greenrobot/greenDAO · error · DaoException

Entity has no key

Error message

Entity has no key

What it means

getKeyVerified() found the entity non-null but getKey(entity) returned null, meaning the entity has no primary key assigned. greenDAO throws DaoException('Entity has no key') because callers of getKeyVerified require a guaranteed key.

Solutions

1. insert(entity) first so the key is assigned before key-required operations.
2. Use insertOrUpdate for upsert semantics.
3. Check dao.getKey(entity) != null before proceeding.
4. Assign the primary key manually if the schema permits (non-autoincrement).

Example fix

// before
if (dao.getKeyVerified(user) != null) { ... } // throws if not inserted
// after
K key = dao.getKey(user);
if (key == null) {
    userDao.insert(user);
    key = dao.getKey(user);
}

K key = dao.getKey(entity);
if (key == null) { dao.insert(entity); key = dao.getKey(entity); }

boolean hasKey(T e) { return e != null && dao.getKey(e) != null; }

try {
    K key = dao.getKeyVerified(entity);
} catch (DaoException e) {
    if ("Entity has no key".equals(e.getMessage())) {
        dao.insert(entity); // assign key, retry
    } else throw e;
}

When it happens

Trigger: Calling getKeyVerified(entity) (directly or via update/delete internals) on a non-null entity whose @Id field is still null — i.e., never inserted.

Common situations: Updating or deleting freshly constructed/un-persisted entities; entities copied without id; entities deserialized from JSON/backups lacking the key field.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Cannot delete entity, key is null
• Cannot update entity without key - was it inserted before?
• Expected unique result, but count was
• Entity does not exist in the database anymore
• ( ) does not have a single-column primary key

AI-assisted analysis of greenrobot/greenDAO@0bbb338e17 (2026-09-08). Data as JSON: /api/errors/ff4380786bd71a13. Report an issue: GitHub.

Appendix: source

Thrown at DaoCore/src/main/java/org/greenrobot/greendao/AbstractDao.java:932

    protected void assertSinglePk() {
        if (config.pkColumns.length != 1) {
            throw new DaoException(this + " (" + config.tablename + ") does not have a single-column primary key");
        }
    }

    public long count() {
        return statements.getCountStatement().simpleQueryForLong();
    }

    /** See {@link #getKey(Object)}, but guarantees that the returned key is never null (throws if null). */
    protected K getKeyVerified(T entity) {
        K key = getKey(entity);
        if (key == null) {
            if (entity == null) {
                throw new NullPointerException("Entity may not be null");
            } else {
                throw new DaoException("Entity has no key");
            }
        } else {
            return key;
        }
    }

    /**
     * The returned RxDao is a special DAO that let's you interact with Rx Observables without any Scheduler set
     * for subscribeOn.
     *
     * @see #rx()
     */
    @Experimental
    public RxDao<T, K> rxPlain() {
        if (rxDaoPlain == null) {
            rxDaoPlain = new RxDao<>(this);
        }
        return rxDaoPlain;

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