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Schema functions

NebulaGraph supports the following schema functions.

For nGQL statements

Note

  • The following functions are only available in the YIELD clauses.
  • The following functions are unavailable in the WHERE clauses.
Function Description
id(vertex) Returns the ID of a vertex. The data type of the result is the same as the vertex ID.
map properties(vertex) Returns the properties of a vertex.
map properties(edge) Returns the properties of an edge.
string type(edge) Returns the edge type of an edge.
src(edge) Returns the source vertex ID of an edge. The data type of the result is the same as the vertex ID.
dst(edge) Returns the destination vertex ID of an edge. The data type of the result is the same as the vertex ID.
int rank(edge) Returns the rank value of an edge.

For statements compatible with openCypher

Function Description
id(<vertex>) Returns the ID of a vertex. The data type of the result is the same as the vertex ID.
list tags(<vertex>) Returns the Tag of a vertex, which serves the same purpose as labels().
list labels(<vertex>) Returns the Tag of a vertex, which serves the same purpose as tags(). This function is used for compatibility with openCypher syntax.
map properties(<vertex_or_edge>) Returns the properties of a vertex or an edge.
string type(<edge>) Returns the edge type of an edge.
src(<edge>) Returns the source vertex ID of an edge. The data type of the result is the same as the vertex ID.
dst(<edge>) Returns the destination vertex ID of an edge. The data type of the result is the same as the vertex ID.
vertex startNode(<path>) Visits an edge or a path and returns its source vertex ID.
string endNode(<path>) Visits an edge or a path and returns its destination vertex ID.
int rank(<edge>) Returns the rank value of an edge.

Examples

nebula> GO FROM "player100" OVER follow REVERSELY \
        YIELD src(edge) AS destination;
+-------------+
| destination |
+-------------+
| "player101" |
| "player102" |
+-------------+
nebula> LOOKUP ON player WHERE player.age  > 45 YIELD id(vertex);
+-------------+-------------+
| VertexID    | id(VERTEX)  |
+-------------+-------------+
| "player144" | "player144" |
| "player140" | "player140" |
+-------------+-------------+

nebula> MATCH (a:player) WHERE id(a) == "player100" \
        RETURN tags(a), labels(a), properties(a);
+------------+------------+-------------------------------+
| tags(a)    | labels(a)  | properties(a)                 |
+------------+------------+-------------------------------+
| ["player"] | ["player"] | {age: 42, name: "Tim Duncan"} |
+------------+------------+-------------------------------+

nebula> MATCH p = (a :player {name : "Tim Duncan"})-[r:serve]-(t) \
        RETURN type(r), rank(r);
+---------+---------+
| type(r) | rank(r) |
+---------+---------+
| "serve" | 0       |
+---------+---------+

nebula> MATCH p = (a :player {name : "Tim Duncan"})-[r:serve]-(t) \
        RETURN startNode(p), endNode(p);
+----------------------------------------------------+----------------------------------+
| startNode(p)                                       | endNode(p)                       |
+----------------------------------------------------+----------------------------------+
| ("player100" :player{age: 42, name: "Tim Duncan"}) | ("team204" :team{name: "Spurs"}) |
+----------------------------------------------------+----------------------------------+
Last update: March 13, 2023