FOREACH clause is used to update data within a collection, whether components of a path, or result of aggregation.
Collections and paths are key concepts in Cypher.
To use them for updating data, you can use the
It allows you to do updating commands on elements in a collection — a path, or a collection created by aggregation.
The identifier context inside of the foreach parenthesis is separate from the one outside it.
This means that if you
CREATE a node identifier inside of a
FOREACH, you will not be able to use it outside of the foreach statement, unless you match to find it.
Inside of the
FOREACH parentheses, you can do any of the updating commands —
If you want to execute an additional
MATCH for each element in a collection then
UNWIND (see Section 10.6, “Unwind”) would be a more appropriate command.
Mark all nodes along a path
This query will set the property
marked to true on all nodes along a path.
MATCH p =(begin)-[*]->(END ) WHERE begin.name='A' AND END .name='D' FOREACH (n IN nodes(p)| SET n.marked = TRUE )
Nothing is returned from this query, but four properties are set.
|Properties set: 4|