Supported subset

NamiDB’s query layer implements a strict subset of Cypher 25 / openCypher 9 / GQL ISO/IEC 39075:2024, scoped to make LDBC SNB Interactive Complex Read IC01–IC14 parse, plan and run end to end. The subset is deliberately smaller than Neo4j Community 5.x or Kùzu; the trade is “what the parser accepts runs or returns a typed error — never a silent warning that changes semantics.”

When in doubt, an unsupported feature produces an explicit UnsupportedFeature error pointing at the RFC where it will land.

Standard reference

• Base standard: GQL ISO/IEC 39075:2024 plus openCypher 9.
• Cypher 25 (Neo4j) is used as a naming reference but no Neo4j-exclusive features are implemented (no db.* functions, no APOC).
• When GQL and openCypher disagree, GQL wins.

See RFC-004 for the full scoping document.

Clauses

Clause	Supported	Notes
MATCH	yes	Fixed and variable-length patterns.
OPTIONAL MATCH	yes	Left-outer-join semantics.
WHERE	yes	Arbitrary predicates over the visible scope.
RETURN	yes	Projection list with AS aliases. DISTINCT supported.
RETURN *	yes	All bound aliases.
WITH	yes	Pipe that re-opens scope. Supports inline WHERE and AS.
WITH *	yes	All bound aliases (pipeline pass-through).
ORDER BY	yes	Multi-key ASC / DESC.
SKIP / LIMIT	yes	Literals or $param; no expressions.
UNWIND	yes	List → rows.
CREATE	yes	Nodes and edges with literal or $param properties.
MERGE	yes	With ON CREATE SET / ON MATCH SET. Single pattern part per MERGE (no multi-label).
SET	yes	Property assign, property replace (=), property merge (+=), label add.
DELETE / DETACH DELETE	yes	Single binding per delete. DELETE without DETACH fails if the node has edges.
REMOVE	yes	Property remove, label remove.
UNION / UNION ALL	yes	Same arity and same aliases on each side.
shortestPath(...)	yes	Wrapped form MATCH p = shortestPath((a)-[*..N]-(b)). Path binding required, single hop, finite upper bound.
allShortestPaths(...)	yes	Same shape as shortestPath; emits every distinct path of the minimum length.

Patterns

Element	Supported	Notes
(a:Label {prop: val})	yes	Multi-label (a:A:B). Inline map property filter.
-[r:TYPE]->	yes	Directions -->, <--, --.
Relationship type alternation -[r:A|B|C]->	yes	Union over the listed types (RFC-024).
Variable-length -[r:KNOWS*1..3]->	yes	Finite bounds required. *..M is shorthand for *1..M.
Pattern chain (a)-[]-(b)-[]-(c)	yes
Multi-part pattern MATCH (a), (b)	yes
Anonymous variable (), []	yes

Expressions

Category	Supported
Literals: int, float, string, bool, null, list [1,2,3], map {k: v}	yes
Parameters $name	yes
Variable reference a, property access a.prop	yes
Arithmetic + - * / % ^	yes
String + (concat), =~ (regex)	yes
Boolean AND OR NOT XOR	yes
Comparison = <> < > <= >=	yes
IS NULL / IS NOT NULL	yes
IN (list membership)	yes
STARTS WITH, ENDS WITH, CONTAINS	yes
CASE WHEN … THEN … ELSE END (simple and multi-branch)	yes
List comprehension [x IN list WHERE pred | expr]	yes
Pattern comprehension [(a)-[]->(b) | b.name]	yes
Pattern predicate WHERE (a)-[]->(b) / EXISTS { ... }	yes

Types

INTEGER (64-bit signed), FLOAT (64-bit), STRING, BOOLEAN, NULL, LIST<T> (heterogeneous allowed, typecheck at runtime), MAP<STRING, T>, NODE, RELATIONSHIP, PATH, DATE, DATETIME (UTC, microseconds), DURATION, VECTOR(Vec<f32>).

Out of scope in v0: BYTES, POINT, LOCALDATETIME, ZONEDDATETIME, LOCALTIME, TIME.

NULL semantics

Three-valued logic:

• NULL = NULL → NULL (not true).
• NULL AND false → false; NULL AND true → NULL.
• WHERE rejects rows whose predicate evaluates to NULL (treated as false).
• IS NULL / IS NOT NULL are the only forms that test for NULL.

LDBC SNB Interactive Complex coverage

Query	v0
IC1 — Friends by name (transitive)	yes
IC2 — Recent messages by friends	yes
IC3 — Friends in two countries	yes
IC4 — New topics on friend posts	yes
IC5 — New groups (membership count)	yes
IC6 — Tag co-occurrence	yes
IC7 — Recent likers	yes
IC8 — Recent replies	yes
IC9 — Recent messages by friends-of-friends	yes
IC10 — Friend recommendation	yes
IC11 — Job referral	yes
IC12 — Expert search by tag class	yes
IC13 — Single shortest path	yes (RFC-023)
IC14 — All shortest paths weighted	yes (RFC-023)

All 14 IC queries parse, lower and run end to end on the current main branch.

Out of scope (v0)

Anything not listed above is explicitly out of scope and produces a typed parse / lower error. Notable exclusions:

Feature	Why it’s out	Where it lands
CALL { ... } (subqueries)	Subquery scoping is subtle; not needed for LDBC IC.	Future RFC
CALL procedure.name(...)	No procedure registry. APOC explicitly excluded.	Future RFC
FOREACH	Imperative; rarely useful in practice.	Future RFC
USE database	Cross-database queries; single namespace per session.	RFC for Cloud
LOAD CSV	Bulk-load happens through WriterSession / merge_nodes.	Never via Cypher in v0.
CREATE INDEX / CREATE CONSTRAINT	DDL handled by the schema API, not Cypher.	Future RFC
EXPLAIN / PROFILE (as Cypher prefix)	Available via the CLI namidb explain.	Future RFC
Explicit transactions (BEGIN/COMMIT/ROLLBACK in Cypher)	Auto-commit per query in v0.	Never via Cypher in v0.
Variable-length without an upper bound (*1..)	Blowup not bounded; rejected explicitly.	Possible with WCOJ.
Zero-length patterns (*0..n)	Semantics around auto-loops not finalised.	Future RFC
MATCH p = (a)-[*]->(b) RETURN p (var-length path bindings)	Path materialisation deferred.	Future RFC
POINT, TIME, ZONEDDATETIME types	Not needed for LDBC SNB Interactive.	Future RFC
db.* / apoc.* namespaces	Vendor-specific Neo4j; non-portable.	Never

Read-your-own-writes

In v0, a single query that writes then reads does not see its own writes. Example:

CREATE (a:Person {name: 'Ada'})
MATCH (p:Person) RETURN p.name

The MATCH sees the snapshot pinned before the CREATE ran. The new Ada appears in the next query. Workaround: run writes and reads in two separate statements (or two separate Client.cypher calls — Cypher writes auto-commit at the end of each statement).

See RFC-009 for the rationale.

What’s next

• Reading data — read clauses with examples.
• Writing data — write clauses and the auto-commit model.
• Operators & functions — the full operator and built-in function catalog.