What is the exact difference on "SCAFFOLD" and "Dynamic Data Binding" , are they same ?
No. Scaffolding means to me : build the interface for the field. Per MSDN : "Scaffolding is the mechanism of generating web page templates based on database schemas."
Binding generally means to link the persisted (usually DB) data values for each interface element.
Related
I'm new to Semantic Web and Jena.
I want to generate an ontology from a OntModel in Jena and I need to use vocabulary and ontologies predefined to caracterize my classes and properties.
In Jena, there are default ontologies like RDF, FOAF...So we can specify class and add property to resource like:
ontClass.setSameAs(FOAF.Person);
ontClass.addProperty(FOAF.name, "name");
or
ontProperty.setRange(XSD.xstring);
But how can I refer my ontClass to another vocabulary/ontology that does not exist in Jena (GeoSparql, Geofla, vocabulary that I defined myself,etc.)? Knowing that I can have the URI for these vocabularies?
This question's already been raised in this topic: How to add vocabulary in Jena? which suggests using Jena Schemagen but I can't see how to do it.
Thank you a lot for helping!
I guess one of the option is to import (or read) theses vocabularies/ontologies so that you can use them using Jena Ontology API.
For example (if we assume that your ontModel is named m) you can read the OWL-Time ontology into your model like so :
m.read("http://www.w3.org/2006/time")
and then you can use the elements it defines using Jena's programmatic API :
OntClass instant = dataModel.getOntClass("http://www.w3.org/2006/time#Instant");
If you don't wan't to read the whole ontology within your model, you can also just "create" the necessary ressource / property using its URI :
Property inXSDDateTime = m.createDatatypeProperty(
"http://www.w3.org/2006/time#inXSDDateTime");
Resource resource = m.createResource("someURIForThisRessource");
Statement s = m.createStatement(
resource, inXSDDateTime, m.createTypedLiteral(someValue));
m.add(s);
It should write the result as expected (but, by doing this, you are not loading the axioms of the ontology you are referencing, so you won't be able to reason about it - but according to your comment, I'm thinking maybe that's what you want)
I have done a RegisterAppStart<FirstViewModel>() in the Core App.cs, now I navigate to FirstViewModel, then SecondViewModel and finally ThirdViewModel using ShowViewModel(),
Is there a way I want to navigate to the viewmodel which has been registered using RegisterAppStart<>(), I mean is this persisted or saved somewhere during run?
All I want is to get this value at runtime.
If you want to use a singleton instance of a view model then you can do this using a custom view model locator - see the wiki - https://github.com/MvvmCross/MvvmCross/wiki/Customising-using-App-and-Setup - "overriding view model location and construction"
We're running into a small problem deploying a web application to another environment.
We created the application's db using Entity Framework Code First approach (db automatic created from Model).
In this development environment, we are using integrated security and the tables are created under the dbo user. The tables are like
[dbo].[myTable]
For our other environment, we are using username/password authentication for the DB.
We scripted the tables and created them on the DB. So they are now named like
[myDbUser].[myTable]
When running the application, we encounter always the problem
Invalid object name 'dbo.myTable'.
Seems like the code is still trying to look for a dbo table, which is not present and thus fails.
Can anyone shed some light on this problem? Where does Entity Framework gets this dbo prefix from?
Thanks
Specify schema explicitly:
[Table("Users", Schema = "dbo")]
public class User { .. }
Or specify default db schema for your user - 'dbo'
To specify schema in fluent
protected override void OnModelCreating(DbModelBuilder modelBuilder)
modelBuilder.Entity<ClassName>().ToTable("TableName", "SchemaName");
I ran into this issue recently as well as we support several different schemas with the same model. What I basically came up with was the passing the schema name to the classes/methods that map the model. So for example, EntityTypeConfiguration subclasses take the schema name as a constructor argument, and pass it along with the hard-coded string to ToTable().
See here for a more detailed explanation: https://stackoverflow.com/a/14782001/243607
I have a tree control in my GUI (with naturally lots of GUI/platform specific functions to handle the nodes).
I have a data model with its own complex set of nodes, children, properties etc..
I want the tree to display a representation of the model, be able to send messages to the nodes inside the model and be told to redraw itself when the model changes.
But I don't want the GUI code to need to know the details of the model's data types and I don't want to pollute the model by linking it to the GUI classes.
I can't get my head around how the controller is supposed to do this and what functions it should provide?
(this is in C++ but that shouldn't matter)
GUI "controls" don't quite fit neatly into a model-view-controller pattern because they typically have their own internal model rather than accepting a reference to one. If the control is structured that way, you'll need an adapter class that "data-binds" the control's internal model to the underlying data model.
This can accomplish something similar to what model-view-controller would, except that the adapter class plays the role both of a view hookup component (updating the GUI from the data model) and a controller (interpreting GUI events into model actions).
Qt provides a group of classes for model-view programming. You can hook a tree view to a filesystem model, for example, and neither directly know anything about each other (except a pointer to the model in the view).
Your requirements are:
Tree displays representation of model
Nodes in tree can send messages to nodes inside model
Tree redraws itself based on model changes
I don't know exactly what kind of data you're working with here, but a hierarchical model is a fairly simple thing. I'll take it as a given you know how to iterate hierarchical data and populate a tree view.
Your controller should have member function(s) for sending messages to the model. The parameters should be a model element and the message you want to send. This way, the UI is completely unaware of how the message gets to the element, but can get the messages through.
The last requirement is more tricky, and depends on a few things (e.g., the lifetime of the controller, application architecture, etc.) I'm going to assume the controller lives as long as the tree view does. If that's the case, then your controller should provide a way to set a callback on model changes. Then, when the controller changes the model, it can callback to the UI without being aware of the UI.
i think your troubles start with an unfortunate choice of words. the 'control' thingies doesn't have anything to do with the 'controller' in MVC. that's why some GUI libraries use other names (widgets is a common one).
your 'tree control' is the view, not the controller. it should be tied to the GUI, both for display, and to get GUI events and turn them into 'tree events'.
the controller gets those 'tree events' and does the necessary modifications to the model. that's where you couple the 'action' with the 'response'.
First Solution: You can implement a "Subject observer" pattern between model and view, with model as the subject and view as the observer. Whenever there is a change in the state of model, it can fire a event to all the observers those are registered, they can update themselves.
Second Solution: Introduce a controller, which registers with model as observer. Upon receiving a event for update from Model, it can update the view. Even you can decouple view from controller using one more subject observer pattern between controller and view
Third Solution: Use MVP pattern. Model view Presenter. This pattern used whenever there is no much computation in controller i.e., job of the controller is just to update its corresponding view. Here controller becomes Presenter.
You need a controller that sits outside the display widget but has the state of the tree (in MFc there are CTreeView/CTreeCtrl classes - there is a similiar separation in Qt) the tree controller handles all the data storage and calls redraws on the tree widget.
Changes in the tree widget get sent to the tree controller - so this controller needs to know about the gui functions.
The model will need set/get functions for all the relevant parameters for the nodes. But these can return simple types so aren't dependent on the gui.
Updating the view form the model requires sending a message, if you don't want the model to know about your gui messaging the best you can do is register a callback function (a void pointer to a function) from the tree controller - and call this to do an update.
This update function can then query the model for the changes.
My good friend, Wikipedia, didn't give me a very good response to that question. So:
What are language bindings?
How do they work?
Specifically accessing functions from code written in language X of a library written in language Y.
Let's say you create a C library to post stuff to stackoverflow. Now you want to be able to use the same library from Python. In this case, you will write Python bindings for your library.
Also see SWIG: http://www.swig.org
In the context of code libraries, bindings are wrapper libraries that bridge between two programming languages so that a library that was written for one language can also be implicitly used in another language.
For example, libsvn is the API for Subversion and was written in C. If you want to access Subversion from within Java code you can use libsvn-java. libsvn-java depends on libsvn being installed because libsvn-java is a mere bridge between the Java programming language and libsvn, providing an API that merely calls functions of libsvn to do the real work.
Okay, now the question has been clarified, this isn't really relevant so I'm moving it to a new question
Binding generally refers to a mapping of one thing to another - i.e. a datasource to a presentation object. It can typically refer to binding data from a database, or similar source (XML file, web service etc) to a presentation control or element - think list or table in HTML, combo box or data grid in desktop software.
...If that's the kind of binding you're interested in, read on...
You generally have to bind the presentation element to the datasource, not the other way around. This would involve some kind of mapping - i.e. which fields from the datasource do you want to appear in the output.
For more information in a couple of environments see:
Data binding in .Net using Windows Forms
http://www.codeproject.com/KB/database/databindingconcepts.aspx
http://www.akadia.com/services/dotnet_databinding.html
ASP.NET data binding
http://support.microsoft.com/kb/307860
http://www.15seconds.com/issue/040630.htm
http://www.w3schools.com/ASPNET/aspnet_databinding.asp
Java data binding
http://www.xml.com/pub/a/2003/09/03/binding.html
Python data binding
http://www.xml.com/pub/a/2005/07/27/py-xml.html
General XML data binding
http://www.rpbourret.com/xml/XMLDataBinding.htm
In Flex (Actionscript 3). Source
A data binding copies the value of a property in one object to a property in another object. You can bind the properties of following objects: Flex components, Flex data models, and Flex data services.
The object property that provides the data is known as the source property. The object property that receives the data is known as the destination property.
The following example binds the text property of a TextInput component (the source property) to the text property of a Label component (the destination property) so that text entered in the TextInput component is displayed by the Label component:
<mx:TextInput id="LNameInput"></mx:TextInput>
...
<mx:Label text="{LNameInput.text}"></mx:Label>
Data binding is usually a simple way to bind a model to user interface components. For example, you have a class with a FirstName property. In flex you could easily bind that property to a textbox by setting the value of the textbox to {Object.FirstName}. Then, every time that FirstName property changes, the textbox will be updated without requiring you to write any code to monitor that property for changes.
Hope that helps.
Matt