Question

我的Neo4j实例中填充了来自当地大学的完整校友数据集。一小部分（15K）的（248K）节点（n：Alumni）包含一个twitter user_name。我的目标是使用GITHUB应用程序（TWIITER到NEO4J）加载和链接twitter screenNames以获取关系数据。我的问题是下面的查询（包含在GITHUB应用程序的java脚本中）Cypher创建了与Alumni screen_name不匹配的不需要的Follower / Following节点。我想写一个只允许从应用程序创建关系的查询。让我知道这是否更清楚......

MERGE (targetNode:Person {screen_name: {screenName}})
FOREACH (friend in {userList} |
MERGE (friendNode:Person {screen_name: friend.screen_name})
ON CREATE SET friendNode=friend
MERGE (targetNode)-[:FOLLOWS]->(friendNode))

这是我的想法 - 我将MERGE设置为MATCH Alumni

MATCH (targetNode:Alumni {screen_name: {screenName}})
WHERE targetNode:Alumni.screen_name = {screen_name} 
FOREACH (friend in {userList} |
MATCH (friendNode:Alumni {screen_name: friend.screen_name})
SET friendNode=friend
MERGE (targetNode)-[:FOLLOWS]->(friendNode))

感谢您的任何想法...

var multiline = require('multiline');

exports.upsertOne = multiline(function(){/*
  MERGE (n:Person {screen_name: {screenName}})
  ON CREATE SET n+={userMap}
  RETURN n
*/});

/*
 * Parameters are:
 *
 * screenName - string, the handle of the person to attach followers to
 * userList - array of objects, people to merge and create relationships
 */
exports.upsertManyAndFollows = multiline(function() {/*
  MATCH (followeeNode:Alumni {screen_name: {screenName}}) 
  UNWIND {userList} as follower 
    MATCH (followerNode:Alumni {screen_name: follower.screen_name})
    SET followerNode=follower
    MERGE (followerNode)-[:FOLLOWS]->(followeeNode)
*/});


/*
 * Parameters are:
 *
 * screenName - string, the handle of the person to attach followers to
 * userList - array of objects, people to merge and create relationships
 */
exports.upsertManyAndFriends = multiline(function() {/*
  MATCH (targetNode:Person {screen_name: {screenName}})
  UNWIND {userList} as friend
    MATCH (friendNode:Person {screen_name: friend.screen_name})
    SET friendNode=friend
    MERGE (targetNode)-[:FOLLOWS]->(friendNode)
*/});

/*
 * Parameters are:
 *
 * screenName - string, the handle of the person that is at the center of the graph.
 * 
 */

Answer 1

您可以尝试使用此功能，但请确保使用正确的屏幕名称（查询中同时包含{screenName}和{screen_name}，因此其中一个错误）。

如果你的：已经创建了校友节点，这应该可行。

MATCH (targetNode:Alumni {screen_name: {screenName}})
UNWIND {userList} as friend
MATCH (friendNode:Alumni {screen_name: friend.screen_name})
SET friendNode=friend
MERGE (targetNode)-[:FOLLOWS]->(friendNode)

需要匹配而不是MERGE

1 个答案: