query abstract method

Future<Page<Entity>> query(
  1. Query query, {
  2. Partition partition,
  3. Transaction transaction,
})

Runs a query on the dataset and returns a Page of matching Entitys.

The Page instance returned might not contain all matching Entitys - in which case isLast is set to false. The page's next method can be used to page through the whole result set. The maximum number of Entitys returned within a single page is implementation specific.

  • query is used to restrict the number of returned Entitys and may may specify an order.

  • partition can be used to specify the namespace used for the lookup.

If a transaction is given, the query will be within this transaction. But note that arbitrary queries within a transaction are not possible. A transaction is limited to a very small number of entity groups. Usually queries with transactions are restricted by providing an ancestor filter.

Outside of transactions, the result set might be stale. Queries are by default eventually consistent.

Implementation

Future<Page<Entity>> query(Query query,
    {Partition partition, Transaction transaction});