> ## Documentation Index
> Fetch the complete documentation index at: https://www.pgschema.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CREATE TYPE

## Syntax

```sql theme={null}
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

## Canonical Format

When generating migration SQL, pgschema produces types in the following canonical format:

```sql theme={null}
-- 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.