# Annotation Type Id

@Retention(CLASS) @Target(FIELD) public @interface Id
Designates the primary-key field of an `@Entity`. Exactly one field per entity must carry `@Id`. The field type may be `long`, `int`, `String`, or a `Property` wrapper of one of those.

- ## Optional Element Summary

  Optional Elements
  Modifier and Type
  Optional Element
  Description
  `boolean`
  `autoIncrement`
  When true (the default) the underlying column is declared `INTEGER PRIMARY KEY AUTOINCREMENT`.

- ## Element Details

  - ### autoIncrement

    boolean autoIncrement
    When true (the default) the underlying column is declared `INTEGER PRIMARY KEY AUTOINCREMENT`. Set false when the application assigns its own keys (UUIDs, server-issued ids, ...).
    Default:
      `true`