Search Results

Search found 13710 results on 549 pages for 'relational model'.

Page 332/549 | < Previous Page | 328 329 330 331 332 333 334 335 336 337 338 339  | Next Page >

  • Are comonads a good fit for modeling the Wumpus world?

    - by Tim Stewart
    I'm trying to find some practical applications of a comonad and I thought I'd try to see if I could represent the classical Wumpus world as a comonad. I'd like to use this code to allow the Wumpus to move left and right through the world and clean up dirty tiles and avoid pits. It seems that the only comonad function that's useful is extract (to get the current tile) and that moving around and cleaning tiles would not use be able to make use of extend or duplicate. I'm not sure comonads are a good fit but I've seen a talk (Dominic Orchard: A Notation for Comonads) where comonads were used to model a cursor in a two-dimensional matrix. If a comonad is a good way of representing the Wumpus world, could you please show where my code is wrong? If it's wrong, could you please suggest a simple application of comonads? module Wumpus where -- Incomplete model of a world inhabited by a Wumpus who likes a nice -- tidy world but does not like falling in pits. import Control.Comonad -- The Wumpus world is made up of tiles that can be in one of three -- states. data Tile = Clean | Dirty | Pit deriving (Show, Eq) -- The Wumpus world is a one dimensional array partitioned into three -- values: the tiles to the left of the Wumpus, the tile occupied by -- the Wumpus, and the tiles to the right of the Wumpus. data World a = World [a] a [a] deriving (Show, Eq) -- Applies a function to every tile in the world instance Functor World where fmap f (World as b cs) = World (fmap f as) (f b) (fmap f cs) -- The Wumpus world is a Comonad instance Comonad World where -- get the part of the world the Wumpus currently occupies extract (World _ b _) = b -- not sure what this means in the Wumpus world. This type checks -- but does not make sense to me. extend f w@(World as b cs) = World (map world as) (f w) (map world cs) where world v = f (World [] v []) -- returns a world in which the Wumpus has either 1) moved one tile to -- the left or 2) stayed in the same place if the Wumpus could not move -- to the left. moveLeft :: World a -> World a moveLeft w@(World [] _ _) = w moveLeft (World as b cs) = World (init as) (last as) (b:cs) -- returns a world in which the Wumpus has either 1) moved one tile to -- the right or 2) stayed in the same place if the Wumpus could not move -- to the right. moveRight :: World a -> World a moveRight w@(World _ _ []) = w moveRight (World as b cs) = World (as ++ [b]) (head cs) (tail cs) initWorld = World [Dirty, Clean, Dirty] Dirty [Clean, Dirty, Pit] -- cleans the current tile cleanTile :: Tile -> Tile cleanTile Dirty = Clean cleanTile t = t Thanks!

    Read the article

  • Unit Testing VS 2008 Using Excel

    - by David
    When using Excel (2003) to provide data for my unit tests it seems to think that when a cell has TRUE / FALSE value that it is null when there has been no preceding cell values e.g. if (TestContext.DataRow["SatisfactionExtremelySatisfied"] != DBNull.Value) model.SatisfactionExtremelySatisfied = (bool)TestContext.DataRow ["SatisfactionExtremelySatisfied"]; Sample Excel Data DataRow SatisfactionExtremelySatisfied 0 1 2 TRUE 3 TRUE When reading the test data using OLEDB the cells with TRUE hold no value but when the preceding cells have the value FALSE entered it correctly gets the values TRUE. Am I missing something?

    Read the article

  • Cast IEnumerable<Inherited> To IEnumerable<Base>

    - by david2342
    I'm trying to cast an IEnumerable of an inherited type to IEnumerable of base class. Have tried following: var test = resultFromDb.Cast<BookedResource>(); return test.ToList(); But getting error: You cannot convert these types. Linq to Entities only supports conversion primitive EDM-types. The classes involved look like this: public partial class HistoryBookedResource : BookedResource { } public partial class HistoryBookedResource { public int ResourceId { get; set; } public string DateFrom { get; set; } public string TimeFrom { get; set; } public string TimeTo { get; set; } } public partial class BookedResource { public int ResourceId { get; set; } public string DateFrom { get; set; } public string TimeFrom { get; set; } public string TimeTo { get; set; } } [MetadataType(typeof(BookedResourceMetaData))] public partial class BookedResource { } public class BookedResourceMetaData { [Required(ErrorMessage = "Resource id is Required")] [Range(0, int.MaxValue, ErrorMessage = "Resource id is must be an number")] public object ResourceId { get; set; } [Required(ErrorMessage = "Date is Required")] public object DateFrom { get; set; } [Required(ErrorMessage = "Time From is Required")] public object TimeFrom { get; set; } [Required(ErrorMessage = "Time to is Required")] public object TimeTo { get; set; } } The problem I'm trying to solve is to get records from table HistoryBookedResource and have the result in an IEnumerable<BookedResource> using Entity Framework and LINQ. UPDATE: When using the following the cast seams to work but when trying to loop with a foreach the data is lost. resultFromDb.ToList() as IEnumerable<BookedResource>; UPDATE 2: Im using entity frameworks generated model, model (edmx) is created from database, edmx include classes that reprecent the database tables. In database i have a history table for old BookedResource and it can happen that the user want to look at these and to get the old data from the database entity framework uses classes with the same name as the tables to receive data from db. So i receive the data from table HistoryBookedResource in HistoryBookedResource class. Because entity framework generate the partial classes with the properties i dont know if i can make them virtual and override. Any suggestions will be greatly appreciated.

    Read the article

  • primary key datatype in sql server database

    - by ooo
    i see after installing the asp.net membership tables, they use the data type "uniqueidentifier" for all of the primary key fields. I have been using "int" data type and doing increment by one on inserts. Is there any particular benefits to using the uniqueIdentifier data type compared to my current model of using int and auto increments on new inserts ?

    Read the article

  • asp.net mvc2 - update list of objects

    - by ile
    I want to display list of objects from database, and on the same page have option to edit them. When submitting, I'd like to submit changes to all of them. I found this link: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx and http://www.hanselman.com/blog/ASPNETWireFormatForModelBindingToArraysListsCollectionsDictionaries.aspx but there is no description how to handle posted data in controller. Thanks in advance!

    Read the article

  • how to bind association in RoR

    - by ashok
    I have two tables, AppTemplate and AppTemplateMeta AppTemplate table has column id, MetaID, name etc. I have associated these two model like this class AppTemplate < ActiveRecord::Base set_table_name 'AppTemplate' belongs_to :app_template_meta, :class_name => "AppTemplateMeta", :foreign_key => 'MetaID' end If we fetch data using AppTemplate.all, I want associated meta details also. But currently it's not returning associated meta details. It just returns AppTemplate details. any guys can help me for this

    Read the article

  • UML tool similar to USE

    - by llazzaro
    Hello, To "simulate" instances from class diagrams I am using USE But I find very frustating to create instances. I am looking for similar tools like this one. I really like USE, but GUI is painfull. I think, that USE is pretty cool to learn how the model "works". Do you know similar tools like this one?

    Read the article

  • Is it possible to mix a named pipe with select in perl?

    - by Haiyuan Zhang
    I need to write a daemon that supposed to have one TCP socket and one named pipe. Usually if I need to implement a multi IO server with "pure" sockets, the select based multi-IO model is always the one I will choose. so does anyone of you have ever used named pipe in select or you can just tell me it is impossible. thanks in advance.

    Read the article

  • php OOP, full sample

    - by lolalola
    Hi, On this site I found a lot of cool examples of PHP OOP. Maybe you know where to find complete examples? Guest books, registration forms, blog... When I look at the full model is much easier to understand OOP PHP. As different classes interacting with each other, exchange data How to use the generic class for sending data to the database Thanks

    Read the article

  • Disable JPanel with visual effect

    - by Ryan
    I'm looking for a good way to disable a JPanel. I'm using a MVC design for a Java Swing GUI. I want the JPanel to be disabled while the model is processing stuff. I've tried setEnabled(false). That disables user input on the JPanel, but I'd like it to be grayed out to add a more visual effect. Thanks in advance!

    Read the article

  • Ruby on rails form validation issue

    - by Anooj
    Am pretty new to ROR. Need help in Rails form validation. Hey, am using rails 2.3.5 I have a basic validates_presence_of for the fields in the form. Now when i don't enter field details, i do get an error, but the error is displayed as: {{count}} errors prohibited this {{model}} from being saved There were problems with the following fields: {{attribute}} {{message}} {{attribute}} {{message}} Any help will be highly appreciated.

    Read the article

  • Doing a count over a filter query efficiently in django

    - by apple_pie
    Hello, Django newbie here, I need to do a count over a certain filter in a django model. If I do it like so: my_model.objects.filter(...).count() I'm guessing it does the SQL query that retrieves all the rows and only afterwards does the count. To my knowledge it's much more efficient to do the count without retrieving those rows like so "SELECT COUNT(*) FROM ...". Is there a way to do so in django?

    Read the article

  • Object value not getting updated in the database using hibernate

    - by user1662917
    I am using Spring,hibernate,jsf with jquery in my application. I am inserting a Question object in the database through the hibernate save query . The question object contains id ,question,answertype and reference to a form object using form_id. Now I want to alter the values of Question object stored in the database by altering the value stored in the list of Question objects at the specified index position. If I alter the value in the list the value in the database is not getting altered by update query . Could you please advise. Question.java package com.otv.model; import java.io.Serializable; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table; import org.apache.commons.lang.builder.ToStringBuilder; @Entity @Table(name = "questions") public class Question implements Serializable { @Id @GeneratedValue @Column(name = "id", unique = true, nullable = false) private int id; @Column(name = "question", nullable = false) private String text; @Column(name = "answertype", nullable = false) private String answertype; @ManyToOne(fetch = FetchType.EAGER) @JoinColumn(name = "form_id") private Form form; // @JoinColumn(name = "form_id") // private int formId; public Question() { } public Question(String text, String answertype) { this.text = text; this.answertype = answertype; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getQuestion() { return text; } public void setQuestion(String question) { this.text = question; } public String getAnswertype() { return answertype; } public void setAnswertype(String answertype) { this.answertype = answertype; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((answertype == null) ? 0 : answertype.hashCode()); result = prime * result + id; result = prime * result + ((text == null) ? 0 : text.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Question other = (Question) obj; if (answertype == null) { if (other.answertype != null) return false; } else if (!answertype.equals(other.answertype)) return false; if (id != other.id) return false; if (text == null) { if (other.text != null) return false; } else if (!text.equals(other.text)) return false; return true; } public void setForm(Form form) { this.form = form; } @Override public String toString() { return ToStringBuilder.reflectionToString(this); } } Form.java package com.otv.model; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Table; import org.apache.commons.lang.builder.ToStringBuilder; @Entity @Table(name = "FORM") public class Form implements Serializable { @Id @GeneratedValue @Column(name = "id", unique = true, nullable = false) private int id; @Column(name = "name", nullable = false) private String name; @Column(name = "description", nullable = false) private String description; @OneToMany(mappedBy = "form", fetch = FetchType.EAGER, cascade = CascadeType.ALL) List<Question> questions = new ArrayList<Question>(); public Form(String name) { super(); this.name = name; } public Form() { super(); } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public List<Question> getQuestions() { return questions; } public void setQuestions(List<Question> formQuestions) { this.questions = formQuestions; } public void addQuestion(Question question) { questions.add(question); question.setForm(this); } public void removeQuestion(Question question) { questions.remove(question); question.setForm(this); } @Override public String toString() { return ToStringBuilder.reflectionToString(this); } public void replaceQuestion(int index, Question question) { Question prevQuestion = questions.get(index); // prevQuestion.setQuestion(question.getQuestion()); // prevQuestion.setAnswertype(question.getAnswertype()); question.setId(prevQuestion.getId()); question.setForm(this); questions.set(index, question); } } QuestionDAO.java package com.otv.user.dao; import java.util.List; import org.hibernate.SessionFactory; import com.otv.model.Question; public class QuestionDAO implements IQuestionDAO { private SessionFactory sessionFactory; public SessionFactory getSessionFactory() { return sessionFactory; } public void setSessionFactory(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; } public void addQuestion(Question question) { getSessionFactory().getCurrentSession().save(question); } public void deleteQuestion(Question question) { getSessionFactory().getCurrentSession().delete(question); } public void updateQuestion(Question question) { getSessionFactory().getCurrentSession().update(question); } public Question getQuestionById(int id) { List list = getSessionFactory().getCurrentSession().createQuery("from Questions where id=?") .setParameter(0, id).list(); return (Question) list.get(0); } }

    Read the article

  • PropertyChanged Event of ObservableCollection

    - by developer
    Hi All, I have a observable collection of viewmodel objects. How can I subscribe to the Property Changed event of each view model in my collection as they are created and track which ones have been changed, so that I can updated them to my database. List<DomainObject> objectsToSave = new List<DomainObject>(); foreach (Test val in dirtyObjs) { objectsToSave.AddRange(val.GetObjectsToSave()); } //DB changes bool saveSucceeded = DataServices.SaveMultiple(objectsToSave);

    Read the article

  • mvc bind/post boolean to radiobutton

    - by Xuan Vu
    Hi all, I have a column in my Model with a NULLABLE boolean value. Now on my View (for editing), I would like to bind that to two radiobuttons: Yes & No. If the value is null, then just have the two radiobutton un-checked. How would I go to do that? Thanks.

    Read the article

  • Cocoa's newbie question: is it possible to bind a NSTableView's selection to another tableview's selection?

    - by cocoaOverloaded
    http://img651.imageshack.us/img651/6999/modelsf.jpg Let'say, I've 2 entities in the Core Data's Model file, one being all "transactions" ever done by X company. The "transactions" entity has among other properties, a "DATE" property and a to-one relationship "COMPANY"(specifying the company with which X company has done that particular transaction). The other entity:"companies" of course contains all the companies' info ,with which X company has done transaction. The "companies" entity has a to-many relationships "TRANSACTIONS" which is an inverse relationship to "transactions" entity's "COMPANY" relationship. So within IB, I created a NSTableView(with its own NSArrayController) showing all the transactions on a particular Date (with the help of NSPredicate). Then I create another table view showing the to-many relationship "TRANSACTIONS" of the company of the selected transaction in the first table view(which shows transactions on a particular date). The 2nd table view's NSArrayController binding is like this: ** bind to: "name of the first tableview's controller", Controller Key: selection, Model Key Path:COMPANY.TRANSACTIONS(the to-many relationship in the "companies" entity)** Everythings work fine up to this moment, the 2nd tableview shows all the transactions X company has done with the company of the selected transactions in the 1st table view. But I have a group of textfields showing details of a particular transactions. Binding the these textfields with the controller of the 1st table view(the one showing transactions on a particular date) is pretty straightforward. But what I want to do are: 1/ Look up the transactions on a particular date in the first table view, select any one of them 2/ Then, check all previous transactions of the company of that transaction( selected in the first table view) from the 2nd table view 3/ Select any previous transactions and check the details of the transaction from that group of textfields So naturally I should have bind the textfields' gp to the 2nd table view's controller. But I found the default selected row in the 2nd table view(the one show all previous transactions of a company) wasn't the transaction I've selected in the 1st tableView for a particular date. Of course, i can manually select that transaction in the 2nd table view again.... So I just want to know if it's possible to have the 2nd table view automatically select the transaction according to the transaction I've selected in the 1st table view thr binding?? After hours of googling, I solved the problem by implementing the tableview Delegate protocol: - (void)tableViewSelectionDidChange:(NSNotification *)aNotification { if (["nameOf1stTableView" selectedRow] > -1) { NSArray *objsArray = ["nameOf2ndTableView'sController" arrangedObjects]; for (id obj in objsArray) { if ([[obj valueForKey:@"DATE"] isEqualToDate: ["nameOf1stTableView'sController".selection valueForKey:@"DATE"]]) { ["nameOf2ndTableView" selectRowIndexes:[NSIndexSet indexSetWithIndex:[objsArray indexOfObject:obj]] byExtendingSelection:NO]; } } } } But,this just look too cumbersome... can it be done with binding alone? Thanks in Advance,

    Read the article

  • Django modelform ForeignKey List

    - by Harry
    How do you get each item in the ForeignKey field in a list, for example: class Delegate(models.Model): excursion = models.ForeignKey(Excursion, limit_choices_to = {'is_activity': False}, related_name='excursion', null=True, blank=True) Template: {% for object in formset.excursion_set.all %} {{ object.lable }} etc {% endfor %} My reason is that I don't want the options to display as a dropdown, but in a custom way that I will style etc.

    Read the article

  • Explain Entity Framework 4's connection strings

    - by metanaito
    I created an Entity Framework file. My database is called MyDB. My Entity Framework file is MyDB.edmx and I used an existing connection string (MyDBConnectionString) to generate the edmx model. It created two more connection strings: MyDBEntities MyDBContainer What are these for? They look exactly the same and both have the information from my old connection string. Do I still need my old connection string?

    Read the article

< Previous Page | 328 329 330 331 332 333 334 335 336 337 338 339  | Next Page >