I'm pretty sure this isn't possible with Odata but, thought I'd ask if anyone has any ideas on how to achieve this before I go off and write a service operation.
Basically, I want to add an $orderby onto the end of an odata qry, a bit like this:
$orderby=SomeIntField-SomeOtherIntField
easy to do in SQL, not sure on how to do this with OData and WCF data services?
Edit - although I initially thought you couldn't do this, it turns out you can. See section 2.2.3.6.1.1 Common Expression Syntax of the MS-ODATA specification for syntax examples. You would need $orderby=SomeIntField sub SomeOtherIntField.
Related
How should a query look like when I want to retrieve last measurements from installations that aren't removed?
Something like that?
/my-web-service/installations/measurements/last?removed=false
The thing is, I don't want to retrieve last measurements that weren't removed from installations. I want to retrieve last measurements from installations that weren't removed.
I see a couple possibilities here:
If you need to read the data from the endpoint transactionally, the way you designed it is the way to go. What I'd change is the name of the param from removed to installationRemoved since it's more descriptive and shorten the endpoint to /my-web-service/measurements/ - since with installations it's unclear in which scope does the client operate. Also, don't you need since param to filter the last measurements?
It there's a chance to split the two endpoints I'd add:
/my-web-service/installations/?removed=false
/my-web-service/measurements/?since=timestamp&installations=<array>
It does not make it better (when it comes to better or worse) but easier and more predictive for the users.
In general try to add more general endpoints with filtering options rather then highly dedicated - doing one particular thing. This way leads to hard to use, loose API. Also, on filtering.
And final notice, your API is good if your clients use it not because they have to but when they like it ;)
According to this best practices article, you could use "aliases for common queries":
To make the API experience more pleasant for the average consumer,
consider packaging up sets of conditions into easily accessible
RESTful paths. For example, the recently closed tickets query above
could be packaged up as GET /tickets/recently_closed
So, in your case, it could be:
/my-web-service/installations/non_removed/measurements/last
where non_removed would be an alias for querying installations that weren't removed.
Hope it helps!
I currently try to solve the following issue in Tableau:
In the end, I would like to have a Tableau dashboard where the user can select a Customer, and then can see the Customer's KPIs. Nothing spectacular so far.
To obtain a Customer's KPIs, there is a CustomSQL query with a parameter "CustomerName" (that returns the KPIs for that Customer).
Now the thing:
I don't want to have a hardcoded list of CustomerNames, as it would be possible with Tableau Parameters. Instead, the CustomerNames should be fetched from another datasource. I did not find a way to "link" a Parameter to a DataSource, and/or inject something other than static Parameters into CustomSQL.
My Question: Is there really no solution for this, or am I just doing something wrong (I hope so).
I found this workaround here https://www.interworks.com/de/blog/daustin/2015/12/17/dynamic-parameters-tableau that seems to work, but that looks like... a workaround.
Few background info:
I have to stick to using a CustomSQL because
It is not viable for me to calculate all KPIs for all CustomerNames
and then filter by Tableau, since the data amount is too big.
It is not viable to replace the CustomSQL with Tableau Calculations
and Filters (already tried that, ended up in having Tableau pulling
too much data instead of pushing the work to the database).
I cannot believe that Tableau does not offer a solution here, since the use case is pretty common I believe.
Do you have some input for me?
Thank you for your help in advance!
Kind Regards
have you tried using rawsql() functions together with stored functions on the database side? I found it pretty useful when needed to load single value from the dataset completely not related to currently used datasource.
For example, running foo stored function which accepts 2 dates and calculated sum of something, Syntax should be something like:
rawsql_int(your_db_schema.foo(%1,%2),[startDateFieldTableau],[endDateFieldTableau])
but you can access it directly:
rawsql_int("select sum(bar) from sales")
but this is bit risky.
Drawbacks:
it relies on the current connection (you create a calculated field (duh!)
it will not work with extract (but you are using custom sql anyways so I believe you are more into live connection
Is there any way to use Regular expressions in Query builder.
Is JCR supports this?
Any pointers on this would be helpful for us.
Thanks in advance.
San
If this QueryBuilder API documentation where to believed as being definitive, then no I would not say there is regex support. However there does seem to be some wildcard support that may be useful. What I would do in this case is try to craft a query around all the properties that you know of about your nodes that can identify them. For example using the debug tool at http://x.x.x.x:4502/libs/cq/search/content/querydebug.html a query like may give you some ideas
type=cq:Page
path=/content/myapp
nodename=*s
1_relativedaterange.property=jcr:content/cq:lastModified
1_relativedaterange.lowerBound=-48h
Where I'm looking for pages in my app content, that end is 's', that have been modified in the last 48 hours. You can even filter by resourceType, template, and any other property that can help you find those nodes. You may even consider adding your own just for this query.
Maybe you can have a sling job, where in Java you could iterate the node names (or whatever) and you do have regex, and tag nodes with a meaningful property that you can then use to query using the query builder.
This question is about why I would use the above keywords. I've found plenty of MSDN pages that explain how. I'm looking for the why.
What query would I be trying to write that means I need them? I ask because the examples I have found appear to be achievable in other ways...
To try and figure it out myself, I created a very simple entity model using the Employee and EmployeePayHistory tables from the AdventureWorks database.
One example I saw online demonstrated something similar to the following Entity SQL:
SELECT VALUE
DEREF(CREATEREF(AdventureWorksEntities3.Employee, row(h.EmployeeID))).HireDate
FROM
AdventureWorksEntities3.EmployeePayHistory as h
This seems to pull back the HireDate without having to specify a join?
Why is this better than the SQL below (that appears to do exactly the same thing)?
SELECT VALUE
h.Employee.HireDate
FROM
AdventureWorksEntities3.EmployeePayHistory as h
Looking at the above two statements, I can't work out what extra the CREATEREF, DEREF bit is adding since I appear to be able to get at what I want without them.
I'm assuming I have just not found the scenarios that demostrate the purpose. I'm assuming there are scenarios where using these keywords is either simpler or is the only way to accomplish the required result.
What I can't find is the scenarios....
Can anyone fill in the gap? I don't need entire sets of SQL. I just need a starting point to play with i.e. a brief description of a scenario or two... I can expand on that myself.
Look at this post
One of the benefits of references is that it can be thought as a ‘lightweight’ entity in which we don’t need to spend resources in creating and maintaining the full entity state/values until it is really necessary. Once you have a ref to an entity, you can dereference it by using DEREF expression or by just invoking a property of the entity
TL;DR - REF/DEREF are similar to C++ pointers. It they are references to persisted entities (not entities which have not be saved to a data source).
Why would you use such a thing?: A reference to an entity uses less memory than having the DEFEF'ed (or expanded; or filled; or instantiated) entity. This may come in handy if you have a bunch of records that have image information and image data (4GB Files stored in the database). If you didn't use a REF, and you pulled back 10 of these entities just to get the image meta-data, then you'd quickly fill up your memory.
I know, I know. It'd be easier just to pull back the metadata in your query, but then you lose the point of what REF is good for :-D
I like knockoutjs, the sooner we get rid of coding directly toward the DOM the better. I'm having trouble understanding how I would do something which I'm going to explain in terms of a question/answer site. (This is probably a general MVC/MVVM question)
In my data model I have a question[id, description] and answer[id, question_id, text]. The browser requests a list of questions which is bound to a tbody, one column will display the question description, while the other should be bound to an answer textbox.
One obvious way of doing this is to have a QuestionAnswer[question_id, answer_id, question_descrition, answer_text] model. Ideally I'd like to keep them separate to minimize transformation when sending/receiving/storing, if there isn't some way of keeping them separate then I have the following question:
Where is the ideal place to create the QuestionAnswer model ? My bet is that by convention its created on the server.
If there is such an example somewhere please point me to it, otherwise I think it would make a good example.
Please help me wrap my head around this, Thanks!
What you could do is to create the combined model on the server, serialize it to json and then use the mapping plugin to add the serialized list to the view model.
I'm doing that here only it isn't a combined model, but shouldn't make any difference. Especially since it seems like your relation is one-to-one.
If you need to create an "object" in your view model, you can use the mapping definition to do so, like I do here.
I use C# to build my model on the server, but I guess you can use whatever you are comfortable with.
The cool thing with the mapping plugin is that it adds the data to the view model so that you can focus on behaviour.
Ok,
I'v gathered my thoughts on what my question is actually asking.
To do data binding on the client side you obviously need your data model there as well. I was conflicted on what I needed to send over and at what time.
To continue with the Question/Answer site idea: Sending down a list of answers each of which have a question in them is what should be done. That way you can bind to the answer list and simply bind the question description of each answer to the first table column.
If later I want to make a question editor I would potentially send a complete different data structure down and not reuse the Answer has a Question structure previously used.
I thought there might be a way of sending down a more complex data structure that references itself. Which apparently is possible in JSon with some extra libraries.