1.使用关键字INDEX ON为节点的属性name创建一个普通的索引
CREATE INDEX ON :Person(name)
输出：
Added 1 index, completed after 46 ms.
2.使用索引来查询
MATCH (n:Person) WHERE n.name IN ["a","b"] RETURN n as Person
得到图：
3.显式使用索引查询
MATCH(n:Person)
USING INDEX n:Person(name)
WHERE n.name = 'a'
RETURN n as Person
4.用DROP关键字删除一个已经存在的索引
DROP INDEX ON :Person(name)
Removed 1 index, completed after 1 ms.
