Constant COLLATE 

pub const COLLATE: ColumnMarker;

Specifies a collation for a text column.

PostgreSQL collation identifiers are quoted names; the DDL emitter wraps whatever you supply here in double quotes, so write the bare name ("en_US", "C", "POSIX", or any CREATE COLLATION value).

Example

#[column(COLLATE = "en_US")]
name: String,

See: https://www.postgresql.org/docs/current/collation.html