Reference documentation and code samples for the Firestore in Datastore mode API class Google::Cloud::Datastore::Query.
Query
Represents the search criteria against a Datastore.
Inherits
- Object
Examples
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("done", "=", false). where("priority", ">=", 4). order("priority", :desc) tasks = datastore.run query
Run the query within a namespace with the namespace
option:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task"). where("done", "=", false) tasks = datastore.run query, namespace: "example-ns"
Methods
#aggregate_query
def aggregate_query() -> AggregateQuery
Creates an AggregateQuery object for the query.
- (AggregateQuery) — New empty aggregate query.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task") .where("done", "=", false) Create an aggregate query aggregate_query = query.aggregate_query
#ancestor
def ancestor(parent)
Add a filter for entities that inherit from a key.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = Google::Cloud::Datastore::Query.new query.kind("Task"). ancestor(task_list_key) tasks = datastore.run query
#cursor
def cursor(cursor)
Set the cursor to start the results at.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). limit(page_size). start(page_cursor) tasks = datastore.run query
#distinct_on
def distinct_on(*names)
Group results by a list of properties.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). distinct_on("type", "priority"). order("type"). order("priority") tasks = datastore.run query
#filter
def filter(name, operator, value)
Add a property filter to the query.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("done", "=", false) tasks = datastore.run query
Add a composite property filter:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("done", "=", false). where("priority", ">=", 4) tasks = datastore.run query
Add an inequality filter on a single property only:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("created", ">=", Time.utc(1990, 1, 1)). where("created", "<", Time.utc(2000, 1, 1)) tasks = datastore.run query
Add a composite filter on an array property:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("tag", "=", "fun"). where("tag", "=", "programming") tasks = datastore.run query
Add an inequality filter on an array property :
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("tag", ">", "learn"). where("tag", "<", "math") tasks = datastore.run query
Add a key filter using the special property key
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("__key__", ">", datastore.key("Task", "someTask")) tasks = datastore.run query
Add a key filter to a kindless query:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new last_seen_key = datastore.key "Task", "a" query = Google::Cloud::Datastore::Query.new query.where("__key__", ">", last_seen_key) tasks = datastore.run query
#group_by
def group_by(*names)
Group results by a list of properties.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). distinct_on("type", "priority"). order("type"). order("priority") tasks = datastore.run query
#initialize
def initialize() -> Query
Returns a new query object.
- (Query) — a new instance of Query
require "google/cloud/datastore" query = Google::Cloud::Datastore::Query.new
#kind
def kind(*kinds)
Add the kind of entities to query.
Special entity kinds such as namespace
, kind
, and
property
can be used for metadata
queries.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind "Task" tasks = datastore.run query
#limit
def limit(num)
Set a limit on the number of results to be returned.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). limit(5) tasks = datastore.run query
#offset
def offset(num)
Set an offset for the results to be returned.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). limit(5). offset(10) tasks = datastore.run query
#order
def order(name, direction = :asc)
Sort the results by a property name. By default, an ascending sort order will be used. To sort in descending order, provide a second argument of a string or symbol that starts with "d".
With ascending sort order:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). order("created") tasks = datastore.run query
With descending sort order:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). order("created", :desc) tasks = datastore.run query
With multiple sort orders:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). order("priority", :desc). order("created") tasks = datastore.run query
A property used in inequality filter must be ordered first:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("priority", ">", 3). order("priority"). order("created") tasks = datastore.run query
#projection
def projection(*names)
Retrieve only select properties from the matched entities.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). select("priority", "percent_complete") priorities = [] percent_completes = [] datastore.run(query).each do |t| priorities << t["priority"] percent_completes << t["percent_complete"] end
A keys-only query using the special property key
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). select("__key__") keys = datastore.run(query).map(&:key)
#select
def select(*names)
Retrieve only select properties from the matched entities.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). select("priority", "percent_complete") priorities = [] percent_completes = [] datastore.run(query).each do |t| priorities << t["priority"] percent_completes << t["percent_complete"] end
A keys-only query using the special property key
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). select("__key__") keys = datastore.run(query).map(&:key)
#start
def start(cursor)
Set the cursor to start the results at.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). limit(page_size). start(page_cursor) tasks = datastore.run query
#where
def where(name, operator, value)
Add a property filter to the query.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("done", "=", false) tasks = datastore.run query
Add a composite property filter:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("done", "=", false). where("priority", ">=", 4) tasks = datastore.run query
Add an inequality filter on a single property only:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("created", ">=", Time.utc(1990, 1, 1)). where("created", "<", Time.utc(2000, 1, 1)) tasks = datastore.run query
Add a composite filter on an array property:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("tag", "=", "fun"). where("tag", "=", "programming") tasks = datastore.run query
Add an inequality filter on an array property :
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("tag", ">", "learn"). where("tag", "<", "math") tasks = datastore.run query
Add a key filter using the special property key
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new query.kind("Task"). where("__key__", ">", datastore.key("Task", "someTask")) tasks = datastore.run query
Add a key filter to a kindless query:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new last_seen_key = datastore.key "Task", "a" query = Google::Cloud::Datastore::Query.new query.where("__key__", ">", last_seen_key) tasks = datastore.run query