datamodel

Let assume 10 devices(dev01,dev02,dev03..etc). It send data with some interval time,we collect those data,so our data schema is dev01 :int signalname :string signaltime :date/time[with YY-MM-DD HHMMSS.mm] Extradata :String I want to push data into cassandra ,which way is best to store those data? My Query is Like , 1 Need to retrive device based current day data,or with some date range? 2 5 Device current day data? I am not sure the following way to store data into cassadra is best model Standard columnfamily Name:signalname row key :dev01 columnname :timeseries(20120801124204)[YYMMDD HHMMSS]

What i'm trying to accomplish is to have an NSMutableArray defined in the AppDelegate. I then have two UIViewControllers. One view is responsible for displaying the array from the AppDelegate. The other view is used to add items to the array. So the array starts out to be empty. View1 doesn't display anything because the array is empty. The User goes to View2 and adds an item to the array in AppDelegate. Then when the user goes back to View1 it now displays one item. Here is how I'm trying to accomplish this @interface CalcAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window;

I've been working with the examples in http://doc.qt.digia.com/4.7/qdeclarativemodels.html which is the Qt page on QML declarative data models. In particular, I'm working with the objectlistmodel example that comes with the Qt SDK (in examples/declarative/modelviews/objectlistmodel). It all seems to work reasonably well, until I try to combine it with the QMLPageControl example at http://www.developer.nokia.com/Community/Wiki/How_to_create_a_Page_Control_component_in_QML . When I try to display a QML-based ListModel (populated with QML ListElements) with a QML ListView like this: import

Whenever I build my project, I'm getting the error: Command /Developer/usr/bin/momc failed with exit code 1 I've read posts here about deleting extraneous Data Model versions as a fix, and nothing works. I'm stumped because nothing changes the behavior of my Build: It always fail with the above error code, regardless of whether I actually have CoreData model files or not. What I did to cause this error: Switched to a versioning model What I tried: Removing new version of Data model Removing any old versions of Data model Removing entire versioning model and using previous version from Git

I wonder how Object Oriented data modeling is different from Object Relational data modeling? Is it something like the pluses of both object oriented and relational data modeling were clubbed to achieve object relational data modeling? cheers Object-Relational data modeling supports some object-oriented concepts, while still supporting some relational concepts: Inheritance -- one table can have an IS-A relationship with another table. Likewise custom data types support inheritance. Distinction between a class and an object (instance of a class) that goes beyond simply the distinction between a

Would it be best practice to create a model in your asp.net mvc - model folder. Use these models with your views and by using a service layer to "adapt" my model to the EF-model. Or have you used another approach. The problem with this approachs is that most of the times my (selfmade)model is a copy of the EF-model (not dry) So can someone explain me what models to use with your view cause it is becomming very confusing. model / viewmodel / Entityframeworkmodel .... Solution : Thanks for answers all guess i am at the moment to refactor some things! The correct approach is using different class

Looking to figure out the proper way to model the below requirements. There are 3 types of “parties” to be concerned with, a Fan, a Band, and a BandMember. That BandMember will always be associated with a Band and can also be a Fan of any band. There are common attributes between a Fan, a Band, and a BandMember, but each of these 3 will also have their own unique attributes. A Fan can be a fan of of any Band or none at all This is a small part of a bigger thought but it is creating confusion in expanding the model. I believe it would have to be diagram 2 or some other option since I don't see