examples · graph · 4 / 7

4. path - reachability check

what this does

Is src connected to dst at all, within max_depth hops? Returns a single boolean. The traversal short-circuits the moment it finds the first connecting path - it does not enumerate every route.

when to use it

Permission checks - "is this user in the org tree under that admin?"
Reachability gates before running an expensive operation - cheaper than full BFS.
"Are these two entities related?" boolean badges in UIs.

schema requirement

The relation must be declared in the schema's [[relations]] block. See schemas/reference#relations.

the request

GET /v1/tenants/:t/graph/:schema/path?rel=...&src=...&dst=...&max_depth=N

curl -G "https://$OC_HOST/v1/tenants/$OC_TENANT/graph/shop.orders/path" \
  --data-urlencode "rel=bought_product" \
  --data-urlencode "src=o001" \
  --data-urlencode "dst=p001" \
  --data-urlencode "max_depth=3" \
  -H "Authorization: Bearer $OC_TOKEN"

result = db.graph.path(
    "shop.orders",
    rel="bought_product",
    src="o001",
    dst="p001",
    max_depth=3,
)

const result = await db.graph.path("shop.orders", {
  rel: "bought_product",
  src: "o001",
  dst: "p001",
  max_depth: 3,
});

result, _ := db.Graph().Path(ctx, "shop.orders", originchain.PathRequest{
    Rel:      "bought_product",
    Src:      "o001",
    Dst:      "p001",
    MaxDepth: 3,
})

what you get back

{ "reachable": true }

One field: reachable: true | false. false means "not within max_depth" - it isn't proof there's no path at higher depth.

how it works

Same BFS frontier as bfs, but it stops the instant dst appears in any expansion.
Worst case (no path) costs the same as a bounded bfs; best case is a single hop.
Use this over bfs whenever you only need the boolean - the savings come from not materialising the visited set.

common mistakes

Reading false as "no path". It only means "no path within max_depth". If you need a definitive answer, raise the depth or use all_simple_paths.
Swapping src and dst on a one-way relation. path is direction-sensitive. If you need the inverse direction, check that the relation is bidirectional.