Advanced: DERIVE, ASSUME, ABDUCE

DERIVE

DERIVE turns inferred relations into graph mutations (edges/nodes/merges depending on clause).

CREATE RULE candidate_friend AS
MATCH (a)-[:KNOWS]->(b)
DERIVE (a)-[:FRIEND]->(b)

ASSUME

ASSUME executes a hypothetical mutation block and evaluates a body against that temporary state.

ASSUME {
  CREATE (:Node {name: 'X'})-[:EDGE]->(:Node {name: 'Y'})
} THEN {
  QUERY reachable RETURN b
}

Think of this as savepoint-scoped what-if execution.

ABDUCE

ABDUCE asks for minimal changes that would make (or prevent) a condition.

ABDUCE NOT reachable WHERE a.name = 'Alice' RETURN b

Typical outputs include modification candidates, validation flags, and costs.

Safe Usage

• Keep candidate search bounded.
• Use explicit constraints in WHERE.
• Validate candidate modifications before applying.

See Errors & Limits for runtime guardrails.