Problem: Load data from multiple tables into a single Java entity.

Approach 1: Use custom SQL loading


@Entity
// Class that will store the query result(s). Class field names are the same than database column names.
@SqlResultSetMapping(name = "customerMapping", entities = @EntityResult(entityClass = CustomerMapping.class))
// Using hibernate annotation to specify out custom SQL queries
@org.hibernate.annotations.NamedNativeQueries(
     {
      @NamedNativeQuery(name = "loadAllCustomers",
      query = "select a.col1,a.col2,b.col1 from table1 a, table2 b where a.col5=b.col5",
      resultSetMapping = "customerMapping"),
      @NamedNativeQuery(name = "loadByCustNum",
      query = "select a.col1,a.col2,b.col1 from table1 a, table2 b where a.col5=b.col5 and a.col1 = ?",
      resultSetMapping = "customerMapping")
     }
)
// Default SQL query to be used when loading this entity through Hibernate
@Loader(namedQuery = "loadByCustNum")
public class CustomerMapping implements Serializable {
... class body
}


Approach 2: Use one-to-one mapping approach


@Entity
@Table(catalog = "myDB", schema = "dbo", name = "customer_mapping")
public class CustomerMapping implements Serializable {
     @OneToOne
     // Foreign Key pointing to the corresponding CustomerMaster data.
     @JoinColumn(name = "gte_cust_num", unique = true, nullable = true)
     // Default hibernate action to be taken when the FK is not null and
     // it's not present in the secondary table.
     // Hibernate can ignore the error and do nothing or throw an exception.
     @NotFound(action=NotFoundAction.IGNORE)
     private CustomerMaster masterData;
... class body
}


@Entity
@Table(catalog="myDB", schema="dbo", name="customer_master")
public class CustomerMaster implements Serializable {
... class body
}


NOTE: Be careful when trying to retrieve the objects using HQL:

hql = "from CustomerMapping cmi where cmi.filterField = 'ABCXXX'";

The query above will result in a performance issue if we are retrieving several CustomerMapping objects. This is because hibernate will generate one query to get all the CustomerMapping objects and N queries to get the data to populate each CustomerMaster object (from the one-to-one relation).

SELECT A,B,C FROM CustomerMapping WHERE filterField = 'ABCXXX';
SELECT D,E,F FROM CustomerMaster WHERE id = ?;
SELECT D,E,F FROM CustomerMaster WHERE id = ?;
SELECT D,E,F FROM CustomerMaster WHERE id = ?;

In other words, if we are retrieving N objects, then we will have N+1 database queries.

In order to avoid this, we need to force Hibernate to use JOIN FETCH to retrieve the CustomerMaster data:

hql = "from CustomerMapping cmi left join fetch cmi.masterData where cmi.filterField = 'ABCXXX'";

The query above will produce only one sql query to retrieve CustomerMapping and CustomerMaster data using a join.

SELECT A,B,C FROM CustomerMapping LEFT JOIN CustomerMaster (....) WHERE filterField = 'ABCXXX';


Durant les formations Symfony, on me pose régulièrement la question : mais quel est le meilleur ORM, Propel ou Doctrine ?

La réponse, mon ami, est soufflée dans le vent,
La réponse est soufflée dans le vent.

J’ai donc décidé de commencer ma réponse par les liens des gens qui en parlent :

• Passage de Propel à Doctrine, retour d’XP (Ze Technology)
• Benchmark des deux ORM (Totalement Geek)
• Quel ORM choisir ? (La Ferme Du Web)

Une petite recherche Google vous aidera pas mal aussi (et vous retrouverez ceux que je viens de vous citer).

Et comme il faut toujours aller chercher l’information à la source, je vous enjoins de lire l’article (d’il y a 6 mois déjà) du blog de Symfony Project : What’s up with Propel and Doctrine ? (1.3)

در اکثر برنامه های کامپیوتری نیاز به ذخیره و بازیابی داده ها وجود دارد. داده هایی که بدون آن ها سیستم نرم افزاری ما معنایی ندارد. برنامه نویسان معمولاً راه های مختلفی برای این کار سراغ دارند. کسانی که با دات نت فریم ورک برنامه نویسی می کنند راه های مختلفی برای دسترسی به داده ها دارند. در این مطلب با تکنولوژی های مایکروسافت برای این کار آشنا خواهیم شد و سه ORM معروف دنیای دات نت را معرفی خواهیم کرد. مایکروسافت انتخاب های زیادی برای دسترسی به داده ها به برنامه نویسان دات نت می دهد که شما باید با بررسی آن ها و با توجه به نیازهای خودتان یکی از آن ها را انتخاب کنید.

ADO.NET

ADO.NET مجموعه ای از کامپوننت هاست که برنامه نویسان می توانند از آن ها برای برقراری ارتباط با دیتابیس های مختلف استفاده کنند. ADO.NET بخشی از کتابخانه کلاس های پایه دات نت فریم ورک است که توسط مایکروسافت توسعه داده می شود. برنامه نویسان به صورت گسترده از این تکنولوژی برای دسترسی و دستکاری داده های ذخیره شده در یک دیتابیس رابطه ای استفاده می کنند. ADO.NET می تواند با اکثر دیتابیس های موجود کار کند، هر چند به صورت پیش فرض در دات نت فریم ورک فقط فراهم کننده های SQL Server، OleDb و Odbc وجود دارد، افراد و شرکت های دیگر فراهم کننده های دیتابیس های دیگر را برای دات نت ایجاد کرده اند.

برای هر Provider کامپوننت هایی وجود دارند که برنامه نویس با استفاده از آن ها به مقصودش می رسد. به طور مثال برای استفاده از SQL Server در روش ADO.NET کامپوننت هایی مانند SQLConnection و SQLCommand وجود دارد که با استفاده از آن ها می توانید یک دستور SQL را روی داده های موجود در یک دیتابیس SQL Server اجرا کنید. با SQLConnection به دیتابیس موجود در SQL Server وصل می شویم و با استفاده از یک SQLCommand می توانیم یک عبارت T-SQL را که می تواند دستور INSERT, UPDATE, DELETE یا SELECT باشد یا حتی یک Stored Procedure یا عبارت DDL باشد را برای مقصود خاصی روی دیتابیس اجرا کنیم. چون ADO.NET در مورد سینتاکس دیتابیس چیزی نمی داند، دستورات را به صورت یک رشته ساده به SQLCommand می دهیم و این شیء نیز به صورت مستقیم به دیتابیس دستور می دهد.

string query = "SELECT * FROM tblCustomers";
SqlConnection con = new SqlConnection(cnnString);
SqlCommand command = new SqlCommand(query, con);
con.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
Response.Write(reader.GetInt32(0) +
reader.GetString(1));
}

نکته ای که باید در مورد ADO.NET بدانید این است که برای استفاده از هر سیستم دیتابیس رابطه ای، مجموعه کامپوننت های جدایی وجود دارد. در مثال بالا از آبجکت های مربوط به SQL Server استفاده کردیم. اگر بخواهید مثلاً از یک دیتابیس اوراکل در برنامه خود استفاده کنید، بایستی از کامپوننت های مربوط به اوراکل استفاده کنید. خوشبختانه تمام این کامپوننت ها بر پایه یک Interface ساخته شده اند، این یعنی شما می توانید با استفاده از کلاس DbProviderFactory برنامه ای بسیازید که با چند نوع دیتابیس مختلف کار کند.

Linq to SQL

مایکروسافت با دات نت فریم ورک 3.0 و 3.5 یک ORM به نام Linq to SQL را به عنوان بخشی از پروژه LINQ خود عرضه کرد. این شرکت مدت ها پیش از آن قول داده بود که یک ORM برای دات نت فریم ورک طراحی کند اما تا نسخه 3.0 دات نت فریم ورک خبری از آن پروژه نشد. Linq to SQL به شما اجازه می دهد که کوئری های LINQ را روی دیتابیس های SQL Server اجرا کنید. علاوه بر این از یک Mapping Framework بهره می برد که به برنامه نویسان اجازه Map کردن جدول های یک دیتابیس را به کلاس ها و بالعکس می دهد. این کار در ویژوال استادیو می تواند به صورت ویژوال یا کدنویسی انجام گیرد. به این صورت که برای هر جدول از دیتابیس یک کلاس تعریف می شود که هر ستون از یک جدول به عنوان یک Property درون آن کلاس تعریف می شود.

نمایی از ابزار طراحی ویژوال Linq to SQL

به مثال زیر توجه کنید :
public class Customer
{
[Column(Name="CustomerID",IsPrimaryKey = true)]
public long ID
{
get { return _ID;}
set { _ID = value;}
}
[Column(Name = "CustomerName")]
public string Name
{
get { return _name; }
set { _name = value; }
}
}
کلاس بالا به جدول tblCustomers که دارای دو ستون CustomerID و CustomerName است Map می شود. قبل از اینکه بخواهید از Linq to SQL استفاده کنید باید این کلاس ها را تعریف کنید. ویژوال استادیو 2008 دارای ابزاری است که به صورت ویژوال به شما امکان Map کردن جدول های یک دیتابیس SQL Server را به کلاس های دات نت می دهد. این ابزار می تواند به صورت اتوماتیک کلاس های مورد نیاز شما را از روی مدل دیتابیس بسازد، و حتی اجازه تغییرات دستی و ایجاد Viewهای مختلف از دیتابیس را به شما می دهد. عملیات Mapping با استفاده از DataContext (که یک رشته اتصال به سرور نیاز دارد) پیاده سازی می شود. سپس شما قادر خواهید بود کوئری های LINQ خود را روی دیتابیس موجود در سرور اجرا کنید، که البته این کوئری ها ابتدا به دستوارت T-SQL متناظر ترجمه و سپس روی دیتابیس مورد نظر اجرا می شوند.

Entity Framework

Entity Framework یک فریم ورک ORM برای دات نت فریم ورک است که نسخه یک آن به همراه دات نت فریم ورک 3.5 سرویس پک 1 عرضه شد اما مورد استقبال توسعه دهندگان قرار نگرفت. نسخه 2 این فریم ورک به صورت بتا به عنوان بخشی از ویژوال استادیو 2010 قابل دسترس است. ADO.NET Entity Framework نام اصلی این فریم ورک است و جزئی از تکنولوژی ADO.NET است.

ابزار طراحی Entity Framework در ویژوال استادیو

Entity Framework مدل رابطه ای موجود در یک دیتابیس را به مدل مفهمومی تبدیل می کند و آن را به اپلیکیشن ما تحویل می دهد. در مدل رابطه ای عناصر ترکیبی از جداول هستند، به همراه کلید های اصلی و خارجی که جدول ها را به هم مرتبط می سازند. برعکس آن، انواع موجودیت ها مدل مفهومی داده را تعریف می کنند. انواع موجودیت  اجتماعی از چند فیلد است (هر فیلد به یک ستون از دیتابیس Map می شود) و می تواند شامل اطلاعات از چند جدول فیزیکی باشد. انواع موجودیت می توانند به هم مرتبط باشند، مستقل از ارتباطاتی که در مدل فیزیکی دارند. شمای منطقی و نگاشت (mapping) آن به شمای فیزیکی به عنوان یک Entity Data Model یا EDM نمایش داده می شوند که مشخصات EDM در یک فایل XML ذخیره می شود. Entity Framework از EDM برای انجام عملیات نگاشت و دادن قابلیت کار با موجودیت ها به اپلیکیشن استفاده می کند. Entity Framework اطلاعات مورد نیاز هر موجودیت را با Join کردن چندین جدول از مدل فیزیکی (دیتابیس) بدست می آورد. هنگامی که اطلاعات یک موجودیت آپدیت می شود، Entity Framework بررسی می کند که داده ها مربوط به کدام یک از جدول های موجود در دیتابیس هستند، سپس آن ها را با دستور SQL مناسب آپدیت می کند.

هر چند Entity Framework و Linq to SQL بسیار شبیه به هم به نظر می رسند، هر دو ابزارهایی برای طراحی گرافیکی و ویزاردی برای نگاشت یک دیتابیس به مدل شیء گرا دارند و هر دو می توانند از کوئری های LINQ برای مقصود خاصی استفاده کنند، اما با هم تفاوت هایی هم دارند. بیان تفاوت های این دو در این مطلب جایی ندارد.

NHibernate

نمی توان در مورد ORMها در دات نت صحبت کرد اما نام NHiernate را ذکر نکرد. NH یک فریم ورک ORM اوپن سورس برای دات نت فریم ورک است که از روی پروژه موفق Hibernate جاوا وارد دنیای دات نت شد. توضیحات بیشتر در مورد NHibernate توضیحات اضافی است، زیرا این فریم ورک هم وظیفه ORMهای دیگر را انجام می دهد. اکثر برنامه نویسانی که از NH برای نگاشت استفاده می کنند، ابتدا کلاس های خود را تعریف می کنند و سپس با استفاده از یک فایل XML آن ها را به جدول های دیتابیس Map می کنند. Linq to SQL و Entity Framework برخلاف NHibernate از روش Model-first یا مبتنی در دیتابیس استفاده می کنند، به این معنی که هر دو ORM تصور می کنند شما دیتابیسی در اختیار دارید که می خواهید آن به تعدادی آبجکت Map کنید.

در مورد Nhibernate بیش از این صحبت نمی کنم، آقای وحید نصیری در اینجا به صورت کامل در مورد این ORM محبوب نوشته است.

farasun.wordpress.com

انتخاب از میان روش های بالا به عهده خود شماست. در این مطلب کوتاه نمی توان به بررسی تمام زوایا و تفاوت های میان آن ها پرداخت. در مطالب آینده سعی میکنم در مورد نحوه استفاده از هر کدام یک مثال عملی بزنم (البته به جز NHibernate).

A good blog post about an advantage of Doctrine over Zend_Db_Table:

http://roetgers.org/2009/10/21/why-i-prefer-propel-over-zend_db_table/

Just Test – Nuff Said? Nah.

Big discussion about unit testing.  Views ranged from 100% coverage is necessary, to some code is not worth the trouble.  The 100% camp was hit with this rebuttal:

How is the coverage measured?
Is it just checking which code blocks ran during the test?
What about covering different code paths?

Everyone was in favor and there were some interesting insights including an example of “correctness by construction” in Haskell:

…”correctness by construction” (aka “making illegal states unrepresentable”).  This approach relies on a rich type-system (and, at a deeper level, an interesting fact technically known as the “Curry-Howard isomorphism”).  Ideally, when this can be achieved you can completely discharge the need for a lot of unit tests (replacing sort of probabilistic certainty with actual certainty).

Plenty of good links were sent and summarized:

This study found bug reductions of 40-90% with 15-25% coding time added.

Some recommend testability above clarity.

Guidelines on proper coding for testability (in Java).

Miscellany

I heard some talk about an A team being formed to take on a project. I’d like to see the problem these guys can’t solve.

Check out this interesting tool for translating a data model into a class model with proper naming and casing using either Entity Framework or Linq2SQL.

All in all, a quiet week as expected.

My  brother is an independent insurance agent in Holt, MI and had the unfortunate luck to run across a troll (we suspect it’s an individual who was caught attempting to commit fraud by insuring a home containing a business with a standard residential policy – he was caught and the policy was canceled and in spite of the fact that his money was refunded he’s still holding a grudge).

As the family’s online reputation  management expert, I’ve been doing some pro bono work to my brother rehab his online presence as a result and it’s a great reminder of how messy a loser with a little bit of free time on their hands can make things.  The breakdown of how to respond to these sorts of things is fairly simple (for those who may not already be familiar):

1. Investigate the scope of the problem.
   1. You can start with a Google search and go from there depending on what you find (the more content, the liklier it is that you’ll want to use other search tools to detect negative references).
   2. Given how incestuously data is handled on the web, it’s likely that one reference in one location is showing up in other locations (for example the Insiderpages.com reviews were being included with Google’s reviews) so you’ll want to make sure you’ve found the source when you begin the purging process.
2. Take action to clean up or minimize the damage.  This will take a number or forms depending on what the problem is and the earlier you can act, the better – the longer content stays up the more likely it will be indexed or scraped and reappropriated elsewhere.
   1. Review / Directory Site: Contact the people who manage the review platform (these sorts of things are routine so if they’re a credible operation they usually have an easy way to reach them to initiate a review process) and write them a polite, adequately-detailed and entirely factual request to remove the content.  Most of the time this should solve the problem.
   2. Personal Blog / Website: Occasionally trolls/griefers will create websites (usually with free services like Blogger or WordPress) to continue the harassment.  Again – contacting those who maintain the site with a polite and factual request usually does the trick.
   3. If you have the means or the defamation is serious enough, you may want to investigate legal remedies.  Technically, as a result of the language in Section 113 of the Violence Against Women and Department of Justice Reauthorization Act, it’s illegal to anonymously “annoy” someone online.  A lot of people (including me) doubt that this law will ultimately stand up if it’s ever challenged, but it’s on the books nonetheless.  As a good example of how nothing online is truly anonymous, some people have been outed and sanctioned for defamation under this law.  For more info, Declan McCullagh did a good writeup a few years ago on ZDNet.
3. Monitor the situation. Occasionally trolls have stamina and will continue the harassment.  You should already be using tools like Backtype , Bloglines , Google Alerts , Google Blogsearch , Social Mention , Steprep, Technorati , Yacktrack , etc. to monitor what is said about you or your organization online – but if you’re not they can be used to set up RSS feeds or automated email notifications when content about you is published.

Back to the current situation with my brother, the troll in question has been posting false negative reviews with a variety of online directories over the past month or two, including:

• Yellowpages.com
• Local.com (other sites aggregate content from here, like local Lansing TV station WLAJ)
• Google Maps/Directory
• InsiderPages.com (Google aggregates content from here for its reviews)

We identified the problem a couple of days ago, and have begun contacting the various directories to dispute the reviews (which are obviously false; the pseudonyms used have only ever published one review a piece and they’re all posted within the same span of time – in some cases on the same day and using some of the same sequence of numbers in the name).  He’s become somewhat more sophisticated than the typical troll by actually returning to his fake reviews and posting comments of agreement or supplemental reviews under other pseudonyms.

Right now I’m incredibly impressed with two companies:

• InsiderPages.com: they reviewed and removed the bogus negative reviews in a matter of hours!  They also sync with Facebook (which is not only convenient, but has the benefit of more solidly establishing a reviewer as legitimate by anchoring them to their social media profile).
• Yellowpages.com: (which is owned by AT&T) they reviewed the content and began the process of removing it less than a day after I submitted my request.

Curiously, the slowest to respond has been Google (which usually has outstanding customer service).  I haven’t given up on them though.  I’m also still waiting to hear back from Local.com.

For posterity, here’s a list of usernames they’ve used thus far:

• Yellowpages.com | BrianMonroe on 08/30/2009
• Yellowpages.com | jason.hansen on 08/21/2009
• Yellowpages.com | SarahConor2122 on 08/15/2009
• Local.com | “Jason” JasonX001 08/18/2009
• Local.com | “John Adams” John5178 08/14/2009
• Local.com | “Kent Black” Kennie517 08/14/2009
• Google Maps | saraho39conor - Aug 15, 2009‎
• Insiderpages.com | Sarah O. – Aug 15, 2009‎

Went to the .Net Meetup Tuesday night and had a great time.  Plenty of interesting discussion and some laughs too. (All that and free pizza too). Highly recommended:

        if (yourGeekiness >= myGeekiness)

Daniel Chait (my boss led the meeting.  The below info is mostly from Dan’s notes which he wrote on the overhead in real-time (I take credit for any errors or omissions).  As you can see, if you didn’t attend, you missed a lot.  These are mostly just the topics.  Each one generated lively discussion:

PDC 2009 started today:

- Microsoft CodeName “Dallas” announced.

Microsoft “Micro Framework” open sourced:

(not including some stuff like Crypto etc)

Scott Hanselman had a podcast about it?

Azure going live in February (cloud services)

Business Model announced.

Cloud Computing : Compare Azure vs others

Vs Amazon EC2?  Amazon gives you a virtual machine, whereas Microsoft gives you specific services (i.e. web, database, WCF services).  Also cloud-based Pub/Sub model.

BizSpark!!!

- For co’s & individuals

–Co less than 3 yrs. old, less than $1MM, private

- You get all Microsoft stuff basically for 3 yrs. free.

- Check out the “Program Guide” off the website for more details

WebSpark?

- You get VS, SQL Server, and Blend, etc. to get started

- 3 year license for free

PowerPivot

- Part of Office 2010 (was codename “Gemini”)

WPF Grid Controls?

- Using DevExpress (WinForms grid)

- Infragistics – not much new there. tech support pretty good.  glaring bugs in new versions.  difficult upgrading between different versions due to problems with style upgrades

- WPF Toolkit has a grid control: very basic, missing a lot of features (i.e. Filtering etc)

- XCeed well regarded. Been around the longest, full featured.  Cons: tech support iffy.  Licensing may be problematic – issues when you convert from demo to licensed version.

Data Direct products:

- XML converters

- Database connectors

- Difficult licenses

.NET Framework v4?

- Tasks, parallel stuff – http://en.wikipedia.org/wiki/Parallel_Extensions

- WorkFlow changing a lot in V4 as well

- Documentation is very minimal at this point

- Maybe some good PDC content coming out?  i.e.
http://microsoftpdc.com/Sessions/P09-22

- Maybe some channel9 stuff to find?
- Hello Workflow 4

- WF4.0 A First Look
- More

What do people actually use WF for?

- Sharepoint development.  Basic stuff.

Architecture in .NET Question: Model Approach to Database Access?

- ORM Software: Developers make clean code which makes horrible queries

- Call Stored Procs from software: nice queries but ugly to call

- Entity Spaces

- Experience: Easy to use, decent performance but on a simple app

- In ALL cases, need to analyze queries in detail, can’t just rely on the ORM to sort it out

- Microsoft Entity Framework 1.0 – not full featured enough

- New one coming out

- Linq2SQL is dead

- Linq2SQL used a GUID(?) which killed query caching

- NHibernate – “granddaddy of them”.

- Cons : “Has a case of the Java’s”.  XML Configuration, FactoryFactoryFactory…, etc.

GRAND CLAIM: Try to avoid open source:

- Hmm…

- IF something is just a small, weekend project on CodePlex, probably worth avoiding.  But, like, …

- NUnit

- NHibernate

- NCover

- NMock, moq, RhinoMock

- Log4Net, nlog

- log better, easier to configure

- Fluent NHibernate

- The MONO project

- Need to treat it more like “code” than a “product” from a vendor.  Actually understand the code don’t just consume it.

- Open source projects are driven by enthusiasm

- JQuery plugins for example

One user mono in production spoke up.

- Follows the Pareto Principle – for example doesn’t use code signing

- Implementing silverlight (i.e. Moonlight) which works on the iPhone

- Castle project – ActiveRecord implementation – says it’s at least as good as say RoR – just does property setting in code, built on top of NHibernate, scaffolding, etc.

The Munawar principle – 20% will be good, 80% will be garbage

FBK #2: Sturgeon’s Law – “90% of everything is crap”

NCover – code coverage tool

“Where’s my LINQ2 Mainframe?”

SubSonic – open source framework for stuff – http://www.subsonicproject.com/

- “A Super High-fidelity Batman Utility Belt that works up your Data Access (using Linq in 3.0), throws in some much-needed utility functions, and generally speeds along your dev cycle.”

[long discourse about non programmers.  in short, they are inconvenient.]

AJAX / ASP.NET – still buying into it?  As opposed to WPF / Silverlight / Flex?

- Corollary – as a novice, what should I be getting in to

- Corollary 2 – if I want to get out of ASP.NET and get into WPF and realtime .NET desktop apps, how do I do it?

- Endless debate about Silverlight vs Flex

- Silverlight can be applied-ish to WPF knowledge

- Flex VERY easy to learn

Silverlight vs WPF?

- Third party controls maybe a bit better in WPF at present

- If heavy desktop integration, use WPF, else Silverlight by default

- Silverlight Out of Browser – still in the sandbox but just looks like the browser is missing.

- Databinding in Silverlight not nearly as good as WPF.  A bit better in 3.0 but still not great

[spontaneous demo of Castle ActiveRecord]

Good localization solution?  Want to translate our site into multiple languages….

- Sharepoint can do some of this but not ALL languages

- New version of Sharepoint (2008?) does this

- Beware of language specifics (i.e. German has long words)

- Maybe any content management solutions that exist?

- How to handle caching?

- Generate static content or regenerate on the fly every time?

- See http://latino.msn.com/ for more

- http://msdn.microsoft.com/en-us/library/c6zyy3s9.aspx

A great article in 7 parts:

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-1.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-2.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-3.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-4.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-5.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-6.aspx

http://www.gutgames.com/post/Creating-an-ORM-in-C-Part-7.aspx

orouboros

Jörmundgandr (midgårdsormen), en av Lokes tre söner, kastas i havet av Oden där han växer så mycket att han till slut omsluter Midgård och kan bita sig i svansen. Vid Ragnarök släpper ormen sin svans och möter sin nemesis Tor.

Tor fångar Midgårsormen

Ormar som biter sin svans och formar en ring är en vida spridd symbol inom många religioner. Detta symboliserar det cykliska kosmos och att något ständigt skapas och återskapas (se inlägg om tidsåldrar).

Redan i Egypten för 4000 år sedan finns bilder på ormar eller drakar som biter sin egen svans. Denna symbolik anammades senare av alkemisterna där Ouroboros blev en symbol för födsel och död, som man ville undslippa. I Vol. 14 av Carl Jungs samlade verk skriver han:

The Ouroboros has been said to have a meaning of infinity or wholeness. In the age-old image of the Ouroboros lies the thought of devouring oneself and turning oneself into a circulatory process, for it was clear to the more astute alchemists that the prima materia of the art was man himself.

Denna symbolik är inte bara en västföreteelse. Aztekerna avbildade inte sällan deras orm-gud Quetzalcoatl bitandes sin egen svans och vissa stammar i Afrika har använt sig av den.

Quetzalcoatl

Hallå där!

Jag lovade ju en liten presentation i förra inlägget så jag får väl göra vad jag lovat också.
Jag heter Max men går under namnet “Allan i dalen” vilket jag hoppas att ni har märkt? Annar har jag misslyckats grovt, vilket dock inte vore första gången.
Vem är jag mer då?
Ja, vad vill ni veta?
Ni kan ju fråga om det är något speciellt så kommer jag med en liten generell beskrivning så länge.

Allan i dalen
En liten påg från djupaste Skåne som på fritiden skriver en himla massa. Allt från noveller och poesi till låttexter,blogginlägg och bara text för att få skriva lite.
Utöver det så teckar jag lite serier och håller på med Herptiler.
Det innefattar alltså inte bara ödlor och ormar utan också spindlar, skorpioner, diverse insekter och groddjur.
Jag lovar att dela med mig av lite fina bilder på djuren sen.

Det är väl en ganska kort och enkel beskrivning av mig, vill ni veta något mer så bara fråga på.

Angående rubriken så ville jag bara säga att på fritiden jobbar jag även som spökskrivare åt diverse bloggare. Det är jag som skriver alla inlägg åt bland annat Blondinbella, Rödräven, Amir, Kissie, Dessie, Kenza och en massa andra.
Var bara tvungen att låta alla fans få veta!

Ha de.
Saarvi!!

Patrick is giving a talk for SwANH (www.swanh.org) on December 1 entitled “Get RefORMed – Stop Writing CRUD”. The hour-long talk will be an introduction to ORMs incl. optimal implementation scenarios; a look at a few of the ORMs out there; a couple of demos and discussions of pros and cons; and some thoughts about data access alternatives when an ORM cannot be used. It’ll be a pretty technical talk, though with plenty of useful material for technical managers and decision-makers too.

Sumber : http://www.developersbook.com

Hibernate Vs. iBatis?
Hibernate or iBatis or both ? Which is better?
Which one to use and when?

These are the few questions that continuously get asked in most of forums.
What’s really difference between two and really more importantly when should I use one over the other. Its pretty interesting question because there are major differences between iBatis and Hibernate.

Within in the java persistence there is no one size, fits all solution. So, in this case Hibernate which is a de facto standard is used in lot of places.

Let us consider a scenario where Hibernate work great for initial model. Now Suddenly if you are using stored procedures, well we can do it in Hibernate but its little difficult; ok we map those, all of sudden we got some reporting type of queries, those don’t have keys have group bys; with some difficulty here we can use name queries and stuff like that, but now starts getting more complicated, we have complex joins, yes you can do in hibernate, but we can’t do with average developer. We have sql that just doesn’t work.

So these are some of the complexities. One of the other things I find is, if am looking at an application that doesn’t work very well with an ORM, aside from these considerations of using stored procedures, already using SQL, complex joins. In other words, Hibernate works very well if your data model is well in sync with object model, because ORM solutions like Hibernate map object to tables. However, let’s suppose data model is not in sync with object model, in this case you have do lot of additional coding and complexities are entering into your application, start coming the beyond the benefits of ORM. So, again all of sudden you are noticing that the flow is gone; our application is becoming very very complex and developers can’t maintain the code.

This is where the model starts breaking down. One size does not fit all. So this is where I like to use iBatis; as the alternative solution for these type of situations, iBatis maps results sets to objects, so no need to care about table structures. This works very well for stored procedures, works very well for reporting applications, etc,.

Now the question is , does it work well for simple CRUD applications? Well, it works because what we have to write is sql. Then why not use Hibernate for that?

You can start see Some of the decision criteria that comes into play. So one of the other follow on questions that typically get is , can I use both? That’s really interesting question! because the answer is sure.

But,such a thing will never ever exists is java persistence world. However we can kind of use both to create this little hybrid. So think of this kind scenario, we have very large application where Hibernate is working very well for it, but we have a reporting piece that just is a real nag , its query only , so we can do is, we can use iBatis to pull up the queries for reporting piece and still use Hibernate for all the operational stuff and updates. This model actually works well, it doesn’t break the transactional model, and it doesn’t affect any of the primary & secondary caches with a Hibernate. It’s a good solution.

• Use iBatis if
  • You want to create your own SQL’s and are willing to maintain them
  • your environment is driven by relational data model
  • you have to work existing and complex schema’s
• Use Hibernate if
  • your environment is driven by object model and wants generates SQL automatically

The message is,

• One size does not fit all the java persistence and the important to know there are other solutions besides the traditional ORMs, and that would be iBatis.
• Both the solutions work well, given their specific domain.
• Look for the opportunity where you can use both.

Hibernate is a powerful, high performance object/relational persistence and query service. It works in sync with the SPRING framework.

(More at IBM ) Hibernate lets you develop persistent classes following object-oriented idiom – including association, inheritance, polymorphism, composition, and collections. Hibernate allows you to express queries in its own portable SQL extension (HQL), as well as in native SQL, or with an object-oriented Criteria and Example API.

For .Net the framework modifies itself as NHibernate. It is an Object – relational mapping (ORM) solution that provides a framework for mapping an object-oriented domain model to a traditional relational database. Its purpose is to relieve the developer from a significant portion of relational data persistence-related programming tasks.

For more details and release histories for HIBERNATE, visit Hibernate : Official Site

Here is a list of tools (mostly free) that I have complied for monitoring brands online reputation. Gathering data is the first step in ORM, second  is interpreting that data and lastly engagement. These tools help  complete the first step in online reputation management cycle, gathering data.

Dashboards

•    iGoogle (www.google.co.za/ig) – Gives a dashboard approach to monitoring

your online reputation, set this as your home page and balance consistently monitoring your clients with useful apps (like Gmail and Facebook notifications).
•    Google Reader (www.google.com/reader) – Aggregator, makes checking your RSS feeds almost as simple as checking your email.
•    Outlook RSS feeds – Set alerts straight into your inbox, like it’s done with Tomato Source.
•    Side widgets/online feeds – Hundreds of readers exist, from your sidebar in Vista to your Facebook account.
•   Yahoo Pipes (http://pipes.yahoo.com/pipes/) – Feed aggregator and manipulator. Set up pipes for news alerts and overviews. Generally Awesome, for the advanced user.

Paid for dashboards
•    BrandsEye (http://www.brandseye.com/)  – Quirk’s BrandsEye is the greatest ORM monitoring tool I have tried to date, its complicated but highly customizable and affordable
•    SaidWot (http://www.saidwot.co.za/) – SaidWot is a simple to use and understand ORM tool, perfect for monitoring that does not need in depth analysis. SaidWot also gives a brand value to mentions which can help justify the online outreach budget.

Brand overviews

•    HowSociable? (http://www.howsociable.com/) – A simple, free, tool that can measure the visibility of your brand on the web across 32 metrics
•    Socialmention (http://socialmention.com/) – A social media search engine offering searches across individual platforms (e.g. blogs, microblogs) or all together with a ’social rank’ score. Whether or not the score is transparent enough to be meaningful is open to debate.
•    Kosmix (http://www.kosmix.com/) – Overview of a brand online posts across multiple platforms, use this for a quick brand audit. Or search for yourself and see what results you get!

Blog searches

Global
•    TECHNORATI Advanced (http://technorati.com/search?advanced) – Technorati’s advanced search page allows you to search for blogs (rather than posts) based on tags.
•    Google Blog Search (http://blogsearch.google.com/)  Google’s index of blog posts. The advanced search tab allows you to search based on additional criteria. Very good for searching between specific dates.
Local
•    Amatomu (http://www.amatomu.com/) – Amatomu is the original blog aggregator and only local category blog chart provider. Unfortunately its reputation and credibility is slipping.
•    Afrigator (http://afrigator.com/) – Afrigator is a blog a aggregator for all African blogs that choose to subscribe to it. It provides RSS feeds for blog searches and is the most reliable blog search service for local blogs. Unfortunately it does not have blog charts by category.

Buzz tracking

•    Google Trends (http://google.com/trends) – shows amount of searches and Google news stories
•    Trendpedia (http://www.trendpedia.com/) – Create charts showing the volume of discussion around multiple topics. Generates cool graphs.

Twitter search

•    Twitter Search (http://search.twitter.com/)  Search keywords on Twitter which “self-refreshes”. See what’s happening — ‘right now’ in a specified location
•    Tweet Deck (www.tweetdeck.com) – one of the many dashboards for monitoring your own tweets and run live searches. Completely addictive for heavy Twitter users
•   TweetBeep (http://tweetbeep.com/) – Track mentions of your brand on Twitter in real time.
•    Twitrratr (http://twitrratr.com/) – Rates mentions of your search term on Twitter as positive/neutral/negative
•   Twilert (http://www.twilert.com/) – Twitter application that lets you receive regular email updates of tweets containing your brand, product, service
•   Twitter Grader (http://twitter.grader.com/)- Grade the influence of twitter users, useful for prioritising our responses.

Website traffic

•    Compete (http://www.compete.com/) – Competitor site traffic reports. Estimates only of monthly visitor data. Best used on large high-traffic Web sites.
•    Quantcast (http://www.quantcast.com/) – Use this on large high-traffic Websites. It allows you to compare multiple web sites in one handy chart. Estimates only of monthly visitor data.
•    Alexa (http://www.alexa.com/) – Comparative site traffic reports. Includes estimated reach, rank and page views.

Multi media search

•    YouTube (http://www.youtube.com/) – Search for videos and channels by keyword.
•    Flickr (http://flickr.com/search/advanced) – Search Flickr for photos, groups or people/users.
•    Viral Video Chart (http://www.viralvideochart.com/) – Displays top 20 most-viewed video (1, 7, 365 days). Includes view counts and charting.
•   Zoopy (http://www.zoopy.com) – The only local image and video hosted, great to save on bandwidth costs. Almost all videos here originate from SA.

If you have anything else you think would be useful please leave me a comment.

Den gröna spetssnoken befann sig på ett tak. Den var uppenbart störd av alla som ville fotografera den och dess smala, långa kropp svängde som en gummisnodd över taket. Ormens smidighet och styrka var häpnadsväckande. På den andra bilden kan man se hur den nästan orkade ställa sig på svansspetsen för att nå upp till grenen. På engelska kallas den green vinesnake och på latin Oxybelis fulgidus.

Det var väldigt svårt att fotografera den andra ormen som befann sig i en trädkrona – man ser i princip bara löv på fotografierna. Ni får därför nöja er med att jag berättar om att jag sett den. Ormen hette på engelska ”Birdeatingsnake” och Pseustes poecilonotus på latin.

Extremt giftiga Eylash viper (”Ögonfrans-huggorm”?) väntade på oss under en båttur längs med floden. Detta exemplar vilar passivt på en trädgren. Vi fick inte fotografera med blixt eftersom detta, enligt guiden, kunde retat denna knallgula giftorm. På latin heter den Bothriechis schlegelii.

En guide lärde oss hur man måste agera då man blir biten av en orm. Till mångas förvåning ska man inte försöka suga ut giftet, eller amputera någon lem. Istället bör man tvätta såret med tvål och vatten. Det är viktigt att ta det lugnt, inte drabbas av panik och ta sig till sjukhus så fort som möjligt. Guidens son blev en gång biten av en korallorm, och blev inte betrodd av doktorn som trodde att det var en myra som bitit honom. Det hann därför bli problematiskt innan han efter en längre tid fick motgift och överlevde.

Under helgens resa till Tortuguero som ligger på Costa Ricas östra kust, och därmed gränsar till Atlanten, har jag hunnit se en hel del.

En del av den hela delen var tre ormar, snart kommer fler delar från den hela delen…