@Index

@Index records index metadata on an entity. See Indexes and Foreign Keys for the full guide.

function Index(
  options?: Omit<IndexMetadata, 'columns'>,
): PropertyDecorator;
function Index(
  fields: string | string[],
  options?: Omit<IndexMetadata, 'columns'>,
): ClassDecorator;

As a property decorator, the column list is inferred from the property it's placed on:

class Customer {
  @Index({ unique: true })
  @Column({ fieldName: 'email' })
  declare email: string;
}

As a class decorator, the column list is explicit (required for composite indexes):

@Entity('customers')
@Index(['countryCode', 'city'], { name: 'idx_customer_location' })
class Customer { /* ... */ }

IndexMetadata reference

Field	Type	Description
columns	string[]	Property names making up the index. Supplied automatically by the property-decorator form; required as the first argument to the class-decorator form.
name	string	Optional index name.
unique	boolean	Marks the index as unique.
primary	boolean	Marks the index as the primary key — set internally by @PrimaryKey; you would not normally set this yourself via @Index.

@Index purely records metadata (accessible via entity.indexes, see EntityMetadata) — it does not generate DDL or alter query planning.