Class: Gcloud::Bigquery::Table::Schema

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

Overview

Table Schema

A builder for BigQuery table schemas, passed to block arguments to Dataset#create_table and Table#schema. Supports nested and repeated fields via a nested block. For more information about BigQuery schema definitions, see Preparing Data for BigQuery .

require "gcloud"

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

table.schema do |schema|
  schema.string "first_name", mode: :required
  schema.record "cities_lived", mode: :repeated do |cities_lived|
    cities_lived.string "place", mode: :required
    cities_lived.integer "number_of_years", mode: :required
  end
end

Constant Summary collapse

MODES =

:nodoc:

%w( NULLABLE REQUIRED REPEATED )
TYPES =

:nodoc:

%w( STRING INTEGER FLOAT BOOLEAN TIMESTAMP RECORD )

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(schema = nil, nested = false) ⇒ Schema

Initializes a new schema object with an existing schema.



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# File 'lib/gcloud/bigquery/table/schema.rb', line 51

def initialize schema = nil, nested = false #:nodoc:
  fields = (schema && schema["fields"]) || []
  @original_fields = fields.dup
  @fields = fields.dup
  @nested = nested
end

Instance Attribute Details

#fields ⇒ Object (readonly)

:nodoc:



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# File 'lib/gcloud/bigquery/table/schema.rb', line 47

def fields
  @fields
end

Instance Method Details

#boolean(name, description: nil, mode: nil) ⇒ Object

Adds a boolean field to the schema.

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)



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# File 'lib/gcloud/bigquery/table/schema.rb', line 141

def boolean name, description: nil, mode: nil
  add_field name, :boolean, nil, description: description, mode: mode
end

#changed? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/gcloud/bigquery/table/schema.rb', line 58

def changed? #:nodoc:
  @original_fields != @fields
end

#float(name, description: nil, mode: nil) ⇒ Object

Adds a floating-point number field to the schema.

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)



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# File 'lib/gcloud/bigquery/table/schema.rb', line 123

def float name, description: nil, mode: nil
  add_field name, :float, nil, description: description, mode: mode
end

#integer(name, description: nil, mode: nil) ⇒ Object

Adds an integer field to the schema.

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)



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# File 'lib/gcloud/bigquery/table/schema.rb', line 105

def integer name, description: nil, mode: nil
  add_field name, :integer, nil, description: description, mode: mode
end

#record(name, description: nil, mode: nil) {|nested_schema| ... } ⇒ Object

Adds a record field to the schema. A block must be passed describing the nested fields of the record. For more information about nested and repeated records, see Preparing Data for BigQuery .

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)

Example

require "gcloud"

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

table.schema do |schema|
  schema.string "first_name", mode: :required
  schema.record "cities_lived", mode: :repeated do |cities_lived|
    cities_lived.string "place", mode: :required
    cities_lived.integer "number_of_years", mode: :required
  end
end

Yields:

  • (nested_schema) 


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# File 'lib/gcloud/bigquery/table/schema.rb', line 198

def record name, description: nil, mode: nil
  fail ArgumentError, "nested RECORD type is not permitted" if @nested
  fail ArgumentError, "a block is required" unless block_given?
  nested_schema = self.class.new nil, true
  yield nested_schema
  add_field name, :record, nested_schema.fields,
            description: description, mode: mode
end

#schema ⇒ Object

Returns the schema as hash containing the keys and values specified by the Google Cloud BigQuery Rest API .



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# File 'lib/gcloud/bigquery/table/schema.rb', line 67

def schema #:nodoc:
  {
    "fields" => @fields
  }
end

#string(name, description: nil, mode: nil) ⇒ Object

Adds a string field to the schema.

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)



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# File 'lib/gcloud/bigquery/table/schema.rb', line 87

def string name, description: nil, mode: nil
  add_field name, :string, nil, description: description, mode: mode
end

#timestamp(name, description: nil, mode: nil) ⇒ Object

Adds a timestamp field to the schema.

Parameters

name

The field name. The name must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_), and must start with a letter or underscore. The maximum length is 128 characters. (String)

description

A description of the field. (String)

mode

The field’s mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable. (Symbol)



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

def timestamp name, description: nil, mode: nil
  add_field name, :timestamp, nil, description: description, mode: mode
end