# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 341
        def initialize(td)
          super
          @constraint_validations = []
          @exclusion_constraint_adds = []
          @exclusion_constraint_drops = []
          @unique_constraint_adds = []
          @unique_constraint_drops = []
        end

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 354
        def add_exclusion_constraint(expression, options)
          @exclusion_constraint_adds << @td.new_exclusion_constraint_definition(expression, options)
        end

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 362
        def add_unique_constraint(column_name, options)
          @unique_constraint_adds << @td.new_unique_constraint_definition(column_name, options)
        end

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 358
        def drop_exclusion_constraint(constraint_name)
          @exclusion_constraint_drops << constraint_name
        end

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 366
        def drop_unique_constraint(unique_constraint_name)
          @unique_constraint_drops << unique_constraint_name
        end

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb, line 350
        def validate_constraint(name)
          @constraint_validations << name
        end