Query for Entities by parent key

Question

I'm looking to query for Datastore Entities by parent key (i.e., to return entities with keys that are 1 path segment under the parent key). I know that I can use a HAS_ANCESTOR query to get the parent and all descendants, but I only want the immediate children.

I was hoping a __parent__ property would be available for this purpose, but this does not seem to work:

{propertyFilter: {
  property: {name: '__parent__'},
  op: 'EQUAL',
  value: {keyValue: {
    partitionId: {projectId: 'myproject'},
    path: [{kind: 'row', name: 'parent'}]
  }}
}

I know I can also record a depth property in each entity to achieve this, but would rather not do that if Datastore supports a query like this natively using the key itself.

Dan McGrath Dan McGrath · Accepted Answer · 2017-06-22T19:59:53

No, this is not currently supported. If the kind of the child is unique to the particular depth in question you can just use that, otherwise you need to create a composite index that includes indexing of a 'depth' property as you mentioned.

Query for Entities by parent key

1 Answers