Search Results

Search found 62199 results on 2488 pages for 'first order logic'.

Page 1/2488 | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• Relational Clausal Logic question: what is a Herbrand interpretation

  - by anotherstat

  I'm having a hard time coming to grips with relational clausal logic, and I'm not sure if this is the place to ask but it would be help me so much with revision if anyone could provide guidance with the following questions. Let P be the program: academic(X); student(X); other_staff(X):- works_in(X, university). :-student(john). :-other_staff(john). works_in(john, university) Question: Which are the Herbrand interpreations of P? AS

  Read the article

• Separating physics and game logic from UI code

  - by futlib

  I'm working on a simple block-based puzzle game. The game play consists pretty much of moving blocks around in the game area, so it's a trivial physics simulation. My implementation, however, is in my opinion far from ideal and I'm wondering if you can give me any pointers on how to do it better. I've split the code up into two areas: Game logic and UI, as I did with a lot of puzzle games: The game logic is responsible for the general rules of the game (e.g. the formal rule system in chess) The UI displays the game area and pieces (e.g. chess board and pieces) and is responsible for animations (e.g. animated movement of chess pieces) The game logic represents the game state as a logical grid, where each unit is one cell's width/height on the grid. So for a grid of width 6, you can move a block of width 2 four times until it collides with the boundary. The UI takes this grid, and draws it by converting logical sizes into pixel sizes (that is, multiplies it by a constant). However, since the game has hardly any game logic, my game logic layer [1] doesn't have much to do except collision detection. Here's how it works: Player starts to drag a piece UI asks game logic for the legal movement area of that piece and lets the player drag it within that area Player lets go of a piece UI snaps the piece to the grid (so that it is at a valid logical position) UI tells game logic the new logical position (via mutator methods, which I'd rather avoid) I'm not quite happy with that: I'm writing unit tests for my game logic layer, but not the UI, and it turned out all the tricky code is in the UI: Stopping the piece from colliding with others or the boundary and snapping it to the grid. I don't like the fact that the UI tells the game logic about the new state, I would rather have it call a movePieceLeft() method or something like that, as in my other games, but I didn't get far with that approach, because the game logic knows nothing about the dragging and snapping that's possible in the UI. I think the best thing to do would be to get rid of my game logic layer and implement a physics layer instead. I've got a few questions regarding that: Is such a physics layer common, or is it more typical to have the game logic layer do this? Would the snapping to grid and piece dragging code belong to the UI or the physics layer? Would such a physics layer typically work with pixel sizes or with some kind of logical unit, like my game logic layer? I've seen event-based collision detection in a game's code base once, that is, the player would just drag the piece, the UI would render that obediently and notify the physics system, and the physics system would call a onCollision() method on the piece once a collision is detected. What is more common? This approach or asking for the legal movement area first? [1] layer is probably not the right word for what I mean, but subsystem sounds overblown and class is misguiding, because each layer can consist of several classes.

  Read the article

• Project structure: where to put business logic

  - by Mister Smith

  First of all, I'm not asking where does business logic belong. This has been asked before and most answers I've read agree in that it belongs in the model: Where to put business logic in MVC design? How much business logic should be allowed to exist in the controller layer? How accurate is "Business logic should be in a service, not in a model"? Why put the business logic in the model? What happens when I have multiple types of storage? However people disagree in the way this logic should be distributed across classes. There seem to exist three major currents of thought: Fat model with business logic inside entity classes. Anemic model and business logic in "Service" classes. It depends. I find all of them problematic. The first option is what most Fowlerites stick to. The problem with a fat model is that sometimes a business logic funtion is not only related to a class, and instead uses a bunch of other classes. If, for example, we are developing a web store, there should be a function that calcs an order's total. We could think of putting this function inside the Order class, but what actually happens is that the logic needs to use different classes, not only data contained in the Order class, but also in the User class, the Session class, and maybe the Tax class, Country class, or Giftcard, Payment, etc. Some of these classes could be composed inside the Order class, but some others not. Sorry if the example is not very good, but I hope you understand what I mean. Putting such a function inside the Order class would break the single responsibility principle, adding unnecesary dependences. The business logic would be scattered across entity classes, making it hard to find. The second option is the one I usually follow, but after many projects I'm still in doubt about how to name the class or classes holding the business logic. In my company we usually develop apps with offline capabilities. The user is able to perform entire transactions offline, so all validation and business rules should be implemented in the client, and then there's usually a background thread that syncs with the server. So we usually have the following classes/packages in every project: Data model (DTOs) Data Access Layer (Persistence) Web Services layer (Usually one class per WS, and one method per WS method). Now for the business logic, what is the standard approach? A single class holding all the logic? Multiple classes? (if so, what criteria is used to distribute the logic across them?). And how should we name them? FooManager? FooService? (I know the last one is common, but in our case it is bad naming because the WS layer usually has classes named FooWebService). The third option is probably the right one, but it is also devoid of any useful info. To sum up: I don't like the first approach, but I accept that I might have been unable to fully understand the Zen of it. So if you advocate for fat models as the only and universal solution you are welcome to post links explaining how to do it the right way. I'd like to know what is the standard design and naming conventions for the second approach in OO languages. Class names and package structure, in particular. It would also be helpful too if you could include links to Open Source projects showing how it is done. Thanks in advance.

  Read the article

• SQL SERVER – UNION ALL and ORDER BY – How to Order Table Separately While Using UNION ALL

  - by pinaldave

  I often see developers trying following syntax while using ORDER BY. SELECT Columns FROM TABLE1 ORDER BY Columns UNION ALL SELECT Columns FROM TABLE2 ORDER BY Columns However the above query will return following error. Msg 156, Level 15, State 1, Line 5 Incorrect syntax near the keyword ‘ORDER’. It is not possible to use two different ORDER BY in the UNION statement. UNION returns single resultsetand as per the Logical Query Processing Phases. However, if your requirement is such that you want your top and bottom query of the UNION resultset independently sorted but in the same resultset you can add an additional static column and order by that column. Let us re-create the same scenario. First create two tables and populated with sample data. USE tempdb GO -- Create table CREATE TABLE t1 (ID INT, Col1 VARCHAR(100)); CREATE TABLE t2 (ID INT, Col1 VARCHAR(100)); GO -- Sample Data Build INSERT INTO t1 (ID, Col1) SELECT 1, 'Col1-t1' UNION ALL SELECT 2, 'Col2-t1' UNION ALL SELECT 3, 'Col3-t1'; INSERT INTO t2 (ID, Col1) SELECT 3, 'Col1-t2' UNION ALL SELECT 2, 'Col2-t2' UNION ALL SELECT 1, 'Col3-t2'; GO If we SELECT the data from both the table using UNION ALL . -- SELECT without ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 GO We will get the data in following order. However, our requirement is to get data in following order. If we need data ordered by Column1 we can ORDER the resultset ordered by Column1. -- SELECT with ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 ORDER BY ID GO Now to get the data in independently sorted in UNION ALL let us add additional column OrderKey and use ORDER BY  on that column. I think the description does not do proper justice let us see the example here. -- SELECT with ORDER BY - with ORDER KEY SELECT ID, Col1, 'id1' OrderKey FROM t1 UNION ALL SELECT ID, Col1, 'id2' OrderKey FROM t2 ORDER BY OrderKey, ID GO The above query will give the desired result. Now do not forget to clean up the database by running the following script. -- Clean up DROP TABLE t1; DROP TABLE t2; GO Here is the complete script used in this example. USE tempdb GO -- Create table CREATE TABLE t1 (ID INT, Col1 VARCHAR(100)); CREATE TABLE t2 (ID INT, Col1 VARCHAR(100)); GO -- Sample Data Build INSERT INTO t1 (ID, Col1) SELECT 1, 'Col1-t1' UNION ALL SELECT 2, 'Col2-t1' UNION ALL SELECT 3, 'Col3-t1'; INSERT INTO t2 (ID, Col1) SELECT 3, 'Col1-t2' UNION ALL SELECT 2, 'Col2-t2' UNION ALL SELECT 1, 'Col3-t2'; GO -- SELECT without ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 GO -- SELECT with ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 ORDER BY ID GO -- SELECT with ORDER BY - with ORDER KEY SELECT ID, Col1, 'id1' OrderKey FROM t1 UNION ALL SELECT ID, Col1, 'id2' OrderKey FROM t2 ORDER BY OrderKey, ID GO -- Clean up DROP TABLE t1; DROP TABLE t2; GO I am sure there are many more ways to achieve this, what method would you use if you have to face the similar situation? Reference: Pinal Dave (http://blog.sqlauthority.com)   Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Breadth First Vs Depth First

  - by Ted Smith

  When Traversing a Tree/Graph what is the difference between Breadth First and Depth first? Any coding or pseudocode examples would be great.

  Read the article

• Synchronization between game logic thread and rendering thread

  - by user782220

  How does one separate game logic and rendering? I know there seem to already be questions on here asking exactly that but the answers are not satisfactory to me. From what I understand so far the point of separating them into different threads is so that game logic can start running for the next tick immediately instead of waiting for the next vsync where rendering finally returns from the swapbuffer call its been blocking on. But specifically what data structures are used to prevent race conditions between the game logic thread and the rendering thread. Presumably the rendering thread needs access to various variables to figure out what to draw, but game logic could be updating these same variables. Is there a de facto standard technique for handling this problem. Maybe like copy the data needed by the rendering thread after every execution of the game logic. Whatever the solution is will the overhead of synchronization or whatever be less than just running everything single threaded?

  Read the article

• SQL SERVER – ORDER BY ColumnName vs ORDER BY ColumnNumber

  - by pinaldave

  I strongly favor ORDER BY ColumnName. I read one of the blog post where blogger compared the performance of the two SELECT statement and come to conclusion that ColumnNumber has no harm to use it. Let us understand the point made by first that there is no performance difference. Run following two scripts together: USE AdventureWorks GO -- ColumnName (Recommended) SELECT * FROM HumanResources.Department ORDER BY GroupName, Name GO -- ColumnNumber (Strongly Not Recommended) SELECT * FROM HumanResources.Department ORDER BY 3,2 GO If you look at the result and see the execution plan you will see that both of the query will take the same amount of the time. However, this was not the point of this blog post. It is not good enough to stop here. We need to understand the advantages and disadvantages of both the methods. Case 1: When Not Using * and Columns are Re-ordered USE AdventureWorks GO -- ColumnName (Recommended) SELECT GroupName, Name, ModifiedDate, DepartmentID FROM HumanResources.Department ORDER BY GroupName, Name GO -- ColumnNumber (Strongly Not Recommended) SELECT GroupName, Name, ModifiedDate, DepartmentID FROM HumanResources.Department ORDER BY 3,2 GO Case 2: When someone changes the schema of the table affecting column order I will let you recreate the example for the same. If your development server where your schema is different than the production server, if you use ColumnNumber, you will get different results on the production server. Summary: When you develop the query it may not be issue but as time passes by and new columns are added to the SELECT statement or original table is re-ordered if you have used ColumnNumber it may possible that your query will start giving you unexpected results and incorrect ORDER BY. One should note that the usage of ORDER BY ColumnName vs ORDER BY ColumnNumber should not be done based on performance but usability and scalability. It is always recommended to use proper ORDER BY clause with ColumnName to avoid any confusion. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• breadth first or depth first search

  - by endroix

  I know how this algorithm works, but cant decide when to use which algorithm ? Are there some guidelines, where one better perform than other or any considerations ? Thanks very much.

  Read the article

• Entity/Component based engine rendering separation from logic

  - by Denis Narushevich

  I noticed in Unity3D that each gameObject(entity) have its own renderer component, as far I understand, such component handle rendering logic. I wonder if it is a common practice in entity/component based engines, when single entity have renderer components and logic components such as position, behavior altogether in one box? Such approach sound odd to me, in my understanding entity itself belongs to logic part and shouldn't contain any render specific things inside. With such approach it is impossible to swap renderers, it would require to rewrite all that customized renderers. The way I would do it is, that entity would contain only logic specific components, like AI,transform,scripts plus reference to mesh, or sprite. Then some entity with Camera component would store all references to object that is visible to the camera. And in order to render all that stuff I would have to pass Camera reference to Renderer class and render all sprites,meshes of visible entities. Is such approach somehow wrong?

  Read the article

• The Work Order Printing Challenge

  - by celine.beck

  One of the biggest concerns we've heard from maintenance practitioners is the ability to print and batch print work order details along with its accompanying attachments. Indeed, maintenance workers traditionally rely on work order packets to complete their job. A standard work order packet can include a variety of information like equipment documentation, operating instructions, checklists, end-of-task feedback forms and the likes. Now, the problem is that most Asset Lifecycle Management applications do not provide a simple and efficient solution for process printing with document attachments. Work order forms can be easily printed but attachments are usually left out of the printing process. This sounds like a minor problem, but when you are processing high volume of work orders on a regular basis, this inconvenience can result in important inefficiencies. In order to print work order and its related attachments, maintenance personnel need to print the work order details and then go back to the work order and open each individual attachment using the proper authoring application to view and print each document. The printed output is collated into a work order packet. The AutoVue Document Print Service products that were just released in April 2010 aim at helping organizations address the work order printing challenge. Customers and partners can leverage the AutoVue Document Print Services to build a complete printing solution that complements their existing print server solution with AutoVue's document- and platform-agnostic document print services. The idea is to leverage AutoVue's printing services to invoke printing either programmatically or manually directly from within the work order management application, and efficiently process the printing of complete work order packets, including all types of attachments, from office files to more advanced engineering documents like 2D CAD drawings. Oracle partners like MIPRO Consulting, specialists in PeopleSoft implementations, have already expressed interest in the AutoVue Document Print Service products for their ability to offer print services to the PeopleSoft ALM suite, so that customers are able to print packages of documents for maintenance personnel. For more information on the subject, please consult MIPRO Consulting's article entitled Unsung Value: Primavera and AutoVue Integration into PeopleSoft posted on their blog. The blog post entitled Introducing AutoVue Document Print Service provides additional information on how the solution works. We would also love to hear what your thoughts are on the topic, so please do not hesitate to post your comments/feedback on our blog. Related Articles: Introducing AutoVue Document Print Service Print Any Document Type with AutoVue Document Print Services

  Read the article

• Logic / Render phases with a single thread

  - by DevilWithin

  The question I have may generate different opinions from different developers, but I'd still like to have an answer on this. Its all about the updating and rendering steps of the game loop, and their use under multi and single threaded environments. Currently, there is one thread running, which takes care of sequentially executing events , logic and rendering. Sometimes, the logic part may wish to change the game state to something else, and in between do some loading of files. The result is that the game hangs completely while loading, and then proceeds to normal rendering of the new state. To go around this, i could make another thread, do the loading there while the main thread renders a smooth loading animation, and then proceed normally. The real question is about if i don't create another thread. I could refresh the screen from the logic thread, and provide some basic loading screen, which could be not so smoothly updated while the files load. In fact, this approach is not loved by a lot of developers, as it scrambles render code in the logic step, which may cause problems of different sorts.. Hope its clear!

  Read the article

• Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

  - by mortezam

  A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail  {     public int BillingDetailId { get; set; }     public string Owner { get; set; }             public string Number { get; set; } } public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } public class CreditCard : BillingDetail {     public int CardType { get; set; }                     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext                                                                          .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount)                       FROM BillingDetails AS b                       WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT  [Extent1].[Discriminator] AS [Discriminator],  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift],  [Extent1].[CardType] AS [CardType],  [Extent1].[ExpiryMonth] AS [ExpiryMonth],  [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) {     modelBuilder.Entity<BillingDetail>()                 .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA"))                 .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>()             .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1))             .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

  Read the article

• Describe business logic with diagrams

  - by Nikos M.

  I am currently developing a web application for my thesis.I was asked by my professor to make diagrams to describe the business logic. Since I don't have a prior experience, I am pretty confused with all the terminology. I managed to clarify,I think, what business rules and business logic are, but I can't find out how you describe the business logic. Is it something particular or is it something more general? Do I need to learn UML? Does the fact that I use MVC affects the way I'll describe it?

  Read the article

• CakePHP: find neighbors, order on 'name' or 'order'

  - by Brelsnok

  Hi, I have a list of ordered items, ordered according to the int field order. I'm creating a gallery in CakePHP 1.2 that has a prev and next button and those should link to the previous and next item according to their ordering, not according to their id. In order to get this result I've included the 'order' parameter to the find function, and populated it with 'Item.order'=>'DESC'. Still the result is an id ordered list. My question is: what do I do wrong? My controller: $this->Item->id = 16; $neighbours = $this->Item->find('neighbors', array('order'=>array('Item.order'=>'DESC'), 'fields'=>array('id','name')));

  Read the article

• OM: Effective Troubleshooting Techniques to Debug Order Import

  - by ChristineS

  There is a new document available to help you debug Order Import in Order Management:  Effective Troubleshooting Techniques to Debug Order Import Issues (Doc ID 1558196.1) The white paper addresses debugging from a technical perspective. This approach is to assist users in understanding the actual issue, as well as help them in the early resolution of any order import issue. It will walk you through several cases, with supporting debug logs / trace files taken for each case. Educating you along the way for what debug logs / trace files should be gathered, as trace files are not always needed.  It will also walk you through the supporting documents so you will know what to look for in your case. Please refer to this note the next time you have an Order Import error. Or you could step through it now, so you are informed the next time you encounter an Order Import error.  Happy debugging!

  Read the article

• mysql order-by original "where order"

  - by Benjamin Dobnikar

  I have this order-by problem I canot crack. I select from my table like this: SELECT * FROM 'sidemodules' WHERE name = 'module1' OR name = 'module2' OR 'name3' Which returns me the modules I want. But the modules lie the table, say in this order: module3 module1 module2 And they are returned to me in this order. How can I get them to display in order AS IN THE WHERE CLAUSE (1,2,3) ? Big thanks!

  Read the article

• The order of a SQL Select statement without Order By clause

  - by Yousui

  As I know, from the relational database theory, a select statement without an order by clause should be considered has not particular order. But actually in SQL Server and Oracle (I've tested on those 2 platforms), if I query from a table without an order by clause multiple times, I always get the results in the same order. Does this behavior can be relied on? Anyone can help to explain a little? Thanks!

  Read the article

• Adding dynamic business logic/business process checks to a system

  - by Jordan Reiter

  I'm wondering if there is a good extant pattern (language here is Python/Django but also interested on the more abstract level) for creating a business logic layer that can be created without coding. For example, suppose that a house rental should only be available during a specific time. A coder might create the following class: from bizlogic import rules, LogicRule from orders.models import Order class BeachHouseAvailable(LogicRule): def check(self, reservation): house = reservation.house_reserved if not (house.earliest_available < reservation.starts < house.latest_available ) raise RuleViolationWhen("Beach house is available only between %s and %s" % (house.earliest_available, house.latest_available)) return True rules.add(Order, BeachHouseAvailable, name="BeachHouse Available") This is fine, but I don't want to have to code something like this each time a new rule is needed. I'd like to create something dynamic, ideally something that can be stored in a database. The thing is, it would have to be flexible enough to encompass a wide variety of rules: avoiding duplicates/overlaps (to continue the example "You already have a reservation for this time/location") logic rules ("You can't rent a house to yourself", "This house is in a different place from your chosen destination") sanity tests ("You've set a rental price that's 10x the normal rate. Are you sure this is the right price?" Things like that. Before I recreate the wheel, I'm wondering if there are already methods out there for doing something like this.

  Read the article

• Implementing a "state-machine" logic for methods required by an object in C++

  - by user827992

  What I have: 1 hypothetical object/class + other classes and related methods that gives me functionality. What I want: linking this object to 0 to N methods in realtime on request when an event is triggered Each event is related to a single method or a class, so a single event does not necessarily mean "connect this 1 method only" but can also mean "connect all the methods from that class or a group of methods" Avoiding linked lists because I have to browse the entire list to know what methods are linked, because this does not ensure me that the linked methods are kept in a particular order (let's say an alphabetic order by their names or classes), and also because this involve a massive amount of pointers usage. Example: I have an object Employee Jon, Jon acquires knowledge and forgets things pretty easily, so his skills may vary during a period of time, I'm responsible for what Jon can add or remove from his CV, how can I implement this logic?

  Read the article

• Dynamically evaluating simple boolean logic in Python

  - by a paid nerd

  I've got some dynamically-generated boolean logic expressions, like: (A or B) and (C or D) A or (A and B) A empty - evaluates to True The placeholders get replaced with booleans. Should I, Convert this information to a Python expression like True or (True or False) and eval it? Create a binary tree where a node is either a bool or Conjunction/Disjunction object and recursively evaluate it? Convert it into nested S-expressions and use a Lisp parser? Something else? Suggestions welcome.

  Read the article

• Why (not) logic programming?

  - by Anto

  I have not yet heard about any uses of a logical programming language (such as Prolog) in the software industry, nor do I know of usage of it in hobby programming or open source projects. It (Prolog) is used as an academic language to some extent, though (why is it used in academia?). This makes me wonder, why should you use logic programming, and why not? Why is it not getting any detectable industry usage?

  Read the article

• Code First / Database First / Model First : are they just personnal preferences?

  - by Antoine M

  Merely knowing the internal functionality of each approaches, and after reading a lot of posts, I still can't figure out if each one of them is just a matter of personnal preference for the developper or if they deserve different axes of productivity ? Does one of them should be applyed for some specific productivity needs or MS is just beeing kind offering three different flavours ? Should we consider CF as a sort of improvement over DBF or MF and thinking of it as a futur standard on wich spending a peculiar intelectual investment ... ? Is there a link showing a sort of synthetic table with un-passionate pros and cons for each approach, a little bit like for web-forms and MVC. Sorry for those who will find this question redondant. I know it is.

  Read the article

• MVC - Business Logic

  - by BriskLabs Pakistan

  I have created a MVC based simple java application. its helps the user to add records through data forms to database..... i want that the data that i put into the database as a record is worked upon i.e by performing calculations on it. the original data should remain unaffected. while the new data after calculations performed must be stored as a new entity record into database. Where should i write the code for this background calculation .. as it is the rules and business logic... in a new java beans file... Please guide. regards

  Read the article

• Oracle EBS?????(Order->AR)

  - by Pan.Tian

  ???? ??:Order Management > Orders,Returns > Sales Orders ???????,??,????,???? ???????,????,??... ??Book Order,??Book??,????????Status??????“Booked”,???????"Awaiting Shipping",?????????,??????????????? ??:??Book??,????????????,????Shipping Transactions Form,????,?????????Line Status?Ready to Release,Next Step?Pick Release Pick Release ??:Order Management > Shipping > Release Sales Orders > Release Sales Orders Pick Release????(?????????).?Order  Number?????????? Auto Pick Confirm???No Auto Allocate???N Auto Allocate?Auto Pick Confirm??????Yes,???????????,??????No,???Yes??,?????Allocate?Pick Confirm??,??????????? ??????????Pick  Release,”Concurrent“??Pick Release?????Concurrent Request???,"Execute Now"????????Pick Release,??????????????User,??????Concurrent??? Pick Release?????????Pick Release?????Pick Wave??Move Order,??Move Order????????????????????(Staging),????INV??????????? INV_MOVE_ORDER_PUB.CREATE_MOVE_ORDER_HEADER???Move Order??(??Pick Release?????????????:Pick Release Process) ????????,?Pick Release??,?????????????Reservation(??),?????????Soft Reservations,?????????????,????Org?????????? ??:????,Shipping Transaction?Line Status?"Released to Warehouse",Next Step?"Transact Move Order";????????Booked,?????”Awaiting Shipping“? Pick Confirm Pick Confirm(????)????????Transact Move Order????,?Allocate????,?Transact Move Order. ??:Inventory > Move Orders > Transact Move Orders ????,Pick Wave??Tab,????? ??TMO????,??Allocate,Allocate?????????Picking Rule?????,??????Suggestion????,Suggestion?????? MTL_MATERIAL_TRANSACTIONS_TEMP?(?Pending Transactions)? ????Allocate??,??????Allocation????Single,Multiple??None???,Single??, ??????????Suggestion?Transaction??,Multiple???????;None??????Suggestion? ?(????????????????) ????????Transact??Move Order ?Transact??,Inventory Transaction Manager ???Suggestion Transactions(MMTT),???????????????,??????Subinventory??????(Staging)??? Transction???Material Transaction?Form????? ????Reservation??,?Transact??,???????,Reservation????????,????Sub,locator???? ??:????,Shipping Transaction?Line Status?"Staged/Pick Confirmed",Next Step?"Ship Confirm/Close Trip Stop";????????Booked,??????”Picked“? Ship Confirm Deliveries ??:Order Management > Shipping > Transactions ???Delivery??,??Ship Confirm(????),????Pick Release???,????Autocreate Delivery,???????Define Shipping Parameters????????,??shipping parameters???????,?????????Ship Confirm?????Action->Auto-create Deliveries. Delivery????????????????,????????.... Delivery??,??Ship Confirm???,???????,"Defer Interface"?????,?????????Interface Trip Stop SRS,????Defer Interface,?OK? Delivery was successfully confirmed!!! Ship Confirm????????????MTL_TRANSACTIONS_INTERFACE??,??MTI??????Sales Order Issue,??????????Interface Trip Stop???,???MTI??MMT??? ??:????,Shipping Transaction?Line Status?"Shipped",Next Step?"Run Interfaces";????????Booked,??????”Shipped“? Interface Trip Stop - SRS ?????Ship Confirm??????Defer Interface,??????????????Interface Trip Stop - SRS? ??:Order Management > Shipping > Interface > Run > Request:Interface Trip Stop - SRS Interface Trip Stop????????:Inventory Interface  SRS(????????)? Order Management Interface  SRS(?????????????AR??)? Inventory Interface  SRS???Shipping Transaction??????MTI,??INV Manager????MTI????MMT??,??Sales Order Issue?transaction??????,???????????Reservation????Inventory Interface  SRS?????,???WSH_DELIVERY_DETAILS??INV_INTERFACED_FLAG???Y? Order Management Interface - SRS??Inventory Interface  SRS?????,??Request?????????????AR??,OM Interface????????WSH_DELIVERY_DETAILS??OE_INTERFACED_FLAG?Y? ??:????,Shipping Transaction?Line Status?"Interfaced",Next Step?"Not Applicable";????????Booked,??????”Shipped“? Workflow background Process ??:Inventory > Workflow Background Engine Item Type:OM Order Line Process Deferred:Yes Process Timeout:No ??program????Deffered???workflow,Workflow Background Process???,???????Order????RA Interface???(RA_INTERFACE_LINES_ALL,RA_INTERFACE_SALESCREDITS_ALL,RA_Interface_distribution) ????????SQL???RA Interface??: 1.SELECT * FROM RA_INTERFACE_LINES_ALL WHERE sales_order = '65961'; 2.SELECT * FROM RA_INTERFACE_SALESCREDITS_ALL WHERE INTERFACE_LINE_ID IN (SELECT INTERFACE_LINE_ID FROM RA_INTERFACE_LINES_ALL WHERE sales_order = '65961' ); 3.SELECT * FROM RA_INTERFACE_DISTRIBUTIONS_ALL WHERE INTERFACE_LINE_ID IN (SELECT INTERFACE_LINE_ID FROM RA_INTERFACE_LINES_ALL WHERE sales_order = '65961' ); ?????RA Interface??,??OE_ORDER_LINES_ALL?INVOICE_INTERFACE_STATUS_CODE????? Yes,INVOICED_QUANTITY?????????????????????????Closed,????????Booked? AutoInvoice ????AR?? ??:Account Receivable > Interface > AutoInvoice Name:Autoinvoice Master Program Invoice Source:Order Entry Default Day:???? ???,?request????”Autoinvoice Import Program“???? ???,????Auto Invoice Program????RA?interface?,?????????????,???????AR???? (RA_CUSTOMER_TRX_ALL,RA_CUSTOMER_TRX_LINES,AR_PAYMENT_SCHEDULES). ?????? Order > Action > Additional Information > Invoices/Credit Memos????????,???????SQL?????AR??, SELECT ooha.order_number , oola.line_number so_line_number , oola.ordered_item , oola.ordered_quantity * oola.unit_selling_price so_extended_price , rcta.trx_number invoice_number , rcta.trx_date , rctla.line_number inv_line_number , rctla.unit_selling_price inv_unit_selling_price FROM oe_order_headers_all ooha , oe_order_lines_all oola , ra_customer_trx_all rcta , ra_customer_trx_lines_all rctla WHERE ooha.header_id = oola.header_id AND rcta.customer_trx_id = rctla.customer_trx_id AND rctla.interface_line_attribute6 = TO_CHAR (oola.line_id) AND rctla.interface_line_attribute1 = TO_CHAR (ooha.order_number) AND order_number = :p_order_number; ??Autoinvoice Import Program???error???,?????RA_INTERFACE_ERRORS_ALL?Message_text??,???????? Closing the Order ?????????,?????????(Close??Cancel)?0.5?,??????Workflow Background Process??????? ????????:you can wait until month-end and the “Order Flow – Generic” workflow will close it for you. Order&Shipping Transactions Status Summary Step Order Header Status Order Line Status Order Flow Workflow Status (Order Header) Line Flow Workflow Status (Order Line) Shipping Transaction  Status(RELEASED_STATUS in WDD) 1. Enter an Order Entered Entered Book Order Manual Enter – Line                              N/A 2. Book the Order Booked Awaiting Shipping Close Order Schedule ->Create Supply ->Ship – Line                       Ready to Release(R) 3. Pick the Order Booked Picked Close Order Ship – Line 1.Released to Warehouse(S)(Pick Release but not pick confirm) 2.Staged/Pick Confirmed(Y)(After pick confirm) 4. Ship the Order Booked Shipped Close Order Fulfill – Deferred 1.Shipped(After ship confirm) 2.Interfaced(C)(After ITS) Booked Closed Close Order Fulfill ->Invoice Interface ->Close Line -> End 5. Close the Order Closed Closed End End ????,shipping txn???,??????????:http://blog.csdn.net/pan_tian/article/details/7696528 ======EOF======

  Read the article

• Where to put business logic in MVC design?

  - by BriskLabs Pakistan

  I have created a simple MVC java application that adds records through data forms to a database. my app collects data, it also validates it and stores it. This is because the data is being sourced online from different users. the data is mostly numeric in nature. now on the numeric data being stored into database (SQL server) , i wish that my app should be able to perform computations... and display it. the user is not interested in how computations are done so they must be encapsulated. the user must only be able to view the simple computed data which for example A column data - B Column data / C column data etc... and just display it to the user... i know how to write stored procedures for same but i want a 3 tier app I want the data, that I put into the database as a record, worked upon by performing calculations on it. However, the original data should remain unaffected, while the new data, post-calculations, must be stored as a new entity record into the database. Where should I write the code for this background calculation? As it is the rules and business logic... in a new java beans files ?

  Read the article

1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >