Scalars — ASL

Built-in scalars

ASL type	PostgreSQL type
str	TEXT
int16	SMALLINT
int32	INTEGER
int64	BIGINT
float32	REAL
float64	DOUBLE PRECISION
bool	BOOLEAN
uuid	UUID
datetime	TIMESTAMPTZ
date	DATE
time	TIME
json	JSON
jsonb	JSONB
bytes	BYTEA
decimal	NUMERIC

json vs jsonb

Axel explicitly distinguishes between PostgreSQL’s JSON and JSONB types:

• jsonb (JSONB): Stored in a decomposed binary format. Preferred for structured data that must be queried, filtered, searched, or indexed (GIN indexes, expression indexes).
• json (JSON): Stored as exact text. Use only when the original JSON formatting, key ordering, or duplicate keys must be preserved, or when the payload is completely opaque.

Using uuid with pgcrypto

To generate UUIDs automatically (e.g. default := gen_random_uuid(); or gen_uuid()), enable the pgcrypto PostgreSQL extension in your schema:

use extension 'pgcrypto';

type User {
  required id: uuid {
    default := gen_random_uuid();
    constraint pk;
  };
  required email: str;
}