我正在测试性能neo4j与OrientDB图形DB。我正在使用neo4j网站上提供的MoiveDatabase数据集。我按照说明操作了：
D:/这是export-graphml -t -o /tmp/out.graphml
CREATE DATABASE plocal:/tmp/db/test
IMPORT DATABASE /tmp/out.graphml storeVertexIds=true
输出，所以我猜导入没问题。
classes但是当我尝试执行此查询时：
CLASSES
----------------------+------------------------------------+------------+----------------+
NAME | SUPERCLASS | CLUSTERS | RECORDS |
----------------------+------------------------------------+------------+----------------+
ACTS_IN | [E] | 14 | 94700 |
DIRECTED | [E] | 13 | 11915 |
E | | 10 | 0 |
FRIEND | [E] | 16 | 6 |
Movie | [V] | 12 | 6379 |
OFunction | | 6 | 0 |
OIdentity | | - | 0 |
ORestricted | | - | 0 |
ORIDs | | 8 | 0 |
ORole | [OIdentity] | 4 | 3 |
OSchedule | | 7 | 0 |
OTriggered | | - | 0 |
OUser | [OIdentity] | 5 | 3 |
Person | [V] | 11 | 50013 |
RATED | [E] | 15 | 30 |
V | | 9 | 61752 |
----------------------+------------------------------------+------------+----------------+
TOTAL = 16 224801 |
----------------------+------------------------------------+------------+----------------+
或SELECT in() FROM Movie LIMIT 10我没有得到任何记录。那是为什么？
我正在尝试重写共同演员查询：
SELEC out() FROM Person LIMIT 10和“共同演员”查询：
MATCH (tom:Person {name:"Tom Hanks"})-[:ACTED_IN]->(:Movie)<-[:ACTED_IN]-(coActor:Person)
RETURN coActor.name
我应该使用MATCH (tom:Person)-[:ACTED_IN]->(movie1)<-[:ACTED_IN]-(coActor:Person),
(coActor)-[:ACTED_IN]->(movie2)<-[:ACTED_IN]-(coCoActor:Person)
WHERE tom.name = "Tom Hanks" AND NOT (tom)-[:ACTED_IN]->(movie2)
RETURN coCoActor.name
吗？
答案 0 :(得分：2)
我创建了这个小数据库来试试你的情况：
create class Person extends V
create class Movie extends V
create class acts_In extends E
create class directed extends E
create class friend extends E
create class rated extends E
create property Person.name String
create property Person.surname String
create property Movie.title String
create vertex Person set name="Tom", surname="Hanks"
create vertex Person set name="Robin", surname="Wright"
create vertex Person set name="Helen", surname="Hunt"
create vertex Person set name="Robert", surname="Zemeckis"
create vertex Person set name="Russell", surname="Crowe"
create vertex Person set name="Ben", surname="Affleck"
create vertex Person set name="Kevin", surname="Macdonald"
create vertex Person set name="John"
create vertex Person set name="Mark"
create vertex Person set name="Paul"
create vertex Person set name="Mel", surname="Gibson"
create vertex Person set name="Nancy", surname="Meyers"
create vertex Movie set title="Forrest Gump"
create vertex Movie set title="Cast Away"
create vertex Movie set title="State of Play"
create vertex Movie set title="What Women Want"
create edge acts_In from (select from Person where name="Tom" and surname="Hanks") to (select from Movie where title="Forrest Gump")
create edge acts_In from (select from Person where name="Tom" and surname="Hanks") to (select from Movie where title="Cast Away")
create edge acts_In from (select from Person where name="Robin" and surname="Wright") to (select from Movie where title="Forrest Gump")
create edge acts_In from (select from Person where name="Robin" and surname="Wright") to (select from Movie where title="State of Play")
create edge acts_In from (select from Person where name="Helen" and surname="Hunt") to (select from Movie where title="Cast Away")
create edge acts_In from (select from Person where name="Helen" and surname="Hunt") to (select from Movie where title="What Women Want")
create edge acts_In from (select from Person where name="Mel" and surname="Gibson") to (select from Movie where title="What Women Want")
create edge acts_In from (select from Person where name="Russell" and surname="Crowe") to (select from Movie where title="State of Play")
create edge acts_In from (select from Person where name="Ben" and surname="Affleck") to (select from Movie where title="State of Play")
create edge friend from (select from Person where name="Mel" and surname="Gibson") to (select from Person where name="Helen" and surname="Hunt")
create edge friend from (select from Person where name="Ben" and surname="Affleck") to (select from Person where name="Russell" and surname="Crowe")
create edge directed from (select from Movie where title="What Women Want") to (select from Person where name="Nancy" and surname="Meyers")
create edge directed from (select from Movie where title="Cast Away") to (select from Person where name="Robert" and surname="Zemeckis")
create edge directed from (select from Movie where title="Forrest Gump") to (select from Person where name="Robert" and surname="Zemeckis")
create edge directed from (select from Movie where title="State of Play") to (select from Person where name="Kevin" and surname="Macdonald")
create edge rated from (select from Movie where title="What Women Want") to (select from Person where name="Paul")
create edge rated from (select from Movie where title="Cast Away") to (select from Person where name="John")
create edge rated from (select from Movie where title="Forrest Gump") to (select from Person where name="Mark")
create edge rated from (select from Movie where title="State of Play") to (select from Person where name="John")
第一次查询：找到Tom Hanks的合作演员
select distinct(name) as name, distinct(surname) as surname from (select expand(in('acts_In')) from Movie where in('acts_In').name in 'Tom'
and in('acts_In').surname in 'Hanks') where name<>'Tom' and in('acts_In').surname<>'Hanks'
<强>输出：
----+------+-----+-------
# |@CLASS|name |surname
----+------+-----+-------
0 |null |Robin|Wright
1 |null |Helen|Hunt
----+------+-----+-------
第二次查询：找到汤姆汉克斯没有加星标的合作演员
select name, surname from (select expand($ris)
let $a=(select from Person where out('acts_In').size()>0 and name<>'Tom' and surname<>'Hanks'),
$b=(select from (select expand(in('acts_In')) from Movie where in('acts_In').name in 'Tom' and in('acts_In').surname in 'Hanks') where name<>'Tom' and in('acts_In').surname<>'Hanks'),
$ris=difference($a,$b))
<强>输出：
----+------+-------+-------
# |@CLASS|name |surname
----+------+-------+-------
0 |null |Russell|Crowe
1 |null |Ben |Affleck
2 |null |Mel |Gibson
----+------+-------+-------
希望有所帮助