Reference documentation and code samples for the Firestore in Datastore mode API class Google::Cloud::Datastore::Dataset.
Dataset
Dataset is the data saved in a project's Datastore. Dataset is analogous to a database in relational database world.
Dataset is the main object for interacting with Google Datastore. Entity objects are created, read, updated, and deleted by Dataset.
Inherits
- Object
Example
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task"). where("done", "=", false) tasks = datastore.run query
Methods
#allocate_ids
def allocate_ids(incomplete_key, count = 1) -> Array<Google::Cloud::Datastore::Key>
Generate IDs for a Key before creating an entity.
-
incomplete_key (Key) — A Key without
id
orname
set. - count (String) — The number of new key IDs to create.
- (Array<Google::Cloud::Datastore::Key>)
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key = datastore.key "Task" task_keys = datastore.allocate_ids task_key, 5
#commit
def commit() { |commit| ... } -> Array<Google::Cloud::Datastore::Entity>
Make multiple changes in a single commit.
- (commit) — a block for making changes
- commit (Commit) — The object that changes are made on
- (Array<Google::Cloud::Datastore::Entity>) — The entities that were persisted.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new datastore.commit do |c| c.save task3, task4 c.delete task1, task2 end
#delete
def delete(*entities_or_keys) -> Boolean
Remove entities from the Datastore.
-
(Boolean) — Returns
true
if successful
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new datastore.delete task1, task2
#entity
def entity(*key_or_path, project: nil, namespace: nil) { |entity| ... } -> Google::Cloud::Datastore::Entity
Create a new empty Entity instance. This is a convenience method to make the creation of Entity objects easier.
- key_or_path (Key, Array<Array(String,(String|Integer|nil))>) — An optional list of pairs for the key's path. Each pair may include the key's kind (String) and an id (Integer) or name (String). This is optional.
- project (String) (defaults to: nil) — The project of the Key. This is optional.
- namespace (String) (defaults to: nil) — namespace kind of the Key. This is optional.
- (entity) — a block yielding a new entity
- entity (Entity) — the newly created entity object
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity
The previous example is equivalent to:
require "google/cloud/datastore" task = Google::Cloud::Datastore::Entity.new
The key can also be passed in as an object:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key = datastore.key "Task", "sampleTask" task = datastore.entity task_key
Or the key values can be passed in as parameters:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task", "sampleTask"
The previous example is equivalent to:
require "google/cloud/datastore" task_key = Google::Cloud::Datastore::Key.new "Task", "sampleTask" task = Google::Cloud::Datastore::Entity.new task.key = task_key
The newly created entity can also be configured using block:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task", "sampleTask" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end
The previous example is equivalent to:
require "google/cloud/datastore" task_key = Google::Cloud::Datastore::Key.new "Task", "sampleTask" task = Google::Cloud::Datastore::Entity.new task.key = task_key task["type"] = "Personal" task["done"] = false task["priority"] = 4 task["description"] = "Learn Cloud Datastore"
#find
def find(key_or_kind, id_or_name = nil, consistency: nil) -> Google::Cloud::Datastore::Entity, nil
Retrieve an entity by key.
-
key_or_kind (Key, String) — A Key object or
kind
string value. -
id_or_name (Integer, String, nil) — The Key's
id
orname
value if akind
was provided in the first parameter. -
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of lookup used. See Eventual Consistency in Google Cloud Datastore for more information.
Finding an entity with a key:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key = datastore.key "Task", "sampleTask" task = datastore.find task_key
Finding an entity with a kind
and id
/name
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.find "Task", "sampleTask"
#find_all
def find_all(*keys, consistency: nil) -> Google::Cloud::Datastore::Dataset::LookupResults
Retrieve the entities for the provided keys. The order of results is
undefined and has no relation to the order of keys
arguments.
- keys (Key) — One or more Key objects to find records for.
-
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of lookup used. See Eventual Consistency in Google Cloud Datastore for more information.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key1 = datastore.key "Task", "sampleTask1" task_key2 = datastore.key "Task", "sampleTask2" tasks = datastore.find_all task_key1, task_key2
#get
def get(key_or_kind, id_or_name = nil, consistency: nil) -> Google::Cloud::Datastore::Entity, nil
Retrieve an entity by key.
-
key_or_kind (Key, String) — A Key object or
kind
string value. -
id_or_name (Integer, String, nil) — The Key's
id
orname
value if akind
was provided in the first parameter. -
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of lookup used. See Eventual Consistency in Google Cloud Datastore for more information.
Finding an entity with a key:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key = datastore.key "Task", "sampleTask" task = datastore.find task_key
Finding an entity with a kind
and id
/name
:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.find "Task", "sampleTask"
#gql
def gql(query, bindings = {}) -> Google::Cloud::Datastore::GqlQuery
Create a new GqlQuery instance. This is a convenience method to make the creation of GqlQuery objects easier.
- query (String) — The GQL query string.
-
bindings (Hash) — Named bindings for the GQL query string, each
key must match regex
[A-Za-z_$][A-Za-z_$0-9]*
, must not match regex__.*__
, and must not be""
. The value must be anObject
that can be stored as an Entity property value, or aCursor
.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT * FROM Task WHERE done = @done", done: false tasks = datastore.run gql_query
The previous example is equivalent to:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = Google::Cloud::Datastore::GqlQuery.new gql_query.query_string = "SELECT * FROM Task WHERE done = @done" gql_query.named_bindings = {done: false} tasks = datastore.run gql_query
#insert
def insert(*entities) -> Array<Google::Cloud::Datastore::Entity>
Insert one or more entities to the Datastore. An InvalidArgumentError will raised if the entities cannot be inserted.
- entities (Entity) — One or more entity objects to be inserted.
- (Array<Google::Cloud::Datastore::Entity>)
Insert a new entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task.key.id #=> nil datastore.insert task task.key.id #=> 123456
Insert multiple new entities in a batch:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task1 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task2 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 5 t["description"] = "Integrate Cloud Datastore" end task_key1, task_key2 = datastore.insert(task1, task2).map(&:key)
#key
def key(*path, project: nil, namespace: nil) -> Google::Cloud::Datastore::Key
Create a new Key instance. This is a convenience method to make the creation of Key objects easier.
- path (Array<Array(String,(String|Integer|nil))>) — An optional list of pairs for the key's path. Each pair may include the key's kind (String) and an id (Integer) or name (String). This is optional.
- project (String) (defaults to: nil) — The project of the Key. This is optional.
- namespace (String) (defaults to: nil) — namespace kind of the Key. This is optional.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key = datastore.key "Task", "sampleTask"
The previous example is equivalent to:
require "google/cloud/datastore" task_key = Google::Cloud::Datastore::Key.new "Task", "sampleTask"
Create an empty key:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key
Create an incomplete key:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key "User"
Create a key with a parent:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key [["TaskList", "default"], ["Task", "sampleTask"]] key.path #=> [["TaskList", "default"], ["Task", "sampleTask"]]
Create a key with multi-level ancestry:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key([ ["User", "alice"], ["TaskList", "default"], ["Task", "sampleTask"] ]) key.path.count #=> 3 key.path[0] #=> ["User", "alice"] key.path[1] #=> ["TaskList", "default"] key.path[2] #=> ["Task", "sampleTask"]
Create an incomplete key with a parent:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key "TaskList", "default", "Task" key.path #=> [["TaskList", "default"], ["Task", nil]]
Create a key with a project and namespace:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new key = datastore.key ["TaskList", "default"], ["Task", "sampleTask"], project: "my-todo-project", namespace: "example-ns" key.path #=> [["TaskList", "default"], ["Task", "sampleTask"]] key.project #=> "my-todo-project" key.namespace #=> "example-ns"
#lookup
def lookup(*keys, consistency: nil) -> Google::Cloud::Datastore::Dataset::LookupResults
Retrieve the entities for the provided keys. The order of results is
undefined and has no relation to the order of keys
arguments.
- keys (Key) — One or more Key objects to find records for.
-
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of lookup used. See Eventual Consistency in Google Cloud Datastore for more information.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_key1 = datastore.key "Task", "sampleTask1" task_key2 = datastore.key "Task", "sampleTask2" tasks = datastore.find_all task_key1, task_key2
#project
def project()
The Datastore project connected to.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new( project_id: "my-todo-project", credentials: "/path/to/keyfile.json" ) datastore.project_id #=> "my-todo-project"
#project_id
def project_id()
The Datastore project connected to.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new( project_id: "my-todo-project", credentials: "/path/to/keyfile.json" ) datastore.project_id #=> "my-todo-project"
#query
def query(*kinds) -> Google::Cloud::Datastore::Query
Create a new Query instance. This is a convenience method to make the creation of Query objects easier.
- kinds (String) — The kind of entities to query. This is optional.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task"). where("done", "=", false) tasks = datastore.run query
The previous example is equivalent to:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = Google::Cloud::Datastore::Query.new. kind("Task"). where("done", "=", false) tasks = datastore.run query
#read_only_transaction
def read_only_transaction() { |tx| ... }
Creates a read-only transaction that provides a consistent snapshot of Cloud Datastore. This can be useful when multiple reads are needed to render a page or export data that must be consistent.
A read-only transaction cannot modify entities; in return they do not contend with other read-write or read-only transactions. Using a read-only transaction for transactions that only read data will potentially improve throughput.
Read-only single-group transactions never fail due to concurrent modifications, so you don't have to implement retries upon failure. However, multi-entity-group transactions can fail due to concurrent modifications, so these should have retries.
- (tx) — a block yielding a new transaction
- tx (ReadOnlyTransaction) — the transaction object
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = datastore.query("Task"). ancestor(task_list_key) tasks = nil datastore.read_only_transaction do |tx| task_list = tx.find task_list_key if task_list tasks = tx.run query end end
#run
def run(query, namespace: nil, consistency: nil) -> Google::Cloud::Datastore::Dataset::QueryResults
Retrieve entities specified by a Query.
- query (Query, GqlQuery) — The object with the search criteria.
- namespace (String) (defaults to: nil) — The namespace the query is to run within.
-
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of query used. See Eventual Consistency in Google Cloud Datastore for more information.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task"). where("done", "=", false) tasks = datastore.run query
Run an ancestor query with eventual consistency:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = datastore.query.kind("Task"). ancestor(task_list_key) tasks = datastore.run query, consistency: :eventual
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"
Run the query with a GQL string.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT * FROM Task WHERE done = @done", done: false tasks = datastore.run gql_query
Run the GQL query within a namespace with namespace
option:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT * FROM Task WHERE done = @done", done: false tasks = datastore.run gql_query, namespace: "example-ns"
#run_aggregation
def run_aggregation(aggregate_query, namespace: nil, consistency: nil) -> Google::Cloud::Datastore::Dataset::AggregateQueryResults
Retrieve aggregate results specified by an AggregateQuery.
- query (AggregateQuery, GqlQuery) — The object with the aggregate criteria.
- namespace (String) (defaults to: nil) — The namespace the query is to run within.
-
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of query used. See Eventual Consistency in Google Cloud Datastore for more information.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task") .where("done", "=", false) aggregate_query = query.aggregate_query res = datastore.run_aggregation aggregate_query
Run an aggregate ancestor query with eventual consistency:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = datastore.query.kind("Task") .ancestor(task_list_key) aggregate_query = query.aggregate_query res = datastore.run_aggregation aggregate_query, consistency: :eventual
Run the aggregate query within a namespace with the namespace
option:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task") .where("done", "=", false) aggregate_query = query.aggregate_query res = datastore.run_aggregation aggregate_query, namespace: "example-ns"
Run the aggregate query with a GQL string.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT COUNT(*) FROM Task WHERE done = @done", done: false res = datastore.run_aggregation gql_query
Run the aggregate GQL query within a namespace with namespace
option:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT COUNT(*) FROM Task WHERE done = @done", done: false res = datastore.run_aggregation gql_query, namespace: "example-ns"
#run_query
def run_query(query, namespace: nil, consistency: nil) -> Google::Cloud::Datastore::Dataset::QueryResults
Retrieve entities specified by a Query.
- query (Query, GqlQuery) — The object with the search criteria.
- namespace (String) (defaults to: nil) — The namespace the query is to run within.
-
consistency (Symbol) (defaults to: nil) — The non-transactional read consistency to
use. Cannot be set to
:strong
for global queries. Accepted values are:eventual
and:strong
.The default consistency depends on the type of query used. See Eventual Consistency in Google Cloud Datastore for more information.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task"). where("done", "=", false) tasks = datastore.run query
Run an ancestor query with eventual consistency:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = datastore.query.kind("Task"). ancestor(task_list_key) tasks = datastore.run query, consistency: :eventual
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"
Run the query with a GQL string.
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT * FROM Task WHERE done = @done", done: false tasks = datastore.run gql_query
Run the GQL query within a namespace with namespace
option:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new gql_query = datastore.gql "SELECT * FROM Task WHERE done = @done", done: false tasks = datastore.run gql_query, namespace: "example-ns"
#save
def save(*entities) -> Array<Google::Cloud::Datastore::Entity>
Persist one or more entities to the Datastore.
- entities (Entity) — One or more entity objects to be saved.
- (Array<Google::Cloud::Datastore::Entity>)
Insert a new entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task.key.id #=> nil datastore.save task task.key.id #=> 123456
Insert multiple new entities in a batch:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task1 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task2 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 5 t["description"] = "Integrate Cloud Datastore" end task_key1, task_key2 = datastore.save(task1, task2).map(&:key)
Update an existing entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.find "Task", "sampleTask" task["priority"] = 5 datastore.save task
#snapshot
def snapshot() { |tx| ... }
Creates a read-only transaction that provides a consistent snapshot of Cloud Datastore. This can be useful when multiple reads are needed to render a page or export data that must be consistent.
A read-only transaction cannot modify entities; in return they do not contend with other read-write or read-only transactions. Using a read-only transaction for transactions that only read data will potentially improve throughput.
Read-only single-group transactions never fail due to concurrent modifications, so you don't have to implement retries upon failure. However, multi-entity-group transactions can fail due to concurrent modifications, so these should have retries.
- (tx) — a block yielding a new transaction
- tx (ReadOnlyTransaction) — the transaction object
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task_list_key = datastore.key "TaskList", "default" query = datastore.query("Task"). ancestor(task_list_key) tasks = nil datastore.read_only_transaction do |tx| task_list = tx.find task_list_key if task_list tasks = tx.run query end end
#transaction
def transaction(deadline: nil, previous_transaction: nil) { |tx| ... }
Creates a Datastore Transaction.
Transactions using the block syntax are committed upon block completion and are automatically retried when known errors are raised during commit. All other errors will be passed on.
All changes are accumulated in memory until the block completes.
Transactions will be automatically retried when possible, until
deadline
is reached. This operation makes separate API requests to
begin and commit the transaction.
-
deadline (Numeric) (defaults to: nil) — The total amount of time in seconds the
transaction has to succeed. The default is
60
. -
previous_transaction (String) (defaults to: nil) — The transaction identifier of a
transaction that is being retried. Read-write transactions may fail
due to contention. A read-write transaction can be retried by
specifying
previous_transaction
when creating the new transaction.Specifying
previous_transaction
provides information that can be used to improve throughput. In particular, if transactional operations A and B conflict, specifying theprevious_transaction
can help to prevent livelock. (See Transaction#id)
- (tx) — a block yielding a new transaction
- tx (Transaction) — the transaction object
Runs the given block in a database transaction:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task", "sampleTask" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end datastore.transaction do |tx| if tx.find(task.key).nil? tx.save task end end
If no block is given, a Transaction object is returned:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task", "sampleTask" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end tx = datastore.transaction begin if tx.find(task.key).nil? tx.save task end tx.commit rescue tx.rollback end
#update
def update(*entities) -> Array<Google::Cloud::Datastore::Entity>
Update one or more entities to the Datastore. An InvalidArgumentError will raised if the entities cannot be updated.
- entities (Entity) — One or more entity objects to be updated.
- (Array<Google::Cloud::Datastore::Entity>)
Update an existing entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.find "Task", "sampleTask" task["done"] = true datastore.save task
Update multiple new entities in a batch:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new query = datastore.query("Task").where("done", "=", false) tasks = datastore.run query tasks.each { |t| t["done"] = true } datastore.update tasks
#upsert
def upsert(*entities) -> Array<Google::Cloud::Datastore::Entity>
Persist one or more entities to the Datastore.
- entities (Entity) — One or more entity objects to be saved.
- (Array<Google::Cloud::Datastore::Entity>)
Insert a new entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task.key.id #=> nil datastore.save task task.key.id #=> 123456
Insert multiple new entities in a batch:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task1 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 4 t["description"] = "Learn Cloud Datastore" end task2 = datastore.entity "Task" do |t| t["type"] = "Personal" t["done"] = false t["priority"] = 5 t["description"] = "Integrate Cloud Datastore" end task_key1, task_key2 = datastore.save(task1, task2).map(&:key)
Update an existing entity:
require "google/cloud/datastore" datastore = Google::Cloud::Datastore.new task = datastore.find "Task", "sampleTask" task["priority"] = 5 datastore.save task