​
Syntax

create_type ::= CREATE TYPE type_name AS enum_type
              | CREATE TYPE type_name AS composite_type

enum_type ::= ENUM ( [ enum_value [, ...] ] )

composite_type ::= ( attribute_definition [, ...] )

type_name ::= [schema.]name

enum_value ::= 'value'

attribute_definition ::= attribute_name data_type
pgschema understands the following CREATE TYPE features:
  • Schema-qualified names: Types can be defined in specific schemas
  • ENUM types: User-defined enumeration types
    • Empty enums (no values)
    • Single-quoted string values
    • Multiple values separated by commas
  • Composite types: Row types with named attributes
    • Multiple attributes with their data types
    • Any valid PostgreSQL data type for attributes
    • Named attributes for structured data

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Canonical Format

When generating migration SQL, pgschema produces types in the following canonical format: 
-- ENUM type with no values
CREATE TYPE [schema.]type_name AS ENUM ();

-- ENUM type with values (multi-line format)
CREATE TYPE [schema.]type_name AS ENUM (
    'value1',
    'value2',
    'value3'
);

-- Composite type (single line)
CREATE TYPE [schema.]type_name AS (attribute1 data_type, attribute2 data_type);
Key characteristics of the canonical format:
  • Uses single-line format for empty enums
  • Uses multi-line format with indentation for enums with values
  • Each enum value is on its own indented line for readability
  • No comma after the last enum value
  • Composite types use single-line format with attributes separated by commas
  • For DROP operations: DROP TYPE IF EXISTS type_name RESTRICT;
  • ENUM types can be modified by adding values with ALTER TYPE type_name ADD VALUE 'new_value' AFTER 'existing_value';
Note: Composite type modifications in pgschema currently require dropping and recreating the type, as PostgreSQL has limited ALTER TYPE support for composite types and complex dependencies make in-place modifications challenging.