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rails / 4.2 / activerecord / connectionadapters / columndumper.html

module ActiveRecord::ConnectionAdapters::ColumnDumper

The goal of this module is to move Adapter specific column definitions to the Adapter instead of having it in the schema dumper itself. This code represents the normal case. We can then redefine how certain data types may be handled in the schema dumper on the Adapter level by over-writing this code inside the database specific adapters

Public Instance Methods

column_spec(column, types) Show source 
# File activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb, line 9
def column_spec(column, types)
  spec = prepare_column_options(column, types)
  (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k}: ")}
  spec
end
migration_keys() Show source 
# File activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb, line 36
def migration_keys
  [:name, :limit, :precision, :scale, :default, :null]
end

Lists the valid migration options

prepare_column_options(column, types) Show source 
# File activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb, line 18
def prepare_column_options(column, types)
  spec = {}
  spec[:name]      = column.name.inspect
  spec[:type]      = column.type.to_s
  spec[:null]      = 'false' unless column.null

  limit = column.limit || types[column.type][:limit]
  spec[:limit]     = limit.inspect if limit
  spec[:precision] = column.precision.inspect if column.precision
  spec[:scale]     = column.scale.inspect if column.scale

  default = schema_default(column) if column.has_default?
  spec[:default]   = default unless default.nil?

  spec
end

This can be overridden on a Adapter level basis to support other extended datatypes (Example: Adding an array option in the PostgreSQLAdapter)

© 2004–2018 David Heinemeier Hansson
Licensed under the MIT License.