forked from fixin.me/fixin.me
64 lines
2.9 KiB
Ruby
64 lines
2.9 KiB
Ruby
class CreateReadouts < ActiveRecord::Migration[8.1]
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def change
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create_table :measurements do |t|
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t.datetime :taken_at, null: false
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#t.references :collector, foreign_key: true
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#t.references :device, foreign_key: true
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#t.references :note, foreign_key: true
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t.timestamps
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end
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add_index :measurements, :taken_at
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# Defining Readouts as a super-/subclass polymorphic relations for different
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# subclass data types (numeric, string, file) is not possible with proper
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# referential integrity constraints. The required constraints are:
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# * for every subclass record to have superclass record,
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# * for every superclass record to have only one type of subclass record,
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# * for every superclass record to have subclass record (unenforcable).
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# * this can be partially remedied by making superlass an abstract class in
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# Rails and disallow direct creation of records, but direct data
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# manipulation can still break referential integrity.
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# Defining separate {Numeric,Text,File}_Readouts tables would make the
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# unique index constraint unenforcable.
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create_table :readouts do |t|
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t.references :user, null: false, foreign_key: {on_delete: :cascade}
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t.references :measurement, foreign_key: {on_delete: :cascade}
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t.references :quantity, null: false, foreign_key: {on_delete: :cascade}
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t.integer :category, null: false, default: 0
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t.float :value, null: false, limit: Float::MANT_DIG
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t.references :unit, null: false, foreign_key: {on_delete: :cascade}
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# TODO: consider additional columns to allow wider range of value types
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# t.text :text
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# t.datetime :time
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# t.references :file
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# Possibly mutually exclusive with :unit or check constraint for:
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# :unit is not null <=> :value is not null
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t.timestamps
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end
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add_index :readouts, [:measurement_id, :quantity_id, :category]
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add_foreign_key :readouts, :quantities, column: [:quantity_id, :user_id],
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primary_key: [:id, :user_id]
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add_foreign_key :readouts, :units, column: [:unit_id, :user_id],
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primary_key: [:id, :user_id]
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# TODO: remove below tables after current setup verified
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#create_table :numeric_values do |t|
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# t.references :readout, null: false, foreign_key: {on_delete: :cascade}
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# t.float :value, null: false, limit: Float::MANT_DIG
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# t.references :unit, null: false, foreign_key: {on_delete: :cascade}
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# # + generated, not stored column :value_type
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# # + foreign key constraint to readouts: [:readout_id, :value_id, :value_type]
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# # or 2 constraints: [:readout_id, :value_id], [:value_id, :value_type]
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# # if readouts.value_id needed, otherwise just one constraint:
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# # [:readout_id, :value_type]
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#end
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#create_table :string_values do |t|
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# t.references :readout, null: false, foreign_key: {on_delete: :cascade}
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# t.string :value, null: false, limit: 32
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#end
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end
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end
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