I'm attempting to model a recursive structure with App Engine NDB:
class Root(ndb.Model):
pass
class Node(ndb.Model):
#Node can have either a Root, or another Node as parent
pass
root_key = Key(Root, 1)
node_a = Key(Root, 1, Node, 2)
node_b = Key(Root, 1, Node, 3)
node_a_a = Key(Root, 1, Node, 2, Node, 4)
From here, I want to query the Root entity for immediate children. What I can do is to query for all descendants of the root:
Node.query(ancestor=root_key) # returns node_a, node_b, and node_a_a
What I'd like to do is:
Node.query(parent=root_key) # returns node_a, node_b
but it seems that querying by (immediate) parent key isn't supported by the ndb api. Hopefully I'm wrong. Looking forward to elucidation. Thanks
It's not an NDB limitation -- the App Engine datastore can't do this. However you can easily simulate this behavior by including the key (or some other unique ID) of the parent as a property.
Related
trying to create a function like :-
addChild(parent graphid,child graphid,relationship text,direction text)
merge(parent)-[r:f(relationship)]->(child) return id(r);
with a typical cal :
relid=addChild(id(a),id(b),'has','U') -- where U means up child to parent
Question is, without a very tedious switch statement , how do I associate a text version of the relationship, or edge type, with an actual edge type?
Took a bit of messing around and the syntax seems a bit last-minute but this works :
return query execute format('match(p) where id(p)=%s with p match(c) where id(c)=%s with p,c merge(p)-[r:%s]->(c) return id(r);',parent,child,reltype);
Where parent and child are graph ids and reltype is text;
I have this statement that is generated by Geoserver
SELECT
shape AS shape
FROM
(
SELECT
c.chantier_id id,
sdo_geom.sdo_buffer(c.shape, m.diminfo, 1) shape,
c.datedebut datedebut,
c.datefin datefin,
o.nom operation,
c.brouillon brouillon,
e.code etat,
u.utilisateur_id utilisateur,
u.groupe_id groupe
FROM
user_sdo_geom_metadata m, lyv_chantier c
JOIN lyv_utilisateur u ON c.createur_id = u.utilisateur_id
JOIN lyv_etat e ON c.etat_id = e.etat_id
JOIN lyv_operation o ON c.operation = o.id
WHERE
m.table_name = 'LYV_CHANTIER'
AND m.column_name = 'SHAPE'
) vtable
WHERE
( brouillon = 0
AND ( etat != 'archive'
OR etat IS NULL )
AND sdo_filter(shape, mdsys.sdo_geometry(2003, 4326, NULL, mdsys.sdo_elem_info_array(1, 1003, 1), mdsys.sdo_ordinate_array(
2.23365783691406, 48.665657043457, 2.23365783691406, 48.9341354370117, 2.76649475097656, 48.9341354370117, 2.76649475097656, 48.665657043457, 2.23365783691406, 48.665657043457)), 'mask=anyinteract querytype=WINDOW') = 'TRUE' );
On my local instance (dockerized if that can explain anything) it works fine, but on another instance I get an error :
ORA-13226: interface not supported without a spatial index
I guess that the SDO_FILTER is applied to the result of SDO_BUFFER which is therefore not indexed.
But why is it working on my local instance ?!
Is there some kind of weird configuration shenanigan that could explain the different behavior maybe ?
EDIT : The idea behind this is to get around a bug in Geoserver with Oracle databases where it renders only the first point of MultiPoint geometries, but works fine with MutltiPolygon.
I am using a SQL view as layer in Geoserver (hence the subselect I guess).
First, you need to do some debugging here.
Connect to each instance, on the same user as your Geoserver's datasource, and run the sql. From the same connections (in each instance) you must also verify that the user's metadata view (user_sdo_geom_metadata) have an entry for the table and the table has a spatial index - whose owner is the same user as the one you connect.
Also, your query ( select ... from 'vtable') has a column 'shape' which is a buffer of the column lyv_chantier.shape. The sdo_filter, in this sql, expects a spatial index on the vtable.shape - which cannot exist. You should try to use a different alias (e.g. buf_shape) and sdo_filter(buf_shape,...) - to see if the sql fails in both instances, as it should.
I'm in a bit of a hurry right now, so my instructions are summarized. If you want, do this debugging and post the results. We then can go into details.
EDIT: Judging from your efforts, I'd say that the simplest approach is: 1) add a second geometry column to lyv_chantier (e.g. buf_shp). 2) update lyv_chantier set buf_shp = sdo_geom.sdo_buffer(shape,...). 3) insert into user_sdo_geom_metadata the values (lyv_chantier, buf_shp, ...). 4) create a spatial index on column buf_shp. You may need to consider a trigger to update buf_shp whenever shape changes...
This is a very practical approach but you don't provide any info about your case (what is the oracle version, how many rows does the table have, how is it used, why do you want to use sdo_buffer, etc), so that's my recommendation for now.
Also, since you are, most likely, using an sql view as layer in Geoserver (you don't say anything about that, either), you could also consider using pure GS functionality to achieve your goal.
At the end, without describing your goal, it's difficult to provide anything more tailor-made.
Am new to Neo4j and trying to do a POC by implementing a graph DB for Enterprise Reference / Integration Architecture (Architecture showing all enterprise applications as Nodes, Underlying Tables / APIs - logically grouped as Nodes, integrations between Apps as Relationships.
Objective is to achieve seamlessly 'Impact Analysis' using the strength of Graph DB (Note: I understand this may be an incorrect approach to achieve whatever am trying to achieve, so suggestions are welcome)
Let me come brief my question now,
There are four Apps - A1, A2, A3, A4; A1 has set of Tables (represented by a node A1TS1) that's updated by Integration 1 (relationship in this case) and the same set of tables are read by Integration 2. So the Data model looks like below
(A1TS1)<-[:INT1]-(A1)<-[:INT1]-(A2)
(A1TS1)-[:INT2]->(A1)-[:INT2]->(A4)
I have the underlying application table names captured as a List property in A1TS1 node.
Let's say one of the app table is altered for a new column or Data type and I wanted to understand all impacted Integrations and Applications. Now am trying to write a query as below to retrieve all nodes & relationships that are associated/impacted because of this table alteration but am not able to achieve this
Expected Result is - all impacted nodes (A1TS1, A1, A2, A4) and relationships (INT1, INT2)
Option 1 (Using APOC)
MATCH (a {TCName:'A1TS1',AppName:'A1'})-[r]-(b)
WITH a as STRTND, Collect(type(r)) as allr
CALL apoc.path.subgraphAll(STRTND, {relationshipFilter:allr}) YIELD nodes, relationships
RETURN nodes, relationships
This faile with error Failed to invoke procedure 'apoc.path.subgraphAll': Caused by: java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.lang.String
Option 2 (Using with, unwind, collect clause)
MATCH (a {TCName:'A1TS1',AppName:'A1'})-[r]-(b)
WITH a as STRTND, Collect(r) as allr
UNWIND allr as rels
MATCH p=()-[rels]-()-[rels]-()
RETURN p
This fails with error "Cannot use the same relationship variable 'rels' for multiple patterns" but if I use the [rels] once like p=()-[rels]=() it works but not yielding me all nodes
Any help/suggestion/lead is appreciated. Thanks in advance
Update
Trying to give more context
Showing the Underlying Data
MATCH (TC:TBLCON) RETURN TC
"TC"
{"Tables":["TBL1","TBL2","TBL3"],"TCName":"A1TS1","AppName":"A1"}
{"Tables":["TBL4","TBL1"],"TCName":"A2TS1","AppName":"A2"}
MATCH (A:App) RETURN A
"A"
{"Sponsor":"XY","Platform":"Oracle","TechOwnr":"VV","Version":"12","Tags":["ERP","OracleEBS","FinanceSystem"],"AppName":"A1"}
{"Sponsor":"CC","Platform":"Teradata","TechOwnr":"RZ","Tags":["EDW","DataWarehouse"],"AppName":"A2"}
MATCH ()-[r]-() RETURN distinct r.relname
"r.relname"
"FINREP" │ (runs between A1 to other apps)
"UPFRNT" │ (runs between A2 to different Salesforce App)
"INVOICE" │ (runs between A1 to other apps)
With this, here is what am trying to achieve
Assume "TBL3" is getting altered in App A1, I wanted to write a query specifying the table "TBL3" in match pattern, get all associated relationships and connected nodes (upstream)
May be I need to achieve in 3 steps,
Step 1 - Write a match pattern to find the start node and associated relationship(s)
Step 2 - Store that relationship(s) from step 1 in a Array variable / parameter
Step 3 - Pass the start node from step 1 & parameter from step 2 to apoc.path.subgraphAll to see all the impacted nodes
This may conceptually sound valid but how to do that technically in neo4j Cypher query is the question.
Hope this helps
This query may do what you want:
MATCH (tc:TBLCON)
WHERE $table IN tc.Tables
MATCH p=(tc)-[:Foo*]-()
WITH tc,
REDUCE(s = [], x IN COLLECT(NODES(p)) | s + x) AS ns,
REDUCE(t = [], y IN COLLECT(RELATIONSHIPS(p)) | t + y) AS rs
UNWIND ns AS n
WITH tc, rs, COLLECT(DISTINCT n) AS nodes
UNWIND rs AS rel
RETURN tc, nodes, COLLECT(DISTINCT rel) AS rels;
It assumes that you provide the name of the table of interest (e.g., "TBL3") as the value of a table parameter. It also assumes that the relationships of interest all have the Foo type.
It first finds tc, the TBLCON node(s) containing that table name. It then uses a variable-length non-directional search for all paths (with non-repeating relationships) that include tc. It then uses COLLECT twice: to aggregate the list of nodes in each path, and to aggregate the list of relationships in each path. Each aggregation result would be a list of lists, so it uses REDUCE on each outer list to merge the inner lists. It then uses UNWIND and COLLECT(DISTINCT x) on each list to produce a list with unique elements.
[UPDATE]
If you differentiate between your relationships by type (rather than by property value), your Cypher code can be a lot simpler by taking advantage of APOC functions. The following query assumes that the desired relationship types are passed via a types parameter:
MATCH (tc:TBLCON)
WHERE $table IN tc.Tables
CALL apoc.path.subgraphAll(
tc, {relationshipFilter: apoc.text.join($types, '|')}) YIELD nodes, relationships
RETURN nodes, relationships;
WIth some lead from cybersam's response, the below query gets me what I want. Only constraint is, this result is limited to 3 layers (3rd layer through Optional Match)
MATCH (TC:TBLCON) WHERE 'TBL3' IN TC.Tables
CALL apoc.path.subgraphAll(TC, {maxLevel:1}) YIELD nodes AS invN, relationships AS invR
WITH TC, REDUCE (tmpL=[], tmpr IN invR | tmpL+type(tmpr)) AS impR
MATCH FLP=(TC)-[]-()-[FLR]-(SL) WHERE type(FLR) IN impR
WITH FLP, TC, SL,impR
OPTIONAL MATCH SLP=(SL)-[SLR]-() WHERE type(SLR) IN impR RETURN FLP,SLP
This works for my needs, hope this might also help someone.
Thanks everyone for the responses and suggestions
****Update****
Enhanced the query to get rid of Optional Match criteria and other given limitations
MATCH (initTC:TBLCON) WHERE $TL IN initTC.Tables
WITH Reduce(O="",OO in Reduce (I=[], II in collect(apoc.node.relationship.types(initTC)) | I+II) | O+OO+"|") as RF
MATCH (TC:TBLCON) WHERE $TL IN TC.Tables
CALL apoc.path.subgraphAll(TC,{relationshipFilter:RF}) YIELD nodes, relationships
RETURN nodes, relationships
Thanks all (especially cybersam)
I'm trying to delete a parent node from an xml document based on the value of a child node
Here's a really simplified example of what I'm looking at
<root>
<someactivity>
<id>123456789</id>
</someactivity>
</root>
What I'd like to be able to do using SQL Server / XQuery is to delete the entire 'someactivity' node and its contents by searching for the id of '123456789' in the child node 'id'.
So far I've got something like this:-
update mytablecontainingXMLcolumns
set xmldata.modify('delete //someactivity/id[text()][contains(.,"123456789")]')
but it's not working as I expected - only seems to be deleting the 'id' node. I'm stuck at this stage. Any help / guidance would be appreciated.
Modify your XPath/XQuery to be selecting the parent someactivity element instead of id :
update mytablecontainingXMLcolumns
set xmldata.modify('delete //someactivity[contains(id,"123456789")]')
or, if there can be multiple id elements within one someactivity and you want to delete the parent if, at least, one id matched :
update mytablecontainingXMLcolumns
set xmldata.modify('delete //someactivity[id[contains(.,"123456789")]]')
ClusterGroup clusterGroup = ignite.cluster().forNodeIds(invalidNodeIds)
final Map<IgniteUuid, ComputeTaskFuture<Object>> computeTaskFutures = ignite.compute(clusterGroup).activeTaskFutures();
when fictitious invalidNodeIds are passed in, even though the backing ClusterGroupAdapter has an empty node ids (Set ids) object, I see valid futures being returned. Isn't this wrong ?
Thanks
IgniteCompute.taskFutures() is local operation, i.e. it returns futures for tasks that were executed by the current node. Having said that, cluster group is not applicable to this method.