SCHEMA SDAI_dictionary_schema;

TYPE base_type = SELECT
  (simple_type,
  aggregation_type,
  named_type);
END_TYPE;

TYPE constructed_type = SELECT
  (enumeration_type,
  select_type);
END_TYPE;

TYPE underlying_type = SELECT
  (simple_type,
  aggregation_type,
  defined_type,
  constructed_type);
END_TYPE;

TYPE type_or_rule =  SELECT
  (named_type,
  global_rule);
END_TYPE;

TYPE explicit_or_derived = SELECT
  (explicit_attribute,
  derived_attribute);
END_TYPE;

TYPE express_id = STRING;
END_TYPE;

TYPE info_object_id = STRING;
END_TYPE;

ENTITY schema_definition;
  name           : express_id;
  identification : OPTIONAL info_object_id;
INVERSE
  entities         : SET [0:?] OF entity_definition FOR parent_schema;
  types            : SET [0:?] OF defined_type FOR parent_schema;
  global_rules     : SET [0:?] OF global_rule FOR parent_schema;
  external_schemas : SET [0:?] OF external_schema FOR native_schema;
UNIQUE
  UR1 : identification;
END_ENTITY;

ENTITY interface_specification;
  current_schema_id : express_id;
  explicit_items    : SET [1:?] OF explicit_item_id;
  implicit_items    : SET [0:?] OF implicit_item_id;
END_ENTITY;

ENTITY interfaced_item
  ABSTRACT SUPERTYPE OF (ONEOF (explicit_item_id, implicit_item_id));
  foreign_schema_id : express_id;
END_ENTITY;

ENTITY explicit_item_id
  ABSTRACT SUPERTYPE OF (ONEOF (used_item, referenced_item))
  SUBTYPE OF ( interfaced_item );
  local_definition : named_type;
  original_id      : OPTIONAL express_id;
END_ENTITY;

ENTITY used_item
  SUBTYPE OF ( explicit_item_id );
END_ENTITY;

ENTITY referenced_item
  SUBTYPE OF ( explicit_item_id );
END_ENTITY;

ENTITY implicit_item_id
  SUBTYPE OF ( interfaced_item );
  local_definition : type_or_rule;
END_ENTITY;

ENTITY external_schema;
  name          : express_id;
  native_schema : schema_definition;
INVERSE
  for_types : SET [1:?] OF domain_equivalent_type FOR owner;
END_ENTITY;

ENTITY domain_equivalent_type;
  external_type_id : express_id;
  native_type      : named_type;
  owner            : external_schema;
END_ENTITY;

ENTITY named_type
  ABSTRACT SUPERTYPE OF (ONEOF(entity_definition, defined_type));
  name          : express_id;
  where_rules   : LIST [0:?] OF where_rule;
  parent_schema : schema_definition;
END_ENTITY;

ENTITY defined_type
  SUBTYPE OF (named_type);
  domain : underlying_type;
END_ENTITY;

ENTITY entity_definition
  SUBTYPE OF (named_type);
  supertypes   : LIST [0:?] OF UNIQUE entity_definition;
  complex      : BOOLEAN;
  instantiable : BOOLEAN;
  independent  : BOOLEAN;
INVERSE
  attributes       : SET [0:?] OF attribute FOR parent_entity;
  uniqueness_rules : SET [0:?] OF uniqueness_rule FOR parent_entity;
  global_rules     : SET [0:?] OF global_rule FOR entities;
END_ENTITY;

ENTITY attribute
  ABSTRACT SUPERTYPE OF (ONEOF(derived_attribute, explicit_attribute,
   inverse_attribute));
  name          : express_id;
  parent_entity : entity_definition;
END_ENTITY;

ENTITY derived_attribute
  SUBTYPE OF (attribute);
  domain      : base_type;
  redeclaring : OPTIONAL explicit_or_derived;
END_ENTITY;

ENTITY explicit_attribute
  SUBTYPE OF (attribute);
  domain        : base_type;
  redeclaring   : OPTIONAL explicit_attribute;
  optional_flag : BOOLEAN;
END_ENTITY;

ENTITY inverse_attribute
  SUBTYPE OF (attribute);
  domain          : entity_definition;
  redeclaring     : OPTIONAL inverse_attribute;
  inverted_attr   : explicit_attribute;
  min_cardinality : OPTIONAL bound;
  max_cardinality : OPTIONAL bound;
  duplicates      : BOOLEAN;
END_ENTITY;

ENTITY uniqueness_rule;
  label         : OPTIONAL express_id;
  attributes    : LIST [1:?] OF attribute;
  parent_entity : entity_definition;
END_ENTITY;

ENTITY where_rule;
  label       : OPTIONAL express_id;
  parent_item : type_or_rule;
END_ENTITY;

ENTITY global_rule;
  name          : express_id;
  entities      : LIST [1:?] OF entity_definition;
  where_rules   : LIST [1:?] OF where_rule; 
  parent_schema : schema_definition;
END_ENTITY;

ENTITY simple_type
  ABSTRACT SUPERTYPE OF (ONEOF(integer_type, real_type, string_type,
   binary_type, logical_type, boolean_type, number_type));
END_ENTITY;

ENTITY number_type
  SUBTYPE OF (simple_type);
END_ENTITY;

ENTITY integer_type
  SUBTYPE OF (simple_type);
END_ENTITY;

ENTITY real_type
  SUBTYPE OF (simple_type);
  precision : OPTIONAL bound;
END_ENTITY;

ENTITY string_type
  SUBTYPE OF (simple_type);
  width       : OPTIONAL bound;
  fixed_width : BOOLEAN;
END_ENTITY;

ENTITY binary_type
  SUBTYPE OF (simple_type);
  width       : OPTIONAL bound;
  fixed_width : BOOLEAN;
END_ENTITY;

ENTITY logical_type
  SUBTYPE OF (simple_type);
END_ENTITY;

ENTITY boolean_type
  SUBTYPE OF (simple_type);
END_ENTITY;

ENTITY enumeration_type;
  elements : LIST [1:?] OF UNIQUE express_id;
END_ENTITY;

ENTITY select_type;
  selections : SET [1:?] OF named_type;
END_ENTITY;

ENTITY aggregation_type
  ABSTRACT SUPERTYPE OF (ONEOF(variable_size_aggregation_type,
  array_type));
  element_type : base_type;
END_ENTITY;

ENTITY variable_size_aggregation_type
  ABSTRACT SUPERTYPE OF (ONEOF(set_type, bag_type, list_type))
  SUBTYPE OF (aggregation_type);
  lower_bound : bound;
  upper_bound : OPTIONAL bound;
END_ENTITY;

ENTITY set_type
  SUBTYPE OF (variable_size_aggregation_type);
END_ENTITY;

ENTITY bag_type
  SUBTYPE OF (variable_size_aggregation_type);
END_ENTITY;

ENTITY list_type
  SUBTYPE OF (variable_size_aggregation_type);
  unique_flag : BOOLEAN;
END_ENTITY;

ENTITY array_type
  SUBTYPE OF (aggregation_type);
  lower_index   : bound;
  upper_index   : bound;
  unique_flag   : BOOLEAN;
  optional_flag : BOOLEAN;
END_ENTITY;

ENTITY bound
  ABSTRACT SUPERTYPE OF (ONEOF(integer_bound, population_dependent_bound));
END_ENTITY;

ENTITY population_dependent_bound
  SUBTYPE OF (bound);
END_ENTITY;

ENTITY integer_bound
  SUBTYPE OF (bound);
  bound_value : INTEGER;
END_ENTITY;

END_SCHEMA; -- SDAI_dictionary_schema