apoc.convert.toTree
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此过程已被 apoc.paths.toJsonTree 废弃。 |
语法 |
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描述 |
返回 |
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输入参数 |
名称 |
类型 |
描述 |
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要转换为树的路径列表。 |
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是否将关系类型转换为小写。默认值为： |
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返回参数 |
名称 |
类型 |
描述 |
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结果树。 |
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配置参数
此过程支持以下配置参数
| 名称 | 类型 | 默认值 | 描述 |
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{} |
每个节点标签要包含或排除的属性，例如包含 |
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{} |
每个关系类型要包含或排除的属性，例如包含 |
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true |
按路径长度对结果进行排序。 |
apoc.convert.toTree 和 apoc.paths.toJsonTree 之间的差异
apoc.convert.toTree 和 apoc.paths.toJsonTree 之间存在一些显著差异。
在简单情况下，这两个过程产生相同的输出。然而，当引入循环时，它们的行为会发生分歧。已废弃的 apoc.convert.toTree 在出现循环时会覆盖自身，提供不正确和误导性的信息。而较新的 apoc.paths.toJsonTree 则会考虑这些循环。
例如，考虑以下路径
(:A)-[:REL]->(:B)
(:A)-[:REL]->(:C)
(:B)-[:REL]->(:C)
(:B)-[:REL]->(:B)
(:C)-[:REL]->(:A)apoc.convert.toTree 将输出 3 条记录MATCH path = ()-[]->()
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths)
YIELD value
RETURN value简化输出
(:A)
(:B)
(:C)-[:REL]->(:A)apoc.paths.toJsonTree 将输出 1 条记录MATCH path = ()-[]->()
WITH collect(path) AS paths
CALL apoc.paths.toJsonTree(paths)
YIELD value
RETURN value简化输出
(:A)-[:REL]->(:B)-[:REL]->(:B)
->(:C)
->(:C)-[:REL]->(:A)用法示例
本节中的示例基于以下样本图
CREATE (Keanu:Person {name:'Keanu Reeves', born:1964})
CREATE (TomH:Person {name:'Tom Hanks', born:1956})
CREATE (TomT:Person {name:'Tom Tykwer', born:1965})
CREATE (JamesThompson:Person {name:'James Thompson'})
CREATE (TheMatrix:Movie {title:'The Matrix', released:1999, tagline:'Welcome to the Real World'})
CREATE (TheMatrixReloaded:Movie {title:'The Matrix Reloaded', released:2003, tagline:'Free your mind'})
CREATE (TheMatrixRevolutions:Movie {title:'The Matrix Revolutions', released:2003, tagline:'Everything that has a beginning has an end'})
CREATE (SomethingsGottaGive:Movie {title:"Something's Gotta Give", released:2003})
CREATE (TheDevilsAdvocate:Movie {title:"The Devil's Advocate", released:1997, tagline:'Evil has its winning ways'})
CREATE (YouveGotMail:Movie {title:"You've Got Mail", released:1998, tagline:'At odds in life... in love on-line.'})
CREATE (SleeplessInSeattle:Movie {title:'Sleepless in Seattle', released:1993, tagline:'What if someone you never met, someone you never saw, someone you never knew was the only someone for you?'})
CREATE (ThatThingYouDo:Movie {title:'That Thing You Do', released:1996, tagline:'In every life there comes a time when that thing you dream becomes that thing you do'})
CREATE (CloudAtlas:Movie {title:'Cloud Atlas', released:2012, tagline:'Everything is connected'})
CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrix)
CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrixReloaded)
CREATE (Keanu)-[:ACTED_IN {roles:['Neo']}]->(TheMatrixRevolutions)
CREATE (Keanu)-[:ACTED_IN {roles:['Julian Mercer']}]->(SomethingsGottaGive)
CREATE (Keanu)-[:ACTED_IN {roles:['Kevin Lomax']}]->(TheDevilsAdvocate)
CREATE (TomH)-[:ACTED_IN {roles:['Joe Fox']}]->(YouveGotMail)
CREATE (TomH)-[:ACTED_IN {roles:['Sam Baldwin']}]->(SleeplessInSeattle)
CREATE (TomH)-[:ACTED_IN {roles:['Mr. White']}]->(ThatThingYouDo)
CREATE (TomH)-[:ACTED_IN {roles:['Zachry', 'Dr. Henry Goose', 'Isaac Sachs', 'Dermot Hoggins']}]->(CloudAtlas)
CREATE (TomT)-[:DIRECTED]->(CloudAtlas)
CREATE (JamesThompson)-[:REVIEWED {summary:'Enjoyed it!', rating:95}]->(TheMatrix)
CREATE (JamesThompson)-[:REVIEWED {summary:'It was alright.', rating:65}]->(TheMatrixReloaded)
CREATE (JamesThompson)-[:REVIEWED {summary:'The best of the three', rating:100}]->(TheMatrixRevolutions);以下将基努·里维斯电影的路径列表转换为嵌套映射
MATCH path = (p:Person {name: "Keanu Reeves"})-[:ACTED_IN]->(movie)
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths)
YIELD value
RETURN value;| value |
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默认情况下，关系类型会转换为小写。要保留原始大小写，请将第二个参数（lowerCaseRels）设置为 false
MATCH path = (p:Person {name: "Keanu Reeves"})-[:ACTED_IN]->(movie)
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths, false)
YIELD value
RETURN value;| value |
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默认情况下，节点标签和关系类型的所有属性都包含在内。要限制节点的属性，请使用 nodes 配置键。对于关系类型，请使用 rels 配置键。
以下查询演示了如何通过设置 nodes 配置键来仅返回 Movie 节点的 title 属性
MATCH path = (p:Person {name: "Keanu Reeves"})-[:ACTED_IN]->(movie)
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths, true, {
nodes: {Movie: ['title']}
})
YIELD value
RETURN value;| value |
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以下查询演示了如何仅返回 James Thompson 评论的 REVIEWED rating 以及 Movie 节点的 title
MATCH path = (p:Person {name:'James Thompson'})-[:REVIEWED]->(movie)
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths, true, {
nodes: {Movie: ['title']},
rels: {reviewed: ['rating']}
})
YIELD value
RETURN value;| value |
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也可以通过在属性前加上减号（-）来明确排除某些属性。以下查询演示了如何排除 Movie 节点上的 title 属性和 REVIEWED 关系上的 rating 属性。
MATCH path = (p:Person {name:'James Thompson'})-[:REVIEWED]->(movie)
WITH collect(path) AS paths
CALL apoc.convert.toTree(paths, true, {
nodes: {Movie: ['-title']},
rels: {reviewed: ['-rating']}
})
YIELD value
RETURN value;| value |
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