io.realm.annotations

Annotation Type PrimaryKey

@Retention(value=RUNTIME)
 @Target(value=FIELD)
public @interface PrimaryKey

The @PrimaryKey annotation will mark a field as a primary key inside Realm. Only one field in a RealmObject class can have this annotation, and the field should uniquely identify the object. Trying to insert an object with an existing primary key will result in an RealmPrimaryKeyConstraintException. Primary key cannot be changed after the object created.

Primary keys also count as having the Index annotation.

It is allowed to apply this annotation on the following primitive types: byte, short, int, and long. String, Byte, Short, Integer, and Long are also allowed, and further permitted to have null as a primary key value.