UPDATE VERTEX¶
The UPDATE VERTEX
statement updates properties on tags of a vertex.
In Nebula Graph, UPDATE VERTEX
supports compare-and-set (CAS).
Note
An UPDATE VERTEX
statement can only update properties on ONE TAG of a vertex.
Syntax¶
UPDATE VERTEX ON <tag_name> <vid>
SET <update_prop>
[WHEN <condition>]
[YIELD <output>]
Parameter | Required | Description | Example |
---|---|---|---|
ON <tag_name> |
Yes | Specifies the tag of the vertex. The properties to be updated must be on this tag. | ON player |
<vid> |
Yes | Specifies the ID of the vertex to be updated. | "player100" |
SET <update_prop> |
Yes | Specifies the properties to be updated and how they will be updated. | SET age = age +1 |
WHEN <condition> |
No | Specifies the filter conditions. If <condition> evaluates to false , the SET clause will not take effect. |
WHEN name == "Tim" |
YIELD <output> |
No | Specifies the output format of the statement. | YIELD name AS Name |
Example¶
// This query checks the properties of vertex "player101".
nebula> FETCH PROP ON player "player101";
+-----------------------------------------------------+
| vertices_ |
+-----------------------------------------------------+
| ("player101" :player{age: 36, name: "Tony Parker"}) |
+-----------------------------------------------------+
// This query updates the age property and returns name and the new age.
nebula> UPDATE VERTEX ON player "player101" \
SET age = age + 2 \
WHEN name == "Tony Parker" \
YIELD name AS Name, age AS Age;
+---------------+-----+
| Name | Age |
+---------------+-----+
| "Tony Parker" | 38 |
+---------------+-----+
Last update: August 17, 2021