我在Neo4j中有一些让我感到困惑的行为。我有一个用Java创建的小型嵌入式网络。以下cypher查询说明了问题。
neo4j-sh (?)$ match (n) return n._id,labels(n);
+------------------------------------------------------------------------------------------------------------+
| n._id | labels(n) |
+------------------------------------------------------------------------------------------------------------+
| "/Users/simonshapiro/NetBeansProjects/XMLTest/src/xmltest/media/project.xml" | ["IdentityNode","Pedigree"] |
| <null> | ["StateNode"] |
| <null> | ["StateNode"] |
| "iqaS5pKAUBxk5wOW" | ["IdentityNode","MetaNode"] |
| <null> | ["StateNode"] |
| "2ahS5pKAUBxk5wOv" | ["IdentityNode","MetaNode"] |
| <null> | ["StateNode"] |
| "N3jS5pKAUBxk5wPJ" | ["IdentityNode","MetaNode"] |
| <null> | ["StateNode"] |
| "btoC1pKAUBxk5wQu" | ["IdentityNode","MetaNode"] |
| <null> | ["StateNode"] |
+------------------------------------------------------------------------------------------------------------+
但是尝试在标签上过滤如下所示不会产生任何结果。
neo4j-sh (?)$ match (n:MetaNode) return n._id,labels(n);
+-------------------+
| n._id | labels(n) |
+-------------------+
+-------------------+
0 row
9 ms