Update

Overview

The update() statement updates custom property values of nodes and edges that meet the given conditions.

System properties of nodes and edges (_id, _uuid) are immutable. Similarly, the source and destination nodes of an edge cannot be reassigned once the edge is created.

Syntax
// Updates nodes
update().nodes(<filter?>)
  .set({<property1>: <value1>, <property2?>: <value2?> ...})

// Updates edges
update().edges(<filter?>)
  .set({<property1>: <value1>, <property2?>: <value2?> ...})

Example Graph

To create the graph, execute each of the following UQL queries sequentially in an empty graphset:

UQL
create().node_schema("user").edge_schema("follow")
create().node_property(@user, "name").node_property(@user, "age", int32).edge_property(@follow, "time", datetime)
insert().into(@user).nodes([{_id:"U001", name:"Jason", age:30}, {_id:"U002", name:"Tim"}, {_id:"U003", name:"Grace", age:25}, {_id:"U004", name:"Ted", age:26}])
insert().into(@follow).edges([{_from:"U004", _to:"U001", time:"2021-9-10"}, {_from:"U003", _to:"U001", time:"2020-3-12"}, {_from:"U004", _to:"U002", time:"2023-7-30"}])

Updating Nodes

To update the name property of nodes whose name is currently Tim:

UQL
update().nodes({name == "Tim"}).set({name: "Tom"})

Updating Edges

To update the time property of edges whose current time is later than 2021-5-21, setting it to one day later, and to return the updated edges:

UQL
update().edges({time > "2021-5-1"}).set({time: dateAdd(time, 1, "day")}) as edges
return edges{*}

Result: edges

Updating All

To update the age property of all nodes by incrementing it to the next integer value:

UQL
update().nodes().set({age: age + 1}) as n
return table(n.name, n.age)

Result:

Limiting the Amount to Update

To limit the number of nodes or edges to update, first retrieve the data from the database using a clause like find(), then apply the LIMIT N clause to keep only the first N rows before passing the alias to the update() clause.

To update the name property of only two @user nodes, setting it to lowercase:

UQL
find().nodes({@user}) as n1 limit 2
update().nodes(n1).set({name: lower(name)}) as n2
return n2{*}

Result: n2

Removing Property Values

To remove the name and age property values of the node with _id U001:

UQL
update().nodes({_id == "U001"}).set({name: null, age: null})