Class: DbMemoize::Value

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/db_memoize/value.rb

Constant Summary collapse

SQL = 
::Simple::SQL
ALL_COLUMNS = 
[
  :val_string,
  :val_integer,
  :val_float,
  :val_time,
  :val_object,
  :val_boolean,
  :val_nil
].freeze

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.ar_create_value(column, entity_table_name:, entity_id:, method_name:, value:) ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 110

def self.ar_create_value(column, entity_table_name:, entity_id:, method_name:, value:)
  # [TODO] this code is not resolving conflicts on the unique index.
  data = {
    :entity_table_name => entity_table_name,
    :entity_id => entity_id,
    :method_name => method_name,
    column => value
  }

  create!(data)
end

.delete_all_ordered ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 32

def self.delete_all_ordered
  relation = self
  relation = all unless is_a?(ActiveRecord::Relation)

  sql = relation.select(:ctid).to_sql
  SQL.ask "    DO $$DECLARE c record;\n    BEGIN\n      FOR c IN \#{sql} ORDER BY ctid LOOP\n        DELETE FROM \#{DbMemoize::Value.table_name} WHERE ctid = c.ctid;\n      END LOOP;\n    END$$;\n  SQL\nend\n"

.fast_create(entity_table_name, entity_id, method_name, value) ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 47

def self.fast_create(entity_table_name, entity_id, method_name, value)
  method_name = method_name.to_s

  # clear out old entry (if any). This makes sure that any existing value
  # is cleared out properly.
  SQL.ask "DELETE FROM #{table_name} WHERE(entity_table_name, entity_id, method_name) = ($1, $2, $3)",
          entity_table_name, entity_id, method_name

  column = case value
           when String   then :val_string
           when Integer  then :val_integer
           when Float    then :val_float
           when Time     then :val_time
           when false    then :val_boolean
           when true     then :val_boolean
           when nil      then :val_nil
           when Hash     then :val_object
           when Array    then :val_object
           else
             raise "Unsupported value of type #{value.class.name}: #{value.inspect}"
           end

  value = JSON.generate(value) if column == :val_object

  # it looks like Simple::SQL somehow drops subsecond resolutions from
  # time objects. AR does not, though. So, for time values, we use the
  # ActiveRecord method; for everything else we use Simple::SQL (for
  # performance reasons: it is 10 times as fast.)
  if column != :val_time
    simple_sql_create_value column, entity_table_name: entity_table_name, entity_id: entity_id,
                                    method_name: method_name, value: value
  else
    ar_create_value column, entity_table_name: entity_table_name, entity_id: entity_id,
                            method_name: method_name, value: value
  end
end

.simple_sql_create_value(column, entity_table_name:, entity_id:, method_name:, value:) ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 94

def self.simple_sql_create_value(column, entity_table_name:, entity_id:, method_name:, value:)
  other_columns = ALL_COLUMNS - [column]
  default_updates = other_columns.map { |c| "#{c}=NULL" }

  sql = "    INSERT INTO \#{table_name}\n      (entity_table_name, entity_id, method_name, \#{column}, created_at)\n      VALUES($1,$2,$3,$4,NOW())\n      ON CONFLICT (entity_id, entity_table_name, method_name)\n      DO UPDATE\n        SET \#{default_updates.join(', ')}, \#{column}=$4, created_at=NOW()\n  SQL\n\n  SQL.ask sql, entity_table_name, entity_id, method_name, value\nend\n".freeze

Instance Method Details

#value ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 27

def value
  # Note: val_boolean should come last.
  val_string || val_integer || val_float || val_time || val_object || val_boolean
end

#value=(value) ⇒ Object 



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# File 'lib/db_memoize/value.rb', line 12

def value=(value)
  self.val_integer = self.val_float = self.val_string = self.val_boolean = self.val_time = nil

  case value
  when String   then self.val_string = value
  when Integer  then self.val_integer = value
  when Float    then self.val_float = value
  when Time     then self.val_time = value
  when false    then self.val_boolean = value
  when true     then self.val_boolean = value
  when nil      then :nop
  else raise "Unsupported type #{value.class.name.inspect}, for DbMemoize"
  end
end