A query statement to retrieve a sub-graph

[sherman-the-tank]

We need a new query statement to retrieve the entire sub-graph from one or multiple vertices. The sub-graph needs to include all edges not only starting from the given vertices, but also between any two vertices in the sub-graph

[laura-ding]

The syntax for getting subgraph

GET SUBGRAPH 2 steps from vid over <edgeTypeList|*> <empty|REVERSELY|BOTH> [WHERE V1.tag_name.prop > 10] [YIELD V0.tag_name.prop, V1.tag_name.prop, V2.tag_name.prop, E1.edge_type.prop, E2.edge_type.prop]

V0 is the starting vertex, V1 is the first-degree vertices, V2 is the second-degree vertices.
E1 is the first-degree edges, E2 is the second-degree edges
If not YIELD, return the vertex id and edge type

The result is JSON format, return all paths from the start vertex. The returned data set has redundant data because it is returned by path.

[jude-zhu]

FYR, subgraph syntax of cypher is:

apoc.path.subgraphAll(startNode <id>Node/list, {minLevel, maxLevel, relationshipFilter, labelFilter, bfs:true, filterStartNode:true, limit:-1}) yield nodes, relationships

Example. Expand to local subgraph (and all its relationships) within 4 traversals:

MATCH (company:Company) WHERE company.name = "RENTON COLLECTIONS INC."
CALL apoc.path.subgraphAll(company, {maxLevel:4}) YIELD nodes, relationships
RETURN nodes, relationships;

Result in table format:

In text format:

In graph format:

[sherman-the-tank]

Very good start point. Here are couple things I can think of

1. Instead of keyword "BOTH" in the edge specification, I would suggest to use "BIDIRECTIONALLY" (or abbreviate to "BIDIRECT"). It is more meaningful

2. In the YIELD sentence, I'm afraid V1, V2.. E1, E2.. are insufficient, because some vertices could be the result of multiple hops (ie. a vertex could be the result of 2-hop, and the result of 3-hop), same as the edges