UPDATE VERTEX¶
The UPDATE VERTEX statement updates properties on tags of a vertex.
In NebulaGraph, UPDATE VERTEX supports compare-and-set (CAS).
Note
An UPDATE VERTEX statement can only update properties on ONE TAG of a vertex.
Syntax¶
ngql
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¶
```ngql // This query checks the properties of vertex "player101". nebula> FETCH PROP ON player "player101" YIELD properties(vertex); +--------------------------------+ | properties(VERTEX) | +--------------------------------+ | {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 | +---------------+-----+ ```