Update operations can update node and edge data in a single or batch manner in the current GraphSet. UQL finds the nodes and edges to be modified according to the filtering rules before modifying its properties except the schema, _id and _uuid.

When updating the start/end node (_from, _to, _from_uuid and _to_uuid) of edge, the new start/end node must exist in the GraphSet, otherwise the operation will fail. Ultipa system will automatically update _from_uuid when _from is updated and vise versa, and same for _to and _to_uuid. When modifying _from and _from_uuid at the same time but the two do not match the correspondence in the GraphSet, Ultipa system subjects to _from_uuid, and same for _to and _to_uuid.

Update operation will induce redundant data into the GraphSet and reduce the query efficiency. It is strongly suggested to be cleared on a regular basis, see command compact() in the previous chapter.

It is not suggested to execute Update operation after streaming return of an algorithm, see details on stream() in document Ultipa Graph Analytics & Algorithms - Using Algorithms - Execution Method.

Syntax:

• Statement alias supported (NODE or EDGE type)

// To update N nodes in the current graphset
update().nodes(<filter>)
  .set({<property1>: <value1>, <property2>: <value2> ...})
  .limit(<N>)

// To update N edges in the current graphset
update().edges(<filter>)
  .set({<property1>: <value1>, <property2>: <value2> ...})
  .limit(<N>)

Example: Update the balance of bank card C001 to 300

update().nodes({_id == "C001"})
  .set({balance: 300})

Example: Update the score of all bank cards @card to the value of level*balance

update().nodes({@card})
  .set({score: level * balance})

Example: Upgrade 5,000 bank cards @card under level 2 but has balance that exceeds 200,000 to the next upper level

update().nodes({@card && level < 2 && balance > 200000})
  .set({level: level + 1})
  .limit(5000)

Analysis: When the amount of data is too large for the memory to process, parameter limit() can be used to set the maximum quantity to handle thus to process in batches.

Example: Update the amount of @transaction.no TRX001 to 100

update().edges({@transaction.no == "TRX001"})
  .set({amount: 100})