Inserindo e buscando informações - Problema (constraint failed) com campo id UNIQUE

Continuo recebendo mensagem de exceção referente ao campo contacts.id ser UNIQUE, mesmo retirando da função save o contactMap['id'] = contact.id;

Performing hot restart...
Syncing files to device sdk gphone x86 arm...
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E/flutter (14097): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: DatabaseException(UNIQUE constraint failed: contacts.id (code 1555 SQLITE_CONSTRAINT_PRIMARYKEY)) sql 'INSERT INTO contacts (id, name, account_number) VALUES (?, ?, ?)' args [0, alex, 1000]}
E/flutter (14097): #0      wrapDatabaseException (package:sqflite/src/exception_impl.dart:11:7)
E/flutter (14097): <asynchronous suspension>
E/flutter (14097): #1      SqfliteDatabaseMixin.txnRawInsert.<anonymous closure> (package:sqflite_common/src/database_mixin.dart:394:14)
E/flutter (14097): <asynchronous suspension>
E/flutter (14097): #2      BasicLock.synchronized (package:synchronized/src/basic_lock.dart:33:16)
E/flutter (14097): <asynchronous suspension>
E/flutter (14097): #3      SqfliteDatabaseMixin.txnSynchronized (package:sqflite_common/src/database_mixin.dart:346:14)
E/flutter (14097): <asynchronous suspension>
E/flutter (14097): #4      main.<anonymous closure> (package:bank/main.dart)
E/flutter (14097): <asynchronous suspension>
E/flutter (14097): 

Funão save do meu app_database:

Future<int> save(Contact contact) {
  return createDatabase().then((db) {
    final Map<String, dynamic> contactMap = Map();
    contactMap['name'] = contact.name;
    contactMap['account_number'] = contact.accountNumber;
    return db.insert('contacts', contactMap);
  });
}

Meu runApp no main.dart:

void main() {
  runApp(BankApp());
  save(Contact(0, 'alex', 1000)).then((id) {
    findAll().then((contacts) => debugPrint(contacts.toString()));
  });
}

Minhas versões:

[√] Flutter (Channel stable, 2.0.3, on Microsoft Windows [versão 10.0.19041.867], locale pt-BR)
[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[√] Chrome - develop for the web
[√] Android Studio (version 4.1.0)
[√] IntelliJ IDEA Community Edition (version 2021.1)
[√] VS Code (version 1.48.2)
[√] Connected device (3 available)