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  • Case convention- Why the variation between languages?

    - by Jason
    Coming from a Java background, I'm very used to camelCase. When writing C, using the underscore wasn't a big adjustment, since it was only used sparingly when writing simple Unix apps. In the meantime, I stuck with camelCase as my style, as did most of the class. However, now that I'm teaching myself C# in preparation for my upcoming Usability Design class in the fall, the PascalCase convention of the language is really tripping me up and I'm having to rely on intellisense a great deal in order to make sure the correct API method is being used. To be honest, switching to the PascalCase layout hasn't quite sunk in the muscle memory just yet, and that is frustrating from my point of view. Since C# and Java are considered to be brother languages, as both are descended from C++, why the variation in the language conventions? Was it a personal decision by the creators based on their comfort level, or was it just to play mindgames with new introductees to the language?

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  • From Imperative to Functional Programming

    - by user66569
    As an Electronic Engineer, my programming experience started with Assembly and continue with PL/M, C, C++, Delphi, Java, C# among others (imperative programming is in my blood). I'm interested in add to my previous knowledge, skills about functional programming, but all I've seen until now seems very obfuscated and esoteric. Can you please answer me these questions? 1) What is the mainstream functional programming language today (I don't want to get lost myself studying a plethora of FP languages, just because language X has the feature Y)? 2) What was the first FP language (the Fortran of functional programming if you want)? 3) Finally, when talking about pure vs. non pure FP what are the mainstream languages of each category? Thank you in advance

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  • Why is JavaScript not used for classical application development (compiled software)?

    - by Jose Faeti
    During my years of web development with JavaScript, I come to the conclusion that it's an incredible powerful language, and you can do amazing things with it. It offers a rich set of features, like: Dynamic typing First-class functions Nested functions Closures Functions as methods Functions as Object constructors Prototype-based Objects-based (almost everything is an object) Regex Array and Object literals It seems to me that almost everything can be achieved with this kind of language, you can also emulate OO programming, since it provides great freedom and many different coding styles. With more software-oriented custom functionalities (I/O, FileSystem, Input devices, etc.) I think it will be great to develop applications with. Though, as far as I know, it's only used in web development or in existing softwares as a scripting language only. Only recently, maybe thanks to the V8 Engine, it's been used more for other kind of tasks (see node.js for example). Why until now it's only be relegated only to web development? What is keeping it away from software development?

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  • What is the right option of programming languages and tools for building our website?

    - by Goma
    We are 3 persons trying to build a large website which will be available in 3 languges. However, we will start with one language and with small idea then we are going to improve it and make it larger! What do you think the best tools and language that we should use? We are caring alot about the speed of loading the pages and tools that provide excellent qulaity with cheaper fees. Edit: We are graphic designers, so we did not choose the programming language yet. But we studied computer science and we have an idea but we found that this is the best place to ask the question and expect the right answer from you. Should we use ASP.NET for example? or PHP? We do not want an expesive option that will cost us alot in the future and we do not want to change the technology at least for the first 5 years. Thanks!

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  • Learning C++ but wanting to develop iOS Apps

    - by DiscreteGenius
    I'm a computer engineering student and taking my second programming class. I'm learning C++ using "C++ Primer Plus" 5th edition by Prata. I want to develop for iOS. I understand the main language for Xcode is Objective-C. Am I hurting myself by learning C++ before any other language (notably before my desired lang Objective-C)? There's got to be a reason the university requires C++ to learn as a basis language. Please offer any helpful guidance or how I should go about this. Thanks//

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  • To use Dart, the Java programmer has to work with 2 languages? [closed]

    - by Sridhar-Sarnobat
    When deciding on a technology to use for web apps, it's become a difficult choice between GWT and Dart and I am looking for guidance in deciding. GWT is a java programmer's dream because they don't have to learn a new language or have to worry about a separate IDE or extra plugin etc. GWT was sold using this value proposition - one didn't need to program in Javascript. But are Google making a U-turn and saying "go through the hassle of learning a new language" afterall? Or is it intended for there to be a Java to Dart compiler so that Java developers do not have to learn a new language? (this is not a rant, so I don't know why you are down-voting the question) Note: "the syntax is very similar" is not a justification. You could say why bother with GWT and just work with Java + Javascript directly.

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  • Google I/O 2012 - Putting the App Back into Web App - Web Programming with Dart

    Google I/O 2012 - Putting the App Back into Web App - Web Programming with Dart Dan Grove, Vijay Menon Do you want to build blazingly fast applications with beautiful graphics and offline support? Would you like to run those apps anywhere on the open web? Would you like to develop those apps in a language that supports modular large-scale development while keeping the lightweight feel of a scripting language? This session will show you how to use the Dart programming language to develop the next generation of amazing applications for the open web. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 187 4 ratings Time: 57:16 More in Science & Technology

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  • Avoid penalties for duplicate (multilanguage) shared hosting

    - by Dave
    My concern is about SEO. Now let me explain the scenario. I am making a 3 languages website. The development is alright, but I was targeting local customers with one domain, and international (english version) with another. Eg: Local http://www.minhalojadesapatos.com.br (this is not the real website, just example!) Other http://www.myshoesstore.com.br Both domain point to exactly the same hosting and content, but when user comes through local domain, default language is set to portuguese, otherwise, default is english. Language handling on backend uses PHP Sessions and cookies, so with just a click users can change content language. How to avoid being SEO-penalised in this context? (yeah, I was hungry when focusing market for choosing two domains but the activity really needs that, it is a travel agency).

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  • Develop a small size software using C only for copying same data to multiple external drives simultaneously [on hold]

    - by VSP
    I want to develop a software that can copy the same data to multiple external drives, simultaneously. For example, consider a file Movie and I have 3 external drives to copy it to, and I want to copy Movie to all these 3 drives(these drives can be flash storage or external hard-disk or pen-drive etc. but have one thing in common, i.e. they are all external drives) at the same time, means when I right-click on Movie there has to be 1 option saying Copy to All Drives. It's a sort of mini-project and I want to use C language only. For starting I would like it to work only on Windows OS. What are the requirements of developing this software (not the system requirements but what will I need to develop such a software, like editor,compiler etc.)? I know this type of software must have already been developed but I want to use C language and C Language only. So, is it possible to develop such a software?

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  • Why did the team at LMAX use Java and design the architecture to avoid GC at all cost?

    - by kadaj
    Why did the team at LMAX design the LMAX Disruptor in Java but all their design points to minimizing GC use? If one does not want to have GC run then why use a garbage collected language? Their optimizations, the level of hardware knowledge and the thought they put are just awesome but why Java? I'm not against Java or anything, but why a GC language? Why not use something like D or any other language without GC but allows efficient code? Is it that the team is most familiar with Java or does Java possess some unique advantage that I am not seeing? Say they develop it using D with manual memory management, what would be the difference? They would have to think low level (which they already are), but they can squeeze the best performance out of the system as it's native.

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  • Deferent ways of solving problems in code.

    - by Erin
    I now program in C# for a living but before that I programmed in python for 5 years. I have found that I write C# very that most examples I see on the web. Rather then writing things like: foreach (string bar in foo) { //bar has something doen to it here } I write code that looks like this. foo.ForEach( c => c.someActionhere() ) Or var result = foo.Select( c => { //Some code here to transform the item. }).ToList(); I think my using code like above came form my love of map and reduce in python while not exactly the same thing the concepts are close. Now it's time for my question. What concepts do you take and move with you from language to language. That allow you to solve a problem in a way that is not the normal accepted solution in that language?

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  • job offer in dead technology

    - by bold
    I have a job offer in a dead technology (specific programming language) that I don't want to work with nor do I believe it will offer many jobs in the future. It requires twice a year travels abroad, which not a plus in my eyes. On the other hand the money on the table is high. What would you do? edit: as its not clear I got a job in a programming language that is different from the academic programming language I worked with. Now I see it as a mistake to head to that direction.

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  • What would you call the concept of CofeeScript or Sass to be?

    - by MaG3Stican
    There is this rising trend with web development of making new pseudo languages to extend the functionality of JavaScript, CSS and HTML given that those are static and their metamorphosis or evolution is painfully slow due to the variety of browser providers. So I am currently having a concept dilema on how to categorize them for a book I was made to write by my employer as no one seems to have a name for these pseudo languages. A tiny list of them : JavaScript: LiveScript, Metalua, Uberscript, EmberScript. HTML: Razor, Java Scriptlets. CSS : LESS, Sass. I believe the concept of these pseudo languages and a language or an extension of a language is quite different. First these languages do not extend any functionality currently existing on HTML or CSS or JavaScript, they simply work around it. And also they do not "compile" to an intermediate language, they are merely 1-1 translated to something that only then can be compiled. What would you call them?

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  • How to get started with programming

    - by S.M.
    I have never programmed before. In the 5th grade, I did write very elementary programs using BASIC and that was 7 year back. I wish to learn how to program and I was wondering if someone could please suggest how to get started. For example, I do not know enough to form a judgement on what language should be appropriate to get started. What programming language would you suggest to get started with programming? What are the resources to learn the language you recommend.

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  • What are steps in making an operating system in C ? [duplicate]

    - by ps06756
    This question already has an answer here: Compiler/OS Design - Where to start [closed] 3 answers I am trying to make an my own OS. This is for educational purpose only, so that I get to understand the internals as well as get a good idea of low level programming. I have some prior application development experience in C#/python/C++/C. I am a noob in assembly language(very less experience and knowledge). I understand that in writing an operating system,we can't go without assembly language. Currently, I have just printed a string in assembly language in the boot sector using qemu and BIOS interrupts. What I want is that, can someone specifically point out the steps that I need to follow to make my operating systems run C programs. So that, I can start writing my OS in C. Any other piece of advice to help a newbie, regarding the same is also welcome. Although, I have looked into many os development related tutorials/websites, I can't seem to find this information anywhere.

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  • The new Facebook Pages removed publication localization (translation)? [closed]

    - by Myka Eyl
    On the previous version of Facebook Pages I was able to specify in which language (or even countries) I wanted to publish a post. I've searched a LOT of time everywhere and I do not find anything like that since the timeline has landed on Facebook Pages. Do you know how I could publish something on a Facebook Page but only for ONE language? Because publishing things in several languages could get the "page fans" angry (too many new items that they could not read) and unlike the page. I would really appreciate how to find some language-specific options for new publications on a Facebook Page (I am admin of that page, of course). Any help will be greatly appreciated! Thanks you

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  • Problem with cascade delete using Entity Framework and System.Data.SQLite

    - by jamone
    I have a SQLite DB that is set up so when I delete a Person the delete is cascaded. This works fine when I manually delete a Person (all records that reference the PersonID are deleted). But when I use Entity Framework to delete the Person I get an error: System.InvalidOperationException: The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted. I don't understand why this is occurring. My trigger is set to clean up all related objects before deleting the object it was told to delete. When I go into the model editor and check the properties of the relationship it shows no action for the OnDelete property. Why isn't this set correctly by pulling it from the DB? If I change this value to Cascade everything works properly, but I would rather not rely on this manual change because what if I refresh my model from the DB and it looses that. Here's the relivent SQL for my tables. CREATE TABLE [SomeTable] ( [SomeTableID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, [PersonID] INTEGER NOT NULL REFERENCES [Person](PersonID) ON DELETE CASCADE ) CREATE TABLE [Person] ( [PersonID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT )

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  • Problem deleting record using Entity Framework and System.Data.SQLite

    - by jamone
    I have a SQLite DB that is set up so when I delete a Person the delete is cascaded. This works fine when I manually delete a Person (all records that reference the PersonID are deleted). But when I use Entity Framework to delete the Person I get an error: System.InvalidOperationException: The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted. I don't understand why this is occurring. My trigger is set to clean up all related objects before deleting the object it was told to delete. When I go into the model editor and check the properties of the relationship it shows no action for the OnDelete property. Why isn't this set correctly by pulling it from the DB? Here's the relivent SQL for my tables. CREATE TABLE [SomeTable] ( [SomeTableID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, [PersonID] INTEGER NOT NULL REFERENCES [Person](PersonID) ON DELETE CASCADE ) CREATE TABLE [Person] ( [PersonID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT )

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  • Displaying Many-To-Many Database relationship in VB.NET 2008 with DataGrid, MS SQL 2008

    - by user337501
    Computer bombed while posting this, couldnt find a duplicate question but if there is one, forgive me. So, I've run into a wall. And rather than use a ladder to avoid it, I'd like go through it. I'm setting up what I can best describe as a many-to-many relationship in a database. To examplify, imagine I have three primary tables: Items, Categories, Sections(nevermind the potential redundancy) Then I have another table, Properties. Items, Categories, and Sections can be associated with many properties. A single property can be associated with one, all, or none of the other tables. The best way I can figure to do this is to have join tables make the relationship. i.e. tblItems----(Foreign Key)----tblItems_To_Properties----(Foreign Key)----tblProperties In this example, tblItems simply has an "ItemID" Primary Key. tblItems_To_Properties has its own Primary Key(tblItems_To_PropertiesID), a Foreign Key to the Item(ItemID) and a Foreign key to the Property(PropertyID). The Properties table simply has its primary key(PropertyID) I hope this example isnt too confusing...if I have to I can find a way to put a diagram up or something. My problem is, I want to display this in a DataGrid using the Master-Detail method(DevExpress GridControl). I use the tblItems as a test, and I can see the Items in the parent view, but in the child view I see(understandably) the join table and that is it. My goal is to make it so the Grid ignores the join table and shows the Properties table as the only child. Any help on this method or insight into another solution would be muuuuuuuch appreciat

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  • RIA Services for transmitting non DB object-graph

    - by Mike Gates
    I have been getting into RIA services because I thought it would simplify dealing with the services layer of web applications I wish to build. I see lots of examples out there showing how to create DomainService classes which expose and consume entities that have some kind of relational database backing, and therefore have foreign-key relationships. However, I would like to know how to expose and consume normal object graphs...objects that contain references to eachother but don't have foreign keys. For example, say I want a service operation called "GetFolderInformation(string pathToFolder)". I want this to return a custom object called "FolderInformation" structured with: - string Name - IEnumerable<FileInformation> Files I cannot get this to work because it seems that RIA wants to deal with entities that have foreign key relationships. Why? Why can't the serializer just see my object references and recreate that in the proxy on the other side? Data exists behind service layers that doesn't necessarily have foreign key relationships...like folder/file for example. EDIT: I realized I hadn't asked my question! My question is, is there a way to do what I am trying to do?

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  • Common one-to-many table for multiple entities

    - by Ben V
    Suppose I have two tables, Customer and Vendor. I want to have a common address table for customer and vendor addresses. Customers and Vendors can both have one to many addresses. Option 1 Add columns for the AddressID to the Customer and Vendor tables. This just doesn't seem like a clean solution to me. Customer Vendor Address -------- --------- --------- CustomerID VendorID AddressID AddressID1 AddressID1 Street AddressID2 AddressID2 City... Option 2 Move the foreign key to the Address table. For a Customer, Address.CustomerID will be populated. For a Vendor, Address.VendorID will be populated. I don't like this either - I shouldn't need to modify the address table every time I want to use it for another entity. Customer Vendor Address -------- --------- --------- CustomerID VendorID AddressID CustomerID VendorID Option 3 I've also seen this - only 1 foreign key column on the Address table with another column to identify which foreign key table the address belongs to. I don't like this one because it requires all the foreign key tables to have the same type of ID. It also seems messy once you start coding against it. Customer Vendor Address -------- --------- --------- CustomerID VendorID AddressID FKTable FKID So, am I just too picky, or is there something I haven't thought of?

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  • one table is shared between several websites

    - by sami
    I have a static table that's shared by several websites. By static, I mean that the data is read but never updated by the websites. Currently, all websites are served from the same server but that may change. I want to minimize the need for creating/maintaining this table for each of the websites, so I thought about turning it to an xml file that's stored in a shared library that all websites have access to. The problem is I use an ORM and use forign key constraints to ensure integrity of the ids used from that table, so by removing that table out of the MySQL database into an XML file, will this affect the integrity of the ids coming from that table? My table looks like this <table name="entry"> <column name="id" type="INTEGER" primaryKey="true" autoIncrement="true" /> <column name="title" type="VARCHAR" size="500" required="true" /> </table> and I use it as a foreign key in other tables <table name="refer"> <column name="id" type="INTEGER" primaryKey="true" autoIncrement="true" /> <column name="linkto" type="INTEGER"/> <foreign-key foreignTable="entry"> <reference local="linkto" foreign="id" /> </foreign-key> </table> So I'm wondering if I remove that table out of the database, is there a way to retain that referential integrity? And of course are these any other efficient ways to do the same thing? I just don't want to have to repeat that table for several websites.

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  • SQL - Query to display average as either "longer than" or "shorter than"

    - by user1840801
    Here are the tables I've created: CREATE TABLE Plane_new (Pnum char(3), Feature varchar2(20), Ptype varchar2(15), primary key (Pnum)); CREATE TABLE Employee_new (eid char(3), ename varchar(10), salary number(7,2), mid char(3), PRIMARY KEY (eid), FOREIGN KEY (mid) REFERENCES Employee_new); CREATE TABLE Pilot_new (eid char(3), Licence char(9), primary key (eid), foreign key (eid) references Employee_new on delete cascade); CREATE TABLE FlightI_new (Fnum char(4), Fdate date, Duration number(2), Pid char(3), Pnum char(3), primary key (Fnum), foreign key (Pid) references Pilot_new (eid), foreign key (Pnum) references Plane_new); And here is the query I must complete: For each flight, display its number, the name of the pilot who implemented the flight and the words ‘Longer than average’ if the flight duration was longer than average or the words ‘Shorter than average’ if the flight duration was shorter than or equal to the average. For the column holding the words ‘Longer than average’ or ‘Shorter than average’ make a header Length. Here is what I've come up with - with no luck! SELECT F.Fnum, E.ename, CASE Length WHEN F.Duration>(SELECT AVG(F.Duration) FROM FlightI_new F) THEN "Longer than average" WHEN F.Duration<=(SELECT AVG(F.Duration) FROM FlightI_new F) THEN 'Shorter than average' END FROM FlightI_new F LEFT OUTER JOIN Employee_new E ON F.Pid=E.eid GROUP BY F.Fnum, E.ename; Where am I going wrong?

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  • JPA 2.1 Schema Generation (TOTD #187)

    - by arungupta
    This blog explained some of the key features of JPA 2.1 earlier. Since then Schema Generation has been added to JPA 2.1. This Tip Of The Day (TOTD) will provide more details about this new feature in JPA 2.1. Schema Generation refers to generation of database artifacts like tables, indexes, and constraints in a database schema. It may or may not involve generation of a proper database schema depending upon the credentials and authorization of the user. This helps in prototyping of your application where the required artifacts are generated either prior to application deployment or as part of EntityManagerFactory creation. This is also useful in environments that require provisioning database on demand, e.g. in a cloud. This feature will allow your JPA domain object model to be directly generated in a database. The generated schema may need to be tuned for actual production environment. This usecase is supported by allowing the schema generation to occur into DDL scripts which can then be further tuned by a DBA. The following set of properties in persistence.xml or specified during EntityManagerFactory creation controls the behaviour of schema generation. Property Name Purpose Values javax.persistence.schema-generation-action Controls action to be taken by persistence provider "none", "create", "drop-and-create", "drop" javax.persistence.schema-generation-target Controls whehter schema to be created in database, whether DDL scripts are to be created, or both "database", "scripts", "database-and-scripts" javax.persistence.ddl-create-script-target, javax.persistence.ddl-drop-script-target Controls target locations for writing of scripts. Writers are pre-configured for the persistence provider. Need to be specified only if scripts are to be generated. java.io.Writer (e.g. MyWriter.class) or URL strings javax.persistence.ddl-create-script-source, javax.persistence.ddl-drop-script-source Specifies locations from which DDL scripts are to be read. Readers are pre-configured for the persistence provider. java.io.Reader (e.g. MyReader.class) or URL strings javax.persistence.sql-load-script-source Specifies location of SQL bulk load script. java.io.Reader (e.g. MyReader.class) or URL string javax.persistence.schema-generation-connection JDBC connection to be used for schema generation javax.persistence.database-product-name, javax.persistence.database-major-version, javax.persistence.database-minor-version Needed if scripts are to be generated and no connection to target database. Values are those obtained from JDBC DatabaseMetaData. javax.persistence.create-database-schemas Whether Persistence Provider need to create schema in addition to creating database objects such as tables, sequences, constraints, etc. "true", "false" Section 11.2 in the JPA 2.1 specification defines the annotations used for schema generation process. For example, @Table, @Column, @CollectionTable, @JoinTable, @JoinColumn, are used to define the generated schema. Several layers of defaulting may be involved. For example, the table name is defaulted from entity name and entity name (which can be specified explicitly as well) is defaulted from the class name. However annotations may be used to override or customize the values. The following entity class: @Entity public class Employee {    @Id private int id;    private String name;     . . .     @ManyToOne     private Department dept; } is generated in the database with the following attributes: Maps to EMPLOYEE table in default schema "id" field is mapped to ID column as primary key "name" is mapped to NAME column with a default VARCHAR(255). The length of this field can be easily tuned using @Column. @ManyToOne is mapped to DEPT_ID foreign key column. Can be customized using JOIN_COLUMN. In addition to these properties, couple of new annotations are added to JPA 2.1: @Index - An index for the primary key is generated by default in a database. This new annotation will allow to define additional indexes, over a single or multiple columns, for a better performance. This is specified as part of @Table, @SecondaryTable, @CollectionTable, @JoinTable, and @TableGenerator. For example: @Table(indexes = {@Index(columnList="NAME"), @Index(columnList="DEPT_ID DESC")})@Entity public class Employee {    . . .} The generated table will have a default index on the primary key. In addition, two new indexes are defined on the NAME column (default ascending) and the foreign key that maps to the department in descending order. @ForeignKey - It is used to define foreign key constraint or to otherwise override or disable the persistence provider's default foreign key definition. Can be specified as part of JoinColumn(s), MapKeyJoinColumn(s), PrimaryKeyJoinColumn(s). For example: @Entity public class Employee {    @Id private int id;    private String name;    @ManyToOne    @JoinColumn(foreignKey=@ForeignKey(foreignKeyDefinition="FOREIGN KEY (MANAGER_ID) REFERENCES MANAGER"))    private Manager manager;     . . . } In this entity, the employee's manager is mapped by MANAGER_ID column in the MANAGER table. The value of foreignKeyDefinition would be a database specific string. A complete replay of Linda's talk at JavaOne 2012 can be seen here (click on CON4212_mp4_4212_001 in Media). These features will be available in GlassFish 4 promoted builds in the near future. JPA 2.1 will be delivered as part of Java EE 7. The different components in the Java EE 7 platform are tracked here. JPA 2.1 Expert Group has released Early Draft 2 of the specification. Section 9.4 and 11.2 provide all details about Schema Generation. The latest javadocs can be obtained from here. And the JPA EG would appreciate feedback.

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  • JMS Step 7 - How to Write to an AQ JMS (Advanced Queueing JMS) Queue from a BPEL Process

    - by John-Brown.Evans
    JMS Step 7 - How to Write to an AQ JMS (Advanced Queueing JMS) Queue from a BPEL Process ol{margin:0;padding:0} .jblist{list-style-type:disc;margin:0;padding:0;padding-left:0pt;margin-left:36pt} .c4_7{vertical-align:top;width:468pt;border-style:solid;border-color:#000000;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c3_7{vertical-align:top;width:234pt;border-style:solid;border-color:#000000;border-width:1pt;padding:0pt 5pt 0pt 5pt} .c6_7{vertical-align:top;width:156pt;border-style:solid;border-color:#000000;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c16_7{background-color:#ffffff;padding:0pt 0pt 0pt 0pt} .c0_7{height:11pt;direction:ltr} .c9_7{color:#1155cc;text-decoration:underline} .c17_7{color:inherit;text-decoration:inherit} .c5_7{direction:ltr} .c18_7{background-color:#ffff00} .c2_7{background-color:#f3f3f3} .c14_7{height:0pt} .c8_7{text-indent:36pt} .c11_7{text-align:center} .c7_7{font-style:italic} .c1_7{font-family:"Courier New"} .c13_7{line-height:1.0} .c15_7{border-collapse:collapse} .c12_7{font-weight:bold} .c10_7{font-size:8pt} .title{padding-top:24pt;line-height:1.15;text-align:left;color:#000000;font-size:36pt;font-family:"Arial";font-weight:bold;padding-bottom:6pt} .subtitle{padding-top:18pt;line-height:1.15;text-align:left;color:#666666;font-style:italic;font-size:24pt;font-family:"Georgia";padding-bottom:4pt} li{color:#000000;font-size:10pt;font-family:"Arial"} p{color:#000000;font-size:10pt;margin:0;font-family:"Arial"} h1{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:24pt;font-family:"Arial";font-weight:normal} h2{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:18pt;font-family:"Arial";font-weight:normal} h3{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:14pt;font-family:"Arial";font-weight:normal} h4{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:12pt;font-family:"Arial";font-weight:normal} h5{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:11pt;font-family:"Arial";font-weight:normal} h6{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:10pt;font-family:"Arial";font-weight:normal} This post continues the series of JMS articles which demonstrate how to use JMS queues in a SOA context. The previous posts were: JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue JMS Step 3 - Using the QueueReceive.java Sample Program to Read a Message from a JMS Queue JMS Step 4 - How to Create an 11g BPEL Process Which Writes a Message Based on an XML Schema to a JMS Queue JMS Step 5 - How to Create an 11g BPEL Process Which Reads a Message Based on an XML Schema from a JMS Queue JMS Step 6 - How to Set Up an AQ JMS (Advanced Queueing JMS) for SOA Purposes This example demonstrates how to write a simple message to an Oracle AQ via the the WebLogic AQ JMS functionality from a BPEL process and a JMS adapter. If you have not yet reviewed the previous posts, please do so first, especially the JMS Step 6 post, as this one references objects created there. 1. Recap and Prerequisites In the previous example, we created an Oracle Advanced Queue (AQ) and some related JMS objects in WebLogic Server to be able to access it via JMS. Here are the objects which were created and their names and JNDI names: Database Objects Name Type AQJMSUSER Database User MyQueueTable Advanced Queue (AQ) Table UserQueue Advanced Queue WebLogic Server Objects Object Name Type JNDI Name aqjmsuserDataSource Data Source jdbc/aqjmsuserDataSource AqJmsModule JMS System Module AqJmsForeignServer JMS Foreign Server AqJmsForeignServerConnectionFactory JMS Foreign Server Connection Factory AqJmsForeignServerConnectionFactory AqJmsForeignDestination AQ JMS Foreign Destination queue/USERQUEUE eis/aqjms/UserQueue Connection Pool eis/aqjms/UserQueue 2 . Create a BPEL Composite with a JMS Adapter Partner Link This step requires that you have a valid Application Server Connection defined in JDeveloper, pointing to the application server on which you created the JMS Queue and Connection Factory. You can create this connection in JDeveloper under the Application Server Navigator. Give it any name and be sure to test the connection before completing it. This sample will write a simple XML message to the AQ JMS queue via the JMS adapter, based on the following XSD file, which consists of a single string element: stringPayload.xsd <?xml version="1.0" encoding="windows-1252" ?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"                xmlns="http://www.example.org"                targetNamespace="http://www.example.org"                elementFormDefault="qualified">  <xsd:element name="exampleElement" type="xsd:string">  </xsd:element> </xsd:schema> The following steps are all executed in JDeveloper. The SOA project will be created inside a JDeveloper Application. If you do not already have an application to contain the project, you can create a new one via File > New > General > Generic Application. Give the application any name, for example JMSTests and, when prompted for a project name and type, call the project   JmsAdapterWriteAqJms  and select SOA as the project technology type. If you already have an application, continue below. Create a SOA Project Create a new project and select SOA Tier > SOA Project as its type. Name it JmsAdapterWriteAqJms . When prompted for the composite type, choose Composite With BPEL Process. When prompted for the BPEL Process, name it JmsAdapterWriteAqJms too and choose Synchronous BPEL Process as the template. This will create a composite with a BPEL process and an exposed SOAP service. Double-click the BPEL process to open and begin editing it. You should see a simple BPEL process with a Receive and Reply activity. As we created a default process without an XML schema, the input and output variables are simple strings. Create an XSD File An XSD file is required later to define the message format to be passed to the JMS adapter. In this step, we create a simple XSD file, containing a string variable and add it to the project. First select the xsd item in the left-hand navigation tree to ensure that the XSD file is created under that item. Select File > New > General > XML and choose XML Schema. Call it stringPayload.xsd  and when the editor opens, select the Source view. then replace the contents with the contents of the stringPayload.xsd example above and save the file. You should see it under the XSD item in the navigation tree. Create a JMS Adapter Partner Link We will create the JMS adapter as a service at the composite level. If it is not already open, double-click the composite.xml file in the navigator to open it. From the Component Palette, drag a JMS adapter over onto the right-hand swim lane, under External References. This will start the JMS Adapter Configuration Wizard. Use the following entries: Service Name: JmsAdapterWrite Oracle Enterprise Messaging Service (OEMS): Oracle Advanced Queueing AppServer Connection: Use an existing application server connection pointing to the WebLogic server on which the connection factory created earlier is located. You can use the “+” button to create a connection directly from the wizard, if you do not already have one. Adapter Interface > Interface: Define from operation and schema (specified later) Operation Type: Produce Message Operation Name: Produce_message Produce Operation Parameters Destination Name: Wait for the list to populate. (Only foreign servers are listed here, because Oracle Advanced Queuing was selected earlier, in step 3) .         Select the foreign server destination created earlier, AqJmsForeignDestination (queue) . This will automatically populate the Destination Name field with the name of the foreign destination, queue/USERQUEUE . JNDI Name: The JNDI name to use for the JMS connection. This is the JNDI name of the connection pool created in the WebLogic Server.JDeveloper does not verify the value entered here. If you enter a wrong value, the JMS adapter won’t find the queue and you will get an error message at runtime. In our example, this is the value eis/aqjms/UserQueue Messages URL: We will use the XSD file we created earlier, stringPayload.xsd to define the message format for the JMS adapter. Press the magnifying glass icon to search for schema files. Expand Project Schema Files > stringPayload.xsd and select exampleElement : string . Press Next and Finish, which will complete the JMS Adapter configuration. Wire the BPEL Component to the JMS Adapter In this step, we link the BPEL process/component to the JMS adapter. From the composite.xml editor, drag the right-arrow icon from the BPEL process to the JMS adapter’s in-arrow.   This completes the steps at the composite level. 3. Complete the BPEL Process Design Invoke the JMS Adapter Open the BPEL component by double-clicking it in the design view of the composite.xml. This will display the BPEL process in the design view. You should see the JmsAdapterWrite partner link under one of the two swim lanes. We want it in the right-hand swim lane. If JDeveloper displays it in the left-hand lane, right-click it and choose Display > Move To Opposite Swim Lane. An Invoke activity is required in order to invoke the JMS adapter. Drag an Invoke activity between the Receive and Reply activities. Drag the right-hand arrow from the Invoke activity to the JMS adapter partner link. This will open the Invoke editor. The correct default values are entered automatically and are fine for our purposes. We only need to define the input variable to use for the JMS adapter. By pressing the green “+” symbol, a variable of the correct type can be auto-generated, for example with the name Invoke1_Produce_Message_InputVariable. Press OK after creating the variable. Assign Variables Drag an Assign activity between the Receive and Invoke activities. We will simply copy the input variable to the JMS adapter and, for completion, so the process has an output to print, again to the process’s output variable. Double-click the Assign activity and create two Copy rules: for the first, drag Variables > inputVariable > payload > client:process > client:input_string to Invoke1_Produce_Message_InputVariable > body > ns2:exampleElement for the second, drag the same input variable to outputVariable > payload > client:processResponse > client:result This will create two copy rules, similar to the following: Press OK. This completes the BPEL and Composite design. 4. Compile and Deploy the Composite Compile the process by pressing the Make or Rebuild icons or by right-clicking the project name in the navigator and selecting Make... or Rebuild... If the compilation is successful, deploy it to the SOA server connection defined earlier. (Right-click the project name in the navigator, select Deploy to Application Server, choose the application server connection, choose the partition on the server (usually default) and press Finish. You should see the message ----  Deployment finished.  ---- in the Deployment frame, if the deployment was successful. 5. Test the Composite Execute a Test Instance In a browser, log in to the Enterprise Manager 11g Fusion Middleware Control (EM) for your SOA installation. Navigate to SOA > soa-infra (soa_server1) > default (or wherever you deployed your composite) and click on  JmsAdapterWriteAqJms [1.0] , then press the Test button. Enter any string into the text input field, for example “Test message from JmsAdapterWriteAqJms” then press Test Web Service. If the instance is successful, you should see the same text you entered in the Response payload frame. Monitor the Advanced Queue The test message will be written to the advanced queue created at the top of this sample. To confirm it, log in to the database as AQJMSUSER and query the MYQUEUETABLE database table. For example, from a shell window with SQL*Plus sqlplus aqjmsuser/aqjmsuser SQL> SELECT user_data FROM myqueuetable; which will display the message contents, for example Similarly, you can use the JDeveloper Database Navigator to view the contents. Use a database connection to the AQJMSUSER and in the navigator, expand Queues Tables and select MYQUEUETABLE. Select the Data tab and scroll to the USER_DATA column to view its contents. This concludes this example. The following post will be the last one in this series. In it, we will learn how to read the message we just wrote using a BPEL process and AQ JMS. Best regards John-Brown Evans Oracle Technology Proactive Support Delivery

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