Search Results

Search found 40226 results on 1610 pages for 'object relational model'.

Page 563/1610 | < Previous Page | 559 560 561 562 563 564 565 566 567 568 569 570  | Next Page >

  • Why exactly is calling the destructor for the second time undefined behavior in C++?

    - by sharptooth
    As mentioned in this answer simply calling the destructor for the second time is already undefined behavior 12.4/14(3.8). For example: class Class { public: ~Class() {} }; // somewhere in code: { Class* object = new Class(); object->~Class(); delete object; // UB because at this point the destructor call is attempted again } In this example the class is designed in such a way that the destructor could be called multiple times - no things like double-deletion can happen. The memory is still allocated at the point where delete is called - the first destructor call doesn't call the ::operator delete() to release memory. For example, in Visual C++ 9 the above code looks working. Even C++ definition of UB doesn't directly prohibit things qualified as UB from working. So for the code above to break some implementation and/or platform specifics are required. Why exactly would the above code break and under what conditions?

    Read the article

  • join 03 table in the database codeIgniter

    - by python
    with my table. person_id serial NOT NULL, firstname character varying(30) NOT NULL, lastname character varying(30), email character varying(50), username character varying(20) NOT NULL, "password" character varying(100) NOT NULL, gender character varying(10), dob date, accesslevel smallint NOT NULL, company_id integer NOT NULL,//Reference to table company position_id integer NOT NULL,//Reference to table position company_id serial NOT NULL, company_name character varying(80) NOT NULL, description character varying(255), address character varying(100) NOT NULL, In my controller ........................ // load data $persons = $this->person_model->get_paged_list(10,0); // generate table data $this->load->library('table'); $this->table->set_empty("&nbsp;"); $this->table->set_heading('No', 'FirstName', 'LastName','E-mail','Company''Gender', 'Date of Birth', 'Actions'); foreach ($persons as $person){ $this->table->add_row(++$i, $person->firstname, $person->lastname, $person->email, $person->company_name, //HOW CAN I GOT THE POSITION TITLE ?, strtoupper($person->gender)=='M'? 'Male':'Female', date('d-m-Y',strtotime($person->dob)), } My model <?php class Person_Model extends Model { private $person= 'person'; function Person(){ parent::Model(); } function list_all(){ $this->db->order_by('person_id','asc'); return $this->db->get($person); } function count_all(){ return $this->db->count_all($this->person); } function get_paged_list($limit = 0, $offset = 0) { $this->db->limit($limit, $offset); $this->db->select("person.*, company.company_name as company"); $this->db->from('person'); $this->db->join('company','person.company_id = company.company_id','left'); //MY QUESTION:? CAN I JOIN MORE WITH TABLE POSITION? $query = $this->db->get(); return $query->result(); } function get_by_id($id){ $this->db->where('person_id', $id); return $this->db->get($this->person); } function save($person){ $this->db->insert($this->person, $person); return $this->db->insert_id(); } function update($id, $person){ $this->db->where('person_id', $id); $this->db->update($this->person, $person); } function delete($id){ $this->db->where('person_id', $id); $this->db->delete($this->person); } } ?>

    Read the article

  • Large number of tables and Hibernate memory consumption

    - by Vedran
    I'm working on a large ERP project which has database model with about 2100 tables. With "only" 500 tables mapped with Hibernate, application deployed on the web server takes about 3GB of working memory. Is there any way to reduce Hibernate's metamodel memory footprint when using that many tables in one persistence unit? Or should I just give up on ORMs and go with plain old JDBC (or even jOOQ)? Right now I'm using Hibernate 4.1.8, Spring 3.1.3, JBoss AS 7.1 and working with MSSQL database. Edit: JavaMelody memory histogram output - with 2000 generated test tables that are a bit smaller in scope from the original db model (hence 'only' 1.3GB of spent memory)

    Read the article

  • Design question?

    - by Mohamed
    I am building music app, where user can do several tasks including but not limited to listening song, like song, recommend song to a friend and extra. currently I have this model: class Activity(models.Model): activity = models.TextField() user = models.ForeignKey(User) date = models.DateTimeField(auto_now=True) so far I thought about two solutions. 1. saving a string to database. e.g "you listened song xyz" 2. create a dictionary about the activity and save to the database using pickle or json. e.g. dict_ = {"activity_type":"listening", "song":song_obj} I am leaning to the second implementation, but not quite sure. so what do you think about those two methods? do you know better way to achieve the goal?

    Read the article

  • Arguments against Create or Update

    - by Nix
    Recently someone stated that they thought all Creates should be CreateOrUpdates. Instinctively i thought bad, but now I am trying to find out if I have any grounds. Situation interface IService{ void Create(Object a); void Update(Object a); } or interface IService{ void CreateOrUpdate(Object a); } My first thought is if you implemented everything CreateOrUpdate then you have no control if someone accidentally sends you wrong data, or concurrency issues where someone changes a "primary" field right before you call update.... But if you remove those cases, are there any other cons?

    Read the article

  • Update database using restful ASP.NET MVC 1.0

    - by Mike
    We are building an MVC 1.0 application right now and using Linq - SQL for our DAL. Following the restful approach we have multiple action events depending on if you are updating or loading or what not. The two that I'm concerned with at this point are the edit and update action methods. Here is the signatures. public ActionResult Update(int customerId, int Id, AggregateModel viewModel) public ActionResult Edit(int customerId, int Id, AggregateModel viewModel) So the idea is that in the Edit method we load up our viewModel and pass it to the view. The user makes changes to the model and then posts back to the Update method. The first thing I could think of to do would be to get the viewModel from the database again, copy the changes in one by one from the posted back model and then submit it back. This would work but does seem clunky to me. What is the best way to insert those changes into the database at this point?

    Read the article

  • Remote Seam Persistence

    Hi. I have a button in a .xhtml file which calls a javascript function which calls a java function remotely (in jboss seam environment). That java function has an entityManager.persist(object). Do you know why this line of code doesn't commit to the DB? It says something that a transaction hasn't started. I supose in a remote context i don't have a transaction began because if i put an action on that button which calls the same java function instead of using javascript is above, it works fine; entityManager persists the object and i can see it in the DB. Does anyone has any ideas how could i make to actually persist the object using javascript to call the java function? (i have to use javascript because i need the callback function )

    Read the article

  • Need some help in understanding SSL concepts

    - by user1115256
    I am new to SSL programming and finding some difficulties in understanding SSL concepts. I tried to get it through openssl site,but it is not much informative. Here is my doubts. What is difference between SSL Buffer and BIO buffer..? I mean layerwise detail will be very helpful. Can I use SSL_Write and SSL_Read without setting any BIO object to SSL object..? What exactly BIO_flush will do... I mean is it going to flush all the data to network buffer from BIO buffer.. ? If it is possible to do write and read data from SSL directly without using any BIO object then is it possible to flush the data from SSL buffer to network buffer by any means.. ? It would be very helpful if any body explain these things or giving any links where I can find answers to my questions.

    Read the article

  • Entity Framework Create Database & Tables At Runtime

    - by dhsto
    I created some tables in an .edmx file and have been generating the database by selecting "Generate Database From Model" and manually executing an .edmx.sql file on the database to build the tables. Now, however, I am creating a setup dialog that allows the user to connect the program up to their own database. I thought running context.CreateDatabase would be good enough to create the database, along with the tables, but the tables are not created. What is the preferred method for creating the database and tables when the user specifies their own server and database to use, when originally starting with a model?

    Read the article

  • QTreeView incorrectly displays the SpinBox if item is checkable and when using QWindowsStyle

    - by Sharraz
    Hello, I'm having a problem with a QTreeView in my program: The SpinBox used to edit the double value of a checkable item is displayed incorrectly when using the Windows style. Only the up and down buttons of the SpinBox can be seen, but not any value. The following example code is able to reproduce the problem: #include <QtGui> class Model : public QAbstractItemModel { public: Model() : checked(false), number(0) {} Qt::ItemFlags flags(const QModelIndex & index) const { return Qt::ItemIsEnabled | Qt::ItemIsEditable | Qt::ItemIsSelectable | Qt::ItemIsUserCheckable; } QVariant data(const QModelIndex &index, int role) const { switch (role) { case Qt::DisplayRole: case Qt::EditRole: return QVariant(number); case Qt::CheckStateRole: return QVariant(checked ? Qt::Checked : Qt::Unchecked); } return QVariant(); } QVariant headerData(int section, Qt::Orientation orientation, int role) const { return QVariant(); } int rowCount(const QModelIndex &parent) const { return parent.isValid() ? 0 : 1; } int columnCount(const QModelIndex &parent) const { return parent.isValid() ? 0 : 1; } bool setData(const QModelIndex &index, const QVariant &value, int role) { switch (role) { case Qt::EditRole: number = value.toDouble(); emit dataChanged(index, index); return true; case Qt::CheckStateRole: checked = value.toInt(); emit dataChanged(index, index); return true; } return false; } QModelIndex index(int row, int column, const QModelIndex &parent) const { if (!row && !column && !parent.isValid()) return createIndex(0, 0); return QModelIndex(); } QModelIndex parent(const QModelIndex &child) const { return QModelIndex(); } private: bool checked; double number; }; int main(int argc, char *argv[]) { QApplication app(argc, argv); QApplication::setStyle(new QWindowsStyle()); QTreeView tree; tree.setModel(new Model()); tree.show(); return app.exec(); } The problems seems to have something to do with the checkbox. If Qt::ItemIsUserCheckable is removed, the SpinBox will be displayed correctly. If the number is replaced by a longer one like 0.01, it can be seen partially. Any idea how this problem can be solved? Do I use the checkbox correctly? Greets, Sharraz

    Read the article

  • What are the best practices for importing large datasets into MongoDB?

    - by snl
    We are just giving MongoDB a test run and have set up a Rails 3 app with Mongoid. What are the best practices for inserting large datasets into MongoDB? To flesh out a scenario: Say, I have a book model and want to import several million records from a CSV file. I suppose this needs to be done in the console, so this may possibly not be a Ruby-specific question. Edited to add: I assume it makes a huge difference whether the imported data includes associations or is supposed to go into one model only. Any comments on either scenario welcome.

    Read the article

  • Can I catch bad pointer errors in C++?

    - by Simon
    Hi there, I was wondering if there is a possibility to catch errors like this in C++: object* p = new object; delete p; delete p; //this would cause an error, can I catch this? Can I check if the pointer is valid? Can I catch some exception? I know I could set the pointer p to NULL after the first object deletion. But just imagine you wouldn't do that. I am using VC++ with Visual Studio 2008/2010. Thank you

    Read the article

  • Cakephp: Extend search capability to hasMany Relationship

    - by Chris
    I have two models: Car hasMany Passengers Passenger belongsTo Car I want to implement a search using Cake Search. The user should input a number and the searchengine should return all cars that have less than this number passengers. In my search form: echo $form->input('passengers', array('label' => 'Passengers', 'div' => false)); In my Car model: public $filterArgs = array( array('name' => 'passengers', 'type' => 'int'), ); In the controller: public $presetVars = array( array('field' => 'passengers', 'type' => 'int') } I thought of adding a function to the model that returns the number of passengers: function countPassengers(){ return(count($this->Car->Passenger)); //Not sure if this works } And how to I implement this search criteria?: return all Cars where countPassengers()<passenger

    Read the article

  • In .NET MVC, is there an easy way to check if I'm on the home page?

    - by Hairgami_Master
    I need to take a particular action if a user logs in from the home page. In my LogOnModel, I have a hidden field: @Html.Hidden("returnUrl", Request.Url.AbsoluteUri) In my Controller, I need to check if that value is the Home page or not. In the example below, I'm checking to see if the user is on a particular page ("Account/ResetPassword"). Is there a way to check to see if they're on the home page without resorting to regular expressions? [HttpPost] public ActionResult LogOnInt(LogOnModel model) { if (model.returnUrl.Contains("/Account/ResetPassword")) { return Json(new { redirectToUrl = @Url.Action("Index","Home")}); } Any ideas? A million thanks!

    Read the article

  • ruby subclass filter

    - by Nik
    Hey! Maybe I am getting the idea of a subclass wrong, but I have a Person model and it has an attrib called "age" so Person.first.age #=> '20' Now I want to have a model that's basically persons 55 or older so I know I can have a class like this: class Senior < Person end But how can I "pre-filter" the Senior class so that every object belonging to that class has age = 55? Senior.first.age #=> 56 Thanks!

    Read the article

  • How to expose a control collection to a property grid at design time

    - by Stefano Delendati
    I have a custom control that with a property that is a collection of custom object. This custom object hava a reference to some component/controls. When at design time I tray to add an item to the collection and select the object, VS tells me that the control is not serializable. This is the code (simplified version - but not to much): public class ViewRefObj { public control view { get; set; } public ViewRefObj() { } } private List<ViewRefObj> _controls=new List<ViewRefObj>(); public List<ViewRefObj> Views { get { return _controls; } }

    Read the article

  • Tracking changes to individual fields - Silverlight

    - by Appu
    I have a page which has got several text boxes. These controls are bound to a model. I am using MVVM. Assume I have three text boxes, FirstName, LastName and Company. So in the model, I have three properties to bind. Now I need to track the changes happened to each field. If FirstName changes from original value, I need the text box to be colored with a different background color. Currently I am creating another property called FirstNameChanged and binding the background to this property. This will be updated when I change the FirstName. For 3 fields, this seems to be OK. But when I have more fields, the number of properties will be too much. Is there a better way to handle this?

    Read the article

  • python mock side_effect or return_value dependent on call_count

    - by user18380
    To test a polling function I want to mock the calling of a sub function so that the first time it is called it will fail, and the second time it is called it will succeed. Here's a very simplified version of it: poll_function(var1): value = sub_function(var1) # First call will return None while not value: time.sleep(POLLING_INTERVAL) value = sub_function(var1) # A subsequent call will return a string, e.g "data" return value Is this possible to do with a Mock object from the mock framework? I know Mock objects have a call_count attribute I should be able to use somehow. Right now I've solved it by creating a custom mock object that I use to monkey patch sub_function(), but I feel there should be a better less verbose way of doing it: def test_poll(): class MyMock(object): def __init__(self, *args): self.call_count = 0 def sub_function(self, *args, **kwargs): if self.call_count > 1: return "data" else: self.call_count += 1 return None my_mock = MyMock() with patch('sub_function', my_mock.sub_function): ok_(poll_function())

    Read the article

  • Instantiating class by string using PHP 5.3 namespaces

    - by Kevin
    I can't get around an issue instantiating a new class by using a string variable and PHP 5.3. namespaces. For example, this works; $class = 'Reflection'; $object = new $class(); However, this does not; $class = '\Application\Log\MyClass'; $object = new $class(); A fatal error gets thrown stating the class cannot be found. However it obviously can be instantiated if using the FQN i.e.; $object = new \Application\Log\MyClass; I've found this to be aparrent on PHP 5.3.2-1 but not not in later versions. Is there a work around for this?

    Read the article

  • On Google AppEngine what is the best way to merge two tables?

    - by gpjones
    If I have two tables, Company and Sales, and I want to display both sets of data in a single list, how would I do this on Google App Engine using GQL? The models are: class Company(db.Model): companyname = db.StringProperty() companyid = db.StringProperty() salesperson = db.StringProperty() class Sales(db.Model): companyid = db.StringProperty() weeklysales = db.StringProperty() monthlysales = db.StringProperty() The views are: def company(request): companys = db.GqlQuery("SELECT * FROM Company") sales = db.GqlQuery("SELECT * FROM Sales") template_values = { 'companys' : companys, 'sales' : sales } return respond(request, 'list', template_values) List html includes: {%for company in companys%} {% for sale in sales %} {% ifequal company.companyid sales.companyid %} {{sales.weeklysales}} {{sales.monthlysales}} {% endifequal %} {% endfor %} {{company.companyname}} {{company.companyid}} {{company.salesperson}} {%endfor%} Any help would be greatly appreciated.

    Read the article

  • Proper usage of Java Weak Reference in case of nested collections

    - by Tong Wang
    I need to define a weak reference Map, whose value is a Set. I use Google collections' MapMaker, like this: Map<Class<? extends Object>, Set<Foo>> map = new MapMaker().weakKeys().weakValues().makeMap(); So, for Set<Foo>, can I use a normal HashSet? Or, do I have to create a weak HashSet, like this: Collections.newSetFromMap(new WeakHashMap<Foo, Boolean>()); And why? Another question, the key of my map is Class objects, when will a Class object become weakly reachable? In other words, what is the lifetime of a Class object? Thanks.

    Read the article

  • Java - Handling Non-Blocking Calls

    - by sarav
    In my application I am using a third-party API. It is a non-blocking method which returns immediately. I have a collection of elements over which I have to invoke this method. Now, my problem is that I have to find a way till all the method execution gets completed and do my next operation. How can I handle this? I cannot modify the third-party API. In short it looks like this for(Object object: objects){ methodA(object); //this is a non-blocking call and returns immediately } // here I want to do my next task only after all the methodA calls completed execution

    Read the article

  • Hibernate entities stored as HttpSession attribute values

    - by njudge
    I'm dealing with a legacy Java application with a large, fairly messy codebase. There's a fairly standard 'User' object that gets stored in the HttpSession between requests, so the servlets do stuff like this at the top: HttpSession session = request.getSession(true); User user = (User)session.getAttribute("User"); The old user authentication layer (which I won't describe; suffice to say, it did not use a database) is being replaced with code mapped to the DB with Hibernate. So 'User' is now a Hibernate entity. My understanding of Hibernate object life cycles is a little fuzzy, but it seems like storing 'User' in the HttpSession now becomes a problem, because it will be retrieved in a different transaction during the next request. What is the right thing to be doing here? Can I just use the Hibernate Session object's update() method to reattach the User instance the next time around? Do I need to?

    Read the article

  • Django template context not working with imported class

    - by Andy Hume
    I'm using Django's templating on appengine, and am having a problem whereby a class I'm importing from another package is not correctly being made available to the template context. Broadly speaking, this is the code. The prop1 is not available in the template in the first example below, but is in the second. MyClass is identical in both cases. This does not work: from module import MyClass context = MyClass() self.response.out.write(template.render(path, context)) This does: class MyClass(object): def __init__(self): self.prop1 = "prop1" context = MyClass() self.response.out.write(template.render(path, context)) If I log the context in the above code I get: <module.MyClass object at 0x107b1e450> when it's imported, and: <__main__.MyClass object at 0x103759390> when it's defined in the same file. Any clues as to what might cause this kind of behaviour?

    Read the article

< Previous Page | 559 560 561 562 563 564 565 566 567 568 569 570  | Next Page >