![22
Concept Chasm
USERS TALK ABOUT…
! Application entities
! e.g. discussions, topics,
communities, etc.
! Likely multiple
abstraction levels
BASE DATA CONTAINS…
! Fine granular data
! Low abstraction
! E.g. individual
twitter messages,
retweet relationships,
etc.
e.g. discussions, topics,
communities, etc.
Likely multiple
levels
CONTAINS
Fine granular data
Low abstraction
[Martin Grandjean, https://commons.wikimedia.org/wiki/File:Social_Network_Analysis_Visualization.png, 2014]
communities, etc.
levels
CONTAINS…
Fine granular data
Low abstraction [http://nodexlgraphgallery.org/Pages/Graph.aspx?graphID=70790]
Query
language
main means
to bridge
concept
chasm
Users talk in high level concepts ! Data captured in low level concepts
" Concept chasm](https://image.slidesharecdn.com/virtualgraphsgraphviewsincypher-180115150609/85/Virtual-Graphs-Graph-Views-in-Cypher-2-320.jpg)
![3
Base data
What do you need?
1. LET USER CREATE ABSTRACT GRAPHS
! Nodes and relationships not present in the base data
but derived from base data
1
2
3
4
5
6 7
8
[:FRIENDS]
MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1)
CREATE VIRTUAL (t:FriendsTriangle)-[:CONTAINS]->(p1),
(t)-[:CONTAINS]->(p2),
(t)-[:CONTAINS]->(p3)
MATCH (t1)-[:CONTAINS]->()<-[:CONTAINS]-(t2)
-[:CONTAINS]->()<-[:CONTAINS]-(t1)
CREATE VIRTUAL (t1)-[:CONNECTED]->(t2)
[:CONTAINS]
[:CONNECTED]
1
2 3
4](https://image.slidesharecdn.com/virtualgraphsgraphviewsincypher-180115150609/85/Virtual-Graphs-Graph-Views-in-Cypher-3-320.jpg)
![4
Base data
What do you need?
1. LET USER CREATE ABSTRACT GRAPHS
! Nodes and relationships not present in the base data
but derived from base data
1
3
4
5
7
8
[:FRIENDS]
5
MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1)
CREATE VIRTUAL (t:FriendsTriangle)-[:CONTAINS]->(p1),
(t)-[:CONTAINS]->(p2),
(t)-[:CONTAINS]->(p3)
MATCH (t1)-[:CONTAINS]->()<-[:CONTAINS]-(t2)
-[:CONTAINS]->()<-[:CONTAINS]-(t1)
CREATE VIRTUAL (t1)-[:CONNECTED]->(t2)
[:CONTAINS]
MATCH (pa)<-[:CONTAINS]-(ta),
tp=shortestPath((ta)-[:CONNECTED*]->(tb)),
(tb)-[:CONTAINS]->(pb)
RETURN pa, pb, length(tp)+1 AS triangleDist
pa pb triangleDist
2 6 3
! ! !
[:CONNECTED]
,
1
2 3
4
[:FRIENDS]
2
6](https://image.slidesharecdn.com/virtualgraphsgraphviewsincypher-180115150609/85/Virtual-Graphs-Graph-Views-in-Cypher-4-320.jpg)
![5
What do you need?
2. LET USER MODULARIZE AND REUSE (SUB)-QUERIES WITH VIEWS
! Create view
! Use view
! Use multiple
views
IN VIEW friendsTriangles { MATCH (p)<-[:CONTAINS]-(t) }
RETURN p, count(t) AS numTriangles
ORDER BY numTriangles DESC LIMIT 10
CREATE VIEW friendsTriangles {
MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1)
CREATE VIRTUAL (t:FriendsTriangle)-[e1:CONTAINS]->(p1),
(t)-[e2:CONTAINS]->(p2),
(t)-[e3:CONTAINS]->(p3)
SAVE t,e1,e2,e3,p1,p2,p3
}
IN VIEW friendsTriangles, connected, ALL { //ALL is base data
MATCH (t1)-[:CONTAINS]->(p)<-[:CONTAINS]-(t2)
-[:CONTAINS]->(q1)-[:KNOWS]-(q2)<-[:CONTAINS]-(t2)
WHERE NOT (t1)-[:CONNECTED]-(t2)
}
RETURN t1,t2,q1,q2](https://image.slidesharecdn.com/virtualgraphsgraphviewsincypher-180115150609/85/Virtual-Graphs-Graph-Views-in-Cypher-5-320.jpg)
Virtual Graphs & Graph Views in Cypher
- 1. Virtual Graphs & Graph Views in Cypher Sascha Peukert1, Hannes Voigt1, Michael Hunger2 1TU Dresden 2Neo Technology
- 2. 22 Concept Chasm USERS TALK ABOUT… ! Application entities ! e.g. discussions, topics, communities, etc. ! Likely multiple abstraction levels BASE DATA CONTAINS… ! Fine granular data ! Low abstraction ! E.g. individual twitter messages, retweet relationships, etc. e.g. discussions, topics, communities, etc. Likely multiple levels CONTAINS Fine granular data Low abstraction [Martin Grandjean, https://commons.wikimedia.org/wiki/File:Social_Network_Analysis_Visualization.png, 2014] communities, etc. levels CONTAINS… Fine granular data Low abstraction [http://nodexlgraphgallery.org/Pages/Graph.aspx?graphID=70790] Query language main means to bridge concept chasm Users talk in high level concepts ! Data captured in low level concepts " Concept chasm
- 3. 3 Base data What do you need? 1. LET USER CREATE ABSTRACT GRAPHS ! Nodes and relationships not present in the base data but derived from base data 1 2 3 4 5 6 7 8 [:FRIENDS] MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1) CREATE VIRTUAL (t:FriendsTriangle)-[:CONTAINS]->(p1), (t)-[:CONTAINS]->(p2), (t)-[:CONTAINS]->(p3) MATCH (t1)-[:CONTAINS]->()<-[:CONTAINS]-(t2) -[:CONTAINS]->()<-[:CONTAINS]-(t1) CREATE VIRTUAL (t1)-[:CONNECTED]->(t2) [:CONTAINS] [:CONNECTED] 1 2 3 4
- 4. 4 Base data What do you need? 1. LET USER CREATE ABSTRACT GRAPHS ! Nodes and relationships not present in the base data but derived from base data 1 3 4 5 7 8 [:FRIENDS] 5 MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1) CREATE VIRTUAL (t:FriendsTriangle)-[:CONTAINS]->(p1), (t)-[:CONTAINS]->(p2), (t)-[:CONTAINS]->(p3) MATCH (t1)-[:CONTAINS]->()<-[:CONTAINS]-(t2) -[:CONTAINS]->()<-[:CONTAINS]-(t1) CREATE VIRTUAL (t1)-[:CONNECTED]->(t2) [:CONTAINS] MATCH (pa)<-[:CONTAINS]-(ta), tp=shortestPath((ta)-[:CONNECTED*]->(tb)), (tb)-[:CONTAINS]->(pb) RETURN pa, pb, length(tp)+1 AS triangleDist pa pb triangleDist 2 6 3 ! ! ! [:CONNECTED] , 1 2 3 4 [:FRIENDS] 2 6
- 5. 5 What do you need? 2. LET USER MODULARIZE AND REUSE (SUB)-QUERIES WITH VIEWS ! Create view ! Use view ! Use multiple views IN VIEW friendsTriangles { MATCH (p)<-[:CONTAINS]-(t) } RETURN p, count(t) AS numTriangles ORDER BY numTriangles DESC LIMIT 10 CREATE VIEW friendsTriangles { MATCH (p1)-[:FRIENDS]-(p2)-[:FRIENDS]-(p3)-[:FRIENDS]-(p1) CREATE VIRTUAL (t:FriendsTriangle)-[e1:CONTAINS]->(p1), (t)-[e2:CONTAINS]->(p2), (t)-[e3:CONTAINS]->(p3) SAVE t,e1,e2,e3,p1,p2,p3 } IN VIEW friendsTriangles, connected, ALL { //ALL is base data MATCH (t1)-[:CONTAINS]->(p)<-[:CONTAINS]-(t2) -[:CONTAINS]->(q1)-[:KNOWS]-(q2)<-[:CONTAINS]-(t2) WHERE NOT (t1)-[:CONNECTED]-(t2) } RETURN t1,t2,q1,q2
- 6. 6 Summary VIEWS ARE AWESOME FOR ! Query modularization ! Reuse of query concepts ! Employing Need to Know for applications (fine-grained access control) ! Performance tuning (with materialized views) OUR CURRENT IMPLEMENTATION IN NEO4J ! Two specializations of the OperationsFacade for handling virtual entities and views ! VirtualEntitiesFacade create entities internally and discards them after end of transaction ! ViewFacade - Keeps list of node and relationship id that are part of the view - Filter queries on views are execution on base data for results that are part of the view GOAL: TRUE CYPHER QUERY REWRITE grained access control)