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Databases

Description — Working With Couchbase Lite Databases With Dart
Related Content — Blobs | Documents | Indexing

Create or Open Database​

You can create a new database and-or open an existing database, using the Database class. The database class provides both synchronous and asynchronous methods for opening and closing databases (see explanation for Synchronous and Asynchronous APIs). Just pass in a database name and optionally a DatabaseConfiguration - see Example 1.

Things to watch for include:

  • If the named database does not exist in the specified, or default, location then a new one is created.

  • The database is created in a default location unless you specify a directory for it — see: DatabaseConfiguration.directory.

    tip

    Best Practice is to always specify the path to the database explicitly.

    See Supported Platforms for the default location for each platform.

Example 1. Opening a Database
final database = await Database.openAsync('my-database');

Close Database​

You are advised to incorporate the closing of all open database into your application workflow.

Closing a database is simple, just call use Database.close. See Example 2. This also closes active replications, listeners, and-or live queries connected to the database.

Example 2. Closing a Database
await database.close();

Database Encryption​

Important

This feature is an Enterprise Edition feature.

Couchbase Lite includes the ability to encrypt Couchbase Lite databases. This allows mobile applications to secure data at rest, when it is being stored on the device. The algorithm used to encrypt the database is 256-bit AES.

Enabling​

To enable encryption, use DatabaseConfiguration.encryptionKey to set the encryption key of your choice. Provide this encryption key every time the database is opened - see Example 3.

Example 3. Opening an Encrypted Database
final key = await EncryptionKey.passwordAsync('secret password');
final config = DatabaseConfiguration(encryptionKey: key);
final database = await Database.openAsync('my-database', config);

Persiting​

Couchbase Lite does not persist the key. It is the application's responsibility to manage the key and store it in a platform specific secure store such as Apple's Keychain or Android's Keystore.

Opening​

An encrypted database can only be opened with the same language SDK that was used to encrypt it in the first place. So a database encrypted using the Dart SDK, and then exported, is readable only by the Dart or C SDK.

Changing​

To change an existing encryption key, open the database using its existing encryption-key and use Database.changeEncryptionKey to set the required new encryption-key value.

Removing​

To remove encryption, open the database using its existing encryption-key and use Database.changeEncryptionKey with a null value as the encryption key.

Database Maintenance​

From time to time it may be necessary to perform certain maintenance activities on your database, for example to compact the database file, removing unused documents and blobs no longer referenced by any documents.

Couchbase Lite's API provides the Database.performMaintenance method. The available maintenance operations, including compact are as shown in the enum MaintenanceType to accomplish this.

This is a resource intensive operation and is not performed automatically. It should be run on-demand using the API. If in doubt, consult Couchbase support.

Command Line Tool​

cblite is a command-line tool for inspecting and querying Couchbase Lite databases.

You can download and build it from the couchbaselabs GitHub repository. Note that the cblite tool is not supported by the Couchbase Support Policy.

Couchbase Lite for VSCode​

Couchbase Lite for VSCode is a Visual Studio Code extension that provides a user interface for inspecting and querying Couchbase Lite databases. You can find more information about this extension from it's GitHub repository.

Troubleshooting​

You should use console logs as your first source of diagnostic information. If the information in the default logging level is insufficient you can focus it on database errors and generate more verbose messages (see LogLevel) — see: Example 4.

Example 4. Increase level of Database Log Messages
Database.log.console.level = LogLevel.verbose;
note

On standalone Dart, logging is configured to directly log to stdandard output and does not go through Dart.