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@ForeignKey

@ForeignKey records a foreign-key relationship from a column to another entity. See Indexes and Foreign Keys for the full guide.

function ForeignKey(type: TypeThunk, targetKey?: string): PropertyDecorator;
@Entity({ tableName: 'customer_tags' })
@PrimaryKey(['customerId', 'tagId'])
class CustomerTag {
  @Column({ fieldName: 'customer_id', notNull: true })
  @ForeignKey(async () => (await import('./customer.entity.js')).Customer)
  declare customerId: number;

  @Column({ fieldName: 'tag_id', notNull: true })
  declare tagId: number;
}
  • type — the referenced entity, or a thunk (() => Type | Promise<Type>) to avoid circular imports, same as @Link and @Embedded.
  • targetKey — the referenced column on the target entity. When omitted, it's resolved the same way an unqualified @Link resolves its target key (defaults to the target's single-column primary key).

Declared foreign keys are stored on entity.foreignKeys and are looked up automatically by @Link when a link declares no explicit sourceKey/targetKey of its own. Like @Index, @ForeignKey only records metadata for @sqb/connect's own use (key resolution, introspection) — it does not emit a DDL constraint.