. Very large ISV applications could once take a year or two to be implemented at an on-premise environment. But it wasn't just the configuration of the application that took the time, it was actually the infrastructure - the different hardware configurations, operating systems and configurations of databases and middleware. Now we strongly believe that it's all about standardisation and repeatability. It's about making sure that our partners can do it once and are then able to roll it out many different times using standard componentry. What actions would you recommend for existing ISV partners that are looking to do more business with Oracle and its customer base, not only to maximise benefits, but also to maximise partner relationships? My team, around the world and in the EMEA region, is available and ready to talk to any of our ISVs and to explore the possibilities together. We run programmes like 'Excite' and 'Insight' to help us to understand how we can help ISVs with architecture and widen their environments. But we also want to work with, and look at, new opportunities - for example, the Machine-to-Machine (M2M) market or 'The Internet of Things'. Over the next few years, many millions, indeed billions of devices will be collecting massive amounts of data and communicating it back to the central systems where ISVs will be running their applications. The only way that our partners will be able to provide a single vendor 'end-to-end' solution is to use Oracle integrated systems at the back end and Java on the 'smart' devices collecting the data—a complete solution from device to data centre. So there are huge opportunities to work closely with our ISVs, using Oracle's complete M2M platform, to provide the infrastructure that enables them to extract maximum value from the data collected. If any partners don't know where to start or who to contact, then they can contact me directly at [email protected] or indeed any of our teams across the EMEA region. We want to work with ISVs to help them to be as successful as they possibly can through simplification and speed to market, and we also want all of the top ISVs in the world based on Oracle. What opportunities are immediately opened to new ISV partners joining the OPN? As you know OPN is very, very important. New members will discover a huge amount of content that instantly becomes accessible to them. They can access a wealth of no-cost training and enablement materials to build their expertise in Oracle technology. They can download Oracle software and use it for development projects. They can help themselves become more competent by becoming part of a true community and uncovering new opportunities by working with Oracle and their peers in the Oracle Partner Network. As well as publishing massive amounts of information on OPN, we also hold our global Oracle OpenWorld event, at which partners play a huge role. This takes place at the end of September and the beginning of October in San Francisco. Attending ISV partners have an unrivalled opportunity to contribute to elements such as the OpenWorld / OPN Exchange, at which they can talk to other partners and really begin thinking about how they can move their businesses on and play key roles in a very large ecosystem which revolves around technology and standardisation. Finally, are there any other messages that you would like to share with the Oracle ISV community? The crucial message that I always like to reinforce is architecture, architecture and architecture! The key opportunities that ISVs have today revolve around standardising their architectures so that they can confidently think: "I will I be able to do exactly the same thing whenever a customer is looking to deploy on-premise, hosted or in the cloud". The right architecture is critical to being competitive and to really start changing the game. We want to help our ISV partners to do just that; to establish standard architecture and to seize the opportunities it opens up for them. New market opportunities like M2M are enormous - just look at how many devices are all around you right now. We can help our partners to interface with these devices more effectively while thinking about their entire ecosystem, rather than just the piece that they have traditionally focused upon. With standardised architecture, we can help people dramatically improve their speed, reach, agility and delivery of enhanced customer satisfaction and value all the way from the Java side to their centralised systems. All Oracle ISV partners must take advantage of these opportunities, which is why Oracle will continue to invest in and support them. Oracle OpenWorld 2010 Whether you attended Oracle OpenWorld 2009 or not, don't forget to save the date now for Oracle OpenWorld 2010. The event will be held a little earlier next year, from 19th-23rd September, so please don't miss out. With thousands of sessions and hundreds of exhibits and demos already lined up, there's no better place to learn how to optimise your existing systems, get an inside line on upcoming technology breakthroughs, and meet with your partner peers, Oracle strategists and even the developers responsible for the products and services that help you get better results for your end customers. Register Now for Oracle OpenWorld 2010! Perhaps you are interested in learning more about Oracle OpenWorld 2010, but don't wish to register at this time? Great! Please just enter your contact information here and we will contact you at a later date. How to Exhibit at Oracle OpenWorld 2010 Sponsorship Opportunities at Oracle OpenWorld 2010 Advertising Opportunities at Oracle OpenWorld 2010 -- Back to the welcome page

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• Masters vs. PhD - long [closed]

  - by Sterling

  I'm 21 years old and a first year master's computer science student. Whether or not to continue with my PhD has been plaguing me for the past few months. I can't stop thinking about it and am extremely torn on the issue. I have read http://www.cs.unc.edu/~azuma/hitch4.html and many, many other masters vs phd articles on the web. Unfortunately, I have not yet come to a conclusion. I was hoping that I could post my ideas about the issue on here in hopes to 1) get some extra insight on the issue and 2) make sure that I am correct in my assumptions. Hopefully having people who have experience in the respective fields can tell me if I am wrong so I don't make my decision based on false ideas. Okay, to get this topic out of the way - money. Money isn't the most important thing to me, but it is still important. It's always been a goal of mine to make 6 figures, but I realize that will probably take me a long time with either path. According to most online salary calculating sites, the average starting salary for a software engineer is ~60-70k. The PhD program here is 5 years, so that's about 300k I am missing out on by not going into the workforce with a masters. I have only ever had ~1k at one time in my life so 300k is something I can't even really accurately imagine. I know that I wouldn't have at once obviously, but just to know I would be earning that is kinda crazy to me. I feel like I would be living quite comfortably by the time I'm 30 years old (but risk being too content too soon). I would definitely love to have at least a few years of my 20s to spend with that kind of money before I have a family to spend it all on. I haven't grown up very financially stable so it would be so nice to just spend some money…get a nice car, buy a new guitar or two, eat some good food, and just be financially comfortable. I have always felt like I deserved to make good money in my life, even as a kid growing up, and I just want to have it be a reality. I know that either path I take will make good money by the time I'm ~40-45 years old, but I guess I'm just sick of not making money and am getting impatient about it. However, a big idea pushing me towards a PhD is that I feel the masters path would give me a feeling of selling out if I have the capability to solve real questions in the computer science world. (pretty straight-forward - not much to elaborate on, but this is a big deal) Now onto other aspects of the decision. I originally got into computer science because of programming. I started in high school and knew very soon that it was what I wanted to do for a career. I feel like getting a masters and being a software engineer in the industry gives me much more time to program in my career. In research, I feel like I would spend more time reading, writing, trying to get grant money, etc than I would coding. A guy I work with in the lab just recently published a paper. He showed it to me and I was shocked by it. The first two pages was littered with equations and formulas. Then the next page or so was followed by more equations and formulas that he derived from the previous ones. That was his work - breaking down and creating all of these formulas for robotic arm movement. And whenever I read computer science papers, they all seem to follow this pattern. I always pictured myself coding all day long…not proving equations and things of that nature. I know that's only one part of computer science research, but that part bores me. A couple cons on each side - Phd - I don't really enjoy writing or feel like I'm that great at technical writing. Whenever I'm in groups to make something, I'm always the one who does the large majority of the work and then give it to my team members to write up a report. Presenting is different though - I don't mind presenting at all as long as I have a good grasp on what I am presenting. But writing papers seems like such a chore to me. And because of this, the "publish or perish" phrase really turns me off from research. Another bad thing - I feel like if I am doing research, most of it would be done alone. I work best in small groups. I like to have at least one person to bounce ideas off of when I am brainstorming. The idea of being a part of some small elite group to build things sounds ideal to me. So being able to work in small groups for the majority of my career is a definite plus. I don't feel like I can get this doing research. Masters - I read a lot online that most people come in as engineers and eventually move into management positions. As of now, I don't see myself wanting to be a part of management. Lets say my company wanted to make some new product or system - I would get much more pride, enjoyment, and overall satisfaction to say "I made this" rather than "I managed a group of people that made this." I want to be a big part of the development process. I want to make things. I think it would be great to be more specialized than other people. I would rather know everything about something than something about everything. I always have been that way - was a great pitcher during my baseball years, but not so good at everything else, great at certain classes in school, but not so good at others, etc. To think that my career would be the same way sounds okay to me. Getting a PhD would point me in this direction. It would be great to be some guy who is someone that people look towards and come to ask for help because of being such an important contributor to a very specific field, such as artificial neural networks or robotic haptic perception. From what I gather about the software industry, being specialized can be a very bad thing because of the speed of the new technology. I When it comes to being employed, I have pretty conservative views. I don't want to change companies every 5 years. Maybe this is something everyone wishes, but I would love to just be an important person in one company for 10+ (maybe 20-25+ if I'm lucky!) years if the working conditions were acceptable. I feel like that is more possible as a PhD though, being a professor or researcher. The more I read about people in the software industry, the more it seems like most software engineers bounce from company to company at rapid paces. Some even work like a hired gun from project to project which is NOT what I want AT ALL. But finding a place to make great and important software would be great if that actually happens in the real world. I'm a very competitive person. I thrive on competition. I don't really know why, but I have always been that way even as a kid growing up. Competition always gave me a reason to practice that little extra every night, always push my limits, etc. It seems to me like there is no competition in the research world. It seems like everyone is very relaxed as long as research is being conducted. The only competition is if someone is researching the same thing as you and its whoever can finish and publish first (but everyone seems to careful to check that circumstance). The only noticeable competition to me is just with yourself and your own discipline. I like the idea that in the industry, there is real competition between companies to put out the best product or be put out of business. I feel like this would constantly be pushing me to be better at what I do. One thing that is really pushing me towards a PhD is the lifetime of the things you make. I feel like if you make something truly innovative in the industry…just some really great new application or system…there is a shelf-life of about 5-10 years before someone just does it faster and more efficiently. But with research work, you could create an idea or algorithm that last decades. For instance, the A* search algorithm was described in 1968 and is still widely used today. That is amazing to me. In the words of Palahniuk, "The goal isn't to live forever, its to create something that will." Over anything, I just want to do something that matters. I want my work to help and progress society. Seriously, if I'm stuck programming GUIs for the next 40 years…I might shoot myself in the face. But then again, I hate the idea that less than 1% of the population will come into contact with my work and even less understand its importance. So if anything I have said is false then please inform me. If you think I come off as a masters or PhD, inform me. If you want to give me some extra insight or add on to any point I made, please do. Thank you so much to anyone for any help.

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• SQLiteDataAdapter Fill exception

  - by Lirik

  I'm trying to use the OleDb CSV parser to load some data from a CSV file and insert it into a SQLite database, but I get an exception with the OleDbAdapter.Fill method and it's frustrating: An unhandled exception of type 'System.Data.ConstraintException' occurred in System.Data.dll Additional information: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. Here is the source code: public void InsertData(String csvFileName, String tableName) { String dir = Path.GetDirectoryName(csvFileName); String name = Path.GetFileName(csvFileName); using (OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + @";Extended Properties=""Text;HDR=No;FMT=Delimited""")) { conn.Open(); using (OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM " + name, conn)) { QuoteDataSet ds = new QuoteDataSet(); adapter.Fill(ds, tableName); // <-- Exception here InsertData(ds, tableName); // <-- Inserts the data into the my SQLite db } } } class Program { static void Main(string[] args) { SQLiteDatabase target = new SQLiteDatabase(); string csvFileName = "D:\\Innovations\\Finch\\dev\\DataFeed\\YahooTagsInfo.csv"; string tableName = "Tags"; target.InsertData(csvFileName, tableName); Console.ReadKey(); } } The "YahooTagsInfo.csv" file looks like this: tagId,tagName,description,colName,dataType,realTime 1,s,Symbol,symbol,VARCHAR,FALSE 2,c8,After Hours Change,afterhours,DOUBLE,TRUE 3,g3,Annualized Gain,annualizedGain,DOUBLE,FALSE 4,a,Ask,ask,DOUBLE,FALSE 5,a5,Ask Size,askSize,DOUBLE,FALSE 6,a2,Average Daily Volume,avgDailyVolume,DOUBLE,FALSE 7,b,Bid,bid,DOUBLE,FALSE 8,b6,Bid Size,bidSize,DOUBLE,FALSE 9,b4,Book Value,bookValue,DOUBLE,FALSE I've tried the following: Removing the first line in the CSV file so it doesn't confuse it for real data. Changing the TRUE/FALSE realTime flag to 1/0. I've tried 1 and 2 together (i.e. removed the first line and changed the flag). None of these things helped... One constraint is that the tagId is supposed to be unique. Here is what the table look like in design view: Can anybody help me figure out what is the problem here? Update: I changed the HDR property from HDR=No to HDR=Yes and now it doesn't give me an exception: OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + @";Extended Properties=""Text;HDR=Yes;FMT=Delimited"""); I assumed that if HDR=No and I removed the header (i.e. first line), then it should work... strangely it didn't work. In any case, now I'm no longer getting the exception. The new problem is here: public void InsertData(QuoteDataSet data, String tableName) { using (SQLiteConnection conn = new SQLiteConnection(_connectionString)) { conn.Open(); using (SQLiteDataAdapter sqliteAdapter = new SQLiteDataAdapter("SELECT * FROM " + tableName, conn)) { Console.WriteLine("Num rows updated is " + sqliteAdapter.Update(data, tableName)); } } } Now the Num rows updated is 0... any hints?

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• Soapui & populating database before

  - by mada

  SoapUi & database data needed Hi, In a J2ee project( spring ws + hibernate +postgresql+maven 2 + tomcat),We have created webservices with full crud operations. We are currently testing them with SoapUi (not yet integrated in the integration-test maven phase ). We need tomcat to test them. Actually before the phase test, with a maven plugin, only one time, some datas are injected in the database before the launch of all tests through many sql files. But the fact is that to test some webservices i need some data entry & their Id (primary key) A- What is the best way to create them ? 1- populate one of the previous .sql test file. But now we have a big dependency where i have to be careful to use the same id use in a insert in the sql file in SoapUi too. And if any developper drop the value, the test will broke. 2- create amongst the .sql file test a soapui.sql where ALL data needed for the Sopaui test will be concentrated. The advantage is that the maintenance will be much more easy. 3-because i have Ws available for all crud operations, i can create before any testsuite a previous testsuite called setup-testsuiteX. In this one, i will use those Ws to inject datas in the databse & save id in variables thanks to the feature "property transfer" 4-launch the soapui test xml file with a junit java test & in the Setup Method (we are using spring test), we will populate the database with DbUnit. Drawback: they are already data in the database & some conflicts may appear due to constraint.And now i have a dependency between: - dbUnit Xml file (with the value primary key) - sopaui test where THOSe value of primarykey will be used advantage: A automatic rollback is possible for DbUnit Data but i dont know how it will react because those data have been used with the Ws. 5- your suggestion ? better idea ? Testing those Ws create datas in the DB. How is the best way to remove them at the end ? (in how daostest we were using a automatic rollback with spring test to let the database clean) Thanks in advance for your hep & sorry for my english, it is not my mother thongue. Regards.

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• How to make a Custom Data Generator for SQL XML DataType.

  - by Keith Sirmons

  Howdy, I am using Visual Studio 2010 and am playing around with the Database Projects. I am creating a DataGenerationPlan to insert data into a simple table, in which one of the column datatypes is XML. Out of the box, the generation plan uses the Regular Expression generator and generates something like this : HGcSv9wa7yM44T9x5oFT4pmBkEmv62lJ7OyAmCnL6yqXC2X.......... I am looking at creating a custom data Generator for this data type and have followed this site for the basics: http://msdn.microsoft.com/en-us/library/aa833244.aspx This example works if I am creating a string datatype and using it for a nvarchar datatype. What do I need to change to hook this Generator to the XML Datatype? Below are my code files. The string property works for nvarchar. The XElement property does not work for the xml datatype, and the RecordXMLDataGenerator is not listed as an option in the Generator column for the generation plan. CustomDataGenerators: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Data.Schema.Tools.DataGenerator; using Microsoft.Data.Schema.Extensibility; using Microsoft.Data.Schema; using Microsoft.Data.Schema.Sql; using System.Xml.Linq; namespace CustomDataGenerators { [DatabaseSchemaProviderCompatibility(typeof(SqlDatabaseSchemaProvider))] public class RecordXMLDataGenerator : Generator { private XElement _RecordData; [Output(Description = "Generates string of XML Data for the Record.", Name = "RecordDataString")] public string RecordDataString { get { return _RecordData.ToString(SaveOptions.None); } } [Output(Description = "Generates XML Data for the Record.", Name = "RecordData")] public XElement RecordData { get { return _RecordData; } } protected override void OnGenerateNextValues() { base.OnGenerateNextValues(); XElement element = new XElement("Root", new XElement("Children1", 1), new XElement("Children6", 6) ); _RecordData = element; } } } XML Extensions File: <?xml version="1.0" encoding="utf-8" ?> <extensions assembly="" version="1" xmlns="urn:Microsoft.Data.Schema.Extensions" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:Microsoft.Data.Schema.Extensions Microsoft.Data.Schema.Extensions.xsd"> <extension type="CustomDataGenerators.RecordXMLDataGenerator" assembly="CustomDataGenerators, Version=1.0.0.0, Culture=neutral, PublicKeyToken=xxxxxxxxxxxx" enabled="true"/> </extensions> Table.sql: CREATE TABLE [dbo].[Record] ( id int IDENTITY (1,1) NOT NULL, recordData xml NULL, userId int NULL, test nvarchar(max) NULL, rowver rowversion NULL, CONSTRAINT pk_RecordID PRIMARY KEY (id) )

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• What .Net Namespace contains Entity for use in a generic repository?

  - by Sara

  I have a question that I'm ashamed to ask, but I'm going to have a go at it anyway. I am creating a generic repository in asp.net mvc. I came across an example on this website which I find to be exactly what I was looking for, but there is one problem. It references an object - Entity - and I don't know what namespace it is in. I typically create my repositories and use Entity Framework but I decided to use a generic repository because I am using the same code in multiple projects over and over again. Here is the code: public interface IRepository { void Save(ENTITY entity) where ENTITY : Entity; void Delete<ENTITY>(ENTITY entity) where ENTITY : Entity; ENTITY Load<ENTITY>(int id) where ENTITY : Entity; IQueryable<ENTITY> Query<ENTITY>() where ENTITY : Entity; IList<ENTITY> GetAll<ENTITY>() where ENTITY : Entity; IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : Entity; ENTITY Get<ENTITY>(int id) where ENTITY : Entity; IList<ENTITY> GetObjectsForIds<ENTITY>(string ids) where ENTITY : Entity; void Flush(); } Can someone please tell me what namespace Entity is in? As you can tell, a constraint is placed on the code so that it must be an Entity type. I know that there is an Entity in System.Data.Entity, but that isn't what I need. I have had instances before where I was looking for some namespace that took me forever to find, but I have searched and I'm unable to find the appropriate namespace to cast my generic items correctly. I could cast it as a class and be done with it, but it is bugging me that I can't find Entity anywhere. Can someone help me....please..... :-) Here is a link to the original post. http://stackoverflow.com/questions/1472719/asp-net-mvc-how-many-repositories

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• SQL Server 2008: FileStream Insertion Failure w/ .NET 3.5SP1

  - by James Alexander

  I've configured a db w/ a FileStream group and have a table w/ File type on it. When attempting to insert a streamed file and after I create the table row, my query to read the filepath out and the buffer returns a null file path. I can't seem to figure out why though. Here is the table creation script: /****** Object: Table [dbo].[JobInstanceFile] Script Date: 03/22/2010 18:05:36 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[JobInstanceFile]( [JobInstanceFileId] [int] IDENTITY(1,1) NOT NULL, [JobInstanceId] [int] NOT NULL, [File] [varbinary](max) FILESTREAM NULL, [FileId] [uniqueidentifier] ROWGUIDCOL NOT NULL, [Created] [datetime] NOT NULL, CONSTRAINT [PK_JobInstanceFile] PRIMARY KEY CLUSTERED ( [JobInstanceFileId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] FILESTREAM_ON [JobInstanceFilesGroup], UNIQUE NONCLUSTERED ( [FileId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] FILESTREAM_ON [JobInstanceFilesGroup] GO SET ANSI_PADDING OFF GO ALTER TABLE [dbo].[JobInstanceFile] ADD DEFAULT (newid()) FOR [FileId] GO Here's my proc I call to create the row before streaming the file: /****** Object: StoredProcedure [dbo].[JobInstanceFileCreate] Script Date: 03/22/2010 18:06:23 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO create proc [dbo].[JobInstanceFileCreate] @JobInstanceId int, @Created datetime as insert into JobInstanceFile (JobInstanceId, FileId, Created) values (@JobInstanceId, newid(), @Created) select scope_identity() GO And lastly, here's the code I'm using: public int CreateJobInstanceFile(int jobInstanceId, string filePath) { using (var connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConsumerMarketingStoreFiles"].ConnectionString)) using (var fileStream = new FileStream(filePath, FileMode.Open)) { connection.Open(); var tran = connection.BeginTransaction(IsolationLevel.ReadCommitted); try { //create the JobInstanceFile instance var command = new SqlCommand("JobInstanceFileCreate", connection) { Transaction = tran }; command.CommandType = CommandType.StoredProcedure; command.Parameters.AddWithValue("@JobInstanceId", jobInstanceId); command.Parameters.AddWithValue("@Created", DateTime.Now); int jobInstanceFileId = Convert.ToInt32(command.ExecuteScalar()); //read out the filestream transaction context to stream the file for storage command.CommandText = "select [File].PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT() from JobInstanceFile where JobInstanceFileId = @JobInstanceFileId"; command.CommandType = CommandType.Text; command.Parameters.AddWithValue("@JobInstanceFileId", jobInstanceFileId); using (SqlDataReader dr = command.ExecuteReader()) { dr.Read(); //get the file path we're writing out to string writePath = dr.GetString(0); using (var writeStream = new SqlFileStream(writePath, (byte[])dr.GetValue(1), FileAccess.ReadWrite)) { //copy from one stream to another byte[] bytes = new byte[65536]; int numBytes; while ((numBytes = fileStream.Read(bytes, 0, 65536)) 0) writeStream.Write(bytes, 0, numBytes); } } tran.Commit(); return jobInstanceFileId; } catch (Exception e) { tran.Rollback(); throw e; } } } Can someone please let me know what I'm doing wrong. In the code, the following expression is returning null for the file path and shouldn't be: //get the file path we're writing out to string writePath = dr.GetString(0); The server is different then the computer the code is running on but the necessary shares appear to be in order and I have also run the following: EXEC sp_configure filestream_access_level, 2 Any help would be greatly appreciated. Thanks!

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• NHibernate many-to-many with composite element

  - by E1

  Hello everyone. I encountered the following problem. In my application uses the entities Owner and Area binding as many to many. public class Area : DomainObject<int> { private ISet<OwnersPeriod> _owners = new HashedSet<OwnersPeriod>(); public ICollection<OwnersPeriod> Owners { get { return _owners; } set { Check.Require(value != null); _owners = new HashedSet<OwnersPeriod>(value); } } } Table Owner2Area has the following fields: CREATE TABLE [dbo].[Owner2Area]( [ID] [int] IDENTITY(1,1) NOT NULL, [IDOwner] [int] NOT NULL, [IDArea] [int] NOT NULL, [FirstDate] [datetime] NOT NULL, [LastDate] [datetime] NULL, CONSTRAINT [PK_Owner2Area] PRIMARY KEY CLUSTERED) Therefore corresponds to the class OwnersPeriod public class OwnersPeriod { private Owner _member; private Area _area; public Owner Owner { get {...} set{...} } public Area Area { get { ... } set { ... } } public DateTime FirstDate { get; set; } public DateTime? LastDate { get; set; } } I wrote mappings <class lazy="false" name="Core.Domain.Area, Core" table="Areas"> ... <set name="Owners" table="Owner2Area" inverse="true" lazy="true" > <key column="IDArea"/> <composite-element class="Core.Domain.OwnersPeriod, Core" > <parent name="Area" /> <property name="FirstDate" type="datetime"/> <property name="LastDate" type="datetime"/> <many-to-one name="Owner" class="Core.Domain.Owner, Core" column="IDOwner"/> </composite-element> </set> </class> For each area existing data are successfully loaded into Owners, but when I add new record in Owner2Area through CreateSQLQuery, these data are not updated for instance of area. If I re-opened the form and got all areas, added link successfully loaded into the collection. How can be forced to load added thus recording of relation many-to-many? Nhibernate v.2.0.1, db MSSQL 2005

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• Deletes not cascading for self-referencing entities

  - by jwaddell

  I have the following (simplified) Hibernate entities: @Entity @Table(name = "package") public class Package { protected Content content; @OneToOne(cascade = {javax.persistence.CascadeType.ALL}) @JoinColumn(name = "content_id") @Fetch(value = FetchMode.JOIN) public Content getContent() { return content; } public void setContent(Content content) { this.content = content; } } @Entity @Table(name = "content") public class Content { private Set<Content> subContents = new HashSet<Content>(); private ArchivalInformationPackage parentPackage; @OneToMany(fetch = FetchType.EAGER) @JoinTable(name = "subcontents", joinColumns = {@JoinColumn(name = "content_id")}, inverseJoinColumns = {@JoinColumn(name = "elt")}) @Cascade(value = {org.hibernate.annotations.CascadeType.DELETE, org.hibernate.annotations.CascadeType.REPLICATE}) @Fetch(value = FetchMode.SUBSELECT) public Set<Content> getSubContents() { return subContents; } public void setSubContents(Set<Content> subContents) { this.subContents = subContents; } @ManyToOne(cascade = {CascadeType.ALL}) @JoinColumn(name = "parent_package_id") public Package getParentPackage() { return parentPackage; } public void setParentPackage(Package parentPackage) { this.parentPackage = parentPackage; } } So there is one Package, which has one "top" Content. The top Content links back to the Package, with cascade set to ALL. The top Content may have many "sub" Contents, and each sub-Content may have many sub-Contents of its own. Each sub-Content has a parent Package, which may or may not be the same Package as the top Content (ie a many-to-one relationship for Content to Package). The relationships are required to be ManyToOne (Package to Content) and ManyToMany (Content to sub-Contents) but for the case I am currently testing each sub-Content only relates to one Package or Content. The problem is that when I delete a Package and flush the session, I get a Hibernate error stating that I'm violating a foreign key constraint on table subcontents, with a particular content_id still referenced from table subcontents. I've tried specifically (recursively) deleting the Contents before deleting the Package but I get the same error. Is there a reason why this entity tree is not being deleted properly? EDIT: After reading answers/comments I realised that a Content cannot have multiple Packages, and a sub-Content cannot have multiple parent-Contents, so I have modified the annotations from ManyToOne and ManyToMany to OneToOne and OneToMany. Unfortunately that did not fix the problem. I have also added the bi-directional link from Content back to the parent Package which I left out of the simplified code.

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• Why does a user have to enter "Profile" data to enter data into other tables?

  - by Greg McNulty

  EDIT It appears the user has to enter some data for his profile, otherwise I get this error below. I guess if there is no profile data, the user can not continue to enter data in other tables by default? I do not want to make entering user profile data a requirement to use the rest of the sites functionality, how can I get around this? Currently I have been testing everything with the same user and everything has been working fine. However, when I created a new user for the very first time and tried to enter data into my custom table, I get the following error. The INSERT statement conflicted with the FOREIGN KEY constraint "FK_UserData_aspnet_Profile". The conflict occurred in database "C:\ISTATE\APP_DATA\ASPNETDB.MDF", table "dbo.aspnet_Profile", column 'UserId'. The statement has been terminated. Not sure why I am getting this error. I have the user controls set up in ASP.NET 3.5 however all I am using is my own table or at least that I am aware of. I have a custom UserData table that includes the columns: id, UserProfileID, CL, LL, SL, DateTime (id is the auto incremented int) The intent is that all users will add their data in this table and as I mentioned above it has been working fine for my original first user I created. However, when i created a new user I am getting this problem. Here is the code that updates the database. protected void Button1_Click(object sender, EventArgs e) { //connect to database MySqlConnection database = new MySqlConnection(); database.CreateConn(); //create command object Command = new SqlCommand(queryString, database.Connection); //add parameters. used to prevent sql injection Command.Parameters.Add("@UID", SqlDbType.UniqueIdentifier); Command.Parameters["@UID"].Value = Membership.GetUser().ProviderUserKey; Command.Parameters.Add("@CL", SqlDbType.Int); Command.Parameters["@CL"].Value = InCL.Text; Command.Parameters.Add("@LL", SqlDbType.Int); Command.Parameters["@LL"].Value = InLL.Text; Command.Parameters.Add("@SL", SqlDbType.Int); Command.Parameters["@SL"].Value = InSL.Text; Command.ExecuteNonQuery(); } Source Error: Line 84: Command.ExecuteNonQuery();

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• Problem with delete operation in many to many relation

  - by Alexey Zakharov

  Hi, I've got to classes Product and Store which have many to many relation I want deleting of store not to cause deleting of related product And deleting of product not to cause deleting of related store. Currently deleting of entity cause exception due to Foreign Key constraint. Here is this classes and their mapping in fluent hibernate: public class Product { public Product() { this.StoresStockedIn = new List<Store>(); } public virtual string Name { get; set; } public virtual double Price { get; set; } public virtual long ProductID { get; set; } public virtual IList<Store> StoresStockedIn { get; set; } } public class Store { public Store() { this.Products = new List<Product>(); this.Staff = new List<Employee>(); } public virtual string Name { get; set; } public virtual IList<Product> Products { get; set; } public virtual IList<Employee> Staff { get; set; } public virtual long StoreID { get; set; } } public class ProductMap : ClassMap<Product> { public ProductMap() { this.Id(x => x.ProductID); this.Map(x => x.Name); this.Map(x => x.Price); this.HasManyToMany(x => x.StoresStockedIn) .Cascade.None() .Table("StoreProduct"); } public class StoreMap : ClassMap<Store> { public StoreMap() { this.Id(x => x.StoreID); this.Map(x => x.Name); this.HasManyToMany(x => x.Products) .Cascade.None() .Inverse() .Table("StoreProduct"); this.HasMany(x => x.Staff) .Cascade.All() .Inverse(); } } Thanks, Alexey Zakharov

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• Fluent NHibernate Self Referencing Many To Many

  - by Jeremy

  I have an entity called Books that can have a list of more books called RelatedBooks. The abbreviated Book entity looks something likes this: public class Book { public virtual long Id { get; private set; } public virtual IList<Book> RelatedBooks { get; set; } } Here is what the mapping looks like for this relationship HasManyToMany(x => x.RelatedBooks) .ParentKeyColumn("BookId") .ChildKeyColumn("RelatedBookId") .Table("RelatedBooks") .Cascade.SaveUpdate(); Here is a sample of the data that is then generated in the RelatedBooks table: BookId RelatedBookId 1 2 1 3 The problem happens when I Try to delete a book. If I delete the book that has an ID of 1, everything works ok and the RelatedBooks table has the two corresponding records removed. However if I try to delete the book with an ID of 3, I get the error "The DELETE statement conflicted with the REFERENCE constraint "FK5B54405174BAB605". The conflict occurred in database "Test", table "dbo.RelatedBooks", column 'RelatedBookId'". Basically what is happening is the Book cannot be deleted because the record in the RelatedBooks table that has a RelatedBookId of 3 is never deleted. How do I get that record to be deleted when I delete a book? EDIT After changing the Cascade from SaveUpdate() to All(), the same problem still exists if I try to delete the Book with an ID of 3. Also with Cascade set to All(), if delete the Book with and ID of 1, then all 3 books (ID's: 1, 2 and 3) are deleted so that won't work either. Looking at the SQL that is executed when the Book.Delete() method is called when I delete the Book with an ID of 3, it looks like the SELECT statement is looking at the wrong column (which I assume means that the SQL DELETE statment would make the same mistake, therefore never removing that record). Here is the SQL for the RelatedBook SELECT relatedboo0_.BookId as BookId3_ , relatedboo0_.RelatedBookId as RelatedB2_3_ , book1_.Id as Id14_0_ FROM RelatedBooks relatedboo0_ left outer join [Book] book1_ on relatedboo0_.RelatedBookId=book1_.Id WHERE relatedboo0_.BookId=3 The WHERE statment should look something like this for thie particular case: WHERE relatedboo0_.RelatedBookId = 3 SOLUTION Here is what I had to do to get it working for all cases Mapping: HasManyToMany(x => x.RelatedBooks) .ParentKeyColumn("BookId") .ChildKeyColumn("RelatedBookId") .Table("RelatedBooks"); Code: var book = currentSession.Get<Book>(bookId); if (book != null) { //Remove all of the Related Books book.RelatedBooks.Clear(); //Get all other books that have this book as a related book var booksWithRelated = currentSession.CreateCriteria<Book>() .CreateAlias("RelatedBooks", "br") .Add(Restrictions.Eq("br.Id", book.Id)) .List<Book>(); //Remove this book as a Related Book for all other Books foreach (var tempBook in booksWithRelated) { tempBook.RelatedBooks.Remove(book); tempBook.Save(); } //Delete the book book.Delete(); }

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• Why does PostgresQL query performance drop over time, but restored when rebuilding index

  - by Jim Rush

  According to this page in the manual, indexes don't need to be maintained. However, we are running with a PostgresQL table that has a continuous rate of updates, deletes and inserts that over time (a few days) sees a significant query degradation. If we delete and recreate the index, query performance is restored. We are using out of the box settings. The table in our test is currently starting out empty and grows to half a million rows. It has a fairly large row (lots of text fields). We are search is based of an index, not the primary key (I've confirmed the index is being used, at least under normal conditions) The table is being used as a persistent store for a single process. Using PostgresQL on Windows with a Java client I'm willing to give up insert and update performance to keep up the query performance. We are considering rearchitecting the application so that data is spread across various dynamic tables in a manner that allows us to drop and rebuild indexes periodically without impacting the application. However, as always, there is a time crunch to get this to work and I suspect we are missing something basic in our configuration or usage. We have considered forcing vacuuming and rebuild to run at certain times, but I suspect the locking period for such an action would cause our query to block. This may be an option, but there are some real-time (windows of 3-5 seconds) implications that require other changes in our code. Additional information: Table and index CREATE TABLE icl_contacts ( id bigint NOT NULL, campaignfqname character varying(255) NOT NULL, currentstate character(16) NOT NULL, xmlscheduledtime character(23) NOT NULL, ... 25 or so other fields. Most of them fixed or varying character fiel ... CONSTRAINT icl_contacts_pkey PRIMARY KEY (id) ) WITH (OIDS=FALSE); ALTER TABLE icl_contacts OWNER TO postgres; CREATE INDEX icl_contacts_idx ON icl_contacts USING btree (xmlscheduledtime, currentstate, campaignfqname); Analyze: Limit (cost=0.00..3792.10 rows=750 width=32) (actual time=48.922..59.601 rows=750 loops=1) - Index Scan using icl_contacts_idx on icl_contacts (cost=0.00..934580.47 rows=184841 width=32) (actual time=48.909..55.961 rows=750 loops=1) Index Cond: ((xmlscheduledtime < '2010-05-20T13:00:00.000'::bpchar) AND (currentstate = 'SCHEDULED'::bpchar) AND ((campaignfqname)::text = '.main.ee45692a-6113-43cb-9257-7b6bf65f0c3e'::text)) And, yes, I am aware there there are a variety of things we could do to normalize and improve the design of this table. Some of these options may be available to us. My focus in this question is about understanding how PostgresQL is managing the index and query over time (understand why, not just fix). If it were to be done over or significantly refactored, there would be a lot of changes.

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• Rush Hour - Solving the game

  - by Rubys

  Rush Hour if you're not familiar with it, the game consists of a collection of cars of varying sizes, set either horizontally or vertically, on a NxM grid that has a single exit. Each car can move forward/backward in the directions it's set in, as long as another car is not blocking it. You can never change the direction of a car. There is one special car, usually it's the red one. It's set in the same row that the exit is in, and the objective of the game is to find a series of moves (a move - moving a car N steps back or forward) that will allow the red car to drive out of the maze. I've been trying to think how to solve this problem computationally, and I can really not think of any good solution. I came up with a few: Backtracking. This is pretty simple - Recursion and some more recursion until you find the answer. However, each car can be moved a few different ways, and in each game state a few cars can be moved, and the resulting game tree will be HUGE. Some sort of constraint algorithm that will take into account what needs to be moved, and work recursively somehow. This is a very rough idea, but it is an idea. Graphs? Model the game states as a graph and apply some sort of variation on a coloring algorithm, to resolve dependencies? Again, this is a very rough idea. A friend suggested genetic algorithms. This is sort of possible but not easily. I can't think of a good way to make an evaluation function, and without that we've got nothing. So the question is - How to create a program that takes a grid and the vehicle layout, and outputs a series of steps needed to get the red car out? Sub-issues: Finding some solution. Finding an optimal solution (minimal number of moves) Evaluating how good a current state is Example: How can you move the cars in this setting, so that the red car can "exit" the maze through the exit on the right?

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• Historical / auditable database

  - by Mark

  Hi all, This question is related to the schema that can be found in one of my other questions here. Basically in my database I store users, locations, sensors amongst other things. All of these things are editable in the system by users, and deletable. However - when an item is edited or deleted I need to store the old data; I need to be able to see what the data was before the change. There are also non-editable items in the database, such as "readings". They are more of a log really. Readings are logged against sensors, because its the reading for a particular sensor. If I generate a report of readings, I need to be able to see what the attributes for a location or sensor was at the time of the reading. Basically I should be able to reconstruct the data for any point in time. Now, I've done this before and got it working well by adding the following columns to each editable table: valid_from valid_to edited_by If valid_to = 9999-12-31 23:59:59 then that's the current record. If valid_to equals valid_from, then the record is deleted. However, I was never happy with the triggers I needed to use to enforce foreign key consistency. I can possibly avoid triggers by using the extension to the "PostgreSQL" database. This provides a column type called "period" which allows you to store a period of time between two dates, and then allows you to do CHECK constraints to prevent overlapping periods. That might be an answer. I am wondering though if there is another way. I've seen people mention using special historical tables, but I don't really like the thought of maintainling 2 tables for almost every 1 table (though it still might be a possibility). Maybe I could cut down my initial implementation to not bother checking the consistency of records that aren't "current" - i.e. only bother to check constraints on records where the valid_to is 9999-12-31 23:59:59. Afterall, the people who use historical tables do not seem to have constraint checks on those tables (for the same reason, you'd need triggers). Does anyone have any thoughts about this? PS - the title also mentions auditable database. In the previous system I mentioned, there is always the edited_by field. This allowed all changes to be tracked so we could always see who changed a record. Not sure how much difference that might make. Thanks.

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• NHibernate Mapping problem

  - by Bernard Larouche

  My database is being driven by my NHibernate mapping files. I have a Category class that looks like the following : public class Category { public Category() : this("") { } public Category(string name) { Name = name; SubCategories = new List<Category>(); Products = new HashSet<Product>(); } public virtual int ID { get; set; } public virtual string Name { get; set; } public virtual string Description { get; set; } public virtual Category Parent { get; set; } public virtual bool IsDefault { get; set; } public virtual ICollection<Category> SubCategories { get; set; } public virtual ICollection<Product> Products { get; set; } and here is my Mapping file : <property name="Name" column="Name" type="string" not-null="true"/> <property name="IsDefault" column="IsDefault" type="boolean" not-null="true" /> <property name="Description" column="Description" type="string" not-null="true" /> <many-to-one name="Parent" column="ParentID"></many-to-one> <bag name="SubCategories" inverse="true"> <key column="ParentID"></key> <one-to-many class="Category"/> </bag> <set name="Products" table="Categories_Products"> <key column="CategoryId"></key> <many-to-many column="ProductId" class="Product"></many-to-many> </set> when I try to create the database I get the following error : failed: The INSERT statement conflicted with the FOREIGN KEY SAME TABLE constraint "FK9AD976763BF05E2A". The conflict occurred in database "CoderForTraders", table "dbo.Categories", column 'CategoryId'. The statement has been terminated. I looked on the net for some answers but found none. Thanks for your help

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• How do I add a column that displays the number of distinct rows to this query?

  - by Fake Code Monkey Rashid

  Hello good people! I don't know how to ask my question clearly so I'll just show you the money. To start with, here's a sample table: CREATE TABLE sandbox ( id integer NOT NULL, callsign text NOT NULL, this text NOT NULL, that text NOT NULL, "timestamp" timestamp with time zone DEFAULT now() NOT NULL ); CREATE SEQUENCE sandbox_id_seq START WITH 1 INCREMENT BY 1 NO MINVALUE NO MAXVALUE CACHE 1; ALTER SEQUENCE sandbox_id_seq OWNED BY sandbox.id; SELECT pg_catalog.setval('sandbox_id_seq', 14, true); ALTER TABLE sandbox ALTER COLUMN id SET DEFAULT nextval('sandbox_id_seq'::regclass); INSERT INTO sandbox VALUES (1, 'alpha', 'foo', 'qux', '2010-12-29 16:51:09.897579+00'); INSERT INTO sandbox VALUES (2, 'alpha', 'foo', 'qux', '2010-12-29 16:51:36.108867+00'); INSERT INTO sandbox VALUES (3, 'bravo', 'bar', 'quxx', '2010-12-29 16:52:36.370507+00'); INSERT INTO sandbox VALUES (4, 'bravo', 'foo', 'quxx', '2010-12-29 16:52:47.584663+00'); INSERT INTO sandbox VALUES (5, 'charlie', 'foo', 'corge', '2010-12-29 16:53:00.742356+00'); INSERT INTO sandbox VALUES (6, 'delta', 'foo', 'qux', '2010-12-29 16:53:10.884721+00'); INSERT INTO sandbox VALUES (7, 'alpha', 'foo', 'corge', '2010-12-29 16:53:21.242904+00'); INSERT INTO sandbox VALUES (8, 'alpha', 'bar', 'corge', '2010-12-29 16:54:33.318907+00'); INSERT INTO sandbox VALUES (9, 'alpha', 'baz', 'quxx', '2010-12-29 16:54:38.727095+00'); INSERT INTO sandbox VALUES (10, 'alpha', 'bar', 'qux', '2010-12-29 16:54:46.237294+00'); INSERT INTO sandbox VALUES (11, 'alpha', 'baz', 'qux', '2010-12-29 16:54:53.891606+00'); INSERT INTO sandbox VALUES (12, 'alpha', 'baz', 'corge', '2010-12-29 16:55:39.596076+00'); INSERT INTO sandbox VALUES (13, 'alpha', 'baz', 'corge', '2010-12-29 16:55:44.834019+00'); INSERT INTO sandbox VALUES (14, 'alpha', 'foo', 'qux', '2010-12-29 16:55:52.848792+00'); ALTER TABLE ONLY sandbox ADD CONSTRAINT sandbox_pkey PRIMARY KEY (id); Here's the current SQL query I have: SELECT * FROM ( SELECT DISTINCT ON (this, that) id, this, that, timestamp FROM sandbox WHERE callsign = 'alpha' AND CAST(timestamp AS date) = '2010-12-29' ) playground ORDER BY timestamp DESC This is the result it gives me: id this that timestamp ----------------------------------------------------- 14 foo qux 2010-12-29 16:55:52.848792+00 13 baz corge 2010-12-29 16:55:44.834019+00 11 baz qux 2010-12-29 16:54:53.891606+00 10 bar qux 2010-12-29 16:54:46.237294+00 9 baz quxx 2010-12-29 16:54:38.727095+00 8 bar corge 2010-12-29 16:54:33.318907+00 7 foo corge 2010-12-29 16:53:21.242904+00 This is what I want to see: id this that timestamp count ------------------------------------------------------------- 14 foo qux 2010-12-29 16:55:52.848792+00 3 13 baz corge 2010-12-29 16:55:44.834019+00 2 11 baz qux 2010-12-29 16:54:53.891606+00 1 10 bar qux 2010-12-29 16:54:46.237294+00 1 9 baz quxx 2010-12-29 16:54:38.727095+00 1 8 bar corge 2010-12-29 16:54:33.318907+00 1 7 foo corge 2010-12-29 16:53:21.242904+00 1 EDIT: I'm using PostgreSQL 9.0.* (if that helps any).

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