Method: ActiveRecord::ConnectionAdapters::SchemaStatements#column_exists?

Defined in:
activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

#column_exists?(table_name, column_name, type = nil, **options) ⇒ Boolean

Checks to see if a column exists in a given table.

# Check a column exists
column_exists?(:suppliers, :name)

# Check a column exists of a particular type
#
# This works for standard non-casted types (eg. string) but is unreliable
# for types that may get cast to something else (eg. char, bigint).
column_exists?(:suppliers, :name, :string)

# Check a column exists with a specific definition
column_exists?(:suppliers, :name, :string, limit: 100)
column_exists?(:suppliers, :name, :string, default: 'default')
column_exists?(:suppliers, :name, :string, null: false)
column_exists?(:suppliers, :tax, :decimal, precision: 8, scale: 2)

Returns:

  • (Boolean) 


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# File 'activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb', line 132

def column_exists?(table_name, column_name, type = nil, **options)
  column_name = column_name.to_s
  checks = []
  checks << lambda { |c| c.name == column_name }
  checks << lambda { |c| c.type == type.to_sym rescue nil } if type
  column_options_keys.each do |attr|
    checks << lambda { |c| c.send(attr) == options[attr] } if options.key?(attr)
  end

  columns(table_name).any? { |c| checks.all? { |check| check[c] } }
end