Class: Google::Cloud::Bigquery::Schema

Inherits:
Object
  • Object
show all
Defined in:
lib/google/cloud/bigquery/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.

Examples:

require "google/cloud"

gcloud = Google::Cloud.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

See Also:

Defined Under Namespace

Classes: Field

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Schema

Returns a new instance of Schema



46
47
48
 
# File 'lib/google/cloud/bigquery/schema.rb', line 46

def initialize
  @nested = nil
end

Instance Method Details

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

Adds a boolean field to the schema.

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.



167
168
169
 
# File 'lib/google/cloud/bigquery/schema.rb', line 167

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

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


59
60
61
 
# File 'lib/google/cloud/bigquery/schema.rb', line 59

def empty?
  fields.empty?
end

#fields ⇒ Object 



50
51
52
 
# File 'lib/google/cloud/bigquery/schema.rb', line 50

def fields
  @fields ||= @gapi.fields.map { |f| Field.from_gapi f }
end

#fields=(new_fields) ⇒ Object 



54
55
56
57
 
# File 'lib/google/cloud/bigquery/schema.rb', line 54

def fields= new_fields
  @gapi.fields = Array(new_fields).map(&:to_gapi)
  @fields = @gapi.fields.map { |f| Field.from_gapi f }
end

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

Adds a floating-point number field to the schema.

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.



152
153
154
 
# File 'lib/google/cloud/bigquery/schema.rb', line 152

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

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

Adds an integer field to the schema.

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.



137
138
139
 
# File 'lib/google/cloud/bigquery/schema.rb', line 137

def integer name, description: nil, mode: :nullable
  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 .

Examples:

require "google/cloud"

gcloud = Google::Cloud.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

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.

Yields:

  • (nested_schema) —

    a block for setting the nested schema

Yield Parameters:

  • nested_schema (Schema) —

    the object accepting the nested schema



220
221
222
223
224
225
226
227
228
229
230
 
# File 'lib/google/cloud/bigquery/schema.rb', line 220

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?
  empty_schema = Google::Apis::BigqueryV2::TableSchema.new fields: []
  nested_schema = self.class.from_gapi(empty_schema).tap do |s|
    s.instance_variable_set :@nested, true
  end
  yield nested_schema
  add_field name, :record, nested_schema.fields,
            description: description, mode: mode
end

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

Adds a string field to the schema.

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.



122
123
124
 
# File 'lib/google/cloud/bigquery/schema.rb', line 122

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

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

Adds a timestamp field to the schema.

Parameters:

  • name (String) —

    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.

  • description (String) —

    A description of the field.

  • mode (Symbol) —

    The field's mode. The possible values are :nullable, :required, and :repeated. The default value is :nullable.



182
183
184
 
# File 'lib/google/cloud/bigquery/schema.rb', line 182

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