Summary

When generating entities using sea-orm-cli generate entity, if a table has a partial unique index on a single column, that column is incorrectly interpreted as globally unique.

This results in incorrect entity annotations and relationship inference, such as:

• The column is marked as #[sea_orm(unique)], even though it’s only conditionally unique.
• The generator infers a has_one relationship instead of the correct has_many.

Example

Consider the following abstract schema:

CREATE TABLE B (
  id SERIAL PRIMARY KEY,
  a_id INTEGER NOT NULL,
  flag BOOLEAN NOT NULL DEFAULT FALSE,
  
  -- 1. Normal unique index
  UNIQUE (a_id, flag),
  
  -- 2. Partial unique index
  UNIQUE (a_id) WHERE flag = TRUE
);

The second constraint is a partial unique index. sea orm cli currently treats this as if the column a_id were fully unique, resulting in the following incorrect code:

// Incorrect: a_id is not globally unique, only under a condition
#[sea_orm(unique)]
pub a_id: i32,
pub flag: bool,

// Generated relation of table A
pub enum Relation {
    // Here should be has_many
    #[sea_orm(has_one = "super::a::Entity")]
    B,
}

Environment

Sea orm cli: 1.1.10
Database: PostgreSQL 17

Feature Request：Infer Conditional has_one from Partial Unique Index

In addition to avoiding incorrect #[sea_orm(unique)] attributes, it would be useful if Sea-ORM could detect common patterns involving partial unique indexes with flags and generate relation for it, such as:

UNIQUE (a_id) WHERE flag = TRUE

pub enum Relation {
    #[sea_orm(has_many = "super::a::Entity")]
    B,
    #[sea_orm(has_one = "super::a::Entity")]
    BAndFlag
}