This seems like a must have feature for graph query language, but I cannot find a command that let me create a vertex with label, nor add a label after a vertex has been created.
I tried the solution here, but it does not work because the property T.label is not recognized.
I am using OrientDB as the db engine, and OrientDB has class hierarchy concept rather than Label concept, and I wonder if that is the problem.
I missed it in the tutorial here
You can use g.addVertex("class:className")
Related
Is there a plugin or way to rearrange a single graphql schema file. Basically I want my graphql schema to be more organized. For example, All types should be at the top, followed by type Query followed by Mutations followed by Subscription and so on. Something similar to the code arrangement we do with class files in Intellij or other IDEs (i.e, constants at the top, followed by private variable, methods and so on)
Yes! There is the great package called format-graphql by Gajus Kuizinas that does exactly this -- enforcing consistent style on your schema. It is somewhat opinionated, so you can either 1) deal with the current custom options provided when you configure the package or 2) fork it, and rewrite this core utility to achieve the desired effect.
I'm coming from Neo4j and evaluating OrientDB, and I had a quick question about classes - do they have to exist prior to inserting a record? That is, in Neo4j there's the 'MERGE' command, which will update or create a node if it doesn't exist. Classes seem roughly equivalent to Neo4j's labels, and if a label doesn't exist when performing a MERGE, it will be created. Is there similar functionality in OrientDB? Currently when I try to insert a record whose class doesn't exist, OrientDB throws an exception, "Class SOME_CLASS not found in database".
I've been reading through the docs trying to get a handle on the various data models available, but I can't find anything explicit on this issue. One thing I tried was to add a cluster, and then insert a record with a class that does not exist. This worked, and in OrientDB Studio, under 'DB', I see the cluster with number of records equal to '1'; however, the class of that new record does not appear under 'Schema'.
If dynamic class creation of this sort isn't possible, is it acceptable to check if a class exists in the schema, and if not, create it, and then proceed with creating the record? A different question is, if it's acceptable, is it good to do this, or should I always define the schema manually?
If you use one of the CREATE commands, then the object is placed in a default class; for example:
CREATE VERTEX
Created vertex 'V#9:0 v1' in 0.047000 sec(s).
(In this case, the class is V.)
And of course if you use the INSERT INTO ... form, then you have to specify a class.
So perhaps your first question boils down to whether it is possible to change the class of an OrientDB vertex or edge.
It is possible to change the parent class of a vertex -- see
http://orientdb.com/docs/2.1/SQL-Move-Vertex.html -- but there are important caveats.
To test whether a class exists programmatically, see e.g. this SO entry:
Check if class exists or not in orientdb
This gives a Java example, but a similar approach is possible using other supported languages.
As to the wisdom of changing the class of an entity dynamically -- perhaps the safe answer is that if you can achieve whatever you want using a property label, then use labels.
As far as I can tell there is no way to specify that an existing schema class should be used when a matching label is specified but default to the general V/E classes otherwise. I have few custom E sub classes that I would like to use but I don't want other edge labels to cause the creation of additional sub classes. The API I'm using is TinkerPop-based and I cannot explicitly specify vertex/edge classes.
The OrientConfigurableGraph.setUseClassForEdgeLabel(boolean) setting is an all or nothing option. If it is set to true schema classes are created for all labels and if it is set to false new vertex/edge instances are set to the general V/E classes even if there is a matching class. Am I correct about this? I would like a configuration option that allows the use of matching schema classes if they are available in the schema but without automatically creating others when there is no match. I'm using version 2.1.8.
After browsing the OrientDB v2.1.x reference documentation and javadocs, i couldn't find a configuration option that configures the graph the way you want, so what you can do, is to open a ticket in the issue tracker at github and request that feature.
Although, in the meantime, you can control this programatically with the Graph API with the custom vertex/edges functions, as explained in the documentation, not ideal, as you need to control this programatically, but for now is the closest i could find.
It says here:
The definition of an edge label, property key, or vertex label cannot
be changed once its committed into the graph.
In contrast SQL Server, which is what I'd normally use, doesn't have a problem with, say, changing the type of a field or the cardinality of a relationship.
This isn't even in the Temporary Limitations section of that web page.
Why is this limitation here and what am I supposed to do when I make a mistake when defining a type? Delete the whole database and import all the data into a new one?
i was just trying to achieve a N:M relation between two of my Domain Models with an attribute.
I tried this Tutorial ( sorry, it's german, but the code is fine. ) and everything works fine in the backend and the database (datarecords are created correctly, relations are visible in backend/tca config).
BUT: When I try to create a Model/Repository/Controller/Plugin ( all with minimal basic configurations, just for testing the output, so nothing fancy here ) and try to output my "firma" with the RepositoryMethod->findAll() I get an Error in SQL Syntax.
Extbase seems to access the wrong tables. Normally the SQL statement should ask for the mitarbeiterid/firmaid in the relation table. But the SQL-Error reveals that Extbase tries to find the column "firmaid" / "mitarbeiterid" in the "mitarbeiter"-table, where those columns do not exist.
Does anyone of you know if this can be fixed, or am I missing something from the tutorial (I'm aware that the first tutorial has some typing errors, but that'S not the problem :( ) ? I tried another tutorial IRRE Tutorial which is basically the same, just a bit more extended. Same SQL-Error in here. What has to be done to get some output in the frontend of these datarecords ?
Thanks in advance.
The tutorial seems to be outdated. seems to be more up to date and actually using extbase/fluid.
But lucky you, its not that hard to achieve what you are aiming for. You need to check this list. Make sure that
Your class names, table names and folder structure are in synch with extbase expectations
You have two domain models of which both have a property that contains a objectStorage that contains instances of the other object
You have configured your TCA for both tables to use a mm table for the property containing the objectStorage