Databases Reference
In-Depth Information
CREATE
(reply_1 {
id
:
'7'
, content:
'response'
}),
(reply_1)-[:REPLY_TO]->(email_6),
(davina)-[:SENT]->(reply_1),
(reply_1)-[:TO]->(bob),
(reply_1)-[:TO]->(charlie);
CREATE
(reply_2 {
id
:
'8'
, content:
'response'
}),
(reply_2)-[:REPLY_TO]->(email_6),
(bob)-[:SENT]->(reply_2),
(reply_2)-[:TO]->(davina),
(reply_2)-[:TO]->(charlie),
(reply_2)-[:CC]->(alice);
CREATE
(reply_3 {
id
:
'9'
, content:
'response'
}),
(reply_3)-[:REPLY_TO]->(reply_1),
(charlie)-[:SENT]->(reply_3),
(reply_3)-[:TO]->(bob),
(reply_3)-[:TO]->(davina);
CREATE
(reply_4 {
id
:
'10'
, content:
'response'
}),
(reply_4)-[:REPLY_TO]->(reply_3),
(bob)-[:SENT]->(reply_4),
(reply_4)-[:TO]->(charlie),
(reply_4)-[:TO]->(davina);
This creates the graph in
Figure 3-12
, which shows numerous replies and replies-to-
replies.
Now it is easy to see who replied to Bob's original email. First locate the email of interest,
then match against all incoming
REPLY_TO
relationships (there may be multiple replies),
and from there match against incoming
SENT
relationships: this reveals the sender(s).
In Cypher this is simple to express. In fact, Cypher makes it easy to look for replies-to-
replies-to-replies, and so on to an arbitrary depth (though we limit it to depth four here):
START
email =
node
:email(
id
=
'6'
)
MATCH
p=(email)<-[:REPLY_TO*1..4]-()<-[:SENT]-(replier)
RETURN
replier.username
AS
replier,
length
(p) - 1
AS
depth
ORDER BY
depth
