本文共 2052 字，大约阅读时间需要 6 分钟。

1.、数据导入

可以使用 LOAD CSV WITH HEADERS FROM “file:///Inventory.csv” AS row MERGE (s:Store {name: row.store}) WITH * MATCH (c:City {name: row.store}) MERGE (s)-[:IN_CITY]-© WITH * MATCH (p:Product {sku: row.sku}) MERGE §-[r:INVENTORY]->(s) SET r.count = toInt(row.number) RETURN *;

想用

call apoc.load.json("///reviews.json") YIELD value AS row MATCH (c:Customer {customerid: toString(row.customerid)}) MATCH (p:Product {sku: toString(row.sku)}) MERGE ©-[r:REVIEWED]->§ SET r.rating = round(toFloat(row.review)) RETURN *; 必须先开启 apoc.import.file.enabled=true

社区发现

解析： “CALL algo.unionFind(label:String, relationship:String, {weightProperty:‘weight’, threshold:0.42, defaultValue:1.0, write: true, partitionProperty:‘partition’}) YIELD nodes, setCount, loadMillis, computeMillis, writeMillis” 输入的为 label 节点类别；relationship 关系类别 可选输入 weightProperty 权重属性 threshold 边界值 defaultValue 默认值，当属性为空时的填充 返回 nodes 节点

CALL algo.unionFind.stream(‘User’, ‘FRIEND’, {weightProperty:‘weight’,

defaultValue:0.0, threshold:1.0, concurrency: 1}) YIELD nodeId,setId RETURN algo.getNodeById(nodeId).id AS user, setId

threshold 门槛 边界

concurrency 并发性

删除全部数据

match (n) detach delete n

查看数据结构

call apoc.meta.graph == call db.schema()

with语句

使用with语句进行聚合过滤查询,示例: MATCH (n {name:“John”})-[:friend]-(friend) WITH n, count(friend) as friendsCount WHERE friendsCount>3 RETURN n, friendsCount

使用with语句进行聚合更新,示例:

MATCH (n {name:‘John’})-[:friend]-(friend) WITH n,count(friend) as friendsCount SET n.friendsCount = friendsCount RETURN n.friendsCount

//collect()将所有满足值聚集在一个列表中

match (p:Person)-[:ACTED_IN]->(m:Movie) with p, count(*) as appearances, collect(m.title) as movies where appearances > 1 return , appearances, movies

optinal match 类似于match ,不同之处在于 如果没有匹配到optinal match将用null作为未匹配到不分的值.

可以理解为mysql中的inner join 如果没有就用null.

查看数据库的图算法

CALL dbms.procedures() YIELD name, signature, description WHERE name starts with “algo” RETURN name, signature, description

查看APOC

CALL dbms.procedures() YIELD name, signature, description WHERE name starts with “apoc” RETURN name, signature, description

转载地址：http://wzru.baihongyu.com/