The tools available in AirTable's Extensions and Interfaces are so similar! I'm having difficulty separating my use cases for them. I'm in charge of creating simple data dashboards for my small nonprofit, which is fun, but I feel as though I've duplicated views.
Does anyone have any examples to share of what helps them differentiate when to use extensions and when to use interfaces? Just curious to see what's out there!
Interfaces are more for proper BI dashboards, like an alternative to Tableau, and are for an audience that doesn't need to see granular data. Extensions are more geared for those referencing the base's underlying data, and even though there are data vis tools, 1) you probably wouldn't use extensions for a BI dashboard replacement and 2) a lot of the extensions are for very specific use cases, like editing a JSON field in the base
Related
I have to integrate various legacy applications with some newly introduced parts that are silos of information and have been built at different times with varying architectures. At times these applications may need to get data from other system if it exists and display it to the user within their own screens based on the business needs.
I was looking to see if its possible to implement a generic federation engine that kind of abstracts the aggregation of the data from various other OData endpoints and have a single version of truth.
An simplistic example could be as below.
I am not really looking to do an ETL here as that may introduce some data related side effects in terms of staleness etc.
Can some one share some ideas as to how this can be achieved or point me to any article on the net that shows such a concept.
Regards
Kiran
Officially, the answer is to use either the reflection provider or a custom provider.
Support for multiple data sources (odata)
Allow me to expose entities from multiple sources
To decide between the two approaches, take a look at this article.
If you decide that you need to build a custom provider, the referenced article also contains links to a series of other articles that will help you through the learning process.
Your project seems non-trivial, so in addition I recommend looking at other resources like the WCF Data Services Toolkit to help you along.
By the way, from an architecture standpoint, I believe your idea is sound. Yes, you may have some domain logic behind OData endpoints, but I've always believed this logic should be thin as OData is primarily used as part of data access layers, much like SQL (as opposed to service layers which encapsulate more behavior in the traditional sense). Even if that thin logic requires your aggregator to get a little smart, it's likely that you'll always be able to get away with it using a custom provider.
That being said, if the aggregator itself encapsulates a lot of behavior (as opposed to simply aggregating and re-exposing raw data), you should consider using another protocol that is less data-oriented (but keep using the OData backends in that service). Since domain logic is normally heavily specific, there's very rarely a one-size-fits-all type of protocol, so you'd naturally have to design it yourself.
However, if the aggregated data is exposed mostly as-is or with essentially structural changes (little to no behavior besides assembling the raw data), I think using OData again for that central component is very appropriate.
Obviously, and as you can see in the comments to your question, not everybody would agree with all of this -- so as always, take it with a grain of salt.
I'm building a rails application and I'm having trouble working out how create diagrams for the application architecture.
I've created UML class diagrams in the past, so consequently that's where I headed. I've found the railroady gem that generates UML class diagrams via a rake task, however it separates the models from the controllers - which feels fragmented to me.
What I want to know is whether there is another (preferably better) way to model an MVC (rails) web application.
I'm not necessarily looking for a gem to generate the diagram for me, I'm happy to create it manually in visio, I just don't know what type of diagram I should be using.
You may want to try the Robustness diagram, also sometimes called MVC diagram.
See for example here and there.
It is not really a UML diagram, but most UML tools manage it through stereotypes and custom icons. The tool I use, Magicdraw UML, uses a class diagram, but I think I heard of tools that use communication diagrams (not sure, though).
However, it may or may not meet your expectations, as it is a very global diagram.
There exist a metodology named UWA (Ubiquitous Web Application) that allows you to describe not only the data structure, but also the navigation, presentation and transaction models.
The UWA methodology has a user-centered approach, which improves the requirement and design definitions. Since this metodology was developed specifically for modelling web applications, it allows a clear separation of content, navigation, transaction, publishing and operational elements.
UWA begins with a goal-oriented requirements engineering that naturally arise to later design stages, revealing key features that should be implemented. This leads to reasoning about some requirements that might have not been identified beforehand, or may have been underrated.
You may find additional information about UWA here.
Even if you decide not to apply this methodology, it may provide you with some tips about adapting UML diagrams to web applications.
Have you ever come across a Use Case Diagram before? It's not strictly a diagram to outline a systems architecture, but it does provide a good visual representation of communication with other parts of the system/ external actors, during a given "use case" (or process).
For example:
User(Actor) --> Update Status(Use Case)--includes-->(Log in)
Here we have a user wanting to update their status. In order to do this, they need to be logged into the site (an included use case). Thinking about this in MVC mode, we know that "Update Status" and "Log in" would both be controller methods, which would both communicate with the attracted website database (also an actor), thus demonstrating the communication path within a system.
Actors of a system can be anything that communicates with the actual system during a process, usually externally, so users, browsers, database, clients etc.
In terms of modelling the MVC architecture, this is done best by the Class diagram, but a Use Case diagram would also aid in the visual representation.
I always draw up a Use Case and Class Diagram together before I start coding, as a way of extracting the system requirements and laying them out in a working design. UML diagrams are design tools after all- there's not really much point in creating one after you've written the system code!
Just something to think about anyway- hope this helps!
brief overview of basic use-case diagrams
I'm trying to get my head around two very different approaches to data sharing: OData and Semantic Web/Linked Data. Is there a good comparison of the two?
As I understand it, OData combines syndication/CRUD (AtomPub), serialisation formats (XML, JSON), a data model, a query language, and some semantics/conventions governing use of those existing technologies. It's primarily intended for exposing data from one system so that others can consume it.
Linked Data is a data model, a rigorous commitment to URIs, an (optional?) serialisation format (RDF/XML), but (correct me if I'm wrong) doesn't say anything about transport, CRUD, etc. It seems intended to allow inferencing across lots of little chunks of data drawn from a wide variety of sources. (Not something of major importance to us right now - we would be synchronising large slabs of data between a small number of sources, and wanting to preserve provenance information).
I'm interested in technologies for sharing data between certain data management platforms, some of which I work on directly. OData seems more appealing as it's very straightforward to explain to developers: implement this API, follow that Atom standard, serialise the data like this. We're already doing something very similar for one platform: sharing XML-serialised data on an Atom feed, with URL parameters used to filter.
By contrast, my past experiences working with RDF have given me an impression of brittle, opaque (massive slabs of RDF/XML), inaccessible (using SPARQL vs SQL) technology - but perhaps I'm confusing the experience of working with a triplestore like Jena with simply exposing an existing database via a linked data API.
Any pointers, comments etc on the differences and similarities between these two approaches in terms of scope, technologies, ease, future potential etc would be great.
I think discussing this in depth is not really what Stackoverflow is meant for, but just to give you some pointers to interesting discussions about differences and overlap:
Oh - it is data on the Web
Microsoft, OData and RDF
One of the key differences seems to be that OData has no means to link data from different sources to each other. Essentially, you're still stuck in a silo.
It might also be interesting to check out various attempts to convert data between the two approaches. See a.o. http://answers.semanticweb.com/questions/1298/has-anyone-written-a-mapping-from-odata-to-rdf .
OData may be easier, but its not better, by any means. SPARQL and RDF (forget RDF/XML, better to look at Turtle) satisfies everything in OData along with providing many more cutting edge features such as:
Federation Extensions
Linked Data
Reasoning and Inference (for the more brave)
Equally, the software supporting the standards is actually quite sophisticated. Most people interested in OData generally come from a Microsoft background, so take a look at dotNetRdf
Here's a comparison matrix:
http://uoccou.wordpress.com/2011/02/17/linked-data-odata-gdata-datarss-comparison-matrix/
Unfortunately the table formatting is pretty horrible, but the content is useful.
I'm looking for some visual statechart-editor, for my customer. I'm building for him server application, and he needs tool to build statecarts and upload them to the servers. Ofcourse, the tool needs to have the capability to export to some readable format (such as SCXML), so I could build a reader for it.
I saw some tools, like fsm-editor. But they can't be good for me, because I want to limit my customer to set of specific set of parametrized-conditions, parametrized-events and parametrized-actions.
For example, I'll define:
conditions: coIsDoorOpen, coIsThereNAppelsOnTheTree(n as uint[0..200]), ...
events: evLightOn, evLightOff, evTimeout(ms as uint[1..10,000]), ...
actions: acSetAlarmOn, acCloseWindowN(n as uint[1..10]), ...
and my customer could build some dozens statecharts with those explicit predefined attributes (conds, events & actions), and upload the export of them to the approperiate places.
There is no need to be strict to one statechart-standard or to another. But I need support on this things:
parametrized conditions/events/actions
before entering/exiting state actions
no need to support inner variables; I can use actions&conditions for it.
Is there any tool for it (preferably free)?
If not - is there any OpenSource (C# / JS) implementation of editor that supports all abpve without the stricting of conds/events/actions, that I could easily break in to it and add the requested strict mode?
Based upon your needs, my knee-jerk reaction of recommending Visio or Dia would be inappropriate here. You appear to require a tool with some form of an API or descriptive language to lock users to a constrained set of components Lemmings-style, and your needs would best be serviced by something relatively simple if possible.
I'm curious why altering the source code to SCXML-GUI (fsm-editor) or Violet would not solve your needs, however. You seem to indicate that an open source utility written in C# or JavaScript is most desirable, which I cannot easily locate.
But, in the interests of completeness, here's a comparable question that may help your search. Most notably, this appears to be exactly what you desire and may be worth purchasing.
Best of luck with your project.
One of the projects I'm working on involves a module that needs to allow end users to create what essentially equates to, their own "object classes," storing data structures / record types that they can design and modify at runtime. The users will also be able to customize the user interface considerably, but that is not so much the scope of this question.
The closest example to what we are striving to build with this functionality, that I've seen, would be something very akin to what InstantObjects provides at design time, except our system would provide it at runtime, and put the class design control in the hands of the end-user (who will generally be pretty technically sophisticated, obviously).
I recently came across this list of Object Persistence Frameworks for Delphi Win32:
http://tdelphihobbyist.blogspot.com/2008/01/win32-object-persistence-frameworks.html
Any recommendations as to which of these might be the most conducive to the kind of runtime flexibility we are trying to create?
There is currently ongoing discussion of this in the tiopf newsgroups. Tiopf is a open source object persistence framework. Currently it doesn't support user modifiable objects but it looks like someone will be adding this functionality shortly.
Main site: http://tiopf.sourceforge.net/
News groups: See http://tiopf.sourceforge.net/Support.shtml
See "tiOPF ad runtime modifications" thread in the support newsgroup.
JSON could be used to declare and modify user-defined data structures at runtime. There are two libraries for Delphi, SuperObject and lkJSON. With JSON, object hierarchies would be easy to build. The SuperObject demo sources include examples for many usage areas.
SuperObject also contains iterator methods for a given JSON object structure.
I use it for a Delphi client library which is able to exchange objects with Java using the ApacheMQ message broker.
You can create some form of persistence using xml and then buil a form acordingly, we do this a lot for configurable filter windows for example