Neo4J Cypher 查询创建的链接比预期的多
Neo4J Cypher query creates more links than expected
在下面的查询中（我从网上找到的一个修改而来）。我正在使用 APOC 创建 14 个节点，而我认为是 12 个边（将每个节点连接成两行）。 IE。如果你取 14 个节点，然后放入两列，每列 7 个项目，你只需要 6 行将它们连接在一起。
无论如何，代码正在使用 APOC 读取 JSON 文件，并且它正在完全按照预期创建节点。但是我得到了 79 个边。肯定有关于 CYPHER 或 UNWIND 的东西我不明白。
你可以清楚地看到，在JSON文件中，我的管道数组中只有12个对象。
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes
UNWIND nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
WITH row
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
{
"graph" : {
"nodes" : [{
"id" : "HW.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "HW.SCIM",
"partition" : "Hardware",
"CSC" : "HW",
"name" : "SCIM",
"rate" : 10,
"caption" : "SCIM"
}
}, {
"id" : "HW.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "HW.GPS",
"partition" : "Hardware",
"CSC" : "HW",
"name" : "GPS",
"rate" : 50,
"caption" : "GPS"
}
}, {
"id" : "HW.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "HW.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "HW.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "HW.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "Platform.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "Platform.SCIM",
"partition" : "Platform",
"CSC" : "Platform",
"name" : "SCIM",
"rate" : 10,
"caption" : "Platform SCIM"
}
}, {
"id" : "Platform.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "Platform.GPS",
"partition" : "Platform",
"CSC" : "Platform",
"name" : "GPS",
"rate" : 50,
"caption" : "Platform GPS"
}
}, {
"id" : "Platform.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "Platform.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "Platform.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "Platform.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "ALFSW.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "ALFSW.SCIM",
"partition" : "Application",
"CSC" : "Application",
"name" : "SCIM",
"rate" : 10,
"caption" : "App SCIM"
}
}, {
"id" : "ALFSW.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "ALFSW.GPS",
"partition" : "Application",
"CSC" : "Application",
"name" : "GPS",
"rate" : 50,
"caption" : "App GPS"
}
}, {
"id" : "ALFSW.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "ALFSW.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "ALFSW.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "ALFSW.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "GNC.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "GNC.SCIM",
"partition" : "GNC",
"CSC" : "MediumRate",
"name" : "SCIM",
"rate" : 10,
"caption" : "GNC Medium Rate"
}
}, {
"id" : "GNC.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "GNC.GPS",
"partition" : "GNC",
"CSC" : "HighRate",
"name" : "GPS",
"rate" : 50,
"caption" : "GNC High Rate"
}
}
],
"pipes" : [{
"type" : "Pipe",
"start" : "HW.SCIM",
"end" : "HW.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "HW.GPS",
"end" : "HW.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "Platform.SCIM",
"end" : "HW.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "Platform.GPS",
"end" : "HW.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "Platform.SCIM",
"end" : "Platform.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "Platform.GPS",
"end" : "Platform.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.SCIM",
"end" : "Platform.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.GPS",
"end" : "Platform.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.SCIM",
"end" : "ALFSW.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.GPS",
"end" : "ALFSW.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "GNC.SCIM",
"end" : "ALFSW.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "GNC.GPS",
"end" : "ALFSW.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}
]
}
}
我认为那是因为你在 UNWIND 内部有 UNWIND，所以它经历第二次展开 x 次，其中 x 是第一个数组大小的值。就像在 FOR loop.Try 中有一个 FOR 循环将其分成两个查询。
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes
UNWIND nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
RETURN *
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
编辑：一步完成 // 无效
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes,row.graph.pipes AS rel
FOREACH (node in nodes |
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n)
WITH row,rel
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
UNWIND row.graph.nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
// aggregation or distinct reduces cardinality to 1 per row again
WITH row, count(*)
UNWIND row.graph.pipes AS rel
// you should use labels here, otherwise you get no lookup benefits
// from indexes, even if you just use a generic :Node label
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
在下面的查询中（我从网上找到的一个修改而来）。我正在使用 APOC 创建 14 个节点，而我认为是 12 个边（将每个节点连接成两行）。 IE。如果你取 14 个节点，然后放入两列，每列 7 个项目，你只需要 6 行将它们连接在一起。
无论如何，代码正在使用 APOC 读取 JSON 文件，并且它正在完全按照预期创建节点。但是我得到了 79 个边。肯定有关于 CYPHER 或 UNWIND 的东西我不明白。
你可以清楚地看到，在JSON文件中，我的管道数组中只有12个对象。
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes
UNWIND nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
WITH row
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
{
"graph" : {
"nodes" : [{
"id" : "HW.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "HW.SCIM",
"partition" : "Hardware",
"CSC" : "HW",
"name" : "SCIM",
"rate" : 10,
"caption" : "SCIM"
}
}, {
"id" : "HW.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "HW.GPS",
"partition" : "Hardware",
"CSC" : "HW",
"name" : "GPS",
"rate" : 50,
"caption" : "GPS"
}
}, {
"id" : "HW.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "HW.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "HW.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "HW.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "Platform.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "Platform.SCIM",
"partition" : "Platform",
"CSC" : "Platform",
"name" : "SCIM",
"rate" : 10,
"caption" : "Platform SCIM"
}
}, {
"id" : "Platform.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "Platform.GPS",
"partition" : "Platform",
"CSC" : "Platform",
"name" : "GPS",
"rate" : 50,
"caption" : "Platform GPS"
}
}, {
"id" : "Platform.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "Platform.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "Platform.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "Platform.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "ALFSW.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "ALFSW.SCIM",
"partition" : "Application",
"CSC" : "Application",
"name" : "SCIM",
"rate" : 10,
"caption" : "App SCIM"
}
}, {
"id" : "ALFSW.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "ALFSW.GPS",
"partition" : "Application",
"CSC" : "Application",
"name" : "GPS",
"rate" : 50,
"caption" : "App GPS"
}
}, {
"id" : "ALFSW.SCIM-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "ALFSW.SCIM-Channel",
"wordLength" : 300,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "ALFSW.GPS-Channel",
"labels" : [
"Channel"
],
"properties" : {
"key" : "ALFSW.GPS-Channel",
"wordLength" : 200,
"channelType" : "Partition",
"timeStamp" : "",
"writer" : ""
}
}, {
"id" : "GNC.SCIM",
"labels" : [
"Actor"
],
"properties" : {
"key" : "GNC.SCIM",
"partition" : "GNC",
"CSC" : "MediumRate",
"name" : "SCIM",
"rate" : 10,
"caption" : "GNC Medium Rate"
}
}, {
"id" : "GNC.GPS",
"labels" : [
"Actor"
],
"properties" : {
"key" : "GNC.GPS",
"partition" : "GNC",
"CSC" : "HighRate",
"name" : "GPS",
"rate" : 50,
"caption" : "GNC High Rate"
}
}
],
"pipes" : [{
"type" : "Pipe",
"start" : "HW.SCIM",
"end" : "HW.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "HW.GPS",
"end" : "HW.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "Platform.SCIM",
"end" : "HW.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "Platform.GPS",
"end" : "HW.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "Platform.SCIM",
"end" : "Platform.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "Platform.GPS",
"end" : "Platform.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.SCIM",
"end" : "Platform.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.GPS",
"end" : "Platform.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.SCIM",
"end" : "ALFSW.SCIM-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "ALFSW.GPS",
"end" : "ALFSW.GPS-Channel",
"properties" : {
"flow" : "OUT"
}
}, {
"type" : "Pipe",
"start" : "GNC.SCIM",
"end" : "ALFSW.SCIM-Channel",
"properties" : {
"flow" : "IN"
}
}, {
"type" : "Pipe",
"start" : "GNC.GPS",
"end" : "ALFSW.GPS-Channel",
"properties" : {
"flow" : "IN"
}
}
]
}
}
我认为那是因为你在 UNWIND 内部有 UNWIND，所以它经历第二次展开 x 次，其中 x 是第一个数组大小的值。就像在 FOR loop.Try 中有一个 FOR 循环将其分成两个查询。
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes
UNWIND nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
RETURN *
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
编辑：一步完成 // 无效
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
WITH row, row.graph.nodes AS nodes,row.graph.pipes AS rel
FOREACH (node in nodes |
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n)
WITH row,rel
UNWIND row.graph.pipes AS rel
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *
CALL apoc.load.json("file:///G:/wwwroot/DataFlow/graph.json") YIELD value AS row
UNWIND row.graph.nodes AS node
CALL apoc.create.node(node.labels, node.properties) YIELD node AS n
// aggregation or distinct reduces cardinality to 1 per row again
WITH row, count(*)
UNWIND row.graph.pipes AS rel
// you should use labels here, otherwise you get no lookup benefits
// from indexes, even if you just use a generic :Node label
MATCH (a) WHERE a.key = rel.start
MATCH (b) WHERE b.key = rel.end
CALL apoc.create.relationship(a, rel.type, rel.properties, b) YIELD rel AS r
RETURN *