The services.odata.org/odata/odata.svc one has a single service operation, but I'm looking for one which takes parameters of different types. I would at least like to see one which takes strings, but guids and dates would be nice as well.
Thanks
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I have a system where there are large dataset(s) where I want to have quick searches, and elastic search is suitable for it. So the data resides in SQL, and is synced to ES. There is an obvious small delay in this sync.
There are consumers of this data which could work with slightly stale data. So if there's an API for UI which end users use to see the dataset. A delay of 3-4 seconds is acceptable. So API handler which deals with ES is perfect here.
Then there are consumers of this data (bots) who want to work with real time data. So for the almost same requirements, should I create another API just like that in UI consumer, which gets data from SQL?
What is the usual best practice which is followed, and I'm assuming this is a very common usecase.
You probably should stick to creating just a sinlge API and use a query string parameter to decide which of the two data sources to use. This will result in less code to maintain.
I wanted to store all the data from my DB to dstore so,
What is maximum number of data or size can be stored in Dojo dstore?
This is a very vague question, since you don't even mention what type of store specifically. With in-memory stores it's usually advisable to keep totals down to a couple of thousand, though modern browsers can certainly scale higher.
However, the entire point of server-based stores like Request and Rest are that not all items need to be stored on the client side at once. If you have hundreds of thousands of data items and your server providing the data supports filtering/sorting/paging arguments in some way, whether restful in the way that Request and Rest expect or otherwise, a server-based store (i.e., one that queries the server for each fetch or fetchRange call, passing arguments based on any preceding sort and filter calls) is a good idea.
You can get an idea for the kinds of server interactions that the Rest store expects here (although this documentation was written for implementations of older store APIs, dstore/Request and dstore/Rest still expect the same type of behavior, but are slightly more configurable).
You can also see an example of configuring and using dstore/Rest with one particular server-side framework, the Django Rest Framework, here.
I'm currently working in a Silverlight / MS SQL project where the Entity Framework has not been implemented and I would like to know what's the best practice to deal with calculated fields in this particular situation.
Considering that some external system might also consume my data directly in the DB or thru a web service, here's the 3 options I can see right now.
1) Force any external system to consume data thru a web service and create all the calculated fields in the objects only.
2) Create the calculated fields in a DB view and resync your object with the server each time a value needs to be calculated.
3) Replicate the calculation rules in the object and the database view.
Any other suggestions would also be welcomed.
I would recommend to follow two principles: data decoupling and minimum functionality duplication. Both would suggest to put your calculations in one place only, and serve them already calculated. So I would implement the calculations in the DB, and serve them via a web service.
However, you have to consider your particular case. For example, if the calculations are VERY heavy, you could delegate them to the client to spare server resources. This could even be the reason you are using Silverlight. I am in a similar situation on a project, and I found that the best compromise is to push raw data to the client and have it do the heavy computations.
Having a best practice or approach for this kind of problem is difficult as circumstances change what was formerly a good approach might start to seem less useful. That said where possible I would do anything data related at the DB level including calculated fields. This way you know no matter where you are looking at the data from you will see the same results. So your web service, SQL reporting and anything else that needs to look at or receive data will see the same result.
I have got a WCF Data Service based on a LINQ to SQL data provider.
I am making a query "get me all the records between two dates".
The problem is that I want to synthesize two extra records such that I always get records that fall on the start and end dates, plus all the ones in between which come from the database.
Is there a way to "intercept" the request so I can synthesize these records and return them to the client?
Thanks
I suspect the answer involves using "Interceptors".
Just stumbled across this...
http://msdn.microsoft.com/en-us/library/dd744842.aspx
The more I think about this the more I would say "please don't do this". The problem is that in WCF Data Services (or OData for that matter), each entity you return (entity == record) needs to have its unique URI. The clients also assume that if the entity is returned from the server (unless it was deleted), the entity can be accessed again.
In your case though, the boundary entities are defined by the query and they really only exist in the context of the query. Given a different query they are different. So all in all, they do not behave like entities, they behave more like some kind of query metadata.
Anyway, if you really think this is the right thing to do... It's rather hard to do this. The only approach I can think of is to hook into the IQueryable returned from the entity set (layer your own IQueryable on top of the one from LINQ to SQL). Then when a query gets executed, you parse the expression tree and find the conditions which define the range, then you return a custom implementation of IEnumerable which will "synthesize" the two special entities at the begining and at the end and it will return the rest from the underlying LINQ to SQL results. All of this is lot of code and it's definitely not easy to do.
A second possible way would be to implement this as a Service operation (requires that the client knows that there's a special operation on the server to do this though). It would also make a bit more sense, as the service operation would get the range as its parameters instead of as a filter and thus is much easier for you to figure out the range (no expression tree parsing).
We are developing a project that involves about 10 different WCF services with several endpoints each. One of the services keeps a few big tables of data cached in memory.
We have found we need access to that data from another service. Rather than keeping 2 copies of the cache, I'd like to be able to share those tables across all services.
I have done some research and found some articles about using an IExtension attached to the servicehosts to store the shared data.
Provided that all the services are running under the same web site, will that work? And is it the right approach? Or should I be looking elsewhere?
If the data that you're caching is required by more than one service, it sounds like - from a Service Oriented Architecture perspective, anyway - that it doesn't belong in either of services you have calling it.
If the data being cached isn't really related to either service, but is something that both services need, then perhaps it belongs in it's own seperate service. Have you considered encapsulating your cache in a third service, and performing a service-to-service call to retrieve the data you need? Benefits include...
It solves your original dilemma, avoiding the need to read the whole cache from the database several times;
It encapsulates the cache in one place for easy maintainance/change later.
It allows you to abstract the implementation of the cache away from the other services by putting another service interface in the way.
All in all, I'd suggest that's the best approach. The only downside is the extra overhead of making the service-to-service call, but that surely outperforms having to read the whole cache from the database.
Alternatively, if the data in your cache is very closely related to BOTH of the services that are calling the cache, i.e. both services add/change the data in the cache, etc. then perhaps the two existing services should be combined into a single service.
If what I'm saying is making some sense, then then principle of SOA I'm drawing on is Service Autonomy.
Provided all your services are part of the same application there doesn't seem to be any reason why you can't share the cache directly via a shared object reference. The simplest way of doing this is via a static field.
If you choose this approach, one thing to be very careful about is thread safety. If your cache is concurrently accessed via two WCF sessions, you must ensure that the two sessions are not going to interfere with each other by both changing the cache at the same time. If the cache is read-only, your need to do this is lessened, but you still might need to synchronrise initialisation of the cache.