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.



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

def initialize
  @connection = nil
  @gapi = {}
end

Instance Attribute Details

#connection ⇒ Object 



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# File 'lib/gcloud/bigquery/view.rb', line 45

def connection
  @connection
end

#gapi ⇒ Object 



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

def gapi
  @gapi
end

Class Method Details

.from_gapi(gapi, conn) ⇒ Object 



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# File 'lib/gcloud/bigquery/view.rb', line 383

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

Instance Method Details

#api_url ⇒ Object

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



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

def api_url
  ensure_full_data!
  @gapi["selfLink"]
end

#created_at ⇒ Object

The time when this table was created.



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

def created_at
  ensure_full_data!
  Time.at(@gapi["creationTime"] / 1000.0)
end

#data(max: nil, timeout: nil, cache: nil, 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: nil) —

    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: nil) —

    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:



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# File 'lib/gcloud/bigquery/view.rb', line 326

def data max: nil, timeout: nil, cache: nil, dryrun: nil
  sql = "SELECT * FROM #{@gapi['id']}"
  ensure_connection!
  options = { max: max, timeout: timeout, cache: cache, dryrun: dryrun }
  resp = connection.query sql, options
  if resp.success?
    QueryData.from_gapi resp.data, connection
  else
    fail ApiError.from_response(resp)
  end
end

#dataset_id ⇒ Object

The ID of the ‘Dataset` containing this table.



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# File 'lib/gcloud/bigquery/view.rb', line 74

def dataset_id
  @gapi["tableReference"]["datasetId"]
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.



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# File 'lib/gcloud/bigquery/view.rb', line 355

def delete
  ensure_connection!
  resp = connection.delete_table dataset_id, table_id
  if resp.success?
    true
  else
    fail ApiError.from_response(resp)
  end
end

#description ⇒ Object

The description of the table.



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

def description
  ensure_full_data!
  @gapi["description"]
end

#description=(new_description) ⇒ Object

Updates the description of the table.



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

def description= new_description
  patch_gapi! description: new_description
end

#etag ⇒ Object

A string hash of the dataset.



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# File 'lib/gcloud/bigquery/view.rb', line 120

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.



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

def expires_at
  ensure_full_data!
  return nil if @gapi["expirationTime"].nil?
  Time.at(@gapi["expirationTime"] / 1000.0)
end

#fields ⇒ Object

The fields of the table.



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# File 'lib/gcloud/bigquery/view.rb', line 234

def fields
  f = schema["fields"]
  f = f.to_hash if f.respond_to? :to_hash
  f = [] if f.nil?
  f
end

#headers ⇒ Object

The names of the columns in the table.



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# File 'lib/gcloud/bigquery/view.rb', line 246

def headers
  fields.map { |f| f["name"] }
end

#location ⇒ Object

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



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# File 'lib/gcloud/bigquery/view.rb', line 211

def location
  ensure_full_data!
  @gapi["location"]
end

#modified_at ⇒ Object

The date when this table was last modified.



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# File 'lib/gcloud/bigquery/view.rb', line 182

def modified_at
  ensure_full_data!
  Time.at(@gapi["lastModifiedTime"] / 1000.0)
end

#name ⇒ Object

The name of the table.



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# File 'lib/gcloud/bigquery/view.rb', line 102

def name
  @gapi["friendlyName"]
end

#name=(new_name) ⇒ Object

Updates the name of the table.



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# File 'lib/gcloud/bigquery/view.rb', line 111

def name= new_name
  patch_gapi! name: new_name
end

#project_id ⇒ Object

The ID of the ‘Project` containing this table.



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# File 'lib/gcloud/bigquery/view.rb', line 83

def project_id
  @gapi["tableReference"]["projectId"]
end

#query ⇒ Object

The query that executes each time the view is loaded.



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# File 'lib/gcloud/bigquery/view.rb', line 255

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:



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# File 'lib/gcloud/bigquery/view.rb', line 279

def query= new_query
  patch_gapi! query: new_query
end

#reload! ⇒ Object Also known as: refresh!

Reloads the table with current data from the BigQuery service.



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# File 'lib/gcloud/bigquery/view.rb', line 370

def reload!
  ensure_connection!
  resp = connection.get_table dataset_id, table_id
  if resp.success?
    @gapi = resp.data
  else
    fail ApiError.from_response(resp)
  end
end

#schema ⇒ Object

The schema of the table.



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# File 'lib/gcloud/bigquery/view.rb', line 221

def schema
  ensure_full_data!
  s = @gapi["schema"]
  s = s.to_hash if s.respond_to? :to_hash
  s = {} if s.nil?
  s
end

#table? ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'lib/gcloud/bigquery/view.rb', line 192

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.



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# File 'lib/gcloud/bigquery/view.rb', line 65

def table_id
  @gapi["tableReference"]["tableId"]
end

#table_ref ⇒ Object

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



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# File 'lib/gcloud/bigquery/view.rb', line 91

def table_ref
  table_ref = @gapi["tableReference"]
  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) 


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# File 'lib/gcloud/bigquery/view.rb', line 201

def view?
  @gapi["type"] == "VIEW"
end