### Running Examples

Source: https://github.com/ycforge/ydb-orm/blob/main/examples/README.md

Commands to install dependencies, build the project, and execute a specific example.

```bash
yarn install
yarn build                     # собрать dist/
yarn examples:build            # скомпилировать src + examples в dist-examples/
node dist-examples/examples/01-users/main.js
```

--------------------------------

### Example Directory Structure

Source: https://github.com/ycforge/ydb-orm/blob/main/examples/README.md

Overview of the available example projects located in the examples directory.

```text
examples/
├── 01-users/          базовый пример: подключение, сохранение и чтение сущности
├── 02-crud/           полный CRUD: insertMany, updateBy, delete, deleteBy, count
├── 03-search/         поиск: find / findOneBy / findAll / findBy, пагинация
├── 04-relations/      связи: 1:N, N:1, 1:1, многие-ко-многим, eager/ленивая загрузка
├── 05-query-builder/  YdbQueryBuilder: AND/OR, сортировка, лимиты, проекция
├── 06-encryption/     шифрование полей, blind index, Security AAD, ленивая дешифровка
├── 07-transactions/   транзакции: runInTransaction, retry, ambient/reuse, таймауты
├── 08-schema-sync/    автосинхронизация схемы БД и проверка через YdbSchemaSyncer
├── 09-migrations/     миграции: runner, loader, пример конфига для CLI
├── 10-repository/     YdbRepository / YdbEntityManager без DI
├── 11-advanced/       продвинутые декораторы: enum, json, TTL, индексы, таймстампы, хуки
└── nestjs/            примеры интеграции с NestJS (подпакет @ycforge/ydb-orm/nest)
    ├── 01-crud/           модуль, Active Record и инжектируемый репозиторий
    ├── 02-transactions/   транзакции через YdbTransactionManager из DI
    ├── 03-encryption/     шифрование через DI-провайдеры
    └── 04-schema-sync/    sync: true при старте и ручная проверка схемы
```

--------------------------------

### Development Commands

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Standard commands for installing dependencies, building, testing, and linting the project.

```bash
yarn install
yarn build        # tsc → dist/ (ESM + .d.ts)
yarn test         # jest (ESM), unit + NestJS-интеграционные тесты
yarn lint         # eslint --fix
yarn format       # prettier --write
```

--------------------------------

### Install @ycforge/ydb-orm

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Commands to install the core package and optional peer dependencies for NestJS integration.

```bash
# единственный устанавливаемый пакет (ядро + подпакет @ycforge/ydb-orm/nest):
yarn add @ycforge/ydb-orm

# опционально, для NestJS-интеграции — peer-зависимости:
yarn add @nestjs/common @nestjs/core reflect-metadata rxjs
```

--------------------------------

### Define YDB ORM Configuration

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Example configuration file structure for YDB ORM, supporting various JS/TS formats.

```ts
import { createAuth, authKeyFromFile } from '@ycforge/auth';
import { UserEntity } from './src/user.entity.js';

export default {
  endpoint: process.env.YDB_ENDPOINT!,
  auth: createAuth(authKeyFromFile('./authorized_key.json')),
  entities: [UserEntity],        // нужно для migration:generate
  migrationsDir: './migrations', // опционально
};
```

--------------------------------

### WHERE Operators

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Example of using logical operators and comparison filters within a query.

```ts
await UserEntity.findAll({
  $or: [
    { balance: { $gte: 100 } },
    { is_admin: true },
  ],
  is_banned: false,
});
```

--------------------------------

### Standalone Transaction Execution

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Basic setup and execution of a transaction using YdbTransactionManager in a standalone environment.

```ts
import { YdbTransactionManager, createExecutor, createDriver } from '@ycforge/ydb-orm';
import { createAuth } from '@ycforge/auth';

const driver = createDriver({
  endpoint: '...',
  auth: createAuth({ type: 'anonymous' }),
});
const executor = createExecutor(driver);
const txManager = new YdbTransactionManager(executor);

await txManager.runInTransaction(async (trx) => {
  const user = await UserEntity.find({ uuid: userId }, { trx });
  await UserEntity.save(user, { trx });
});
```

--------------------------------

### QueryBuilder Usage

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Demonstrates basic query construction, execution methods, and YQL generation.

```ts
const photos = await PhotoEntity.query()
  .where({ is_public: true })
  .andWhere({ author_email: 'a@b.c' }) // encrypted + blind index — как в find
  .orderBy('rating', 'DESC')
  .addOrderBy('title')
  .limit(20)
  .offset(10)
  .getMany();

await PhotoEntity.query().where({ is_public: true }).getOne();   // первая или null
await PhotoEntity.query().where({ is_public: true }).getCount(); // COUNT(*)
const { sql, values } = await PhotoEntity.query().where({ is_public: true }).toYql(); // без выполнения
```

--------------------------------

### Configure the YDB Executor

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Initialize the driver and executor with database credentials, then register entities to enable Active Record functionality.

```typescript
const opts = {
  endpoint: 'grpcs://ydb.serverless.yandexcloud.net:2135/?database=/ru-central1/...',
  auth: createAuth(authKeyFromFile('./authorized_key.json')),
};

const driver = await createDriver(opts);
const executor = createExecutor(driver, opts);

configureEntities([UserEntity], { executor });
// с этого момента Active Record-методы сущности работают
```

--------------------------------

### Use the Repository Pattern

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Access data via a repository instance for more granular control, or use YdbEntityManager to manage multiple repositories.

```typescript
import { getOrCreateRepository } from '@ycforge/ydb-orm';

// репозиторий создаётся автоматически после configureEntities
const repo = getOrCreateRepository(UserEntity);

const user = await repo.findOneBy({ uuid });
const users = await repo.findAll({ name: 'Ivan' }, { limit: 50 });
const count = await repo.count({ is_admin: true });
await repo.save(entity);
await repo.insertMany([u1, u2]);
await repo.updateBy({ status: 'old' }, { status: 'archived' });
await repo.deleteBy({ status: 'deprecated' });
```

```typescript
import { YdbEntityManager } from '@ycforge/ydb-orm';

const manager = new YdbEntityManager();
const userRepo = manager.getRepository(UserEntity);
const postRepo = manager.getRepository(PostEntity);

// CRUD через репозиторий
const user = await userRepo.findOneBy({ uuid });
const users = await userRepo.findAll({ is_admin: true }, { limit: 10 });
await userRepo.save(user);

const posts = await postRepo.findBy({ author_uuid: user.uuid });
await postRepo.insertMany([post1, post2, post3]);
await postRepo.updateBy({ status: 'draft' }, { status: 'published' });
await postRepo.deleteBy({ status: 'archived' });

// QueryBuilder
const popular = await postRepo.query()
  .where({ is_public: true })
  .orderBy('views', 'DESC')
  .limit(20)
  .getMany();

// Транзакции — передаём { trx } в любой метод
const txManager = new YdbTransactionManager(executor);
await txManager.runInTransaction(async (trx) => {
  await userRepo.save(user, { trx });
  await postRepo.save(post, { trx });
});
```

--------------------------------

### Migration CLI Commands

Source: https://github.com/ycforge/ydb-orm/blob/main/examples/README.md

Commands for managing database migrations using the YDB ORM CLI.

```bash
yarn build
yarn ydb-orm migration:status
yarn ydb-orm migration:run
yarn ydb-orm migration:revert
```

--------------------------------

### YDB-ORM CLI Commands

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Commonly used commands for migration management, entity creation, and metadata inspection.

```bash
ydb-orm migration:create CreateUsers      # пустая миграция ./migrations/<ts>-CreateUsers.ts
ydb-orm migration:generate AddPhotos      # миграция по diff сущностей и БД
ydb-orm migration:run                     # применить все новые миграции
ydb-orm migration:revert                  # откатить последнюю
ydb-orm migration:show                    # статус миграций (алиас — migration:status)
ydb-orm migration:check                   # проверка готовности для CI (exit != 0, если не готово)
ydb-orm migration:repair 1755000000000-CreateUsers --as-applied   # прерванная миграция дозаведена вручную
ydb-orm entity:create UserProfile         # сущность ./src/user-profile.entity.ts
ydb-orm metadata:dump                     # метаданные сущностей в JSON (stdout, без БД)
ydb-orm entity:diagram                    # Mermaid ER-диаграмма по метаданным (stdout/--output, без БД)
ydb-orm completion bash                   # скрипт shell-автодополнения (bash|zsh|fish)
```

--------------------------------

### Configure AuthManager strategies

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Initialize AuthManager with different authentication strategies provided by @ycforge/auth.

```ts
import { createAuth, authKeyFromFile } from '@ycforge/auth';

// authorized key сервисного аккаунта
const auth = createAuth(authKeyFromFile('./authorized_key.json'));

// или другие стратегии:
const auth = createAuth({ type: 'metadata' });
const auth = createAuth({ type: 'anonymous' });
const auth = createAuth({ type: 'iam_token', token: process.env.IAM_TOKEN! });
const auth = createAuth({ type: 'static', username: 'user', password: 'pass' });
```

--------------------------------

### Configure Shell Autocompletion

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Enable command and flag autocompletion for bash, zsh, and fish shells.

```bash
# bash
ydb-orm completion bash | sudo tee /etc/bash_completion.d/ydb-orm
# zsh (путь из $fpath)
ydb-orm completion zsh > ~/.zsh/completions/_ydb-orm
# fish
ydb-orm completion fish > ~/.config/fish/completions/ydb-orm.fish
```

--------------------------------

### Configure Multiple YDB Scopes in Standalone

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use createOrmScope to define named configurations and assign entities to specific executors.

```typescript
import { createOrmScope, configureEntities, createDriver, createExecutor } from '@ycforge/ydb-orm';
import { createAuth } from '@ycforge/auth';

// Конфигурация 'default' (как обычно)
const defaultExecutor = createExecutor(
  createDriver({ endpoint: 'grpcs://default...', auth: createAuth({ type: 'metadata' }) }),
);
configureEntities([UserEntity], { executor: defaultExecutor });

// Именованная конфигурация 'reporting' с собственными executor и настройками
const reportingScope = createOrmScope('reporting', {
  transactions: { ambient: true, warnOutsideTransaction: true },
});
const reportingExecutor = createExecutor(
  createDriver({ endpoint: 'grpcs://reporting...', auth: createAuth({ type: 'metadata' }) }),
);
configureEntities([ReportEntity], { executor: reportingExecutor, scope: reportingScope });
```

--------------------------------

### Configure Encryption Providers

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Pass encryption and blind index providers into the module or standalone configuration.

```ts
{
  encryptionProvider: myEncryptionProvider,   // { encrypt(value, aad, ctx) → Uint8Array, decrypt(ciphertext, aad, ctx) → string }
  blindIndexProvider: myBlindIndexProvider,   // { hash(value, ctx) → string }
}
```

--------------------------------

### createOrmScope

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Creates a standalone ORM configuration scope.

```APIDOC
## createOrmScope(name, { transactions })

### Description
Creates a scope for a configuration, which is then passed to configureEntities.

### Parameters
- **name** (string) - Required - The name of the configuration.
- **transactions** (Object) - Required - Transaction settings for the scope.
```

--------------------------------

### Export Metadata

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Execute this command to dump entity metadata to stdout in JSON format without connecting to the database.

```bash
ydb-orm metadata:dump
```

--------------------------------

### Default Configuration Injection Tokens

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Standard injection tokens for the 'default' configuration remain backward compatible.

```typescript
// эквивалентно: InjectRepository(UserEntity) и module.get(YdbTransactionManager)
@InjectRepository(UserEntity)           // → getRepositoryToken(UserEntity)
@Inject(YdbTransactionManager)          // → getTransactionManagerToken('default')
```

--------------------------------

### Implement Custom CredentialsProvider

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Create a custom provider by extending CredentialsProvider and pass it to the driver or NestJS module.

```ts
import { CredentialsProvider } from '@ycforge/ydb-orm';
import { createDriver } from '@ycforge/ydb-orm';

class OAuthTokenProvider extends CredentialsProvider {
  getToken(): Promise<string> {
    return fetchOAuthToken(); // ваша реализация получения токена
  }
}

// standalone
const driver = createDriver({
  endpoint: process.env.YDB_ENDPOINT!,
  credentialsProvider: new OAuthTokenProvider(),
});
```

```ts
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    endpoint: process.env.YDB_ENDPOINT!,
    credentialsProvider: new OAuthTokenProvider(),
  }),
});
```

--------------------------------

### Implement a custom QueryLogger

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Define a custom logger to handle transaction warnings and query logs.

```ts
const myLogger: QueryLogger = {
  log(entry) {
    // SQL, paramNames, maskedParams, durationMs, error
  },
  warn(message) {
    // '[ydb-orm] UserEntity: query executed outside any transaction ...'
  },
};
```

--------------------------------

### Configure Standalone Query Logging

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Enable query logging in a standalone YDB ORM executor using the default ConsoleQueryLogger.

```ts
import { createExecutor, createDriver, ConsoleQueryLogger } from '@ycforge/ydb-orm';
import { createAuth, authKeyFromFile } from '@ycforge/auth';

const driver = createDriver({
  endpoint: '...',
  auth: createAuth(authKeyFromFile('./authorized_key.json')),
});

const executor = createExecutor(driver, {
  logQueries: true, // ConsoleQueryLogger по умолчанию
});
```

--------------------------------

### Generate Mermaid ER Diagrams

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Render entity metadata into a Mermaid ER diagram without requiring a database connection.

```bash
ydb-orm entity:diagram                    # Mermaid-текст в stdout
ydb-orm entity:diagram --output docs/schema.mmd   # в файл (перезапись запрещена)
```

--------------------------------

### createEntityFileFromSpec

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Programmatically generates an entity file based on a provided specification.

```APIDOC
## createEntityFileFromSpec

### Description
Generates a new entity file in the specified directory based on the provided entity configuration object.

### Signature
`createEntityFileFromSpec(directory: string, spec: EntitySpec): boolean`

### Parameters
- **directory** (string) - Required - The target directory path for the generated file.
- **spec** (object) - Required - The entity specification containing className, tableName, and columns definition.

### Example
```ts
import { createEntityFileFromSpec } from '@ycforge/ydb-orm';

const created = createEntityFileFromSpec('./src', {
  className: 'OrderEntity',
  tableName: 'orders',
  columns: [
    { name: 'uuid', type: 'Uuid', primary: true },
    { name: 'status', type: 'Utf8', enumValues: ['active'], enumStorage: 'Utf8' },
    { name: 'created_at', type: 'Timestamp', createDate: true },
  ],
});
```
```

--------------------------------

### Configure NestJS Query Logging

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Enable query logging within the YdbCoreModule configuration for NestJS applications.

```ts
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    endpoint: '...',
    auth: createAuth(authKeyFromFile('./authorized_key.json')),
    logQueries: true,
    // logQueries: myLogger, // или свой экземпляр QueryLogger
  }),
});
```

--------------------------------

### Initialize Driver with AuthManager

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Pass the AuthManager instance to the driver configuration for standalone or NestJS usage.

```ts
const driver = createDriver({
  endpoint: process.env.YDB_ENDPOINT!,
  auth,
});
```

```ts
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    endpoint: process.env.YDB_ENDPOINT!,
    auth,
  }),
});
```

--------------------------------

### buildMetadataDump

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Programmatically generates a deterministic JSON dump of entity metadata.

```APIDOC
## buildMetadataDump

### Description
Generates a metadata dump object for a list of entities. This operation is read-only and does not require a database connection.

### Signature
`buildMetadataDump(entities: any[]): MetadataDump`

### Parameters
- **entities** (array) - Required - A list of entity classes or configurations to process.

### Returns
- **MetadataDump** (object) - A deterministic JSON structure containing entity definitions, relations, indexes, and TTL settings.
```

--------------------------------

### @InjectRepository

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Decorator for injecting a repository into a class constructor.

```APIDOC
## @InjectRepository(Entity, connectionName?)

### Description
Decorator used to inject a repository for a specific entity and configuration into a class.

### Parameters
- **Entity** (Class) - Required - The entity class.
- **connectionName** (string) - Optional - The name of the configuration.
```

--------------------------------

### Programmatic Entity Creation

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use this API to generate entity files programmatically in scripts or tools.

```ts
import { createEntityFileFromSpec } from '@ycforge/ydb-orm';

const created = createEntityFileFromSpec('./src', {
  className: 'OrderEntity',
  tableName: 'orders',
  columns: [
    { name: 'uuid', type: 'Uuid', primary: true },
    { name: 'status', type: 'Utf8', enumValues: ['active'], enumStorage: 'Utf8' },
    { name: 'created_at', type: 'Timestamp', createDate: true },
  ],
});
```

--------------------------------

### Configure retry policy for executors

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Set up retry policies for standalone executors or wrap existing ones using withRetryPolicy.

```ts
import { createAuth } from '@ycforge/auth';
import { createExecutor, createDriver } from '@ycforge/ydb-orm';

const driver = createDriver({ endpoint: '...', auth: createAuth({ type: 'anonymous' }) });

// standalone:
const executor = createExecutor(driver, { retry: { maxAttempts: 5 } });

// Вручную поверх готового executor'а (оборачивать ОДИН раз):
import { withRetryPolicy } from '@ycforge/ydb-orm';
const resilient = withRetryPolicy(executor, { maxAttempts: 5 });
```

--------------------------------

### YdbOrmModule.forFeature

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Registers entities for a specific YDB configuration.

```APIDOC
## YdbOrmModule.forFeature(entities, connectionName?)

### Description
Registers entities into a specific YDB configuration. If connectionName is omitted, it defaults to 'default'.

### Parameters
- **entities** (Array) - Required - List of entity classes to register.
- **connectionName** (string) - Optional - The name of the configuration to register entities into.
```

--------------------------------

### Transaction Execution Options

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Configuring transaction behavior with isolation levels, timeouts, and idempotency.

```ts
await txManager.runInTransaction(
  async (trx, signal) => {
    await OrderEntity.save(order, { trx });
  },
  {
    isolation: 'snapshotReadWrite',   // serializableReadWrite (по умолчанию) | snapshotReadOnly | snapshotReadWrite
    timeout: 5_000,                    // таймаут НА КАЖДУЮ ПОПЫТКУ (см. ниже)
    signal: controller.signal,         // ГЛОБАЛЬНАЯ отмена: вся операция, все попытки
    idempotent: true,                  // см. «Retry-семантика» ниже
  },
);
```

```ts
await txManager.runInTransaction(fn, {
  idempotent: true,
  signal: AbortSignal.timeout(30_000), // общий лимит на все попытки
});
```

--------------------------------

### Execute Transaction with Retry Policy

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Demonstrates running a transaction with an idempotent retry policy, allowing the ORM to handle retries for transient errors.

```ts
await txManager.runInTransaction(
  async (trx) => {
    await OrderEntity.save(order, { trx });
  },
  {
    idempotent: true,   // семантика #98: колбэк обязан быть устойчивым к повтору
    retry: true,        // или объект политики; нельзя совмещать с reuse
    maxAttempts: 5,
  },
);
```

--------------------------------

### Inject Repositories and Transaction Managers by Name

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use configuration names to inject specific repositories and transaction managers in NestJS services.

```typescript
@Injectable()
export class ReportService {
  constructor(
    // репозиторий из конфигурации 'reporting'
    @InjectRepository(ReportEntity, 'reporting')
    private readonly reportRepo: YdbRepository<ReportEntity>,
    // менеджер транзакций из конфигурации 'reporting' (отдельный инстанс)
    @Inject(getTransactionManagerToken('reporting'))
    private readonly txManager: YdbTransactionManager,
  ) {}
}
```

--------------------------------

### Define a migration class

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Implement the YdbMigration interface to define schema changes. Use import type for YdbMigration and YdbExecutor to avoid runtime errors with native TypeScript stripping.

```ts
import type { YdbMigration, YdbExecutor } from '@ycforge/ydb-orm';
import { executeSql } from '@ycforge/ydb-orm';

export class CreateUsers1755000000000 implements YdbMigration {
  readonly name = '1755000000000-CreateUsers';

  async up(executor: YdbExecutor): Promise<void> {
    await executeSql(executor, 'CREATE TABLE `users` (`uuid` Uuid, PRIMARY KEY (`uuid`))');
  }

  async down(executor: YdbExecutor): Promise<void> {
    await executeSql(executor, 'DROP TABLE `users`');
  }
}
```

--------------------------------

### Define Lifecycle Hooks in YDB Entity

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use decorators like @BeforeInsert and @AfterFind to attach logic to entity lifecycle events. These methods execute automatically during database operations.

```ts
@YdbEntity('users')
class User extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid') uuid: string;
  @YdbColumn('Utf8') name?: string;

  @BeforeInsert
  normalize() {
    this.name = this.name?.trim();
  }

  @AfterFind
  touch() {
    // вызывается и для корневых сущностей, и для eager/lazy relations
  }
}
```

--------------------------------

### Standalone Schema Synchronization

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use YdbSchemaSyncer to verify or synchronize database schemas manually. Verification checks for discrepancies without modifying the database, while sync applies necessary changes.

```ts
import { YdbSchemaSyncer } from '@ycforge/ydb-orm';

const syncer = new YdbSchemaSyncer(executor);

// verify — проверяет схему, ничего не меняет
const issues = await syncer.verify([UserEntity, PostEntity]);

// sync — подстраивает схему
await syncer.sync([UserEntity, PostEntity]);
```

--------------------------------

### Configure YDB ORM in NestJS Module

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use YdbCoreModule.forRootAsync to configure the connection and YdbOrmModule.forFeature to register entities. The sync option should only be enabled for development environments.

```ts
import { Module } from '@nestjs/common';
import { createAuth, authKeyFromFile } from '@ycforge/auth';
import {
  YdbCoreModule,
  YdbOrmModule,
  YdbBaseEntity,
  YdbEntity,
  YdbPrimaryColumn,
  YdbColumn,
} from '@ycforge/ydb-orm/nest';

@YdbEntity('users')
export class UserEntity extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid')
  uuid!: string;

  @YdbColumn('Utf8')
  name!: string;
}

@Module({
  imports: [
    YdbCoreModule.forRootAsync({
      useFactory: () => ({
        endpoint: 'grpcs://ydb.serverless.yandexcloud.net:2135/?database=/ru-central1/...',
        auth: createAuth(authKeyFromFile('./authorized_key.json')),
        sync: true, // как synchronize в TypeORM — только для dev!
      }),
    }),
    YdbOrmModule.forFeature([UserEntity]),
  ],
})
export class AppModule {}
```

--------------------------------

### Configure retry policy in NestJS

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Enable retry policies globally within a NestJS application using YdbCoreModule.

```ts
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    endpoint: '...',
    auth: createAuth({ type: 'anonymous' }),
    retry: true, // или объект YdbRetryPolicyOptions; false/undefined — выключено
  }),
});
```

--------------------------------

### Ambient Transaction Context

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Configuring ambient transactions to automatically include repository operations in the active transaction.

```ts
// NestJS: глобально при инициализации модуля
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    // ...
    transactions: { ambient: true },
  }),
});

// Standalone: через опции модуля (YdbModuleOptions)
// или точечно, на один вызов:
await txManager.runInTransaction(async () => {
  await OrderEntity.save(order);          // уйдёт в транзакцию автоматически
  await OrderEntity.save(other, { trx }); // явный trx тоже работает
}, { ambient: true });
```

--------------------------------

### getRepositoryToken

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Retrieves the DI token for a repository associated with a specific entity and configuration.

```APIDOC
## getRepositoryToken(Entity, connectionName?)

### Description
Returns the DI token for the repository of the given entity. For the 'default' configuration, it returns the standard format; for named configurations, the token is suffixed with @<name>.

### Parameters
- **Entity** (Class) - Required - The entity class.
- **connectionName** (string) - Optional - The name of the configuration.
```

--------------------------------

### Enable transaction warnings

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Configure the ORM to issue warnings when queries are executed outside of a transaction.

```ts
transactions: { warnOutsideTransaction: true } // предупреждение на каждый такой запрос
```

--------------------------------

### Filtering by Related Entities

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Demonstrates filtering root entities based on conditions applied to their relationships.

```ts
// Пользователи, у которых есть роль 'admin' (one-to-many)
await UserEntity.findAll({ userRoles: { is_global: true } });

// Несколько related-предикатов + обычные условия корня (AND)
await PhotoWithTagsEntity.findAll({
  title: { $like: '%sunset%' },
  tags: { name: 'nature' },          // many-to-many через join-таблицу
  author: { status: 'active' },      // many-to-one
});

// Логические группы смешивают колонки корня и связи
await UserEntity.findAll({
  $or: [
    { uuid: someUuid },
    { userRoles: { role_uuid: adminRoleUuid } },
  ],
});
```

--------------------------------

### Synchronize Database Schema

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use YdbSchemaSyncer to verify or apply schema changes to the database based on entity definitions.

```typescript
import { YdbSchemaSyncer } from '@ycforge/ydb-orm';

const syncer = new YdbSchemaSyncer(executor);

// проверка без изменений
const issues = await syncer.verify([UserEntity]);
console.log(issues);

// применение (CREATE TABLE / ALTER TABLE ADD COLUMN)
await syncer.sync([UserEntity]);
```

--------------------------------

### Configure Multiple YDB Modules in NestJS

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Register multiple YdbCoreModule instances with unique names and bind entities to them via YdbOrmModule.forFeature.

```typescript
@Module({
  imports: [
    // 'default' конфигурация
    YdbCoreModule.forRootAsync({
      useFactory: () => ({
        endpoint: 'grpcs://default...',
        auth: createAuth({ type: 'metadata' }),
      }),
    }),

    // 'reporting' конфигурация — отдельный executor, отдельные транзакции
    YdbCoreModule.forRootAsync({
      name: 'reporting',
      useFactory: () => ({
        endpoint: 'grpcs://reporting...',
        auth: createAuth({ type: 'metadata' }),
        transactions: { ambient: true, warnOutsideTransaction: true },
      }),
    }),

    // Сущности привязываются к своей конфигурации:
    // forFeature без имени → 'default'; forFeature([...], 'reporting') → 'reporting'
    YdbOrmModule.forFeature([UserEntity]),
    YdbOrmModule.forFeature([ReportEntity], 'reporting'),
  ],
})
export class AppModule {}
```

--------------------------------

### Active Record CRUD and Query Operations

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Provides methods for interacting with entities, including finding records, counting, saving, and batch inserting. Note that save operations handle both insert and update based on the presence of a UUID.

```ts
await UserEntity.find({ uuid });                    // одна запись или null
await UserEntity.findAll({ name: 'Ivan' }, { limit: 50, offset: 0 });
await UserEntity.count({ name: 'Ivan' });
await UserEntity.save(user);                        // insert (uuid генерируется, по умолчанию v7) или update по uuid
await UserEntity.insertMany([u1, u2]);              // батчи по 100
await user.loadRelations(['roles']);
```

--------------------------------

### NestJS Schema Synchronization Configuration

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Enable automatic schema synchronization in NestJS by setting the sync option to true within YdbCoreModule. This should be restricted to development environments.

```ts
YdbCoreModule.forRootAsync({
  useFactory: () => ({
    endpoint: '...',
    auth: createAuth(authKeyFromFile('./authorized_key.json')),
    sync: true, // только для dev! В проде — миграции.
  }),
});
```

--------------------------------

### Nested Transaction Handling

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Managing nested transactions using the reuse option to join an existing transaction context.

```ts
await txManager.runInTransaction(async () => {
  await txManager.runInTransaction(async (trx2) => {
    // Error: Nested runInTransaction() detected ...
  });
});

await txManager.runInTransaction(async () => {
  await txManager.runInTransaction(async (sameTrx) => {
    // та же транзакция, что и снаружи
  }, { reuse: true });
});
```

--------------------------------

### Integrate with @ycforge/auth/nestjs

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Inject an AuthManager instance from a NestJS module into the YdbCoreModule.

```ts
import { Module } from '@nestjs/common';
import { YcAuthModule, InjectAuth } from '@ycforge/auth/nestjs';
import { YdbCoreModule } from '@ycforge/ydb-orm/nest';

@Module({
  imports: [
    YcAuthModule.forRoot({
      config: authKeyFromFile('./authorized_key.json'),
      global: true,
    }),
    YdbCoreModule.forRootAsync({
      useFactory: (@InjectAuth() auth) => ({
        endpoint: process.env.YDB_ENDPOINT!,
        auth,
      }),
      inject: [YcAuthModule], // или токен YCFORGE_AUTH
    }),
  ],
})
export class AppModule {}
```

--------------------------------

### Define JSON Columns in Entity

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use decorators to map JSON data to YDB columns, supporting native JSON types or stringified Utf8 storage.

```ts
@YdbEntity('events')
class EventEntity extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid') uuid: string;

  @YdbJson()
  @YdbColumn('Utf8')
  metadata: Record<string, any>;

  @YdbColumn('Json')
  payload: any;
}
```

--------------------------------

### Execute Standalone Retry Wrapper

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Provides an explicit wrapper for retrying operations outside of a transaction context.

```ts
import { runWithRetry } from '@ycforge/ydb-orm';

const result = await runWithRetry(async () => {
  const user = await UserEntity.find({ uuid }, {});
  const orders = await OrderEntity.findBy({ userId: user.uuid }, { limit: 50 });
  return buildReport(user, orders);
}, { maxAttempts: 5 });
```

--------------------------------

### Query JSON Columns

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Perform JSON-specific queries using operators like andWhereJsonExists and andWhereJsonValue.

```ts
await EventEntity.query()
  .andWhereJsonExists('metadata', '$.settings.theme')
  .andWhereJsonValue('metadata', '$.role', 'admin')
  .getMany();
```

```ts
// metadata: $.settings.theme существует И $.role = 'admin'
await EventEntity.query()
  .andWhereJsonExists('metadata', '$.settings.theme')
  .andWhereJsonValue('metadata', '$.role', 'admin')
  .getMany();
// WHERE (JSON_EXISTS(`metadata`, $metadata_0_jsonexists)
//    AND JSON_VALUE(`metadata`, $metadata_1_jsonvalue_path) = $metadata_1_jsonvalue_val)
```

--------------------------------

### Пример использования связей ManyToMany

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Определение сущностей с использованием декораторов @EagerLoad и @ManyToMany для связи между фотографиями и тегами.

```ts
@YdbEntity('photos')
@EagerLoad(['tags'])
class Photo extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid') uuid: string;
  @YdbColumn('Utf8') title: string;

  @ManyToMany(() => Tag, (tag) => tag.photos)
  @JoinTable('photo_tag')
  tags: Tag[];
}

@YdbEntity('tags')
class Tag extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid') uuid: string;
  @YdbColumn('Utf8') name: string;

  @ManyToMany(() => Photo, (photo) => photo.tags)
  photos: Photo[];
}
```

--------------------------------

### Define a YDB Entity

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use the @YdbEntity decorator to define a database table and @YdbPrimaryColumn or @YdbColumn to map class properties to YDB columns.

```typescript
import {
  YdbBaseEntity, YdbEntity, YdbPrimaryColumn, YdbColumn,
  configureEntities,
  createDriver, createExecutor,
  YdbTransactionManager,
} from '@ycforge/ydb-orm';
import { createAuth, authKeyFromFile } from '@ycforge/auth';

@YdbEntity('users')
class UserEntity extends YdbBaseEntity {
  @YdbPrimaryColumn('Uuid')
  uuid!: string;

  @YdbColumn('Utf8')
  name!: string;
}
```

--------------------------------

### Пример наследования сущностей и конфликтов имен

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Демонстрация наследования колонок при создании новой таблицы и ошибка при дублировании имени таблицы.

```ts
@YdbEntity('events')
@YdbTtl({ interval: 'P30D', column: 'created_at' })
class EventEntity extends YdbBaseEntity { /* ... */ }

// Своя таблица: колонки родителя наследуются, TTL/индексы — нет
@YdbEntity('audit_events')
class AuditEventEntity extends EventEntity { /* ... */ }

// Ошибка: Duplicate table name "events"
@YdbEntity('events')
class BrokenChildEntity extends EventEntity { /* ... */ }
```

--------------------------------

### Perform Active Record Operations

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Execute CRUD operations directly on the entity class using static methods like find, findAll, and save.

```typescript
// одна запись по PK
const user = await UserEntity.find({ uuid: '...' });

// выборка с условиями и лимитом
const admins = await UserEntity.findAll({ is_admin: true }, { limit: 50 });

// INSERT/UPDATE
const u = new UserEntity();
u.name = 'Ivan';
await UserEntity.save(u);  // uuid генерируется автоматически (v7)

// транзакции
const txManager = new YdbTransactionManager(executor);
await txManager.runInTransaction(async (trx) => {
  await UserEntity.save(user, { trx });
});
```

--------------------------------

### NestJS Transaction Injection

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Injecting YdbTransactionManager into a NestJS service for transaction management.

```ts
@Injectable()
export class OrderService {
  constructor(private readonly txManager: YdbTransactionManager) {}

  async transfer(fromId: string, toId: string) {
    await this.txManager.runInTransaction(async (trx) => {
      const from = await UserEntity.find({ uuid: fromId }, { trx });
      await UserEntity.save(from, { trx });
    });
  }
}
```

--------------------------------

### releaseOrmScope

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Releases all entities associated with a specific scope.

```APIDOC
## releaseOrmScope(scope)

### Description
Releases all entities of the provided scope. This is called automatically by app.close() in NestJS.

### Parameters
- **scope** (Object) - Required - The scope to release.
```

--------------------------------

### Mark operations as idempotent

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Explicitly mark queries as idempotent to allow the retry policy to safely re-execute them upon transient errors.

```ts
// ❌ Не помечен (INSERT/UPSERT/UPDATE/DELETE по умолчанию):
// выполнится РОВНО ОДИН раз даже при retry: true.
await UserEntity.save(user);

// ❌ Транзитная ошибка у незнакомой записи → повтор небезопасен:
await OrderEntity.findBy({ status: 'new' }); // тоже один раз

// ✅ Помечен идемпотентным: политика может повторить при
// ABORTED / UNAVAILABLE / OVERLOADED.
const users = await UserEntity.findAll({}, { idempotent: true });
await UserEntity.save(user, { idempotent: true }); // операция устойчива к повтору
await executor`SELECT ...`.idempotent(true);       // прямой executor
```

--------------------------------

### getTransactionManagerToken

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Retrieves the DI token for the YdbTransactionManager.

```APIDOC
## getTransactionManagerToken(name)

### Description
Returns the DI token for YdbTransactionManager. For 'default', it returns the class-token; for named configurations, it returns a symbol.

### Parameters
- **name** (string) - Required - The name of the configuration.
```

--------------------------------

### Inject YDB Repository in NestJS Service

Source: https://github.com/ycforge/ydb-orm/blob/main/README.md

Use the @InjectRepository decorator to access YdbRepository for CRUD operations within a service.

```ts
import { Injectable } from '@nestjs/common';
import { InjectRepository, YdbRepository } from '@ycforge/ydb-orm/nest';
import { UserEntity } from './user.entity.js';

@Injectable()
export class UserService {
  constructor(
    @InjectRepository(UserEntity)
    private readonly userRepo: YdbRepository<UserEntity>,
  ) {}

  async getByUuid(uuid: string) {
    return this.userRepo.findOneBy({ uuid });
  }
}
```

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