TypeDB.Concept (TypeDB v0.9.0)

The concepts TypeDB returns inside conceptRows answers.

Every entry in a row is one of:

Struct	TypeQL	Notes
`TypeDB.Concept.Entity`	an entity instance	`iid`, optional `type`
`TypeDB.Concept.Relation`	a relation instance	`iid`, optional `type`
`TypeDB.Concept.Attribute`	an attribute instance	`iid`, `value`, `value_type`, optional `type`
`TypeDB.Concept.Value`	a computed value	`value`, `value_type`
`TypeDB.Concept.EntityType`	`entity` type	`label`
`TypeDB.Concept.RelationType`	`relation` type	`label`
`TypeDB.Concept.AttributeType`	`attribute` type	`label`, optional `value_type`
`TypeDB.Concept.RoleType`	a relation role	`label`
`nil`	an unbound optional variable
a list	a list-valued variable	elements are concepts

type is nil when the query ran with include_instance_types: false.

Values

value holds the value exactly as it came over the wire, which is what the HTTP API defines: JSON primitives for boolean, integer, double and string, and strings for decimal, date, datetime, datetime-tz and duration.

Use typed_value/1 to convert to native Elixir terms:

iex> attr = %TypeDB.Concept.Attribute{iid: "0x1", value: "2024-03-01", value_type: "date"}
iex> TypeDB.Concept.typed_value(attr)
~D[2024-03-01]

Conversion never loses information: datetime-tz and duration become TypeDB.DateTimeTZ and TypeDB.Duration structs, which keep the original wire form alongside the parsed fields.

Summary

Types

category()

What kind of thing a concept is, in one atom.

entry()

A row entry: a concept, an unbound variable, or a list of concepts.

instance()

t()

type()

Functions

cast(value, arg2)

Casts a wire value given its TypeDB value type name.

category(arg1)

What kind of thing a concept is.

decode(entries)

Decodes one wire-format row entry into concept structs.

iid(arg1)

Returns the iid of an instance, or nil for types and values.

instance?(concept)

Whether the concept is data rather than schema.

label(arg1)

Returns the label of a type, or of the type of an instance when it was included.

type?(concept)

Whether the concept is a type.

typed_value(arg1)

Returns the value converted to a native Elixir term.

value(arg1)

Returns the wire-format value of an attribute or value concept, nil otherwise.

value?(concept)

Whether the concept is a bare value — a computed one, belonging to no instance.

Types

category()

@type category() ::
  :entity
  | :relation
  | :attribute
  | :entity_type
  | :relation_type
  | :attribute_type
  | :role_type
  | :value

What kind of thing a concept is, in one atom.

The same eight the protocol distinguishes, spelled the way Elixir spells atoms — :entity_type, not :entityType.

entry()

@type entry() :: t() | nil | [t()]

A row entry: a concept, an unbound variable, or a list of concepts.

instance()

@type instance() ::
  TypeDB.Concept.Entity.t()
  | TypeDB.Concept.Relation.t()
  | TypeDB.Concept.Attribute.t()

t()

@type t() :: instance() | type() | TypeDB.Concept.Value.t()

type()

@type type() ::
  TypeDB.Concept.EntityType.t()
  | TypeDB.Concept.RelationType.t()
  | TypeDB.Concept.AttributeType.t()
  | TypeDB.Concept.RoleType.t()

Functions

cast(value, arg2)

@spec cast(term(), String.t()) :: term()

Casts a wire value given its TypeDB value type name.

category(arg1)

@spec category(t()) :: category()

What kind of thing a concept is.

The counterpart of Rust's Concept::get_category, and the reason it is worth having in a language with pattern matching: a case on this is one line per branch, where matching the structs means knowing all eight module names.

iex> TypeDB.Concept.category(%TypeDB.Concept.Entity{iid: "0x0", type: nil})
:entity

iex> TypeDB.Concept.category(%TypeDB.Concept.AttributeType{label: "name"})
:attribute_type

Rust's other thirty-odd accessors are deliberately not here. try_get_integer and its dozen siblings say in a method what typed_value/1 says once, and is_entity is match?(%Entity{}, concept) — a predicate that reads worse than the match it wraps. What survives the translation is this, plus the three predicates below, which answer questions the struct name alone does not.

decode(entries)

@spec decode(term()) :: entry()

Decodes one wire-format row entry into concept structs.

Raises TypeDB.Error with kind: :decode when the payload does not look like anything the HTTP API can produce.

iid(arg1)

@spec iid(t()) :: String.t() | nil

Returns the iid of an instance, or nil for types and values.

instance?(concept)

@spec instance?(t()) :: boolean()

Whether the concept is data rather than schema.

iex> TypeDB.Concept.instance?(%TypeDB.Concept.Entity{iid: "0x0", type: nil})
true

iex> TypeDB.Concept.instance?(%TypeDB.Concept.EntityType{label: "person"})
false

label(arg1)

@spec label(t()) :: String.t() | nil

Returns the label of a type, or of the type of an instance when it was included.

type?(concept)

@spec type?(t()) :: boolean()

Whether the concept is a type.

iex> TypeDB.Concept.type?(%TypeDB.Concept.RoleType{label: "friendship:friend"})
true

typed_value(arg1)

@spec typed_value(t()) :: term()

Returns the value converted to a native Elixir term.

boolean → boolean
integer → integer
double → float
string → String.t()
decimal → Decimal.t() when the optional Decimal library is loaded, otherwise a string. TypeDB renders decimals with TypeQL's literal suffix ("12.345dec"), which is stripped either way — the value differs in type when Decimal is absent, not in content. The suffix survives in TypeDB.Concept.value/1, which is the raw wire value
date → Date.t()
datetime → NaiveDateTime.t()
datetime-tz → TypeDB.DateTimeTZ.t()
duration → TypeDB.Duration.t()

Values that cannot be parsed are returned unchanged rather than raising, so a future TypeDB value type never breaks a running application.

value(arg1)

@spec value(t()) :: term()

Returns the wire-format value of an attribute or value concept, nil otherwise.

value?(concept)

@spec value?(t()) :: boolean()

Whether the concept is a bare value — a computed one, belonging to no instance.

iex> TypeDB.Concept.value?(%TypeDB.Concept.Value{value: 3, value_type: "integer"})
true

An attribute is not one: it has a value and is also a thing in the database. value/1 and typed_value/1 read both.