Class: PlantWatchdog::Model::Schema

Inherits:
ActiveRecord::Migration
  • Object
show all
Defined in:
lib/plantwatchdog/model.rb

Class Method Summary collapse

Class Method Details

.down ⇒ Object

self.up



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# File 'lib/plantwatchdog/model.rb', line 131

def self.down
  drop_table :syncs
  drop_table :devices
  drop_table :plants
  drop_table :users
  drop_table :measurement_chunks
  drop_table :metadata
end

.up ⇒ Object 



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# File 'lib/plantwatchdog/model.rb', line 70

def self.up

  create_table :users do |t|
    t.column :id, :integer # prim key
    t.column :timezone, :string # for converting UTC to local time
    t.column :password, :string
    t.column :name, :string
    # *_year is a performance optimization: it is used from the UI to find the years
    # for which there is data avalailable.
    # it could always be restored by looking at the available measurement_chunks
    t.column :start_year, :integer
    t.column :end_year, :integer
  end

  create_table :plants do |t|
    t.column :id, :integer # prim key
    t.column :user_id, :integer # foreign key
    t.column :aggregationrule_id, :integer # foreign key
  end

  # single table inheritance: inverter and sunmeter are devices
  create_table :devices do |t|
    t.column :type, :text # single table inheritance
    t.column :plant_id, :integer # foreign key
    t.column :aggregationrule_id, :integer # foreign key
    t.column :metadata_id, :integer # foreign key
    t.column :name, :string
    # the unique id is needed for the synchronization in order to assign measurements to a device
    # an example for a unique would be the serial number of an inverter
    t.column :unique_id, :string
  end

  create_table :measurement_chunks do |t|
    t.column :type, :text # for single table inheritance
    t.column :device_id, :integer
    t.column :plant_id, :integer # a Measurement Aggregate can belong to a plant instead of a device

    # the day on which data was collected according to local time
    t.column :time_year, :integer
    t.column :time_day_of_year, :integer

    t.column :data, :text, :limit => 16000000 # raw csv, limit to 16MB
    t.column :metadata_id, :integer # description of the columns of data
  end

  # metadata, used for describing the content of measurements and for describing aggregation rules
  # description must not be altered. Instead, create new records
  # whenever the column description changes
  create_table :metadata do |t|
    t.column :description, :string # serialized representation (JSON)
  end

  # performance only, could be retrieved by scanning the measurements table
  create_table :syncs do |t|
    t.column :user_id, :integer # foreign key
    t.column :device_id, :integer
    t.column :last_time, :integer # utc, epoch secs
  end

end