Class: Gcloud::Bigquery::View

Inherits:
Object
  • Object
show all
Defined in:
lib/gcloud/bigquery/view.rb

Overview

# View

A view is a virtual table defined by a SQL query. You can query views in the browser tool, or by using a query job.

BigQuery’s views are logical views, not materialized views, which means that the query that defines the view is re-executed every time the view is queried. Queries are billed according to the total amount of data in all table fields referenced directly or indirectly by the top-level query.

Examples:

require "gcloud"

gcloud = Gcloud.new
bigquery = gcloud.bigquery
dataset = bigquery.dataset "my_dataset"
view = dataset.create_view "my_view",
         "SELECT name, age FROM [proj:dataset.users]"

Instance Attribute Summary collapse

Attributes collapse

Lifecycle collapse

Data collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ View

Returns a new instance of View.



55
56
57
58
 
# File 'lib/gcloud/bigquery/view.rb', line 55

def initialize
  @service = nil
  @gapi = Google::Apis::BigqueryV2::Table.new
end

Instance Attribute Details

#gapi ⇒ Object 



51
52
53
 
# File 'lib/gcloud/bigquery/view.rb', line 51

def gapi
  @gapi
end

#service ⇒ Object 



47
48
49
 
# File 'lib/gcloud/bigquery/view.rb', line 47

def service
  @service
end

Class Method Details

.from_gapi(gapi, conn) ⇒ Object 



417
418
419
420
421
422
 
# File 'lib/gcloud/bigquery/view.rb', line 417

def self.from_gapi gapi, conn
  new.tap do |f|
    f.gapi = gapi
    f.service = conn
  end
end

Instance Method Details

#api_url ⇒ Object

A URL that can be used to access the dataset using the REST API.



168
169
170
171
 
# File 'lib/gcloud/bigquery/view.rb', line 168

def api_url
  ensure_full_data!
  @gapi.self_link
end

#created_at ⇒ Object

The time when this table was created.



198
199
200
201
202
203
204
205
 
# File 'lib/gcloud/bigquery/view.rb', line 198

def created_at
  ensure_full_data!
  begin
    Time.at(Integer(@gapi.creation_time) / 1000.0)
  rescue
    nil
  end
end

#data(max: nil, timeout: 10000, cache: true, dryrun: nil) ⇒ Gcloud::Bigquery::QueryData

Runs a query to retrieve all data from the view.

Examples:

require "gcloud"

gcloud = Gcloud.new
bigquery = gcloud.bigquery
dataset = bigquery.dataset "my_dataset"
view = dataset.table "my_view"

data = view.data
data.each do |row|
  puts row["first_name"]
end
more_data = data.next if data.next?

Parameters:

  • max (Integer) (defaults to: nil) —

    The maximum number of rows of data to return per page of results. Setting this flag to a small value such as 1000 and then paging through results might improve reliability when the query result set is large. In addition to this limit, responses are also limited to 10 MB. By default, there is no maximum row count, and only the byte limit applies.

  • timeout (Integer) (defaults to: 10000) —

    How long to wait for the query to complete, in milliseconds, before the request times out and returns. Note that this is only a timeout for the request, not the query. If the query takes longer to run than the timeout value, the call returns without any results and with QueryData#complete? set to false. The default value is 10000 milliseconds (10 seconds).

  • cache (Boolean) (defaults to: true) —

    Whether to look for the result in the query cache. The query cache is a best-effort cache that will be flushed whenever tables in the query are modified. The default value is true. For more information, see [query caching](developers.google.com/bigquery/querying-data).

  • dryrun (Boolean) (defaults to: nil) —

    If set to ‘true`, BigQuery doesn’t run the job. Instead, if the query is valid, BigQuery returns statistics about the job such as how many bytes would be processed. If the query is invalid, an error returns. The default value is ‘false`.

Returns:



372
373
374
375
376
377
378
 
# File 'lib/gcloud/bigquery/view.rb', line 372

def data max: nil, timeout: 10000, cache: true, dryrun: nil
  sql = "SELECT * FROM #{query_id}"
  ensure_service!
  options = { max: max, timeout: timeout, cache: cache, dryrun: dryrun }
  gapi = service.query sql, options
  QueryData.from_gapi gapi, service
end

#dataset_id ⇒ Object

The ID of the ‘Dataset` containing this table.



76
77
78
 
# File 'lib/gcloud/bigquery/view.rb', line 76

def dataset_id
  @gapi.table_reference.dataset_id
end

#delete ⇒ Boolean

Permanently deletes the table.

Examples:

require "gcloud"

gcloud = Gcloud.new
bigquery = gcloud.bigquery
dataset = bigquery.dataset "my_dataset"
table = dataset.table "my_table"

table.delete

Returns:

  • (Boolean) —

    Returns ‘true` if the table was deleted.



397
398
399
400
401
 
# File 'lib/gcloud/bigquery/view.rb', line 397

def delete
  ensure_service!
  service.delete_table dataset_id, table_id
  true
end

#description ⇒ Object

The description of the table.



178
179
180
181
 
# File 'lib/gcloud/bigquery/view.rb', line 178

def description
  ensure_full_data!
  @gapi.description
end

#description=(new_description) ⇒ Object

Updates the description of the table.



188
189
190
191
 
# File 'lib/gcloud/bigquery/view.rb', line 188

def description= new_description
  @gapi.update! description: new_description
  patch_gapi! :description
end

#etag ⇒ Object

A string hash of the dataset.



158
159
160
161
 
# File 'lib/gcloud/bigquery/view.rb', line 158

def etag
  ensure_full_data!
  @gapi.etag
end

#expires_at ⇒ Object

The time when this table expires. If not present, the table will persist indefinitely. Expired tables will be deleted and their storage reclaimed.



214
215
216
217
218
219
220
221
 
# File 'lib/gcloud/bigquery/view.rb', line 214

def expires_at
  ensure_full_data!
  begin
    Time.at(Integer(@gapi.expiration_time) / 1000.0)
  rescue
    nil
  end
end

#fields ⇒ Object

The fields of the view.



281
282
283
 
# File 'lib/gcloud/bigquery/view.rb', line 281

def fields
  schema.fields
end

#headers ⇒ Object

The names of the columns in the view.



290
291
292
 
# File 'lib/gcloud/bigquery/view.rb', line 290

def headers
  fields.map(&:name)
end

#id ⇒ Object

The combined Project ID, Dataset ID, and Table ID for this table, in the format specified by the [Query Reference](cloud.google.com/bigquery/query-reference#from): ‘project_name:datasetId.tableId`. To use this value in queries see #query_id.



108
109
110
 
# File 'lib/gcloud/bigquery/view.rb', line 108

def id
  @gapi.id
end

#location ⇒ Object

The geographic location where the table should reside. Possible values include EU and US. The default value is US.



261
262
263
264
 
# File 'lib/gcloud/bigquery/view.rb', line 261

def location
  ensure_full_data!
  @gapi.location
end

#modified_at ⇒ Object

The date when this table was last modified.



228
229
230
231
232
233
234
235
 
# File 'lib/gcloud/bigquery/view.rb', line 228

def modified_at
  ensure_full_data!
  begin
    Time.at(Integer(@gapi.last_modified_time) / 1000.0)
  rescue
    nil
  end
end

#name ⇒ Object

The name of the table.



139
140
141
 
# File 'lib/gcloud/bigquery/view.rb', line 139

def name
  @gapi.friendly_name
end

#name=(new_name) ⇒ Object

Updates the name of the table.



148
149
150
151
 
# File 'lib/gcloud/bigquery/view.rb', line 148

def name= new_name
  @gapi.update! friendly_name: new_name
  patch_gapi! :friendly_name
end

#project_id ⇒ Object

The ID of the ‘Project` containing this table.



85
86
87
 
# File 'lib/gcloud/bigquery/view.rb', line 85

def project_id
  @gapi.table_reference.project_id
end

#query ⇒ Object

The query that executes each time the view is loaded.



299
300
301
 
# File 'lib/gcloud/bigquery/view.rb', line 299

def query
  @gapi.view.query if @gapi.view
end

#query=(new_query) ⇒ Object

Updates the query that executes each time the view is loaded.

Examples:

require "gcloud"

gcloud = Gcloud.new
bigquery = gcloud.bigquery
dataset = bigquery.dataset "my_dataset"
view = dataset.table "my_view"

view.query = "SELECT first_name FROM [my_project:my_dataset.my_table]"

Parameters:

  • new_query (String) —

    The query that defines the view.

See Also:



323
324
325
326
327
 
# File 'lib/gcloud/bigquery/view.rb', line 323

def query= new_query
  @gapi.view ||= Google::Apis::BigqueryV2::ViewDefinition.new
  @gapi.view.update! query: new_query
  patch_view_gapi! :query
end

#query_id ⇒ Object

The value returned by #id, wrapped in square brackets if the Project ID contains dashes, as specified by the [Query Reference](cloud.google.com/bigquery/query-reference#from). Useful in queries.

Examples:

require "gcloud"

gcloud = Gcloud.new
bigquery = gcloud.bigquery
dataset = bigquery.dataset "my_dataset"
table = dataset.table "my_table"

data = bigquery.query "SELECT name FROM #{table.query_id}"



130
131
132
 
# File 'lib/gcloud/bigquery/view.rb', line 130

def query_id
  project_id["-"] ? "[#{id}]" : id
end

#reload! ⇒ Object Also known as: refresh!

Reloads the table with current data from the BigQuery service.



408
409
410
411
412
 
# File 'lib/gcloud/bigquery/view.rb', line 408

def reload!
  ensure_service!
  gapi = service.get_table dataset_id, table_id
  @gapi = gapi
end

#schema ⇒ Object

The schema of the view.



271
272
273
274
 
# File 'lib/gcloud/bigquery/view.rb', line 271

def schema
  ensure_full_data!
  Schema.from_gapi(@gapi.schema).freeze
end

#table? ⇒ Boolean

Checks if the table’s type is “TABLE”.

Returns:

  • (Boolean) 


242
243
244
 
# File 'lib/gcloud/bigquery/view.rb', line 242

def table?
  @gapi.type == "TABLE"
end

#table_id ⇒ Object

A unique ID for this table. The ID must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_). The maximum length is 1,024 characters.



67
68
69
 
# File 'lib/gcloud/bigquery/view.rb', line 67

def table_id
  @gapi.table_reference.table_id
end

#table_ref ⇒ Object

The gapi fragment containing the Project ID, Dataset ID, and Table ID as a camel-cased hash.



93
94
95
96
97
 
# File 'lib/gcloud/bigquery/view.rb', line 93

def table_ref
  table_ref = @gapi.table_reference
  table_ref = table_ref.to_hash if table_ref.respond_to? :to_hash
  table_ref
end

#view? ⇒ Boolean

Checks if the table’s type is “VIEW”.

Returns:

  • (Boolean) 


251
252
253
 
# File 'lib/gcloud/bigquery/view.rb', line 251

def view?
  @gapi.type == "VIEW"
end