I am newbie to neo4j and I really need help.
I have created nodes properties NAME, EMAIL and AGE. These nodes are having relationship: IS_FRIEND_OF with property SINCE with other nodes.
I have given property values in NAME as “A”, “B”, “C”, “D” and so on.
Now when I fire a query in console like: Start n=node(*) where n.NAME=’A’ return n;
It is giving an exception like: EntityNotFoundException: The property 'NAME' does not exist on Node[0]
Now if I add a property NAME = “” on node [0] and then fire the same query, it is providing the correct output. For small data set it can work but for larger ones specifying each property for node [0] doesn’t seems to be the good solution.
Is it the only workaround or something else and better can be applied?
STARTn=node(*) WHERE n.NAME! = "A" RETURN n
The exclamation mark will do the following:
TRUE if n.prop = value, FALSE if n is NULL or n.prop does not exist
Cypher has two special operators: ? and ! to use in this case to handle this exception
Using ? will evaluate to true if n.prop is missing:
START n=node(*) WHERE n.NAME? = "A" RETURN n
And using ! will evaluate to false if n.prop is missing:
START n=node(*) WHERE n.NAME! = "A" RETURN n
Related
I have a subject like "accessTo" = ["123", "123-edit"]
and a resource like "interestedId" = "123"
Now I'm trying to write a condition - where it checks "interestedId" concatenated with "-edit" equals "123-edit" in "AccessTo".
Im trying to write rule like this
anyOfAny_xacml1(function[stringEqual], "accessTo", "interestedId"+"-edit")
It is not allowing to do this.
Any help is appreciated.
In addition to the answer from Keerthi S ...
If you know there should only be one value of interestedId then you can do this to prevent the indeterminate from happening:
stringBagSize(interestedId) == 1 && anyOfAny(function[stringEqual], accessTo, stringOneAndOnly(interestedId) + "-edit")
If more than value is present then evaluation stops prior to reaching the function that expects only one value. This condition would return false if more than one value is present.
On the other hand if interestedId can have multiple values then this would work:
anyOfAny(function[stringEqual], accessTo, map(function[stringConcatenate],interestedId, "-edit"))
The map function will apply the stringConcatenate function to all values in the bag.
Since Axiomatics products are compliant with XACML specification, all attributes by default are assumed to contain multiple values(called as 'bags').
So if you would like to append a string to an attribute use stringOneAndOnly XACML function for the attribute to indicate that the attribute can have only one value.
So assuming you mean accessTo has attribute ID as Attributes.access_subject.subject_id, interestedId has the attribute ID as Attributes.resource.resource_id and anyOfAny_xacml1 is equivalent to anyOfAny XACML function, the resulting condition would look like,
anyOfAny(function[stringEqual], Attributes.access_subject.subject_id, stringOneAndOnly(Attributes.resource.resource_id) + "-edit")
I have a custom field being added on user story (HierarchicalRequirement) level.
The WSAPI documentation shows the following details for the field:
c_CustomFieldName
Required false
Type string
Max Length 32,768
Sortable true
Explicit Fetch false
Query Expression Operators contains, !contains, =, !=
When trying to create a report using Custom List to identify user stories where this field is empty, I add (c_CustomFieldName = "") to the query.
And yet, the result shows rows where this field is not empty.
How can that be?
I tried querying on null, but it didn't work.
thx in advance
What you're doing should work- are you getting errors, or just incorrect data? It almost seems like it's ignoring your query altogether.
I tried to repro both with the custom list app and against wsapi directly and the following all worked as expected:
(c_CustomText = "") //empty
(c_CustomText = null) //empty
(c_CustomText != "") //non-empty
(c_CustomText != null) //non-empty
It's possible you're running into some weird data-specific edge case in your data. It may be worth following up with support.
So my Top-Level problem is I am trying to return whether a MERGE resulted in the creation of a new Node or not.
In order to do this I was thinking I could just create a simple temp boolean setting it to TRUE using ON CREATE
How I imagine it working:
MERGE(: Person {id:'Tom Jones'})
WITH false as temp_bool
ON CREATE set temp_bool = true
RETURN temp_bool
Obviously this does not work.
I am looking for a way to create arbitrary temp values within a Cypher query, and have the ability to return those variables in the end.
Thanks
You can do what you want, here's how (combination of my first answer, with #cybersam's addition). You just do it with a node property you create and then remove, instead of an unbound variable as you've been trying.
MERGE(tom:Person {id:'Tom Jones'})
ON CREATE set tom.temp_bool = true
ON MATCH set tom.temp_bool = false
WITH tom, tom.temp_bool AS result
REMOVE tom.temp_bool
RETURN result;
In simple merging cases like this where maximum one node could be created, a cleaner way to achieve what you are looking for could be checking the result stats. I case of using Bolt API you should check:
results.consume().counters.nodes_created = 1
i'm facing issue in xpath-I need do a check two attribute values, if the condition satisfies need to do hard code my own value. Below is my xml.
I need to check the condition like inside subroot- if ItemType=Table1 and ItemCondition=Chair1 then i have to give a hard coded value 'Proceed'( this hard coded value i will map to target side of datamapper).
<Root>
<SubRoot>
<ItemType>Table1</ItemType>
<ItemCondition>Chair1</ItemCondition>
<ItemValue>
.......
</ItemValue>
</SubRoot>
<SubRoot>
<ItemType>Table2</ItemType>
<ItemCondition>chair2</ItemCondition>
<ItemValue>
.......
</ItemValue>
</SubRoot>
....Will have multiple subroot
</Root>
I have tried to define rules as below, but it is throwing error
Type: String
Context:/Root
Xpath: substring("Proceed", 1 div boolean(/SubRoot[ItemType="Table1" and ItemCondition="Chair1"]))
But it is throwing error like
net.sf.saxon.trans.XPathException: Arithmetic operator is not defined for arguments of types (xs:integer, xs:boolean)
Is there any other shortcut way to perform this.Could you please help me, i have given lot more effort. Not able to resolve it. Thanks in advance.
I am not sure where you are applying this but the XPath expression you are looking for is:
fn:contains(/Root/SubRoot[2]/ItemCondition, "chair") and fn:contains(/Root/SubRoot[2]/ItemType, "Table")
So here is an example returning "Proceed" or "Stop" as appropriate:
if (fn:contains(/Root/SubRoot[1]/ItemCondition, "Chair") and fn:contains(/Root/SubRoot[2]/ItemType, "Table")) then 'Proceed' else 'Stop'
To implement the above condition , i was initially tired to do in xpath, gave me lot of error. I have implemented by simple if else condition in script part of data mapper
if ( (input.ItemType == 'Table') and (input.ItemCondition == 'chair')) {
output.Item = 'Proceed'}
else {
output.Item = 'Stop '};
Make sure about your precedence. Example, Here in the xml structure( or converted POJO) ItemType has to be checked first then followed with ItemCondition.
&& not seems to be working for me, change to 'and' operator
If you were first time trying to implement the logic. It may help you.
I think that the title is a little bit vague, so I'm going to explain precisely my problem.
I am creating some nodes in Neo4j and then index them like this :
Index<Node> myindex = graphDb.index().forNodes(
"myindex",
MapUtil.stringMap(IndexManager.PROVIDER, "lucene", "type",
"fulltext"));
Node n = graphDb.createNode(); //create the node
node.setProperty("firstname", "firstname"); //add properties
node.setProperty("familyname", "familyname");
myindex.add(node, "familyname", "familyname"); //index it
But when I need to update Node "n" 's properties (for instance change "familyname" to "fname"), this node can't be found anymore through an index based search!
So before updating the property, this cypher query
start n= node:myindex(familyname:"familyname") return n
was returning the Node, whereas after update, I am expecting :
start n= node:myindex(familyname:"fname") return n
to return the same node with the new property, but it doesn't work ! While the first query is always working, like if the index is bound to the property "familyname"
Any thoughts about this ?
Thanks
So as tstorms suggested, the solution is to remove the index after updating the property :
n.setProperty("familyname","fname");
myindex.remove(n);
then add it with the new property :
myindex.add(n, "familyname","fname");