I am trying to create a graph in OrientDB where the weight of edges has to be calculated on demand using data from another database. I would like to know if there is a way to do this, since all example I´ve seen use static weight properties, none of which is dynamic by nature.
If I could use a stored function as a property and have it evaluate each time I call shortestPath then it would solve my problem, but I haven´t found any documentation on this topic.
Help would be greatly appreciated!
This isn't supported by OrientDB out of the box, even if it would be something nice to have. Could you open a new issue?
About the solution I suggest to clone the OSQLFunctionDijkstra class, do your changes and plug into OrientDB engine with a different name.
Related
After many attempts to make a version of SpectatorView functional using UNet, I was able to successfully communicate between client / server using Azure Spatial Anchor to share anchor information. Many errors have occurred, including an unknown error, which appears to resolve the deletion of the MRTK 2.2.0 library. This has already been resolved, but now at random a problem occurs in the function CloudManager.CreateAnchorAsync, which says just like this: Not enough Neighborhood Spatial Data was available to complete the desired Create operation.
This problem does not happen directly, but randomly makes it impossible to find a pattern to try to think of a solution to this problem.
Remembering that the CloudManager.SessionStatus.RecommendedForCreateProgress variable is above 1 before calling the creation function.
Could you give me more information about this problem? What do I do to not do a project to solve it?
The usecase
We got multiple changelogs stored in the database, and want to create a histogram monitoring the duration between changes.
The problem
There doesn't seem to be a way to set the start time of a Historgram.Timer, e.g we want to set it to lastUpdated given the current changelog.
Avenues of approach
1 Subclassing Histogram
Should work. However the java-lib use protected/package-private extensively, thus making it hard without copying large portions of the library.
2 Using reflection
After a Histogram.Timer is created it should be possible to use reflection to set the start field. The field is marked as private final, and thus a SecurityManager could stop us in some environments.
Ideas?
Neither of the solutions seems like the correct way to go, and I suspect that I'm overlooking a simpler solution (but could find anything at SO or google). We're using grafana to visualize our metrics, if thats at all helpful in this scenario.
You don't need to subclass Histogram, as you don't need to use Histogram.Timer only because your histogram is measuring times.
Simply call myHistogram.observe(System.now() - lastUpdated) every time you record a new change in the database.
I am a complete newbie to computation of gps, gis and all these geoinformatical stuff. First I describe my lessons learned to arrive at gps data. You can skip this and go to the last two paragraphs where I explain my problem with osrm and how to map a route onto an OSM map via qgis or similar tools.
I tried to do some route optimization for a bunch of addresses to support my son's paper deliverer job. I was able to generate a list of gps data by using the Nomatim engine that is available via geopy.geocoders. It's kind of a Travelling Salesman problem (TSP).
By using geopy's distance calculator and the or-tools from Google to Generate a shortest list recommendation. That worked well but it was only a TSP solution for air line :-(.
Then I was looking for route optimization toolkits but i struggled to get one for free. I thought osrm could be the right tool. I followed the descriptions given at Github, see here. I was able to generate a JSON file - at least I supposed that it's kind of a JSON file. But I was unable to project this back onto a map in QGis or any online tool from OSM. Can anyone help me?
The file with such JSON-like formatting:
{"code":"Ok","waypoints":[{"hint":"Jh4BgEUzI4BhAAAACwAAAKIAAABZAAAAkLAjQgpyikBay4dCWsuHQmEAAAALAAAAogAAAFkAAAArAAAAxwB4AARI3AI3AXgAWEbcAgIADwXVhXd1","location":...
Due to privacy issues I cannot post it here with any locations. Sorry for this. But does anyone have kind of a recipe / step-by-step guide what I need to do to plot it? I even have no idea how to "open" a map within qgis. You need to do this as kind of a database but this is totally new for me. I would prefer to work with an easier method to plot it.
Thanks in advance for any help.
Please follow the API documentation here. From that documentation
hint Unique internal identifier of the segment (ephemeral, not
constant over data updates) This can be used on subsequent request to
significantly speed up the query and to connect multiple services.
E.g. you can use the hint value obtained by the nearest query as hint
values for route inputs.
You can get the geometry in many ways. Widely GeoJSON is being used by developers. OSRM returns a very clean GeoJSON which can easily be used with Leaflet, Mapbox or other Map APIs. You need to send steps parameter true to get the full step by step direction. You can get the each segments of steps in legs. So call the GeoJSON within the geometries of every legs with loop. You can also get the geometry without passing the steps parameter true. For that you will get full geometry in a single GeoJSON within the routes property.
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
i would like to simulate what-if analysis on a OLAP cube
For example, i would like to know the impact on departmental resource budgets by moving employees between departments or the movement in cost of manufacture if a product is moved from one factory to another.
so should i use an rolap cube'mondrian' or molap ?
i will greatful if you can give me some exemple , tuto ... ;)
thank you in advance
Actually mondrian does support "writeback" (via olap4j) so you can do what if analysis.
Check out Saiku - AFAIK it's the first and only tool to have implemented it so far.
Here is how it works - it's pretty rudimentary:
http://julianhyde.blogspot.co.uk/2009/06/cell-writeback-in-mondrian.html
Martin is close to the point though, it doesn't actually update the raw data, only objects in the cache. But you wouldnt want to update raw data if you were doing what if analysis anyway!
I would say that Mondrian is an engine to query an existing database that is has a dedicated structure for Olap (usually some kind of star schema).
It is definitely not something to manipulate (or even) change data. Since each what-if analysis needs to change data in some way or another, Mondrian is not the tool for it.