Shape query results

Return properties, computed values, aggregates, and correlated binding rows

Guide

Projection operations turn a traversal stream into the response shape your application needs. They are terminal: a projection finishes that traversal entry.

Choose a projection

Intent	Operation
Selected fields	valueMap / value_map
Renamed or computed fields	project
Correlated row fields	projectBindings / project_bindings
Scalar values	id, label, values
Aggregates	count, sum, min, max, mean, groupCount

Virtual fields include $id, $label, $from, $to, $distance, and $score where the preceding operation provides them.

Rename fields

Rust

g().n_with_label("User").project(vec![
    PropertyProjection::renamed("$id", "user_id"),
    PropertyProjection::new("name"),
])

Project correlated bindings

projectBindings / project_bindings emits one row per traversal result, reading values from names captured earlier with bind. projectDistinctBindings / project_distinct_bindings also removes duplicate projected tuples.

When alternative branches bind different names, a row carries only the bindings its own path set. Use coalesce to take the first binding that is present. This request maps each service to a workload ID, whichever branch found it:

Rust

read_batch()
    .var_as(
        "workloads",
        g().n_with_label("Service")
            .bind("service")
            .out(Some("ROUTES_TO"))
            .bind("pod")
            .optional(sub().in_(Some("CREATES")).bind("deployment"))
            .union(vec![
                sub().in_(Some("MANAGES")).bind("owner"),
                sub().out(Some("ROUTES_TO")).bind("workload"),
            ])
            .project_distinct_bindings(vec![
                BindingProjection::binding("service", "$id", "service_id"),
                BindingProjection::coalesce(
                    vec![
                        BindingValueRef::binding("deployment", "$id"),
                        BindingValueRef::binding("owner", "$id"),
                        BindingValueRef::binding("workload", "$id"),
                    ],
                    "workload_id",
                ),
            ]),
    )
    .returning(["workloads"]);

Aggregate

Append count() to a filtered traversal and return that named entry; aggregation runs inside the transaction instead of materializing every row in the client.

Keep responses small

• Project only fields the caller uses.
• Project $distance before traversing away from a search hit if the score is needed later.
• Use aggregates in the engine instead of returning full rows for client-side counting.
• Add distinct only when duplicate elimination is semantically required.

Next steps

Bindings and branches

Preserve row-local values across optional and union operations.

Vector search

Create an index, rank vector hits, and preserve distance metadata.