Path pattern prefix

When defining path patterns, we can specify a search prefix and a path mode. The path mode will filter results if elements are repeated in a path, and the search prefix will select the paths by their length.

When using a search prefix, the results are partitioned, so that each path from a partition has the same first and last node. Then, a result is selected from each partition.

Search prefix	Description
`ALL`	All paths. The default search prefix.
`ANY`	Any path for each partition.
`ALL SHORTEST`	All shortest paths.
`ANY SHORTEST`	Any shortest path for each partition.
`SHORTEST k`	The k shortest paths for each partition.

Path mode	Description
`WALK`	Does not filter any path. The default path mode.
`TRAIL`	Filters paths with repeated edges.
`ACYCLIC`	Filters paths with repeated nodes.
`SIMPLE`	Filters paths with repeated nodes, unless the repeated nodes are the first and last nodes.

Examples

In this query, we return paths of followers, without any repeated nodes. If this query does not contain the ACYCLIC keyword, then it is an invalid query.

MATCH ACYCLIC p = (a)-[:Follows]->*(b)
RETURN p

In this query, we return again a path of followers, but selecting all shortest paths for each pair of followers.

MATCH ALL SHORTEST ACYCLIC p = (a)-[:Follows]->*(b)
RETURN p

In this query, we return all trails of length 2.

MATCH TRAIL p = ()->{2}()
RETURN p